Heroic interventions – What medicine can do in the face of the unknown

OK, we’ve just looked at the medical implications of ordinary, everyday, gunfire

But now you want to have monsters spitting super acids, mysterious alien diseases, and exotic nanotechnological poisons.

Because you’ve read my previous articles don’t want to resolve this by having one of your characters mix up a super DNA reversion serum just in time for the credits, using only the contents of their rucksack, the rare Acturian sunflower (that can only be found in the fire swamp), and the power of friendship. I’m pretty sure that this was the plot of roughly half the cartoons ever produced in the 80’s.

So what can a doctor actually do in the face of seriously weird shit? And what are the odds that it will work?

 

Slash and burn

The patient didn’t need that leg anyway.

Limbs can be cut off, surrounding tissue can be excised, and wounds can be cauterized. Most doctors will be reluctant to resort to this kind of treatment immediately so they need to be made aware of the necessity.

The likelihood of success is going to depend on exactly what is afflicting the character and the speed with which treatment is provided, most likely every second is going to count.

In the event of a battlefield amputation, the next challenge is going to be preventing the character from bleeding to death. This can involve cauterizing tissue and tying off arteries physically (which will be messy). The medic’s chance of pulling this off without killing the patient is obviously going to be much increased if they have experience of trauma surgery, in the military especially, as battlefield surgery gives lots of chances to practice amputation.

 

Life support

This is involves follows the same basic theory as CPR. You keep the blood flowing and the lungs moving until the patient recovers or you get better help. If you have access to a reasonably modern medical facility this can be done for a substantial amount of time.

This will work in scenarios in which you expect whatever is affecting your character to wear off in time, without doing much additional damage to their tissues in the meantime.

Most nerve poisons can be treated in this way as well as anything else that can cause temporary paralysis (which prevents breathing).

If you want your patient to live you will need to get them to a substantial medical setup very quickly indeed or have a fairly slow onset of symptoms. In sci-fi, a small first-aid device that can sustain a patient by directly stimulating heart and chest muscles isn’t pushing credibility much.

 

Opposite day

This involves doing the exact opposite of whatever is occurring in the patient.

For example, if the poison is slowing the patient’s heart rate, you give them a drug to speed it up or block the sites within their body that would typically increase heart rate. If the patient’s temperature is rising you might try to cool them down physically.

This is often far from ideal for the patient, but much less so than dying.

Doctors doing this need to be particularly careful to monitor the patient to make sure that whatever they are doing to the patient diminishes at the same rate as whatever they are treating. but failure to do this is an extremely plausible mistake for a rookie medic to make.

 

Put them to sleep

This could be done to prevent the patient from something that is attacking their central nervous system, or otherwise afflicting their thought processes. For example, inducing a coma is integral to new treatments for rabies.

There are obviously a lot of common science fiction scenarios that could be addressed in this way, including a few that are unlikely to crop up in med school.

It should be noted that rendering a patient safely unconscious, especially for an extended period of time is not a trivial challenge for modern medicine, especially outside of a medical facility and without a trained anesthetist.

 

Ready with the hayfever tablets

It’s considerably more realistic for a patient to have a serious allergic reaction to an alien venom than they are to actually be poisoned by it.

Inflammatory responses are very rapid in onset and dramatic, while still being reversible, which gives them a lot of narrative potential.

Recognizing this and responding appropriately with anti-inflammatory drugs is well within the ability of a modern medic and the drugs that will be available to him.

Anti-inflammatory medication is also available to the general public, anti-histamine tablets are probably going to be far too slow, but an EpiPen could easily save a characters life.

 

Putting the patient on ice

If you can’t treat someone right this minute you can try storing them until you can. This is not really plausible with modern medical technology, but could easily be a mainstay of science fiction medicine.

Technological advances that might lead to this might involve drugs that could be used on the patient, preventing their tissue from being damaged by ice crystals forming as they freeze, and such natural anti-freeze does already exist in nature. A future space colonist might even have been genetically engineered to already express them within their body.

This type of intervention also requires a way of cooling the patient throughout their entire body very quickly.

 

Local remedies

OK, we’re back to the Acturian Sunflower here… sort of…

Whilst it’s not plausible to cure the patient of alien disease just by grinding up a flower and doing twenty minutes of Nobel prize winning medicine, the local life is an excellent place to start looking at if longer term research is involved.

A better scenario to consider here, is our own discovery of penicillin, if you want alien antibiotics then alien molds and microorganisms are a good place to start looking.

 

Next up in our medical trope series, we are going to take a more in depth look at the likely differences between terrestrial biology and the more alien stuff.

Medical Tropes – How to shoot your characters without killing them

We are all familiar with the standard cop show cliché, a character is shot in the shoulder, but is perfectly fine in time for the next commercial break.

It goes without saying that this isn’t a terribly realistic portrayal of likely event, but as characters getting shot at is a very common situation in certain genres, I think an article discussing the mechanics of this will probably be handy.

Things to keep in mind.

 

The type of gun.

All guns are not alike.

  • A bullet from a small caliber pistol is obviously going to transfer much less energy into a target than a high velocity rifle bullet.
  • A shotgun fired at long range is liable to cause unpleasant superficial injuries, but less likely to be fatal.
  • Some modern sniper rifles are officially designated as light anti-tank weapons, so use your imagination regarding the likely effect on the human body.
bullet-comparison

Some bullets are scarier – it’s not rocket (propelled grenade) science

 

The type of injury

Fatal injuries are likely to result from major damage to a vital organ, infection, or blood loss. Whilst your arms and legs are devoid of vital organs they still contain arteries, they are not free fire zones.

Major organs tend to be very well supplied with blood, and can be difficult locations in which to stop bleeding.

Non fatal bullet wounds to the face and head are possible but are likely to result in severe disfigurement or cognitive impairment.

Wounds to the legs, arms, and hands may severely disrupt the use of those limbs, this may, or may not, be repaired via surgery. Moving an injured limb is not just a matter of willpower.

 

The degree and type of penetration

A high velocity round that passes straight through its target with striking anything vital often cause less damage than lower velocity bullets that dissipate all of their energy into the target. This will be heavily influenced by the type of ammunition used.

Glancing bullet wounds will be less dangerous, but can still cause life threatening blood loss. Bullets that strike bone can shatter it, making full recovery more difficult and painful, and potentially sending fragments of bone into other tissue.

 

The possibility of infection

Infection can dramatically influence the severity of an otherwise nonthreatening injury. This can be influenced by environment (e.g. a rat infested warehouse), the geographical location (infection is more likely in tropical locations), the time taken to seek treatment, quality of available medical facilities, and access to antibiotics.

Any wound to the gastrointestinal tract can be expected to result in severe infections due to release of material from the stomach or intestines into the body, as well as chemical inflammation from stomach acids and digestive enzymes. Contrary to popular belief, prognosis for abdominal injuries is actually reasonably good, given access to modern antibiotics and surgical techniques, but would drop considerably without them.

 

Bleeding

Generally speaking, the closer that you get to the heart, the greater the potential for life threatening bleeding is.  Severing the artery in your thumb is less severe than severing the artery in your shoulder, but is always going to be a big deal.

On a practical basis, severe bleeding is a good choice for dramatic potential, as bleeding is probably the easiest way to threaten a characters life without necessitating long term injury or even extended recovery time. But this isn’t always the case, if blood loss is severe, then organs, including the brain, will be damaged by the loss of oxygen. Damaged arteries or veins can be difficult to repair and prone to re-rupturing.

 

Hands and limbs

Whilst damage to muscle tissue, is less serious than damage to most other organs, that muscle is still there for a reason.

If a character loses large chunks of muscles, joints, or sustains damage to the tendons that link muscle to bone, a character is likely to suffer some degree of permanent mobility loss, and will often require painful and time consuming reconstructive surgery.

Joints, especially, knees, are very easy to damage, and very difficult to repair, and injuries to the joints may also trigger arthritis.

Severing a tendon effectively means cutting the cords that allow a limb to move, like cutting a puppet’s string. This  is especially important when considering injuries to the hands, which do not actually contain muscle tissue, and are completely reliant on tendons linking to muscles in the arm for movement.

Injuries to the forearm can therefore impair the hand, and it is very easy for damage to the hand to sever tendons and stop movement completely. It is common to see movie characters impaled through the hand, but in reality it’s nearly impossible for this to occur without severing tendons, these tendons are also very prone to injury from knives.

 

A word about body armor

The efficacy of body armor is severely overstated in a lot of fiction. A reasonable working assumption is that a civilian or police quality vest (that has been designed to protect against bullets, and not just stab wounds) will provide decent protection against low caliber ammunition and limited protection against higher caliber pistol rounds, but almost no protection against a rifle. Repeated hits, especially in the same location, will degrade the protection.

Military grade armor may be supplemented with (heavy) ceramic plates that provide limited protection against rifle rounds. Helmets provide limited protection against very low caliber bullets, and might deflect a heavier round away from the skull.

 

Associated injuries

If bullets are being sprayed around, it is  just as likely for people to be hit by flying fragments of glass, stone or metal as the bullets, these injuries should not be discounted.

It would also be very easy for a character, especially an out of shape one, to injure themselves in the mere act of seeking cover during a gunfight.

 

Summing Up

This has obviously been something of a whistle stop through traumatic medicine, so if there is anything that people would like more detail about, please don’t be afraid to ask in the comments, and, as always, general feedback is appreciated.

Stats 4 – Assumptions, the root of all applicable evil

Part 4 of An astonishingly useful guide to data analysis for people that don’t like maths

So, we’ve had our little refresher on mean, medians, and modes, Now we are going to look at the data, the starting point for your analysis, and very often the starting point for your screw ups.

 

Categories of data

Data can be broken down in to a broad range of different categories, all of which have distinct names; and this has a big impact on what you can do with it.

In deference to my lack of faith in your ability to remember names and my continued scepticism as to the actual real world value of remembering what things are called, I’m not going to approach this in the traditional manner and list them all.

What’s important is that you think about your data. If you think about your data, what it represents, and what you are intending to do with it, there are actually only a few situations in which you are likely to run into trouble.

This is mostly intuitive stuff. For example, a lot of the potential problems involve non-numerical data. Consider the previously used example of data regarding the mode of transport used to get to a hospital,  it is not appropriate to do most statistical operations on this data, but it is also conveniently impossible to perform most mathematical operations on it, making this very easy to remember.

Algebra example

"Dammit, this algebra has got me stumped"

You can calculate a mode for this data, but we’ve already discussed why you probably won’t need reminding to do this.

 

There are some data types that you need to watch out for however.

 

1)      Numbers that aren’t really numbers – for example numbered groups. Consider a school that has divided its students into ten separate reading groups arbitrarily.

Class 1 Class 2 Class 3
Student allocation 1,3,5,8,4,7,3,4,2,9 6,3,4,2,6,1,2,1,7,10 9,2,6,3,7,4,10,3,6,2,4

 

As there is no discernible relationship between the groups it is obviously not possible to manipulate this data mathematically. You can’t add the numbers up for each category and you can’t take a mean. Just remember treat the numbers as if they aren’t numbers.

2)      Groups that are related in an irregular manner– Consider the following, completely different, example.

Class 1 Class 2 Class 3
Student allocation 1,3,5,8,4,7,3,4,2,9 6,3,4,2,6,1,2,1,7,10 9,2,6,3,7,4,10,3,6,2,4

This represents a similar situation to before but, in this case; the students have been placed in groups according to relative ability, but still with no consistent mathematical relationship between groups. E.g. the students in group 2 should be better readers than those in groups 1 but it is impossible to suggest that they are twice as good. You can start to examine this data and make judgements using it, but you need to be careful. It’s not appropriate to indicate a mean. You couldn’t assume that group 5 represents average ability and you can’t make reliable judgements by adding numbers.

3)      Groups that are related in a regular manner, within a seperately defined range

In the real world, this kind of situation is more likely to occur with things like percentages of defined values, such as maximum possible height. Because these numbers are quantitatively related to each other you can take means and you can perform statistics.

You need to be aware however, that when values are expressed in relation to something else, that value will change as it does.  It is impossible for a person to be at 110% of the current maximum human height, but they can be at 110% of what was the maximum human height in the year 1800 or 110% of the average human height.  A bear can always be at 110% of the maximum human height because he isn’t a human.

4)      Groups that are related in a regular manner, but with an inconsistent zero. –

The best of example of this is with temperature. Both the Centigrade and Fahrenheit scales have values that relate to each other in regular way but have arbitrary zero values. Therefore it is impossible to use such as scale to make assumptions about the relative absolute magnitude of values. 2^C is not twice as hot as 1^C. In these cases you can not express values as ratios of each other and you can not multiply and divide values (although you could convert the values to a scale in which it was permissible to do this, such as Kelvin for temperature). You can still calculate values for standard deviation and standard error and you can still perform a t-test.

5)      Values that are expressed in multiple units or irregular units. –

Once again, this is common sense. The usual examples of this are the typical expression of times and dates.  8:05 is not the same as 8.05 hours, 0.30 of an hour is not equal to 30 minutes. You just need to make sure that you have converted data to a single unit for calculations, that you remember to convert them back again if necessary, and that you don’t convert units inappropriately. In particular you want to avoid using units that can have variable relationship with others such as months, or converting such values to other units without stating any assumption that you are making in doing so.

 

Speaking of assumptions…

Assumptions are the root of some evil, and a lot of fuckups

You may have noticed that in the previous section I used the same set of data for two separate examples. This was not entirely a result of laziness. What I wanted to illustrate is that in all three examples, the information that you have available to you is completely eclipsed by the information that you don’t. When you don’t have information available to you, you are forced to replace it with assumption, assumptions are bad, and it’s not always obvious when you are making them.

Class 1 Class 2 Class 3
Student allocation 1,3,5,8,4,7,3,4,2,9 6,3,4,2,6,1,2,1,7,10 9,2,6,3,7,4,10,3,6,2,4

We’ve already discussed why it’s critical that you understand what each value represents and how they relate to the other values.

Some other important things that we don’t know about this data yet –

  • Whether it encompasses all the classes in the school and all the students in each class.
  • If it doesn’t, it doesn’t tell us what criteria were used to select the data we’ve been given.
  • It doesn’t tell us whether the students were assigned to their groups by the same person and whether the criteria that should have been used to make the assignments were properly enacted.
  • It doesn’t tell us when the allocation was made, if all the allocations were made at the same time, and whether they are still valid.
  • It doesn’t tell us how the separate classes relate to each other, for example, it doesn’t tell us whether all the children are in the same year group.
  • If classes in the schools are usually distinguished by number it doesn’t confirm for us that the classes mentioned in the data are numbered using the same scheme.
  • It doesn’t identify any unusual circumstances that might apply to individual groups.

These are all important factors in evaluating this data, and if we don’t have this information available to us then we are forced to make assumptions.

In terms of good practice we should always make the most conservative assumption about the quality of data available, but in reality we aren’t always going to be able to do that and will have to try and weigh the likelihood that an assumption is false.

You will almost never be given all of the information that you need, but that doesn’t excuse you from thinking about the information that you have, considering the assumptions that you are making, obtaining further information if possible (and if you can’t get it from the client, that doesn’t necessarily mean you can’t get it from somewhere else.

If nothing else, when you have identified your assumptions you will be able to clearly state the assumptions that you are making in your work.

This right here is most of data analysis, think about your data, make sure it means what you think it means, and identify the assumptions that you are making. Almost all of the bad data analysis that I’ve seen, was doomed from the very beginning because of failures to do this.

 

Next Friday – Size Matters, talking about sample size and rambling about randomness

Softer Science – Ten tips for writing “soft” science fiction

Following from the previous article disscussing hard science fiction, today we discuss some of the points to consider when writing with looser, or “softer” science.

1 – Set the tone early.

You should try to communicate the tone you are aiming for and the looseness of the science as quickly as possible. Otherwise the audience is probably going to make their own mind up, which can be very jarring if the tone seems to departs from that half way through the story.

2 – Soft doesn’t have to mean stupid

A story can still examine very complicated concepts or themes while playing fast and loose in other areas. There are a lot of concepts that are near impossible to work into a really hard science story because of some other insurmountable issue. Time travel is notoriously difficult to write about in a realistic way, and many of the best examinations of it have been very light in tone just because they can get away with a lot more, Back to the Future, for example,  has an incredibly clever script.

Futurama is another great show that plays as fast and loose with the facts as you’d expect, but is not afraid to make very clever jokes about science.

And do the research anyway; just like the best parodies should work as an example of the genre, you really need to understand the rules before you can break them properly.

3 – Soft probably shouldn’t mean inconsistent.

Unless you are taking a very light tone, you should pay attention to what you are saying and try not to contradict it in future. This may actually be harder to do with soft science than with hard, because you are effectively making up your own rules rather than following existing ones. In particular Space Opera seems to attract fans that can be fanatical about canon.

If you are producing a long running series, then pay attention to what the guest writers are writing. Even if they are celebrities.

4 – You can get away with more if there is a payoff

Your audience is more likely to overlook something stupid if the concept is cool enough or it leads to some interesting some character development or examination of a problem. That doesn’t mean that you shouldn’t look for a more plausible way to achieve the same thing, but sometimes it’s worth running with something silly that you can get a lot of mileage out of.

5 – Soft science isn’t a blank check

Just because you are representing your story as space opera, doesn’t mean that you are exempt from suspending your audience’s disbelief. No matter how wacky the tone, it’s still going to be possible for the story to feel stupid, or inconsistent, or the resolution to be overly convenient.

Star Trek has always been very soft in its science but “Threshold” is a great example of an episode that pushed it too far.

6 – If you can’t hide it, consider hanging a lampshade on it

You can get away with a lot of stuff by acknowledging the problem with a wink to the audience. In doing so, you acknowledge the problem and ask them to overlook it. As long as you don’t get carried away with this, it can work surprisingly well. This is obviously easier with a lighter tone, but even with harder stuff, having a character actually state that something doesn’t really make sense or pointing out the impossibility and shrugging about it might be better than not saying anything.

Just make sure that you aren’t too clever or obscure in how you do it. Avatar got a lot of stick for its “Unobtanium” from people who didn’t catch the reference.

7 – Be alert for stray implications

One problem with soft science is that it can easily leave a lot of loose threads unacknowledged. This was the bane of Star Trek’s existence. If you have characters invent something that could logically be used to raise the dead, end poverty, cure cancer or otherwise transform their society, make sure that you address the reasons that they don’t.

Even a rather lazy “we will destroy this thing, because mankind is not ready for it” is better than bringing the captain back from the dead without comment and then forgetting about it completely when the first officer dies three weeks later.

8 – Tone can change, but it shouldn’t happen accidentally

It’s probably less damaging for soft science fiction to take a harder line on something, than the other way round, but it’s worth paying attention to. And consider the extent to which your hard science could be weakened by the softer foundations.

9 – Soft science work better in some places than others

Traditionally softer science works well with a lighter tone of story. Some genre’s such as pulp or steampunk practically require the science to be soft. Space Opera also arguably requires softer science, but the term is sometimes used to encompass work that is significantly harder, especially where very advanced technology is involved. Horror stories are often hard in tone, because it supports a more unforgiving tone of story, but this is certainly not an insurmountable problem.

10 – It’s fun to be stupid sometimes

Even harder science stuff can be a lot of fun when you play fast and loose with it. This is the reason that Halloween episodes or reality alteration stories can be so much fun. “It was all a dream”, however, can probably be considered as having been played out by about the time that Shakespeare was doing it.

The Hard Stuff – Ten tips for writing “hard” science fiction

 

1 – You don’t have to make a declaration, and you can mix things up.

Be careful about making statements about the veracity of the science in your work. If you declare that you are writing realistic, hard science fiction, then your readers are going to take this as a challenge. There’s no rule that says that you can’t keep things fairly realistic in one area but much softer in another, just be aware that this might make it harder for your reader to suspend disbelief regarding the softer stuff. It’s easier for readers to overlook this, if it’s done between fields. For example, soft science space travel combined with hard science terraforming.

2 – Strict Science tends to change the type of story that you can examine.

Hard science tends to make some particular tropes and types of story very difficult. DNA mutation, dogfighting spaceships, short ranged space combat, last minute reset buttons, psychic powers and human like aliens, and many other things, become much harder to include. You still have plenty of options, but it’s a good idea to think about this before you start writing.

3 – Hard doesn’t mean boring.

Hard science can come across as very dry, but it doesn’t have to be. Science is fantastic; there are all sorts of mind boggling things that you can still examine. Beyond the science, no one is going to give you points for accuracy if your story sucks.

4 – Hard Science is harder.

If you want to shoot for hard science, then you are probably going to need to do more research. As always Wikipedia is an excellent starting point. Don’t be afraid to contact scientists working in a field if you think they could help you, or you want to run an idea past them, you may be surprised how accessible and helpful they can be. Just don’t expect them to do lots of work for you for free. Message boards are often an excellent source of people willing to talk about your ideas, be honest about why you are asking. Stay away from the academic papers and resources, unless you are really writing on the cutting edge, because…

5 – Hard doesn’t mean infallible.

You will never be absolutely right, and you are wasting your time trying. Quite frankly, no one cares if the leading authority on a subject can see glaring holes in what you are writing. If you have to choose between the science and the story, the story should come first.

6 – Hard science should never be too hard for the reader.

Think about who is going to read your books and what they want to get out the story. No one wants to read something that makes them feel stupid. Even if your readers are capable of understanding very complicated concepts, doing so is quite literally exhausting (your brain uses a lot of energy when it’s thinking). If your entire story reads like a textbook then even very smart people are likely to give up, because reading it just isn’t any fun.

7 – Explaining science is just as important at getting it right.

If you are writing about complex stuff then you probably need to spend at least as much time thinking about how to get the concepts across as you do researching them. Some of the best science fiction writer are the best because they are particularly good at this. Think about what enthuses you, and then try to convey that enthusiasm to the audience. Carl Sagan is great at this, both in his fiction and none fiction. Richard Feyneman is also particularly worth looking up, as his lectures, if somewhat dated now, represent some of the finest science teaching ever recorded and are a master class in explaining some insanely difficult concepts.

8 – But, you don’t have to explain everything, so don’t get carried away.

Just because you can explain something doesn’t mean the story will improve if you do. And if you need to excise a chunk of story, don’t let the amount of work you did researching it stop you. Injecting large amounts of information into a narrative without damaging it is a huge writing challenge, so make sure that you don’t do it unless you need to.

9 – Near future hard science is usually more difficult.

Long term hard science can still invoke “indistinguishable from magic” super technology, as long you don’t get carried away with it. Short term stuff can’t rely on that as a crutch. Try to avoid starting a book that will be obsolete before it’s published.

10 – Hard science dates quickly in some respects, but the story doesn’t have too.

The harder the science, and the more explicit you are about the workings, the more likely that real science will catch up with the specifics. However the actual story may stand up better if it’s been grounded on a more realistic framework. The early cyberpunk stuff stands up remarkably well today, as long as you don’t delve into the specifics of the technology described.

 

So, thanks for reading guys, I’d love any feedback you might have. If you enjoyed this article, you might be interested in the next one, offering another set of tips for writing looser “soft” science

Stats 3 – That stuff you hated in school

Part 3 of An astonishingly useful guide to data analysis for people that don’t like maths

 

Hopefully, after the last article, you know why you are here.

Now we are going to start learning stuff for real.

Now we embark on our magical mystery tour, through stuff that is so awesomely fun that you’ve probably relearned and forgotten it several times already.

Obviously this time will be different.

 

Mean, Median, and Mode

You just groaned in despair, didn’t you?

Mean, median, and mode, are the three concepts which we get introduced to at school and then promptly mix up for the rest of our lives. They are also often associated with “range”, that we forget about completely because it doesn’t begin with M.

Median and mode represent concepts that most of us fail to absorb in school, and in most cases our lives have notably failed to be adversely affected. At this point you may even have come to the conclusion that you are better off leaving them well alone. If this is a prejudice that you have somehow acquired, then I’m right here to tell you that, well, you are pretty much right… mostly…

Let’s start things off with the mean, means are unambiguously important and if you somehow failed to get this one straight in school , we need to rectify that.

 

A memorable memorandum, regarding the multifarious means by which a mean or malicious man could confuse your mind, mayhap  mentioning the many meanings of the multiple, most meaningful, manifestations of the mathematical mean

The mean is what most people think of as an average. It’s the sum of all the values in a dataset divided by the number of separate values.

If you are having trouble visualising this, imagine a set of containers with different quantities of liquid inside. When you take the mean, you are mixing all the liquid from all the containers together and then splitting it back up equally. Means are intrinsically unhygienic.

Because statistics is nothing if not needlessly confusing, whilst the mean is always the average, the average is not always a mean.

Strictly defined “average” refers to the most appropriate measurement of central tendency; it therefore can also refer to the median or mode.

You don’t need to worry about this, if you can legitimately calculate the mean, then the average is the mean anyway, and the chances that you will come across the term “average” used for something else, without this being explicitly indicated are small. Just try to make sure that you personally use “mean” unless you feel that your audience will be more comfortable with “average” or you happen to be playing scrabble.

 

More confusion can arise from the way that, usually, when we are talking about means, we are referring to one of two different numbers, they are both means, but they are means of different things.

The sample mean is that mean of the subset of data you are actually working on. The population mean is the true mean of the entire population that you drew that sample from. It’s possible for these to be the same if you have sampled the entire population, but, most often you will find yourself calculating a sample mean in order to try and predict the value of the population mean.

Like a lot of stuff with stats, the key to remembering this is to understand what the things are, rather than try to memorize the terms.

  • Population mean = mean of the whole population
  • Sample mean = mean of your sample
  • Often you will already have the sample mean, and be using it to predict the value of the population mean

When other people use these terms it should be clear from context, what they are talking about.  Just try to ensure that your own work is clear in indicating which data the mean is associated with, and be ready to request clarification if other people haven’t done the same.

 

Range

The range, as defined in maths, is chiefly troublesome on account of being difficult for blog authors to clearly describe without using the word range in its everyday sense, thus risking confusion.

This is because they are the same thing.

You can work out the range by subtracting the smallest value in a dataset from the largest.

20,30,90,40

MEAN = 45

RANGE= 70

If you regularly use the term range correctly in other contexts, you are almost certainly going to use it correctly in this context too.

 

The Mode, a concept too simple to teach?

This is the point where many people start to struggle.

The problem with the mode is that it is an intensely intuitive concept, which is often taught in an extremely unintuitive way. People will tend to use the mode automatically when appropriate, they just won’t realise that.

A lot of the problem stem from the way that the Mode is taught, as it usually bundled together with the median and mean, in order to use the same examples.

The mode is that value that occurs most often in a dataset, for example, in the number sequence below, the mode is 2

1,1,3,4,2,5,2,4,3,2

This is easy to understand, but doesn’t do a particularly good job of telling us why we need to use the mode.

That is because we wouldn’t.

It’s important to realise that while mean, median, and mode are taught together, they aren’t usually used together. For the sequence above, the mean is far more useful than the mode.

Consider the following example, however.

Taxi,taxi,bus,motorbike,car,helicopter, car, motorbike,bus, car

Which is more likely to be recorded in the form of a table, like so

 

Taxi

Bus

motorbike

car

helicopter

2

2

2

3

1

 

Knowing that “car” occurs most often is of obvious value, but most people will automatically use data like this, without putting a term to what they are doing.

It’s worthwhile, to try and remember what the mode refers to, but it’s unlikely you will come across the term used much in the wild; it’s really just a descriptive term for something that is probably too simple to need one.

 

The median, does not work well alone

The median represent another straightforward concept. It’s the middle value of a sequence of numbers (or group of numbers that can be placed into sequence).  If the sequence is even numbered then it’s usually taken to be the mean of the two middle numbers, although it can also be given as a pair of numbers.

e.g. – for the sequence 1,2,3,4,5 the median value is 3. For 1,2,3,4,5,6. The median value is 3.5.

The problem here is that, whilst determining the median is fairly straightforward, it is not a terribly useful value in and of itself, and it can be very easy for people to confuse a median value for a mean.

Some statistical operations will require a median value, so it is useful to know what one represents, but a medium value should not be presented by itself.

 

In summary

Ensure that you are clear on the precise meanings of mean, and range. Remember to specify which data a mean value refers to. Try not to use the term average, unless you believe that your audience may be unfamiliar with mean, as it is less precise.

Don’t worry about the mode, it’s just not a very helpful term for most audiences, as it represents a concept that is much more straightforwardly represented in a chart or table. In theory, it may be helpful to remember the definition in case you come across someone else referring to it, but I’d tend to suggest that it might be more productive to just pelt them with rotten vegetables instead.

It’s quite possible that you will need to determine a median value at some point, but unless you are confident that will be able to recall the precise definition, it might be sensible to look it up when you need it. Do not present a median value unless you have a clear reason to do so.

OK?

 

Now that I should be able to talk about mean numbers, without people worrying that I am projecting a tad too much, we can proceed to the next article, where we are going to talk about the starting point of analysis.

The data

This is, traditionally, also the point, at which analysis goes horribly, horribly, wrong.

 

 

Stats 2 – What are statistics, and what did they ever do for me?

 

This is the point when I’m probably supposed to break out the dictionary definition of statistics, but I’m not going to because it means pretty much what you probably think it does. What I am going to do though, in somewhat bewildered obeisance to the fact that there are now even specific clichés associated with stats tutorials is break out the quotation.

 

There are three kinds of lies, lies, damn lies, and statistics

 

Everyone has heard this one. It is usually attributed to Mark Twain, but the Internet informs me that its creation should instead be associated with one of a much broader range of historical people who, as with most famous quotations, almost certainly stole it from another witty but significantly less famous person anyway.

This is a great line, and you should be sure to share it with any statisticians that you know, especially if you are bigger than them and it wouldn’t be considered socially acceptable for them to hit you at that specific point in time.

And there is certainly an element of truth to it. Although is something very wrong about the thought that even mathematicians get opportunities to use their powers for evil, statistics can, and often is, abused.  A lot of problems in this world can be attributed to the fact that statistics allows people to replace “because I said so” with the smug presentation of pages of very complicated sums.

When someone makes an argument with words then anyone can respond with more words, but when they make it with maths most people find themselves helpless. People don’t like this. Statistics allow disreputable people to mislead and stupid or lazy people to make mistakes that will go unnoticed because checking their work would involve a lot of work.

All too often then, we take this quotation to heart, repeat it to every statistician that we meet until they flee sobbing into the night, and use it to kindle a smug sense of superiority because, if there is one thing that we love, it’s opportunities to feel smugly superior about people we are worried are smarter than us.

There is just one huge problem with all of the above, and that is that all of the problems I just mentioned, are actually problems with people.

 

The terrible truth

If there is a dark secret concerning statistics, it is simply this, statistics works. Statistics does exactly what it says on the tin, even if people seldom bother to actually read that tin and the labels can be swapped round by other unscrupulous people to sell you tins of caviar that will later turn out to be composed entirely of beans.

Happily, as you may have noted, this doesn’t really let the statisticians off the hook, so you can probably carry on feeling superior to them if you really want to.

 

If you can’t beat them…

So while I appreciate at this point you may not be experiencing any upswing in warm fuzzy feelings about statistics, I hope you can see a few reasons to actually learn more about it

First of all, you were absolutely correct to be suspicious of other people’s statistics, and I hate to break it to you, but if you want to find yourself in a position to identify and fend off bad data as it is presented to you, you will have to study this stuff yourself. In this respect, and only this respect, statistics are exactly like Jedi force powers.

Secondly, if you find yourself with data of your own to analyse, you have a lot to gain by using proper stats. Stats do work, using them is nothing to be ashamed of (honest), and no one is going to make you buy a pocket protector unless you really want to.

Stats will tell you whether your data tells what you think it does. This is important. And whilst, as I have previously suggested, finding out that your data doesn’t tell you it what you want it to be telling you is heart breaking, you may wish to consider that finding that out subsequent to the expenditure of another two years of budget  can be heart stopping. And you need all the help you can get with this, because you have a brain that is terrible at this stuff.

 

Yes, I just insulted your brain.

And not just your brain, everybody’s brains. Your Brain is a miracle of evolution (or if you are American, sometimes theology) that has happened to develop in such a way as to be really bad at this kind of data analysis.

Specifically, your brain is good at searching for patterns in things, because finding patterns has been critical to the vast majority of all of the things that people have ever done. In the evolutionary sense patterns means prizes, and in many cases these prizes involve not being eaten or poisoned by things that have eaten or poisoned other people in the past, thus establishing very important trends. Your brain is much better at finding patterns than it is at not finding patterns. Conversely data manipulation often involves ignoring what seem to be obvious patterns in favour of voluntarily doing arithmetic. We can’t really blame Nature for not anticipating this.

People are especially bad at recognising or producing random data. You can investigate this yourself, if you ask people to give you a random number between one and five they will tend to give you a three, between one and ten, a seven, because these numbers feel the most random.

 

Also, you’re biased

People also tend to seek out results or patterns that confirm their own prejudices or expectations. Taking the previous example, you’ll notice that I’ve not given a cite. The above factoid is a much discussed one, and it ties with my personal experience, but there is a danger here. I can find citations for this which offer experimental tests for this, but none of them actually met the standards for data-set size or results presentation I’m going to use in the rest of this article, and so I’m not going to use them.

The danger is that once something has become acknowledged as “fact” it tends to be reinforced. People will start running their own experiments and only reporting the results if they match their expectations. I started off searching for an example here by using search terms that would lead me to experimental confirmation of trends involving 3 and 7 but would probably miss other people whose experiments had instead found a bias for 1 and 2.

In this particular case I’m fairly confident the pattern is real and does exist, but it’s important to consider this issue, it’s much easier to find something that you expect to find. And it’s very tempting to use data that you don’t really trust because it supports your own position, especially if you can blame someone else if it turns out to be bad.

This leads us neatly to the really important bit.

 

The really important bit

You’ll notice that I’m distinguishing between data analysis and stats. In my mind (and I don’t really care if the dictionary agrees with me) data analysis is what you do, stats is one of the things that you do it with. Stats are tools, and they are only a subset of the tools that are available to you.

Picture the scene, you are in a room, in front of you is a very complicated machine, a set of mostly recognisable tools and an engineer. That engineer is going to stand silently watching you use his, very expensive, tools to disassemble the machine. You’ll most likely pick up something that looks vaguely like a wrench and move towards something that looks vaguely like a bolt, but first, please look carefully over towards the engineer, you’ll probably notice that the man is wincing.

Statistics comprises a lot of techniques that are used to perform a lot of tasks. Most of these are things that you couldn’t or shouldn’t do yourself, and that’s fine, because you are unlikely to need to.  But even with the basic stuff it’s not enough to have a tool, you need to know how and when to use them.

The process of data analysis needs to follow the golden rules and the rules are very simple.

  1. Stop
  2. Think
  3. Maths (if you really have to)

You’ll notice that thinking comes first. The mistake that a lot of people make is assuming that it’s the maths that you need to be thinking about. It’s very easy to obsess about selecting the appropriate test to use and performing it properly. This is what a lot of statistics guides obsess on. That is certainly important, but there are a lot of other places that you can go wrong first.

This is why I told you at the start of this article that searching for a simple guide to the statistical test that you think you should be using is a bad idea, and that is why I’m going to spend a lot of time in the next couple of chapters talking not about statistics, but about the starting point, the data.

 

So join me next week for Part 3, That stuff you hated in school

Stats 1 – An astonishingly useful guide to data analysis for people that don’t like maths

What this is

This article is aimed at the average person who wants to know more about evaluating their data. It is an examination of the theory behind statistics and guide to some of the most obvious pitfalls and problems.

It is intended to form an accessible introduction to data analysis for people who don’t come from an analytical background such as journalists, social media account managers, and new graduate students. Essentially this is the guide that I wish that I had when I was starting my PhD.

I will be presenting some walkthroughs on basic statistical techniques, but I’m also going to spend quite a lot more talking about them. If you are the kind of person that is currently consolidating all your data into two means on a single bar chart and feely vaguely guilty about it then this is the guide for you, and I will do my best to make you feel considerably more guilty by the end of all of all this.

 

Chart 1 - Bad example

Lazily quantifying your projected shame

 

What this isn’t

Statistics is a very complicated subject and this is not an exhaustive examination of it. I have worked quite a bit with stats and I have worked hard to check this article and point out the inevitable over simplifications as I make them, however my background is in science, I am not a statistician or a mathematician.

Obviously the standard disclaimer applies, if you are need to do something absolutely critical with data, you probably shouldn’t be relying solely on random blog articles. I’ll pause now so you can contemplate the wisdom of this, possibly make a mental note to double check anything you learn at some vaguely undefined point in the future, and then proceed as normal, because, after all, we all seem to learn everything from random blog articles these days.

 

And I should read this because?

A reasonable question to ask at this point then, probably involves why exactly you should read this guide. Why you shouldn’t look for something written by some distinguished statistician who is most certainly not going to make any mistakes, or at least none that won’t later form the subject of someone else’s thesis.

This is going to come down to what may seem to be a bewildering admission. I do not like stats.

 

Wait, What?

I am not a natural mathematician, I do not enjoy sums. I am a biologist, I have had to work quite a lot with data and like many other biologists I did not enjoy doing so. My natural inclination when approaching data analysis is to do as little actual maths as possible.  Like many other scientists I have sat at my keyboard, heart sinking as the application of a treacherous sum suddenly tells me that the results that I needed are suddenly beyond my reach again.

I do not like stats.

Why is this good?

Well for a start, when I tell you that you need to know about this, you can really believe me. I am not someone who is quick to resort to numbers but I’m about to spend quite a lot of time selling you on their importance.  When I tell you that you need to apply a statistical test to something you can be assured that, in the same situation, I have probably devoted far too much mental energy into trying to avoid doing so.

It also means that I have something of an appreciation of the stumbling blocks for those amongst you that don’t intuitively understand numbers, which let’s face it, is pretty much everyone apart from the specific subset of people that typically write statistics guides.

I have an appreciation for the second part of this picture that far too many people miss. Data analysis is about much more than statistics and maths. They are important, but they are only part of the picture. More than anything else, the best and most effective way of reducing the amount of time you will have to spend doing stats, is to make sure that when you do, you are always doing the right stats using the right data.

 

The Bad news

I want to start off with some honesty. This is a basic guide to a complicated subject. There is only so much material that can be skipped over, before this whole endeavor becomes meaningless.

This isn’t a short series of articles, and some of the concepts are sufficently complicated that they will likely require some breaks and re-reading, but if they are in the guide, it’s because I honestly believe that you will need to understand them to perform useful data analysis.

Over all else, statistics is a subject that requires a solid grounding in the fundamentals, and the failure to achieve this will often doom your analysis before you have even finished assembling your data.

So, please try to work through these articles in the order that they are presented in. The subjects are presented in a particular order for a reason. There will probably be some repetition of concepts for a lot of readers, but I hope that there will be valuable material throughout, for just about everyone.

 

Structure

1)      This Introduction – The one that you are reading now. In which I describe what I am trying to achieve with these articles.

2)      So what are statistics, and what did they ever do for me?  – A discussion of exactly what statistics is, why you should care about it. It is also going to talk about why data analysis is about a lot more than maths, charts and stats.

3)      That stuff you hated in school – Is a reintroduction to basic statistical concepts such as the mean, medians, and modes (oh my).  As well as the much neglected Range.

4)      Assumptions, the root of all applicable evil – is going to talk about the importance of understanding your data, knowing where it came from and cultivating an awareness of the assumptions that you are making.

5)      Size Matters – Why big groups are better. Talks about sample size, as well as distribution and normality, and formally introduces you to Variance.

6)      More stuff that you hoped you’d never come across again – Is going to talk about basic data analysis, error bars, chart usage and spread sheet techniques as well as problems with the above. In a rare act of mercy, there will be an option to skip past the charts and spread sheets bits for people who are already familiar with them.

7)      How to lie with statistics and why you shouldn’t – Is going to contain quite a lot of examples about how data can be presented in a misleading fashion, and why you shouldn’t do this.

8)      I bet you never thought you’d look forwards to stats – Is going to involve actual statistics, primarily a discussion of t-tests and a walkthrough to performing them with Excel. It is possible but unlikely that the sense of anticipation that you will feel as a result of the delay in getting to this part will overrule the small detail that maths will have to happen.

9)      Numbers in their natural environment- Will provide a series of randomised datasets that people can use to practice these techniques, and get a feel for realistic datasets as well as instructions for generating your own.

 

So, starting off

Why should you even care about statistics?

Join me in part 2 to find out.

Common Tropes I – Building a better Alien invasion

invasion-guide

 

This is a pretty common science fiction theme. It’s also a notoriously unforgiving one from a plausibility standpoint.

If you want to write really hard sci-fi, you might be well advised to stay away from the invading Martians.

That said though, there are ways to approach the concept that can help a lot, and I’m going to discuss them here. This article is, more or less, just a list of observations about the plausibility of different aspects of this trope. The intent is not that people should feel obliged to write scrupulously plausible Space Invaders, the intent is for people to pick and choose useful ideas.

People like alien invasion stories, and they are probably willing to give you more than the standard amount of leeway in writing about them. This will not stop them bitching about it if they feel that using a laptop to wipe out the invasion fleet was a step too far.

The following  are the major sticking points for this type of plot, and all represent reasonable enough assumptions that you really need to specifically address them, and work hard, in order to go in a different direction.

 

What they have going for Them

Technological supremacy –

Any species that can get itself here, likely has a massive technological advantage over us. The harder your science, the bigger the advantage is probably going to be.

Technological supremacy is a really big deal.

There is a tendency, especially in film and television to depict advanced technology as regular tech with better special effects, that is to say, alien weapons for example, aren’t really shown as any more dangerous than a regular weapon.

Whilst the whole point about futuristic technology, for a writer, is that you can have it do pretty much whatever you want, you should be careful not to make it less effective than modern stuff, and be aware that the modern stuff is already much nastier than most people realize.

Tactical advantage –

Assuming that your alien invaders are starting out from space, and retain the ability to move around in space, then they already have a lot going for them.

They call it a gravity well for a reason, just picture two regular people, one of whom is at the bottom of a regular well, and one of whom is standing at the top, with a big pile of regular rocks, which of them are you going to put your money on?

Space is full of rocks.

It’s very difficult, probably impossible, for us to project force upwards into space at short notice, and it’s very easy for something else to project force downwards out of space.

Better Intelligence-

A species that can get itself here can, and will, almost certainly have scouted us out first without being observed. At the very least they can learn a lot about us from television from a long way away. They have the opportunity to sabotage our infrastructure in advance and figure out in advance exactly how we will respond and where from. We are unlikely to have any information about them at all.

 

So, what might we have going for us?

The issue then is as follows, given the above assumptions, the aliens would tend to have an overwhelming advantage, especially if they just want to destroy all humans.

They can drop rocks on us, they can sabotage our infrastructure, they can nuke our cities’, or worse, and there is very little we can do about it.

If you want your human race to have a chance, you are probably going to have to do some work to give it to them.

 

Resources

There is no reason that an alien invasion needs to be an unstoppable juggernaut of destruction. We would have more of a chance if the invaders own resources are more limited.

Numbers –

It’s already likely that an invading alien force will be significantly outnumbered, perhaps overwhelmingly so. This will impair their ability to actually invade and hold territory.

Perhaps the aggressors only represent a very small opportunistic raiding force that needs to be beaten before they can leave and return in greater numbers?

Travel capability –

they might have precisely calculated their fuel usage to get here, or have used a means of travel that does not allow them to move effectively over short distances. Either would prevent them exploiting the advantages that their presence in space would normally give them.

They might be limited in the number of troops that they can move around at the same time.

Time-

They may be pushed to act immediately, their arrival may be impossible to conceal, or they might slip up and reveal themselves early.

Their spacecraft could be becoming uninhabitable, and they might have no choice but to land and attempt to establish a foothold immediately, or they might not use spacecraft at all, arriving directly on the surface.

Time constraints are a great way of preventing the aliens making effective use of some of the advantages that they should logically have, or of provoking a conflict that might otherwise be resolved with diplomacy.

Weapons –

They might not have expected a fight at all; or they may be acting on a target of opportunity and pushing their capabilities. It may become vitally important to prevent them from building infrastructure that can construct more weapons.

They may have lots of weapons but have only limited supplies of ammunition, and replacement parts, for them.

 

Alien psychology?

Aliens are unlikely to behave the same way that humans might, it’s possible that might give us an unexpected advantage or an oppurtunity that we could exploit.

They don’t want to kill us –

At least not straight away. They may want to minimize loss of life, or even avoid it completely.

They don’t want to kill all of us –

They might wish to spare specific individuals such as children or members of a given professions. They might treat individual societies on earth differently, either as a result of negotiation, or according to their own values and views of human society.

They may offer people the ability to choose not to resist on an individual basis, or actually intend to spare collaborators.

They are testing us –

They want to see our response or test our capabilities. In these circumstances it’s possible that we could fail by “winning”, as they may intend to wipe out species that attain a specific level of technology or capability.

They may be looking for evidence of aggression, or its absence. They may want to see how ruthless we can be.

They may wish to see whether we will behave honorably and keep to agreements.

They are manipulating us –

Perhaps they are manufacturing a threat in order to make us work together or induce us to prepare defenses against a secondary threat. Maybe they need to provoke us into some action to justify additional action against us. Maybe they believe in advancement through adversity.

They may wish reduce our population, perhaps in a very specific way.

They are indifferent to us –

They may have a goal that they intend to pursue with as little interaction with us as possible. Their goal may be positive or negative for us, or simply inscrutable.

They have no choice –

They may not wish to harm us, but they may not feel compelled into action by circumstances beyond their control. Some of them may be willing to offer us aid.

They want a challenging fight –

They are deliberately restricting their capabilities, probably not to the point of fairness. They may be testing their own capabilities, or being punished. They may intend to die fighting. They may wish us to appear more threatening than we actually are.

There are multiple factions or species involved–

They may be constrained in their actions to avoid reprisals or punishment from an external authority.

They may be fighting against another species, possibly one that would be willing to aid us, or who entered the fight as a third party. They may be fighting over us.

In all of these cases, picking the right side to support might be very important and difficult to figure out (although this is also something of a cliché, and difficult to set up without the resulting twist being very obvious)

They are inexperienced at fighting, or otherwise hampered in combat –

Maybe they come from a race that has no history of fighting amongst themselves, this could reduce the extent that their technological supremacy is actually reflected in the capabilities of their weapons. Maybe they aren’t very ruthless, or particularly committed to their objective.

Perhaps they value their own safety to the extent that it interferes with their effectiveness.  Maybe they are unable to anticipate our actions.

They are mindless –

Perhaps they represent some kind of natural space dwelling organism attacking from space, possibly they represent an artificial entity of some type.

They miscalculated –

Perhaps they didn’t expect the planet to be populated at all. Maybe they are dealing with additional problems that we are unaware of.

Maybe they lost weapons, resources, and troops in an accident on their way here, perhaps their leader died of natural causes or in an accident.

 

Their Goal?

Not just their primary objective, but any sub-objectives or priorities that they have that may inhibit their ability to deploy their full capacity against us.

Our resources-

There are a lot of resources in space, which should be easier to get at than planet bound resources, however, human civilization may provide opportunities for raiding aliens to target artificial concentrations of materials. Nuclear power facilities could be targeted for purified fissionable material, or Fort Knox for its gold. This could be especially credible if the invaders need the material at short notice, to fix their ship, say.

Human habitations also represent large concentrations of refined materials, so you might want to explore the potential of aliens intending to literally mine our cities.

Remember that moving materials out of a gravity well is a lot of work, so you probably want to concentrate on smaller amounts of rare materials.

Stealing resources makes less sense as a long term goal, and if they intend to gather their own resources then you need to explain why they are doing so on earth, rather than on some random uninhabited world.

Lifeforms and biodiveristy? –

It likely that the earths ecosystem, as well as underlying biochemistry, would be of tremendous interest to an Alien species, and it’s also possible that an alien race might want to at least preserve samples of things that they destroy.

They wouldn’t need large quantities of material to study, but such research could plausibly be time consuming, and require them to leave ecosystems as intact as possible, until they are finished.

This is not a consideration that is likely to stop aliens bombing our cities to rubble, but it might dissuade them from irradiating entire continents or using indiscriminate biological or chemical weapons.

The “invading earth to protect the planet from humanity” plotline isn’t really credible for a variety of reasons, but, more importantly, it’s been very overexposed.

Knowledge? –

Whilst their own technology is likely to be much advanced over our own, it is quite possible that we’d know at least few things that they didn’t.

The problem here, is that we have already made our knowledge very readily accessible. Much of what we know is either freely available or weakly protected and connected to the internet somewhere. We certainly have some secrets that aren’t plugged into a network, but these only represent a tiny proportion of our most significant knowledge from an outsider’s perspective.

This could be important if the invaders didn’t have any time in advance to research us. If they didn’t have the opportunity to access, decode, and download phenomenal amounts of information in advance, then any large scale destruction from them could easily disrupt the opportunity for them to easily take our information in the future.

Stopping them accessing this information could become a short term priority, although, realistically, it would make much more sense for us to do this by pulling information offline, than by trying to fight a “cyber war” with alien invaders.

Food? –

The chances of alien invaders being able to eat Earth’s life forms, let alone justify invading an entire planet for food, makes this rather unlikely. It’s vaguely possible that a sadistic alien race might enjoy eating alien or even intelligent life, as some kind of delicacy (possibly after altering the organism to be more compatible with their biochemistry), but this only really makes sense as a side plot.

Life forms on earth do represent a concentration of complicated organic compounds that could plausibly attract unintelligent life that had evolved to spread through space and be very flexible in what it eats, but intelligent life is likely to be able to find or make its own food much more easily.

Us? –

It’s unlikely that there is anything intrinsically special about humanity (on more than purely a biological and biochemical level) that would make us useful to advanced alien life, simply because they are likely advanced enough to create their own lifeforms, potentially incorporating any biological advantages that we did possess.

It’s certainly possible that an expansionist alien race would wish to conquer the planet without killing its population. It’s also possible that a race might invade to stop us annihilating ourselves or to steer our development in a specific way. This all requires at least some minor degree of benevolence on the part of the invaders however, as it’s difficult to justify them gaining anything special by sparing us in the long term.

Of course, it’s quite possible that they might be motivated to invade simply because they want to enslave or torture us for fun.

Our Brains? –

This B-movie staple is actually a fairly credible objective. If an alien race wants to examine our thought processes, record or archive our consciousness, upload us to a virtual environment, or even package us neatly for transport, then taking just our brains makes sense.

“Infrastructure”? –

This is somewhat lazily evoked in a lot of fiction. The Aliens “don’t want to destroy our infrastructure”. If you are going to use this as an excuse, it’s probably sensible to consider what exactly the aliens want to preserve and why.

There is actually very little of our existing infrastructure that would be of much use to invading aliens with radically different technology, aside from the (xeno)anthropological perspective.

Our infrastructure is also fairly resistant to a lot of things that can be expected to kill us, such as radiation, and chemical or biological weapons.

A base of operations? –

This makes more sense if the aliens are able to breathe our atmosphere and can tolerate similar gravity, radiation and temperatures, as the presence of a hospitable environment is one of the main advantages provided by a planetary location.

The ocean could be an attractive environment for some alien life, and the presence of large quantities of accessible oxygen or water might be convenient, even if they do not intend to take them in large quantities. If they do just want a base of operations rather than a conquered planet then they may be amenable to negotiating a compromise or just trying to ignore us.

 

How things might play out

So, if the Aliens invade tomorrow, what is likely to happen?

Killing all humans –

If the aliens intend to wipe us out completely, then they are likely to deploy biological or chemical weapons against us, or simply bombard out cities directly. There isn’t that much in our cities that would justify putting troops down into urban centers, even if they are trying to preserve them for future examination, in fact, especially if they want to preserve them.

Fleeing into the countryside will only save people if the aliens don’t intend to be thorough, or hang about for long, and, regardless, the rural area in most nations would only be able to sustain a tiny proportion of their total population. If the invaders wish to preserve infrastructure they can use EMP devices and watch millions of people starve.

It’s possible that they might send ground forces to hit specific targets, but there is little incentive for them to fight us on the ground until they have thoroughly softened us up, no matter how overwhelming their military technology is. If they have any significant intelligence about us at all you can expect military bases and nuclear weapons to be priority targets.

Surrender or die –

In the event they present a demand we surrender, the more gung-ho amongst you might be disappointed. The military advisors of most countries will probably advise that we comply (there is evidence that the US, at least, has significant war planning for this) and your leaders will most likely follow that advice.

If any surrender is accepted then you can expect the aliens to move quickly to secure our leaders, disarm our troops, and establish complete control over telecommunications.

What happens next is probably out of our control.

Spamming the nuke button –

Assuming that the military situation doesn’t seem utterly hopeless (a single ship crashed in the desert, say), and the risk of escalating the situation isn’t considered too great, then you can probably expect nuclear weapons to represent our best hope of actually pulling off a military victory. The contamination potential from a well-executed nuclear strike is actually a very minor consideration when measured against the overall seriousness of the situation.

Regardless, any chance of a military victory requires the possibility of attacking the invasions headquarters or staging point, if this happens to be in space we are probably out of luck. It’s theoretically possible that we could target nearby space targets with missiles or somehow smuggle a nuclear bomb up, so you can expect any half way competent space invader to take steps to guard against that.

 

What happens next?

Personally I think that aftermath of an alien invasion has a lot more potential for interesting fiction than the preamble, I also think that aspects of this haven’t been explored that much, especially in visual media.

We win?

In the unlikely event that we have pulled of a victory, then we are still likely in a lot of trouble. It’s reasonable to expect more aliens to show up at some point, and they are likely to be angrier and better prepared for the second round.

Priority is obviously going to be rebuilding, as well as trying to reverse engineer as much alien technology as possible and attempting to fortify the planet against the next wave. Even if we can reduce the technological gap, defending a planet is a very difficult, possibly hopeless tactical problem. We may be better off trying to use captured technology to flee into space before they come back.

Expect some interesting political ramifications, especially if the initial attack created any power vacuums.

We lose?

Forget scrappy rebellions, if we can’t defeat the aliens with all of our military and resources intact, we aren’t going to do it when we are firmly under their thumb, barring some mystic maguffin or secret weakness and an improbable opportunity to simultaneously wipe out all the invaders simultaneously.

Life on a planet ruled by aliens who aren’t secretly plotting to render us down into food or use us to gestate their eggs (and at this point, why would they need to lie about that) is rather under explored and lends itself to an awful lot of different types of story.

 

In conclusion

In the event of an alien invasion we’re probably doomed, but that doesn’t necessarily mean that your characters have to be.

I hope that something in this article is useful to anyone writing about this type of story, if there is anything in this article that people want explored in more detail than don’t hesitate to let me know about it in the comments.

 

Death Rays 101 – The Laser

 

laser-guide

 

This is the first in a series of articles discussing the technology of science fiction, both from the perspective of existing usage in fiction and in the real world. It’s aimed at writers of genre fiction, and is intended to act as a resource for creating fiction over a wide range of tones, “hardness”, and even genres.

Rather than exhaustive technical details, I am intending to provide information about what technology will look like, and sound like, how much it might weigh and what might distinguish it from more mundane technology. I’m going to prioritize information that might be of narrative significance and I’m going to discuss existing genre conventions and how well they fit in with the Science.

Or at least, that’s the plan.

I welcome any feedback on how things work out. I’m intending that this blog turn into a substantial resource for writers, producers and anyone else involved in bringing the future to life, so if you enjoy this article please don’t hesitate to tell as many people as possible.

I’m going to start by looking at that perennial mainstay of futuristic killing – the laser.

 

So what is it –

LASER is an acronym, it stands for Light Amplification by Stimulated Emission of Radiation. This is one of those acronyms that is probably trying harder to sound cool than actually provide useful information, but it’s worth noting that “Radiation” is referring to electromagnetic radiation in general, not (usually) the ionizing radiation that many people associate with the term.

The laser fires a coherent beam of light, that is, the light is released in such a way as to all be travelling in the same direction and all at the same wave length. From a practical point of view, this means that a laser beam is simply very consistent and intense light.

The beam will travel in a perfectly straight line towards the target at the speed of light. The beam will eventually spread out over a wider area, but, depending on the laser, this will often occur over a very large distance. The minimum rate of spread can be very precisely calculated, as there are hard physical limits at work, but spread will also be influenced by the quality of construction of the laser.

 

How does it work –

There are a lot of different types of lasers, but the basics are as follows.

An existing light source, as well as a lot of additional energy, is released into a material called a Gain Medium. This material has the property of amplifying light that passes through it, by emitting new photons as other photons are absorbed, once this reaches a critical point is reached (the lasing threshold) more light is released than absorbed.

This is not is not free energy, as other forms of energy must be absorbed by the Gain Medium for lasing to occur, but the result is that light within the device is amplified. The laser amplifies only the light that meets specific criteria, which results in an extremely consistent beam.

Once the beam has been created, lenses can be used to focus it into a tighter or wider beam, or onto a small area. Different laser designs can produce continuous beams or shorter duration pulses.

 

Is any of that technical stuff actually important to me? –

The gain medium is the main thing that differentiates the different types of laser. The common association of lasers with “crystals” in fiction likely stems from early lasers using ruby rods in the gain medium, and not from any requirement to use crystals as lenses.

Lenses are not required for the production of a beam, although focusing the beam is important to a lot of applications.

Therefore the “laser requires specific rare crystal maguffin” plot line does not really work in hard science.

The ability of some systems to produce discrete pulses of energy allows for higher power, but shorter duration, energy release.

Many modern lasers user specially designed diodes as the medium, these are effectively LED’s that are also capable of producing the lasing effect. These laser diodes are easy to manufacture and integrate with other electronics, they also have properties that allow the pulsing, described above, to be achieved easily.

 

Important stuff that you should know

The thing that never seems to be talked about with regards to lasers in genre fiction is blindness. Eyes are extremely sensitive to light, so any laser that is capable of doing significant damage to a person, let alone any type of armored vehicle, would have the capacity to blind not just on a direct hit to the eyes but via reflection off of any nearby vaguely reflective surfaces. This is a major problem when considering the use of lasers as often depicted within science fiction.

This is also likely to become a real world problem as increasingly powerful lasers become readily available to the general public. Eye protection is possible to some degree, but might rely on some knowledge of the specific types of device that your opponent is using. The range of lasers and their capacity to produce continuous beams, also serve to increase the potential for accidents.

Lasers can be reflected, but a proportion of the energy will still be absorbed, depending on the quality of the mirror, if this absorption is large enough the mirror will be destroyed. Don’t have a character reflect a super-laser with their makeup compact. Lasers are also extremely prone to being blocked by suspended particles such as fog, as these particles absorb the laser’s energy without being able to transfer it anywhere else, or reflect the beam unpredictably, diffusing it.

 

Genre conventions

Lasers are generally depicted as being extremely accurate, and firing at long range, and are now typically depicted as beams rather than projectiles. They are often shown firing as continuous beams and depicted as having tremendous potential to penetrate and cut, but are sometime instead shown as rapidly firing discrete pulses. They are often depicted as red, especially in older media, with blue and green lasers becoming increasingly common reflecting changes in real world technology.

 

Is this correct?

The main issue is probably the depiction of laser beams within the atmosphere. A laser beam will be invisible until it hits something, Very high power lasers will produce enough fluorescence to be weakly visible and they are much easier to see in smoke or fog, although this will significantly reduce the range of the beam.

Lasers used in military applications are likely to release their energy as short pulses instead of a continuous beam, as this allows for more energy in the individual pulses.

The depiction of lasers as a hyper powerful cutting tool is also somewhat problematic. This may stem from the usage of lasers in industry to produce very accurate cutting, as well as an expectation that a continuous beam will continue cutting through a material. However, lasers transfer the majority of energy to the target in the form of heat which tends to be transmitted poorly.

Essentially, lasers are intrinsically quite poor at penetrating through most materials, but a very high power laser can be an effective cutting implement because of its ability to focus a lot of energy onto a small area.

 

Size and weight

This really depends on the laser, or more probably, on the power supply. The lasing component itself is likely to be insignificant in size compared to the power supply used to support it, at least with modern laser technology. The power supply could take almost any form, but in the near future it is most likely to be comprised of batteries or fuel cells. Capacitors are also likely to be involved and these also tend to be heavy.

It would also be possible for a handheld device to be made lighter by tethering it to a power supply by cable. This obviously reduces its mobility and flexibility.

There is unlikely to be any physical requirement for a handheld weapon to have a long “barrel”, but practically speaking it probably will, as this makes it easier for a person to aim and use the weapon, especially if they are accustomed to firearms. If the weapon has the capacity to adjust or refocus the light that it emits then this might significantly increase the size and unwieldiness of the device.

A larger laser is likely to be directly connected to the power grid or have its own dedicated generator and/or capacitors. Large lasers may incorporate complicated lens and mirror assemblies that may require some degree of mechanical insulation from movement or explosions.

 

Recoil

The question of whether lasers can produce recoil is a rather complicated one. The obvious knee-jerk response is that photons do not have mass (although this itself is an oversimplification), and therefore according to the classical physics equation they have no momentum.

However, Photons do have momentum, and thus also produce recoil, but this recoil is exceedingly negligible compare to a firearm delivering an equivalent amount of energy, although obviously more significant if the laser is releasing that energy in very short duration pulses.

I’d suggest that writers research this topic carefully if they somehow need to make a definitive statement on the issue in a story, but otherwise treat lasers as if they do not produce recoil, as even a very well educated audience’s expectation is likely to be that they don’t.

It’s worth noting that the same issues mean that a laser beam striking a target will not knock them over, although it might cause an explosion of evaporated material that could.

 

Sound

The laser beam itself makes no sound. Given that they are often associated with a large power supply, this may produce a humming noise and associated capacitors can make a distinctive whining noise as they charge. A very high power laser could make produce noise as the beam ionizes the air and there may be hissing, sizzling, or popping, as the water in a target evaporates.

 

Colour

A laser can be any colour of visible light as well as light in the invisible portions of the spectrum. This is obviously a function of wavelength of the light and is usually determined by the type of laser. The colour of laser can be important for specific applications and the colour of the target object can be relevant for a low power laser, for example a red object reflects red light, although obviously if a high power laser is used, the target colour is likely to change as the object burns.

You can’t change a lasers colour with a filter, as all of the light is the same wavelength, meaning that the filter will either stop all of it or none of it.

Invisible laser beams will still blind, and are actually more dangerous, both because the invisible beam is easier to misdirect, and because they will not trigger the eye’s blink reflex.

 

How destructive?

By convention lasers are rated according the energy they transmit to the target. Here are some approximate power values for modern lasers.

1-5mw                  – Laser Pointer

5-10mw               -DVD reader

250mw                 – DVD burner

30 -100 W           – Surgical Laser

100 W  – 3 KW   – Industrial cutting laser

100 KW                – Projected output for military laser in near future

Some lasers designed for use in high energy physics are listed as producing even higher energies, but they are pulsed lasers and produce those energies only for a very short period of time.

 

A worked example

The following are very approximate figures for energy delivered by a single round from representative modern weaponry. Starting at 30 Joules for an air rifle, up to around 500 joules for a handgun, 1000 – 2000 Joules for an modern rifle, and 10-20 thousand joules for a high powered sniper rifle.

Let’s go with the handgun.  Wattage indicates Joules per second. You can see that a laser that puts out as much energy as the impact from a handgun each second (500 watts), is well within the range of modern technology. However we cant expect this to make a terribly effective weapon.

The kinetic energy from a handgun is delivered over a very short time period and comes with a lot of momentum that will transfer it throughout the target. The energy from the laser is delivered over an entire second and will tend to stay in one place as heat.

500 Joules is roughly enough energy to raise 2 grams of water in the target from body temperature to boiling point, which will certainly cause a nasty surface injury, but is unlikely to cause serious harm in itself, especially if the laser has been unable to remain fixed on a single spot, or the target is wearing lightly coloured or thick clothing.

However any laser over 5mw is considered a very significant risk to sight. Any laser over half a watt (500mw) is capable of causing eye damage due to reflection from light coloured matte surfaces. Therefore our laser gun is 100 Thousand times more intense than the level that is considered to pose a major risk to sight, and a thousand times over the level at which the operator can accidentally blind himself by firing at a nearby unreflective object such as the target’s white t-shirt.

Assume our laser is 30% efficient, which is a solid upper range for modern lasers. So the laser gun requires a pretty hefty 1.7kw power supply to run continuously.

You can see that the military laser is predicted to deliver around ten times that of a very high powered rifle every second, which probably would be enough energy to destroy or badly damage aircraft or other light vehicles, but it’s likely that such a laser would require almost all the interior space of a very large aircraft to operate.

 

Lasers as weapons

The use of lasers as handheld weapons is therefore problematic.

1)      The heat energy supplied by lasers is rather inefficient at transferring itself throughout a target compared to the kinetic energy applied by projectile weapons. High power lasers are likely to rely on extremely limited or bulky power sources for the foreseeable futures.

2)      The tremendous potential of lasers to maim by blinding is likely to make their use against human targets unpalatable, although this could obviously increase their attraction as terror weapons. They put both their operator, and any bystanders at significant risk of accidental injury.

3)      Lasers can be defeated or attenuated by reflective surfaces or smoke. The latter of which is readily found on a battlefield. Deliberately formulated reflective particle aerosols would be even more effective. Insulating material can also provide effective protection from the transfer of heat.

Essentially a laser transfers energy in a form that is not particularly effective at damaging physical objects, and is relatively easy to protect against, but predisposed to maim unprotected targets such as civilians.

However, Lasers do excel in other respects

1)      Speed – There is no possibility to evade an unexpected laser beam, as it is moves at the speed of light. You can not detect it before it hits you and you are unlikely to be able to move fast enough to get out of the way.

2)      Accuracy – The lasers path to target is predictable, and the laser beam may also provide feedback about the current impact point allowing rapid adjustments to be made.

3)      Range – Especially in a low atmosphere or vacuum, lasers can travel incredible distances, but perhaps more importantly, retain accuracy over that entire distance.

4)      Scalability – Lasers can concentrate an extremely large amount of energy on a very small target over a very short period of time.

5)      Stealth (sometimes)– A laser can fire light that invisible to the naked eye, probably very quietly. The nature of the attack might not be obvious to the victim immediately and it will defeat modern systems designed to identify the firing point of firearms. However, if the beam is visible, especially to an automated system that can detect a wider range of wavelengths than our eyes, the situation could be dramatically reversed.

This means that lasers will tend to work well against relatively fragile, fast moving targets at long ranges, especially if they can be deployed from a fixed emplacement with a large power supply. They are ideal for air defence, especially as this is unlikely to result in bystanders being blinded.

The ability to reflect lasers off of mirrors could make them useful in situation where establishing a direct line of sight to the target is difficult and can also allow a single laser to fire from multiple emplacements.

They are particularly viable in situations where obtaining sufficient power is not an issue.

Lasers may offer some potential as long range sniping weapons, because of their accuracy, potential for stealth, and because, properly implemented, usage at range would reduce the danger to the operator. The possibility of injuries to bystanders would obviously remain a concern. Some mechanism would need to be in place to protect an operator viewing the target through a scope, but this could be done by occluding the scope at the instant that the weapon fires, or just not having the operator use traditional optical sights.

 

Other Applications

Lasers are important components in a large number of different devices. They are used for cutting, for reading information from or recording on optical media. Their consistency makes them very important for surveying and rangefinding applications.

On the battlefield, Lasers can be directed onto an object and used to guide munitions that will home in on the reflected laser dot.

They can concentrate very high energies onto a small space for a short time and are critical for high energy physics research, or for processes that must be triggered by a large initial energy input such as nuclear fusion.

I’m going to focus, however, on the two incidental applications of lasers that fiction tends to stuff up the most.

 

Laser sights

Laser sights make for great cinema, they just don’t make any sense as typically depicted. The first issue is that laser sights are intended for use with short range weapons, and allow the operator to see where the gun is aiming without using sights. If the operator is using properly calibrated optical sights he doesn’t need a laser dot to see where he is aiming. It certainly doesn’t offer any advantage that would override the massive disadvantage of allowing the target to see the dot.

If the sights are electronic, there is no good reason for a light dot to use visible wavelengths of light. A real sniper might use laser range finding equipment to calibrate his optical sights, but this will use an invisible laser and only needs a single discrete pulse to measure the distance to the target.

I understand that this trope has narrative value, although it’s probably way over-used if nothing else. There is potential to score some credibility points here by incorporating invisible lasers into the scenario, especially with sci-fi. Have the cyborg character able to rescue the ambassador specifically because he is the only one present that can see the dot, or recognize the flash of a range finder.

I’d also note that modern armies tend to use light within the invisible range of the spectrum for a lot of different applications such as target marking, pulsating friendly troop beacons, and landing site marking. There is potential here for them to have unexpected problems when fighting an enemy that can see these things. You might have soldiers suddenly realize that the aliens can see the pulsating beacons that they had all forgotten that they were wearing.

 

Laser tripwire

Once again, problem A is that the real tripwire is likely to use invisible wavelengths of light. This would mean that you need special equipment to see the beam, rather than just squirting aerosols about.

The second problem is that writers sometimes fail to understand that the alarm is triggered by the beam being blocked from reaching a sensor, this means that reflecting the beam with a mirror will trigger the alarm. It is theoretically possible for a complex arrangement of mirrors to divert the beam back to the sensor but in probably impossible to maneuver this into place without interrupting the signal. It’s also worth noting that using an aerosol to make a beam visible might also occlude the beam enough to trigger the alarm, especially if the sensors are carefully calibrated.

There are a lot of obvious ways of playing with this scenario. A clever thief might somehow set up mirrors to reflect the lasers while the sensors are not activated, such as when the museum is open during the day. He might disable the emitters and train his own lasers on the detectors.

A clever villain might user visible laser traps to guide an intruder into invisible sensors. He could have aerosol detectors. The system could even be designed so that the obviously visible beams have to be broken to disable the security.

 

Key concepts –

A laser strikes its target instantly.

A laser can be fired very accurately.

Lasers require large amounts of energy.

Lasers can be diverted using mirrors and are easily blocked by airborne particles

They can easily cause blindness at any intensity that could cause significant physical damage to a target.

Lasers are therefore unlikely to be used as hand held weapons.

They may be well suited to use as anti-aircraft weapons.

Lasers are inefficient weapons, but scale well in transferring very high energies to very precise targets.

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