After my pathetic begging last week I got asked several questions; thanks if you did so! I’ll be answering them at the rate of about one per week, so I should have them all done by the end of the month.

Adam Benton asks

I know this is a rather difficult question, and one you’ve probably answered before, but what game/tv/film depiction to you think is one of the most accurate glimpses of the future?

For example, on the one hand we have Mass Effect, which postulates some crazy advanced technology but seems to keep it within the laws of physics (as much as I know). On the other hand we have BSG, which has less crazy technology but does have dogfights in space ships which – as your most recent post suggested – is unlikely to happen.

We have to work with a given value of “accurate” here, since nearly every single fictional depiction of the future has taken certain liberties with present-day physics in order to make their universe easier to portray/easier for us to understand. Your examples are a good illustration of this. Mass Effect does no more than pay lip service to real-life physics with things like mass drivers and the Normandy’s stealth technology. It gets worse as the series progresses and the writers change and Bioware is less concerned with a coherent universe and more concerned with THRILLING PLOT TWISTS, but even in the first title the mass effect fields, kinetic barriers, even the gun tech which is dressed up with a fair amount of technobabble handwaving – all that stuff is pretty much space magic. As for BSG, which is a gritty, grimy, “realistic” take on sci-fi, even the humans have got things like artificial gravity and FTL travel, which are acceptable concessions to narrative necessity, but they’re also running the Galactica on what appears to be the futuristic equivalent of a 486 processor, which isn’t.

Most accurate, therefore, is only going to be a relative title. Every sci-fi story that’s been shown on a screen of some form has taken liberties with the science, and for good reason; nobody wants to watch a show where it takes a minimum of four years to travel to the nearest star and you get repeatedly fried by solar radiation on the way out of the solar system. You’re more likely to find accurate sci-fi in written form, where it is known as “hard” science fiction; a good example is the Red/Green/Blue Mars trilogy, where the first book (at least) is a decent jab at how we might believably go about colonising Mars, but which is nonetheless an absolute nightmare to read because the characters are all crap. There seems to be a tradeoff: you can focus on the characters and character conflicts and use the science as an enabling device and tell an interesting story, or you can focus on getting your science as right as you possibly can, but you can’t do both, which is why the people who make films and tv shows tend to focus on the former.

As a result the most scientifically accurate depiction of the future is going to end up being something which mentions the science as little as possible. The less it talks about it, the less likely it is to be caught out in an outright contradiction of what we currently know to be possible. Something like Blade Runner would be a good contender; there is only one scientific concept stated overtly in the film (that it is possible to make androids that look, sound and act just like humans) and even that doesn’t outright break science. Everything else is shown to the viewer or mentioned in the background; we are never told explicitly how the flying cars work or why there are wars going on in the offworld colonies. We just know that they exist, and that, at least, is something that falls within the bounds of the scientifically possible.

Therefore the question is more a literary one about how sci-fi narratives are constructed than it is about scientific verisimilitude. If I absolutely had to pick, though, then it would come down to a choice between two titles, and both of them are video games.

Alpha Centauri.

Otherwise known as The Game That Got Me Into Astrophysics. Alpha Centauri’s tech tree is a thing of wonder: exhaustively researched, initially grounded in “real” science and advances we suppose to be just around the corner, like fusion and superstring theory, and then as the game progresses branching out into truly fantastical technologies like teleportation and singularity engines. You can probably quibble about the timescale – I doubt humanity is going to have working anti-gravity devices by 2300, for example – but while it is somewhat suppository it is at least based on the probable direction we think science might be headed in over the next couple of centuries. The stuff you actually do in-game is also pretty damn convincing; the terraforming mechanics in particular are a work of art, scientifically speaking. Of course, Alpha Centauri is working with the advantage that as a 4X it doesn’t really have to bother itself with telling a story (although unusually for the genre there is the skeleton of one in there). If you want a viable future world that does work with that constriction then you should look no further than…

Deus Ex

Not Human Revolution or Invisible War, which both ventured into what would have been space opera had any of it actually been set in space, but the original dystopian world of tomorrow. Like the best sci-fi stories, it takes just one big scientific concept – the incipience of nanotechnology as a viable… uh, technology – and bases its entire structure around examining the social and personal effects that this advance might have on people. There’s some of the other near-future tropes in there as well – sentient AI, robotics, cybernetic augmentations – but this is all stuff that genuinely is going to happen within the next century (Deus Ex is set in 2052). Nanotech is the big pill that the audience is asked to swallow, but once they have, every other fantastical device in the game – think the Dragon’s Tooth sword, Denton’s augmentations, the Universal Constructor – follows on naturally and logically from that one scientific leap. In other words, if we had functioning nanotech we really could do all this stuff, and that’s why I think the world of Deus Ex is the one that’s most connected to the world of today: it takes only one liberty with science, and even that is not completely out of the question. Nanotech is possible, if perhaps not feasible. It’s not even in the same league as some of the things we routinely swallow like anti-gravity, which outright break the established laws of physics.

You’ll notice that both these games have a lot of roots in what is going on in the research laboratories of today. That’s because it’s easier for me to say something is believable when I can draw a straight line between now and the future. If you have something set in the mid-to-far future, like Star Trek, the whole thing becomes far murkier. I can’t make predictions about what 24^th century science is going to be like any more than Isaac Newton could have predicted the microchip. So who knows? It’s possible that some of the things depicted in Mass Effect may actually come to pass given the development of magic 22^nd century technologies. That’s the nice thing about the future: anything could be possible. It’s a heartening thought.

(Battlestar Galactica is still balls any way you look at it, though.)

The post It’s About The Future, Because That’s Where We’re Going. appeared first on The Scientific Gamer.

Innokenti asks

Weapons in space. I imagine Sci-Fi shows lie to us lots about the sort of stuff that might be effective in a space-battle. For example as I understand nukes would only be of minimal use out there in space.

What are the most efficient weapons for space-battles though? (Assuming largely human technology of near-future imagination rather than magic alien energy shields and stuff.)

Yes. Yes they do lie to you, in the same way that spaceships don’t actually handle like jet fighters in a vacuum what with having no atmosphere to react against. Space combat, if it ever happened, would likely be ridiculously crude and nasty thanks to the Newtonian nature of space. Things are whizzing around very quickly making them hard to target, but at the same time you can accelerate a projectile up to unheard-of velocities thanks to not having to worry about any of that pesky atmospheric drag. Most current theories about space weapons involve adaptations of current Earth-based weapons systems, but they all carry certain advantages and disadvantages inherent in their design.

Real examples of weapons in space.

There is one! Back when the Cold War was in full swing the Soviets decided it would be a good idea to mount a 23mm anti-aircraft cannon on Salyut-3 (a space station) to defend against “US space-based interceptors”, with integrated rocket boosters to cancel out the recoil thrust that might have resulted in de-orbiting the space station. It wasn’t the most elegant of space weapons since it could not track a target independently, instead requiring the entire space station to be oriented towards the target. There are conflicting reports on whether it was ever used; it was certainly never used while there were cosmonauts on board due to the inherent risk of firing high-explosive cannon shells via an untested system in a vacuum, but it may have been test-fired after the cosmonauts left. Barring any of the top-secret weapons programs so enamoured of Hollywood, this remains (to my knowledge) the only actual example of the weaponization of space.

Anyway, you wanted to know about current or near-future weapons systems that might be adapted for space use. This means we’re talking bullets, missiles or (mirroring current developments in the way high-technology nations fight wars) drones of some kind. However, thanks to the ranges at which a space engagement would be fought and the speeds at which spaceships travel, there are some quirks involved with each one.

1) Conventional high explosives are now pretty much useless.

High explosives are “high” because they have what is called a high brisance; essentially the rate of expansion of the explosive gas. If this is very high it’ll compress the atmosphere around it and force it outwards in a highly destructive shockwave that does most of the damage – it’s like being hit by a solid wall of air moving at the speed of sound, which is easily enough to knock down buildings and rip limbs from their sockets. But in space, of course, there is no atmosphere; no medium through which the explosive can transmit its destructive force. All it’ll have left will be the force of the explosive gas itself which, while considerable, will diminish considerably over distance thanks to the inverse square law. This means that most conventional explosives – including nukes – are much less effective in space. There are two ways you could adapt an explosive to make it more useful:

Use it as the explosive force for some kind of flak or fragmentation shell. This at least alleviates the problem of having your destructive force dispersing uniformly into an expanding sphere by transferring it to discrete fragments or projectiles which concentrate the kinetic energy of the explosion. Unfortunately I doubt you’d get a whole lot of velocity out of a high explosive burst, so the fragments themselves still wouldn’t pack that much of a punch. Much like real-world flak this would be useful for area denial and little else.

Shape the explosion so that it is focused in one direction. Shaped charges are all the rage these days, and if you got your shaped charge in contact with an enemy spaceship there’s no reason why it wouldn’t do just as much damage to it as a High Explosive Anti-Tank (HEAT) shell would to an Iraqi T-55. This too has a drawback, though, and it’s that if you have to score a near-hit with a shaped charge to do any damage, you may as well take out the explosive and make your shell a solid lump of metal instead. This brings us to…

2) Bullets are now absurdly deadly.

Or at least, their lethal potential is now drastically increased. A regular gun you could buy in a shop in the US would work just fine in the vacuum of space – the primer and cordite explosive used to accelerate the bullet come with their own oxidiser, so lack of oxygen would not be a problem. The bullet would also leave the barrel slightly faster too what with it not having to force its way through any atmospheric gas. However, a regular gun is not going to be significantly more lethal in space than on Earth. If whatever you’re shooting at is armoured in any way then the bullets will still bounce off. Bullets do most of their damage via kinetic energy, or

Which is about the zillionth time I’ve used this equation. There’s a maximum velocity achieveable by gunpowder weapons (details of why are in my post on light gas guns), and so there’s a hard ceiling on the potential kinetic energy of a normal bullet. We’re not too concerned about this on Earth because honestly the guns we have kill people pretty good, but if you took even the anti-aircraft cannon they mounted on Salyut and tried to kill a spaceship with it you’d run into a big problem: namely that spaceships move really fast. We’re talking relative velocities of at least several kilometres per second. Unless it’s coming towards you, the spaceship will be able to simply outrun your bullets, and even if they were they would be an incredible pain in the ass to target. Consider that Goalkeeper/Phalanx CIWS systems have trouble shooting down incoming anti-ship missiles — which are moving a lot slower than our hypothetical spaceship — and you have some idea of the scale of the problem.

The “good” news is that even future spaceships will likely not mount a huge amount of armour plating without some kind of revolutionary new engine system that renders all that extra mass irrelevant. If you scored a hit with even a simple kinetic slug you’d do an awful lot of damage; micrometeoroid impacts are a big problem for orbiting satellites, and those are just tiny chunks of rock a few millimetres in diameter. The trick, both to ensure a hit and to ensure that hit scores a kill, is to make your projectile go as fast as possible. This is something that gunpowder weapons simply aren’t capable of so you’d need to chuck out that system and replace it with a functioning railgun system or something, but it’s certainly theoretically possible. Even then, though, at the engagement ranges spaceship battles are likely to take place at (thousands of kilometres at the very least) it would be trivial for your target to take evasive action if they saw you coming. So you either have to blanket space with a lot of projectiles, or else make your projectiles guided in some way.

3) Missiles are a middle-of-the-road approach.

When I talk about space missiles, I’m not talking about what you’d normally conceive of as a missile, with the rocket booster that constantly burns to provide thrust. This would be redundant and silly on a space missile, since if you had the tech to accelerate a kinetic projectile up to several km/s as in 2) it’d be far easier to launch the missile that way rather than relying on chemical fuel rockets. No, a space missile would consist of a very sparse maneuvering system for making course corrections along with a guidance package to make sure it hits the target. It’d have more in common with the ubiquitous idea of the “killsat” – a satellite designed to take out other satellites by colliding with them – than it would a conventional missile. The advantage of this design would be that your chances of hitting the target increase exponentially once you make the projectile guided. The disadvantages would be exactly the same as those of regular missiles: they would need some sort of active sensor system in order to track their target that the target would see coming several thousand kilometres away.

4) Manned space fighters are not going to happen.

Sorry, but there aren’t going to be any Starbucks or Apollos flying around in the space battles of the future. While it might seem like a neat idea to get in an X-Wing and go gallivanting around the galaxy, if you actually put a human in a military space vehicle all you would be doing is introducing a massive weak point and drain on the resources of the spacecraft. Humans need food, water, oxygen, heat, and all those other little amenities we take for granted here on Earth, and any manoeuvring the spacecraft did would be limited by the requirement to not kill the people inside through excessive G-forces. All this, and a human wouldn’t actually add very much to the spacecraft. Like jet airliners modern spacecraft are all flown by computers these days anyway (yes, even the Space Shuttle) so there’s no real need to have humans on board.

5) Drone fighters almost certainly are.

That thing in the picture? That’s a Predator drone, one of many which can be found flying over Afghanistan and Iraq looking for “terrorists”. At first Predators were simple reconnaissance craft that were supposed to guide vehicles driven/piloted by actual live humans to their targets, but eventually some bright spark came up with the idea of arming Predator drones with Hellfire missiles. Now the Predators hunt all on their own, with the only human intervention coming in the form of a control signal from a trailer park near Las Vegas, Nevada.

That, if anything, is the sort of weapon that is going to be fighting a space war; an autonomous computer-controlled spacecraft capable of deploying subsidiary weapons systems on its own say-so¹. Solving the problem of true autonomy is a significant hurdle, but if an AI can be developed which is capable of running a spacecraft on its own with very little intervention from Earth beyond broad strategic directions then drone spacecraft would be by far the best option for fighting in space. They can move faster, react quicker and are actually capable of targeting other spacecraft moving at several km/s with a fair chance of scoring a hit. A drone fighter wouldn’t look like a Predator; instead, it’d resemble a militarised version of a space probe since aerodynamics and armour would be completely irrelevant in space. At its most basic level the drone would simply attempt to collide with an enemy spacecraft, much like the guided “missile” concept above. There’s more potential in it than that, though; you’d need to launch the drone from somewhere and that somewhere would probably be a larger drone mothership which would be the actual military asset, the smaller drones fulfilling a role similar to cruise missiles on Earth.

Wars in space would therefore take place with a minimum of human intervention. You would need the long-term strategic planning capacity of the human brain, but past that everything would be in the hands of the machines. It would be a war fought by remote control, where the combatants and casualties have no first and last names but merely a make and model. We’re moving in this direction in our enthusiastic pursuit of atmospheric combat at the bottom of a gravity well, so I see no reason why we wouldn’t apply the same technology and the same concepts to space.

Of course, this assumes that the human race would ever get around to fighting a space war. Right now we can’t even be bothered to go to the Moon; interplanetary war seems at least a couple of centuries beyond us. By then technology will have likely changed beyond all recognition, so all of what I just wrote was complete bollocks. I just hope it was entertaining bollocks, is all.

1. Predator drones don’t quite have this level of autonomy because it makes people a bit nervous, but they could if the US military didn’t have a problem with a machine making a wrong call and incinerating a bunch of civilians with an erroneously-targeted Hellfire missile. Oddly enough it’s A-OK when human pilots do this, as if having your bloody violent death dispensed by an actual person is somehow a more palatable idea for Western civilization to swallow.

The post In The Grim Darkness Of The Far Future There Is Only War. appeared first on The Scientific Gamer.

 This post stems from a conversation I was having with Josh about the possibility of colonising Mars. I was saying how the major stumbling block would be finding a solution to the solar radiation problem since Mars is geologically dead. We’re protected from all the harmful stuff on Earth by the magnetosphere, which is generated by a spinning liquid iron core that basically acts as a giant electromagnet, but Mars’ internal dynamo – if it ever had one – ceased activity a long time ago. Josh then asked the following question:

“Could we restart it?”

Ahahaha. Ahahahahaha. Ahaha. No.

Subsequent questioning revealed that he hadn’t actually seen The Core and my blood pressure started to return to normal, but Hollywood and the media are responsible for a very large-scale misunderstanding about what science can do. Specifically, they have led people to believe that if you throw enough nukes at a problem it’ll go away: after all, to a person a nuclear explosion looks pretty big, right? Everyone’s seen the pictures of what was left of Hiroshima and Nagasaki and the spectre of nuclear war has been hanging over the world ever since the damn things were invented, and just because they can cause the extinction of the human race people have gotten the idea that nukes are the final solution to anything.

But the thing is, nukes aren’t actually that powerful. The fireball will burn and blind anyone standing within a couple of kilometres of the blast zone, but anyone standing outside that would survive the first second or so after a nuke went off. Nukes do most of their damage via explosive overpressure; that is, a shockwave of compressed air moving so fast that when it reaches you it’s like being hit bya concrete wall at several hundred miles per hour (this is why ICBMs were set to explode several hundred metres above a city in an airburst so that the shockwave would travel downwards and flatten everything beneath it with little loss of destructive energy). In other words nuclear weapons are destructive because we detonate them inside an atmosphere. If you take them out of that atmosphere they become far less effective, and this is what Hollywood doesn’t seem to understand as it continues to chuck nukes at all of its problems. Asteroid going to wipe out all life on Earth? Throw a nuke at it. Sun dying out? Throw a nuke at it. Core of the world stopped spinning? Throw a nuke at it. Let’s run through a few of the more high-profile scenarios where Nuclear Weapons Saved The World.

The premise of The Core is that the Earth’s iron core has stopped rotating, collapsing portions of the magnetosphere and causing certain people unlucky enough to step out into direct sunlight to quickly take on the appearance of an overcooked chicken. A team of plucky scientists is tasked to venture deep into the Earth’s interior and restart the core by means of detonating a chain of nukes placed around it in strategic locations.

Now, the amount of bad science in The Core is by no means limited to its abuse of nuclear weapons (and no, I don’t care that the movie is somewhat tongue-in-cheek about it) but let’s just think about that one idea for a second. The Earth’s core:

a)      is just a bit smaller than the Moon.

b)      is made of very dense iron-nickel alloy, giving it a mass roughly twenty-five times larger than that of the Moon.

If you stuck twenty-five Moons together and detonated a few nukes on the surface, do you think you could get them to spin? I don’t. Just for the comedy value I’ll crunch some numbers.

One megaton of TNT releases 4.184 10¹⁵ joules of energy. Let’s be generous and assume they have thirty 50 megaton bombs (this being equivalent to the largest nuclear weapon ever detonated, the Tsar Bomba), which gives them a total explosive power of 6.276 × 10¹⁸ joules. Let’s further assume that they can somehow direct all of this explosive force so that it’s translated into rotational moment on the Earth’s core with no loss. The Earth’s core has about 30% of the Earth’s mass, or 1.79 × 10²⁴ kg. The explosion of all thirty bombs will therefore impart 0.00000356 joules of energy per kilogram – in other words, it’ll be enough to accelerate the core up to a whopping two millimetres per second velocity. And remember, this is assuming some things regarding the efficient transmission of the explosive energy that aren’t physically possible.

The point to take away from this is that when you compare nuclear explosions to people, they’re pretty big. When you compare them to planets they’re the equivalent of a gnat farting. But what about stuff that is smaller than planets? Surely if an asteroid were about to hit the Earth, for example, we could just send up some nukes to blow it out of the sky? Uh, no.

First you have the Armageddon example, which features an asteroid “the size of Texas” that’s on a collision course with the Earth. A team of zany oil drillers led by Bruce Willis is sent up to drill a big hole into the asteroid and drop a nuke down onto a fault line with the hope of splitting the asteroid in half and deflecting the bits so that they miss the Earth. This premise is less stupid than it could have been, while still being pretty stupid. By embedding the nuke into the asteroid they’re at least ensuring that all of the explosive energy will be absorbed by it rather than having most of it dissipate into space in a surface detonation, and they actually get Jason Isaacs to emphasise this in the film with a firecracker analogy that’s not completely terrible. That’s about all the credit I give it, though, because Armageddon really is one of the dumbest movies ever made.

Okay so — leaving aside why exactly it’s easier to train oil drillers to be astronauts than it is astronauts to dig a hole, leaving aside the space shuttles that handle like fighter jets and the magic space station that can spin fast enough to produce 1g of gravity without coming apart at the seams, leaving aside that godawful scene with the minigun (seriously what the hell) – this asteroid is apparently about the size of Texas. Texas is 1200 km across and the asteroid as shown in the film appears to be roughly elongated so we’ll assume that’s the long axis, with the short axes being half that. This gives the asteroid a volume of about 6.53 × 10⁸ km³, which is apparently a mix of rock and iron. Assuming a generous 90-10 split in the quantities there, the asteroid has a mass of 1.75 × 10²¹ kg. They’ve only got one bomb but I’ll assume it’s really, really big at 100 megatons, and they’re trying to split the asteroid in half so each potential half will have a mass of 8.53 × 10²⁰ kg. Detonating the bomb inside the asteroid will, in theory, give half the bomb’s energy to each half of the asteroid, so that’s an energy density of 0.000254 J kg^-1 which, if entirely converted to kinetic energy, will give each half a lateral velocity of three centimetres per second. Earth has a radius of 6,400 km, so in order for the two pieces to just miss it (and this is saying nothing of the leeway we’d need if we didn’t want the Earth’s gravity to pull them back in in a massive loop and slam into it anyway) this bomb would have to be set off seven years before the impact date.

(And that is assuming the plan would work as advertised. More likely — since the hole Bruce Willis digs is 800 feet deep, or 0.08% of the asteroid’s radius; this is like detonating a bomb in a particularly deep mine on Earth and expecting it to split the planet in half — what it’ll do is blow off a big chunk of the surface material and leave the majority of the asteroid completely intact.)

And then there’s Deep Impact, which is basically the same as Armageddon except instead of an asteroid it’s a comet. It’s a bit unfair to include it here since Deep Impact has science which, on the whole, is pretty solid – the governments of Earth see the comet coming several years in advance and build a magic spaceship (handwaved away in the film as using experimental Russian tech so it’s less offensively stupid) to take a team of granite-jawed astronauts up there to do something about it. Unfortunately that something, rather predictably, is burying a bunch of nukes to blow the comet to smithereens, which is pretty much the polar opposite of what we’d actually do if we saw a space rock/comet coming for us and had some time to prepare. Comets are not solid objects; they are instead loose agglomerations of ice with some silicate content thrown in, which makes setting nukes off inside them a bad idea for the following reasons:

1. Porous objects like comets have been shown to soak up impact energy (somewhat like a sponge) in a startlingly effective manner, as it all goes towards crushing out the pores rather than fracturing the object itself. The effectiveness of any nuclear explosion is going to be significantly dampened by this.
2. It is, however, much easier to knock fragments off of them because of their loose structure, so not only would a nuke fail to destroy the comet but it’d turn one large incoming object into several radioactive ones.

Point 2) is at least somewhat covered in the film, but the fact remains that this is not what we would do with that sort of lead time. The only way to avoid being hit by an incoming object is to deflect it somehow, not to destroy it, and nukes are a really, really bad way of doing this. If we had, say, five years warning (and we’d be astoundingly lucky to see if coming that far off) we could attach some rocket motors to the side of the asteroid and move it to a safe trajectory over a period of several years. If we only had a few months we’d be kind of boned; comets and asteroids are massive on a scale most people have trouble comprehending, and that mass makes them very, very hard to deflect.

Finally there’s Sunshine, which I’m not even going to dignify with a rebuttal except to say that we could crash Jupiter into the Sun and it would swallow it up with barely a burp. A nuke ain’t going to do squat.

So yeah, nukes: not as useful as Hollywood would have you believe. They are devices designed to be used on Earth to kill thousands of people at a time, not as a catch-all solution to space rocks, solar dimming, geological upheaval and alien invasion. We’d do well to remember that.

The post Nukes: The Swiss Army Knife Of Hollywood. appeared first on The Scientific Gamer.