Thursday 13 November 2014

Relativity Bitches!

Recently to my horror there has been many science fiction novels, and in popular culture, that have absolutely no respect or understanding of the laws of physics.

One egregious example was in the novel that shall not be named (Earth Unaware by Orson Scott Card and someone else). In an early part of the book a person can’t go on a spacewalk because they are “travelling too fast”. I stopped reading at this point and went into a Nerdrage! Which involves a lot of exotic, sometimes invented, swear words.

Anyway, there is no air in space so it is not like going out onto the wing of an aircraft when it’s in supersonic flight. In fact the spacecraft will feel like it is going zero because in relation to the spacecraft you are anchored to you are in fact going zero relative to said spacecraft.

Yes there are micro meteorites throughout the solar system, but they are all in different orbits flying around all over the place. If a micro meteorite hits you and it is in an orbit very different to yours yes it could kill you, but whatever orbit you are in you are still going to have a similar chance of being hit by a micro meteorite.

So in the book they slow down to “zero” and make the repairs. But zero relative to what? According to the Monty Python Galaxy song:

Just remember that you're standing on a planet that's evolving and revolving at nine hundred miles an hour, that's orbiting at ninety miles a second, so it's reckoned, a sun that is the source of all our power. The sun and you and me and all the stars that we can see are moving at a million miles a day in an outer spiral arm, at forty thousand miles an hour, of the galaxy we call the 'Milky Way'. …
Do you feel like you are moving right now? Of course, the answer is no you are sitting in a beanbag curled up reading your favourite blog with no sense of movement at all, unless of course said beanbag is on the back seat of a car and / or bus and / or you suffer from vertigo. The fact is you are travelling at a tremendous velocity with the Earth’s rotation and all the other things mentioned in the Monty Python song. You don’t feel like you are moving because everything around you is also travelling along with you. The exact same thing happens when you are on a spacecraft.

So back to this misunderstanding of physics in the book that shall not be named. That is one hell of a star drive that can slow to zero and then speed back up in a couple of hours. In fact this process is repeated pointlessly again and again all the way through the book. Can you imagine the amount of propellant mass they would have wasted - for absolutely no reason.

In one part of the book they do a “dangerous” rendezvous and docking between two ships at “great speed.” But again the ships were not going very fast relative to each other. It would be exactly, and I do mean exactly, the same as docking in Earth orbit - which is a slow relaxing and leisurely affair, most of the time.

What really set me off this morning was, ironically, the landing of the Rosetta Lander Philae on a comet. This is a fantastic achievement, but all these ridiculous reports, “it was like hitting a bullet with a bullet”, or it must have been “so hard” to land on an object going over 90 miles a second. It’s boneheaded stupidity. If you have an understanding of orbital mechanics and have a team of people behind you with software to help it is relatively easy to fly a spacecraft through the solar system.

The big worry is that one of those micro meteorites could damage the spacecraft, or maybe a software glitch could kill it. Its on-board computer could crash. Robotic spacecraft often have to be in space for a very long time as they build up speed and momentum using multiple gravity assists. Space is a harsh environment that could destroy a spacecraft before it has a chance to complete its mission.

Orbital mechanics is not hard. The speed you are going really doesn’t matter (unless of course you are going really really fast - a percentage of the speed of light). Docking or undocking a spacecraft is not like docking or undocking two aircraft at supersonic speeds in an atmosphere, that truly would be stupid and suicidal.

Another gripe is a small one about the game Wolfenstein: The New Order all round a very good game. But, in the moon level I thought it was a little strange how the gravity appeared to be Earth normal instead of 1/6 of the Earth’s gravity. I thought, whatever, but then I made a prediction to myself. I bet myself that’s the instant I walk out the airlock onto the moon’s surface the gravity will somehow revert to 1/6 of a G. Sure enough I was proved correct.

Maybe the Nazis had discovered how to control gravity, if that was the case, why was I launched to the moon on a chemical rocket? Or why didn't they make the whole area around the base Earth gravity as well? So obviously, in this fictional universe the Nazis haven't discovered how to control gravity. But how did the moon know to change the gravity the instant I stepped out of the base? Maybe the developers of the game believed that gravity is the result is of having air to breathe?

All these examples are incredibly stupid and increase the level of ignorance of the greater community - a great evil in my book. And it is a problem that never needs to happen. There are plenty of physicists and other scientists out there who would gladly advise the creators of these sorts of works. Many would probably do it for free. I myself have been asked to be a consultant for a science-fiction novel and I did for free.

Scientific principles and theories can be difficult for some people to comprehend simply because it is not their field. I studied science throughout high school and studied science at university, subscribed to New Scientist and tried to understand Einstein’s General theory of relativity. Alas, I am shit at maths so got into computer programming instead (the computers work out all the sums). And now I write.

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