An object at rest stays at rest. An object in motion stays in motion

[conuly]

with the same speed and direction unless acted upon by another force.

What this means, science fiction authors of the world, is that if you are accelerating happily along in space and your engines suddenly cut out, you will not stop short, nor even slow down. You will merely stop accelerating, and continue at a constant speed until you bump into something else or fix your engines.

I'm willing to accept, for the sake of story, that space travel is exactly like ship travel (so no relativity) except that you're worried about explosive decompression instead of drowning/sharks. I'll even believe in space pirates, despite the fact that space is incomprehensibly vast and pirates are comparatively tiny and thus implausible. (I'll just assume you didn't comprehend that part, and anyway, the story needs pirates.) But unless you're going to technobabble at me about subspace or warp or hyperspace or whatever, I'm gonna assume you're traveling in the real, observable universe (sans relativity!) and Newton's laws of motion apply exactly as they do in the real world.

Inertia. Learn it.

Also: If it takes these two until the end of the book to kiss, I'm not buying the sequel.

Edit: Geez. Okay. Space is cold. Why is it cold? Because it is a vacuum... like your thermos bottle. If the contents of your shuttle are cold, then they will stay cold. If the contents of your shuttle are warm, and continue to produce heat, because they are mammals and that is what mammals do, then they will stay warm. If all your systems were just fried, our protagonist should not be shivering because the heating is offline, she should be sweating because there's nowhere for her body heat to go. Her shuttle is a giant thermos, and she's the soup.

Edit again: If his deceased identical twin did it, I'm not buying the sequel. (Oh, who'm I kidding? There's nothing I love more than a good nitpick. I'm definitely buying the sequel.)

Edit the third: It took them within 50 pages of the end of the book, and it was his deceased twin all along, but in an actually shocking revelation his not-so-deceased identical twin isn't evil, he's a philanthropist. It's their dad and/or the government that's operating on dubious ethics.

Comments

[wpadmirer]

LOL!

[conuly]

It gets worse. Read the edit.

[jack]

LOL. Excellent rant. I've just given up, mostly, that lots of scifi run on 1950s pulp physics. Although it really breaks my suspension of disbelief when everything else has been realistic and then a spaceship banks in a sharp turn!

I'm surprisingly willing to accept pirates. "Floating around until you happen to meet someone" doesn't work. But "hanging around near an insufficiently defended port" and "waiting on the most logical route between two major ports" should work ok :)

...what is this book? Although it sounds like I shouldn't read it :)

[conuly]

I'm reading for the cheesy romance, thank goodness.

[kengr]

Oh god yes, banking turns. Yech. Right up there with space battles where you can *see* the other ships (much less have them in the same frame for more than a tiny fraction of a second.

At least some of us managed to talk JMS into at least having the *Earth* ships obey physics on Babylon 5 (years back on usenet).

[conuly]

I'd be happy if that's all it was. No, their engines cut out and our protagonist fell on the floor and hurt herself because they came to an abrupt stop. They had to then bargain with pirates to get a replacement part otherwise the government spooks chasing them would be sure to catch up because they were limping along at a snail's pace.

Edit: Whoops this was a reply to a reply. Disregard.

[jack]

:O

OK, that's a very high level of not understanding newtonian physics.

Um, come to think of it, "fell to the floor" sounds pretty dodgy.

(I guess it could make sense, if they were spinning the ship AND accelerating to produce a combined 1G, and then stopped accelerating, that would feel like 'a sudden stop'. And even if you're at the same speed, it's 'slower' if people chasing you keep accelerating. But I don't suppose it was any of those things :) )

[conuly]

Yuuuuuup.

She fell to the floor due to the artificial gravity. I guess the author envisions it like a sudden brake in a car to avoid a squirrel?

[jack]

That's what it sounded like! I mean, even in ACTUAL cars, if the engine fails, they'll start gliding to a stop, I think, not suddenly be stationary.

[jack]

Oh, very cool! I hadn't realised the B5 usenet arguments were so too way.

That actually turned out pretty well: there are some bits where it ignored physics, but I thought the contrast between the earth ships and the militarily-not-completely-out-of-our-league-but-more-advanced minbari and centauri ships added a lot to the feel of the galaxy.

[kengr]

Yeah, they were. That was fun. While *technically* some of us might be owed an acknowledgement, just seeing things done more right than usual was great.

JMS studiously ignored us when we pointed out that the "million tons of [something] spinning in the night" in the intro for the first(?) season was way off base.

A simple calculation showed that the *air* in B5 massed more than a million tons. The square-cube law strikes again.

And I'm probably one of the folks responsible for the attack on the Narn homeworld. I made a point of how kinetic strikes using mass drivers were a really nasty weapon... Imagine my surprise when they got used...

I also treasure a private email I got from John Ringo a decade or so back. He asked if I'd been one of the folks answering a newbie's questions about antimatter and other things on rec.arts.sf.science some years before.

Yup, the newbie had been him, and the answers I and others gave wound up shaping the Legacy of the Aldenata series.

Let this be a lesson. Offering folks info about how to get the science *right* can have unexpected dividends.

ps. I love Ringo's line in one of the aldenata books about "This is what happens when you let rednecks play with antimatter"

[conuly]

And I'm probably one of the folks responsible for the attack on the Narn homeworld. I made a point of how kinetic strikes using mass drivers were a really nasty weapon... Imagine my surprise when they got used...

You... monster!

[jack]

I feel like we're overdue for some sci-fi that goes back to "suppose we settle the solar system and obey the laws of physics, what would that happen" worldbuilding... :)

[conuly]

You want some decently hard YA sci-fi, try Losers in Space. Hard as rocks, but boy are the characters morally ambiguous. It's easy enough to say that the villain and his father are legit sociopaths, but to be fair, so's the protagonist. The book ends with her casually reminiscing about murdering some imbecilic pop star for the propaganda value and discussing the extremely cold-blooded murders of the aforementioned villain and his dad. (Admittedly, they had it coming several times over, but still.)

[kengr]

Thing is, so much of that got written in the 40s & 50s, that it really doesn't attract that many writers to it.

Clarke, Heinlein & del Rey really covered many of the bases.

[archangelbeth]

http://www.sjgames.com/transhuman/ IIRC had Laws of Physics in it? I never really got into the series, though, and it's tabletop RPG rather than fiction...

[wpadmirer]

Hmmmm... and this is "science" fiction?

[conuly]

Very fiction. Much lol.

[kengr]

Getting rid of waste heat on a spaceships something almost *nobody* gets right. It's an extremely *hard* problem.

Also, if you cut the acceleration, then things don't start floating in the air.

And unless the ship has artificial gravity, you *can't* fall on the floor when the drive cuts out.

[conuly]

They stated they have artificial gravity (and not of the spinning around sort) so I accept artificial gravity. Made-up physics is fine, you just have to justify it somehow.

[jack]

Ah! Well, if they have artificial gravity and then something goes wrong the power, no wonder they're suddenly accelerated in a nonsensical direction! :)

[sabotabby]

This is a good post and you should feel good.

[conuly]

This book would've been better with jetpacks.

[loligo]

I'm going to disagree with your edit: heat transfer happens via three routes, conduction, convection, and radiation. The first two require molecules bumping into each other, but the third one doesn't. So I think the answer to how cold our fictional space travelers will be depends a lot on their unique context - it could be possible that they'd have more heat radiating out than they can handle.

[conuly]

I assure you, you've already put more thought into this than the author did. Oh well. I wasn't reading for the dubious science anyway.

[kengr]

It's almost *certain* that they'll have too much heat.

Remember, you have to have the radiators operating at or below the temp you want to cool things to. And the amount of heat energy they can radiate at a given temp is governed by a *4th* power law.

That is, if they are at twice the temp (in degrees K) they'll be radiating *16* times the energy per square meter.

But since you need to keep most of the ship/station/whatever at *room* temp for humans to be able to live and work, you are stuck with a really *low* radiator temp.

First thing the Space Shuttle did upon reaching orbit was open the payload bay doors.

Why? Because they had to expose the radiators lining the inner surface of the doors to keep the shuttle habitable.

Those solar arrays on the ISS are backed with radiators to keep *it* livable.

Remember, a *resting* human body puts out about 100 watts of heat. And active one puts out a lot more. Then add in all the electronics, motors and other things on board.

[peoriapeoriawhereart]

But what sort of surround would make a small easy bake oven out of a resting person (as the light bulb, not the cake.)

[kengr]

Spacesuit in vacuum that's run out of coolant.

Any ship that has too little surface area for the number of people in it. Also color makes a big difference in how fast heat radiates away. Alas, the better the surface is at not absorbing energy (like getting heated by sunlight) the worse it is at getting rid of heat.

Thermodynamics is a bitch.

Oh yeah, earthbound example. Wrap somebody in saran wrap or something else impervious to sweat, have the air temp be "neutral" and people *have* gotten hyperthermia problems.

A lot of "sold on tv" type "weight loss" gimmicks amount to that sort of thing. EMTs get to deal with the results a lot.

Exercising, or high air temps just make it happen faster.

[peoriapeoriawhereart]

Those first two the person is both light bulb and cake.

Real lightbulbs must be less harmed by their own heat than people are. =)

[thornsilver]

You are not correct about heat transfer in a vacuum. Any heat from a warm object will attempt to transfer to a colder object. That is why we need insulation. And your shuttle will be insulated, or it would not be able to maintain internal temperature. However, no insulation is absolute. Items in a thermos get colder or hotter, it just takes more time. The better your shuttles insulation the longer it would maintain a climate hospitable to human life with the climate control down. But that is not going to be indefinite. Also, people in your shuttle could very well die from overheating, but that would happen because they are in direct light from the star they are orbiting and cannot dump the heat.

[kengr]

Sorry, but you are very much wrong.

See my reply above https://conuly.dreamwidth.org/2718506.html?thread=26917162#cmt26917162

Now consider that NASA and others discovered *long* ago that the problem in space, at least anywhere in the inner solar system is to keep from roasting in your own juices.

You radiate away heat, yes. But you also *absorb* heat from things like sunlight.

That's why things are either reflective or painted white. To minimize heating.

You need *enormous* amounts of radiator area to get rid of enough of the heat generated by people and equipment so that you can keep the temp inside low enough for humans (and the equipment) to be comfortable.

Not kidding, not making it up. This is a known, serious and hard to solve problem.

Spacesuits get around this by using evaporative cooling. They have tanks of water which they let evaporate into the vacuum as needed to keep temps down. That's what limits EVA time. You run out of water for the cooling system.

Can't do it that way for ships & stations because you can't carry enough coolant for more than a few days at most

[thornsilver]

I think I was not completely clear in my explanation. I dis not say that overheating is not a problem in vaccuum. I said that loss of heat is also a problem in the vaccuum. Because there is no moderating effect of atmosphere, you bake when you are in direct sunlight and freeze when you are in shadow.

Will dig up some links when no longer on the phone. But, honestly, any aricle on hazards of space travel mentions both options.

[thornsilver]

https://www.universetoday.com/9768/some-of-the-hazards-in-space/

https://van.physics.illinois.edu/qa/listing.php?id=1837

https://macaulay.cuny.edu/eportfolios/sciencefordessert/2013/02/02/is-space-cold-or-hot/

Basically: yes, overheating is a giant problem in space. However, you will still lose heat in a vacuum in a process called radiation. Since vacuum of space is so much colder than, say, human-operating temperature, you will keep slowly losing heat until the temperatures inside and outside are in equilibrium, unless you atmosphere is artificially heated by internal sources or sunlight.

[conuly]

Again I'm going to say that you've already put a lot more thought into this than the author did.

[thornsilver]

*dies* Oh, I totally agree with that one.

[archangelbeth]

*ponders*

So Borg ships tend to be black because they have a heat-to-energy conversion going in order to fuel their ridiculously tech-based systems? They want to absorb heat and convert it technobabbily into electricity, which they can then store for later use in blowing up half the Federation fleet attacking them at Wolf whatever it was?

[conuly]

You can, actually, convert heat to electricity.

[jesuswasbatman]

Converting heat to electricity is what all our current generating technologies do except hydroelectric and photovoltaic solar.

[conuly]

Well, yes, but... it's not technobabblicious if it's real, I meant.

[archangelbeth]

It's the conversion part that's possibly treknobabble: incredibly effective nanotech-based heatlight (thermo-solar! thermo-stellar?) panels must be plating the Borg cubes! ^_^

[thewayne]

I once played a role-playing game called Teenagers From Outer Space, and I had a giant manga robot. I don't remember the circumstances, but I got smacked hard and was falling uncontrolled and was just about to hit the ground then I came up with the brilliant solution of pulling the power block out just before I impacted, freezing the mech suspended just about the ground. Wiping my brow with a *phew*, and me as the player knowing exactly what would happen but relishing the moment and cinematics, I plugged the block back in and slammed in to the the ground full force.

Cartoon physics, gotta love 'em.

Yeah, getting rid of heat is a serious problem in space. I read an article a long time ago about the process of certifying equipment to take up to the ISS, and it's a multi-year process. They have to convert it to the station's power grid voltages, make sure it doesn't draw to much current, check what kind of poison gasses it produces if it burns, what it outgasses in normal operations, and even how it cools: computer CPUs are heavily reliant on gravity for cooling!

Space is very hard.

Sounds like a pretty badly researched book, or a book that wasn't researched at all - i.e. pure fiction. :-)

[conuly]

a book that wasn't researched at all - i.e. pure fiction.

You gotta love it.

[rhoda_rants]

Dude. Dude. What are you reading???

[conuly]

A cheesy romance that wanted to be grungy space western but ended up missing the mark a bit.

[rhoda_rants]

Aw man, that sounds so potentially amazing!

[archangelbeth]

*happily technobabbles about microjump hyperdrive, spectre engines, warp bubbles, and Star Trek fanfic*

See, the microjump hyperdrive works by making multiple teeny jumps, often whilst also accelerating with the normal reactionless thrusters, but if you're not using the thrusters then it'd be basically "dead in space" and then "dead in space" in a different location along the path...

Except I totally trashed the hyperwarp engines on the main ship, so it's only of use as background tech, really... OXD

Ahem. So, what book were you reading? O:D

[conuly]

Oh, I wouldn't want to spoil the surprise. It's got a nice cover, anyway.

[cellio]

*applause*

Improbable pirates once prompted me to ask this question on Worldbuilding.SE.

You're not gonna tell us what book you're reading, are you?

[conuly]

Honestly, no. It'd have to be completely unreadable for me to shame it that badly.