Stars, planets and other Sci-Fi peeves

Blue Mountain said:
One thing that bugs me about depictions of spaceflight is the cinematographers consistently treat space as if it was a two dimensional environment, or at best a very limited 3-D like we have on Earth with airplanes. But space is fully 3-D like the ocean, with the added effect that there's no up/down reference frame (an ocean has one due to gravity.) So we see things like two spacecraft "meeting" in space, and both are positioned exactly the same with reference to each other, the same way two cars might on Earth. It could just as easily be one ship is upside-down with respect to the other and in a different plane.

One example of this is from Star Trek, The Wrath of Khan. In the final battle, the Enterprise and the Reliant were in the same horizontal plane, and Spock noted that Khan appeared to be thinking in two dimensions. Kirk first moved his ship "down", and then slowly brought it back up so it matched Reliant's 2-D position, and behind it. But why go back up? When they were below the Reliant, why not angle up the Enterprise about 90 degrees so its bow pointed at Reliant's keel, and fire a few blasts that way?
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Long, complicated story shortened and over-simplified because the days before CGI you had to use motion controlled models which were a lot more limited in how they could be shot.
 
HansMustermann said:
@Skeptic Ginger
To be entirely honest, though, that depends on WHAT belt we're talking about. One around a star, fairy 'nuff, is going to be very sparse. One around a planet, weeell, that's a whole different thing. IIRC some of the objects in Saturn's rings are merely a metre or so (or yard or so for your imperials, ince it's rounded anyway) apart. Good luck flying a ship through THAT one.
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In the science documentaries I speak of, they always show a cluttered field of asteroids in the asteroid belt in our solar system. If the asteroids were that thick in the belt, we'd likely be able to see a thin line when we looked out toward it with the Sun behind us.
 
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Lurch said:
... Case in point: Pitch Black, with Vin Diesel. During the dramatic sequence when the once-in-a-thousand-year eclipse is getting underway, ...
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Which brings up another oft repeated sci fi flaw: predators without a source of prey until the humans show up.
 
That's kinda my point, though. All the documentaries are along the lines of "ah-ha, but the Sun's asteroid belt isn't that thick! Gotcha!" And yes, as I've said, a belt around a star won't be very dense. (Because of the sheer size of the orbit it's spread around.)

But I don't recall many SF movies saying that that's explicitly the kind of belt they're dealing with. It COULD very well be around some gas giant or whatever. It's not llike they're rare in SF anyway. Yavin in Star Wars is almost twice the radius of Jupiter (which incidentally would mean dense enough to become a red dwarf, but let's not dwell on that;)) and big enough to have planet-sized moons that can sustain human life as moons. Bespin is about the size of Jupiter. Endor, I think its size is never stated, but it again has at least one moon big enough to sustain complex life. Etc.

My point is that if we accept something that has moons the size of Venus (and yes, technically it's still a moon not a planet, because it doesn't orbit a sun), why not its own belts or rings? Which, as I said for Saturn, can be MUCH denser than a star's asteroid belts. And indeed can be seen as white bands from a distance.

OR, in cases where no sun seems to be around, how do we even know if it isn't realy an accretion disk? Just look at the mass of the Sun and at one point all that was swirling down the drain in a much closer orbit around the centre of the future solar system.

And in some cases, don't get me wrong, they do make it clear it's the wrong kind of belt. But in others we don't really know, since it's never explained in the movie. And it seems to me like people are quick to jump to the conclusion that it's the wrong kind.
 
Yeah what the hell was that giant tube worm that lived in the asteroid eating until Han and the rest of the Falcon crew came along?

I could "almost" give a pass to the (pre-Special Edition) Sarlac since it's more or less immobile, I could probably fanwank away it's also partially plant so it could also be drawing nutrients from the ground, and that particular one just got that big since Jabba kept feeding his enemies to it.
 
Skeptic Ginger said:
Which brings up another oft repeated sci fi flaw: predators without a source of prey until the humans show up.
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Oh aye. Bonus points where its something silicon based or whatever, living in a volcano, and which needs humans to parasitize. As seen in for example the X Files.

Or the silicon based space virus from Enterprise. How the heck did that evolve or reproduce until humamns came around?
 
Blue Mountain said:
One example of this is from Star Trek, The Wrath of Khan. In the final battle, the Enterprise and the Reliant were in the same horizontal plane, and Spock noted that Khan appeared to be thinking in two dimensions. Kirk first moved his ship "down", and then slowly brought it back up so it matched Reliant's 2-D position, and behind it. But why go back up?
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Because it looked more awesome.
 
Lurch said:
Gases escaping from a ruptured hull should not look like tepid wafts of 'steam'. Rather, decompression is so explosively violent (velocities up to at least 1km/s in a fraction of a second) that a more or less diffuse 'bubble' of vapor is essentially instantly seen (assuming water vapor content), and whose volume depends on the rate of gas escape.
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While we're on that topic, decompression usually is depicted as way too long for the volume of air available. And way too forceful.

As for other oft-mentioned issues, I have no problem with sound in space. Silence is so boring.
 
HansMustermann said:
@Blue Mountain
Actually they don't really need to even do that, since the phaser banks and torpedo banks are repeatedly shown to be able to fire at an angle. You really don't need to even angle the ship to fire either.

That said, to be entirely fair to Star Trek, they do ONCE have two ships deliberately meet in a belly to belly configuration in Enterprise. You know, before the show degenerated into the ship committing space piracy and the Vulcan space officers literally huffing paint. Jumping the shark for ratings is a harsh mistress...
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Very good. I saw what you did there!
 
Let's consider dynamics. The asteroid field in Empire Strikes Back is improbable because of the *differential motion* of the bodies. More technically, the velocity dispersion is too large for the separation-to-size ratio. Over even a *very* short interval collisions will dampen the velocity dispersion to near zero. Provided, of course, the system is organized and constrained against disruption, along the lines of a ring system. But if not so constrained, and if the total mass of the system is insufficient to gravitationally bind the system into a cluster (where particles have velocities exceeding escape velocity), the field will quickly disperse. And if a system in isolation, where the particles do not exceed the escape velocity, the natural consequence is coalescence into a single body.

The presence of the 'asteroid worm' suggests a long lived system, far too ancient for the observed kinematics and their dynamical consequences.
 
HansMustermann said:
Here are some of my peeves with space, the final frontier, in books and movies. At best these elements are not even mentioned, and at worst (read: usually) they're exactly wrong. Maybe it will help someone who's writing a SF to get it right for a change.

1. Rogue planets. I.e., planets that escaped the gravity well of a sun, and are just going solo like Leeroy Jenkins.

Thing is, SF seems to love depicting them as normal planets, even with plants and strange animal life and all, only dark. You know, for lack of a sun. As seen for example in DS9.

Now even skipping the issue of plant life without a sun, quick what's the temperature in places that don't get much sun influx?
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Not only it won't support any kind of life, but here's a thought: it's 10K below the FREEZING point of oxygen (54.36K) and almost 20k below that of nitrogen (63.2K).
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While we rely on solar energy here on earth, we do get a small amount from internal sources (left over heat from the formation of the earth and from radioactive decay.)

In theory, a SF writer could hand-wave away the problem of cold from missing solar energy by suggesting that the planet is either newer that earth (i.e. has more left over heat from creation) or has more radioactive compounds which causes more heating from within. Granted, I doubt it would make up the difference in reality, but at least its a way to pay lip service to the problem.
 
Very simple lifeforms could possibly evolve alongside hydrothermal vents on an ocean floor. It's a viable ecosystem here on Earth that isn't dependent on sunlight. Not sure if you could make an interesting sci-fi story with those limitations though.
 
@Segnosaur
I dread to even think of the tectonics that would dissipate that kind of energy. Let's just say you woudn't have to ask if the earth moved for her ;)

More likely you'd have a Venus scenario, where periodically (and quite more often than Venus) the whole crust melts into magma.
 
Lurch said:
Let's consider dynamics. The asteroid field in Empire Strikes Back is improbable because of the *differential motion* of the bodies. More technically, the velocity dispersion is too large for the separation-to-size ratio. Over even a *very* short interval collisions will dampen the velocity dispersion to near zero. Provided, of course, the system is organized and constrained against disruption, along the lines of a ring system. But if not so constrained, and if the total mass of the system is insufficient to gravitationally bind the system into a cluster (where particles have velocities exceeding escape velocity), the field will quickly disperse. And if a system in isolation, where the particles do not exceed the escape velocity, the natural consequence is coalescence into a single body.

The presence of the 'asteroid worm' suggests a long lived system, far too ancient for the observed kinematics and their dynamical consequences.
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Good call. The speed differential is somewhere between stupid and insane in almost any depiction of an asteroid belt. (Again, except for The Expanse.)
 
Another thing is explosions. They always look like explosion in atmosphere. The outer layers of the hot gasses from the explosion are slowed down or straight out moving back, giving the explosion typical cloud or even mushroom cloud shape.
In vacuum explosions look way different. Things will just move away from the center, at constant speed. Gasses will move fastest, forming spherical cloud which will simple expand, while getting thinner and thinner. Solid debris would rotate, but it will all follow linear trajectories, without slowing down.
 
Dr.Sid said:
Another thing is explosions. They always look like explosion in atmosphere.
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That's because they are. Before CGI they couldn't make true voids for filming; besides air explosions look more impressive (hell, look at the last TIE fighted the Falcon shoots down as it escapes the Death Star in the first movie and tell me it wasn't impressive (if entirely over-the-top).)

But yeah, I'd like to see more realistic explosions in sci-fi. They're pretty impressive in real life, too.
 
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