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Stars, planets and other Sci-Fi peeves

HansMustermann

Penultimate Amazing
HansMustermann
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Mar 2, 2009
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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? Like, say, the Antarctic? Yeah. But even that gest some heat through the atmosphere from the places that do get some sun. So a more apt comparison is, quick, what's the surface temperature of Pluto? Yeah, it's 44 Kelvin (-229 Celsius or -380 Fahrenheit). This will eventually end up even colder.

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). Now that will go up a bit as the atmospheric presure drops as most of it freezes, but it won't be the kind of place where you can breathe without a helmet.
 
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2. Blue giants and red dwarfs.

Blue giants are really big and bright, and red dwarfs are really smal and not very bright. So they tend to be represented as such in the sky. A blue giant is gigantic size in the field of view, while a red dwarf, well, that's at best as big as our sun. As seen for example in Supernova.

Now think about their energy output. A blue giant not only has a surface, which is proportional to the square of its radius, but also MUCH higher temperature. It can put out literally millions of times more energy than our sun.

The only way to even not be vapourized, is basically to take advantage of the inverse square law, and be a thousand times or more (depending on the star) farther away from the star, until you're getting about the same energy influx. Because if you actually were at the distance where it looks as big and ominous as in Supernova, not only a ship would instantly vapourize and be blown away by the solar wind, but so would a planet.

What I'm getting at is that if your planet or asteroid or whatever is around a blue giant, actually the star will look like a small dot in the sky. A very very bright dot, but that kind of size.

Incidentally, a year will also be in the range of thousands of earth years, so it won't as much have seasons, unless it has some strange axis precession independent of that, but ages. The winter will be a whole glacial age, and the summer will be like the Paleocene-Eocene Thermal Maximum.

The opposite holds true for a red dwarf. Not only its surface is smaler, but its surface temperature is much lower, so a habitable planet would have to be MUCH closer to it. This would be when you get a giant star in the sky, although not very bright, so you could just look at it, and years that are actually measured in days.
 
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3. Time dilation and other general (or even special) relativity effects. As seen in, for example, Interstellar.

Thing is, time effects tend to be oversimplified to the point of botching them, even when they ask a scientist. E.g., time dilation in Interstellar wouldn't just affect how long a time has passed since that probe ship landed, but also the wavelengths. If you sent your signal up even in the millimeter band, it would end up dilated to be higher wavelength than the cosmic background radiation. In fact, it wouldn't even end up in the microwave spectrum like that one, but as long wave at best. That kind of a difference. And any modulation you put on it to send a signal would end up stretched over months or years, so it wouldn't even look modulated.

Nobody would receive that signal if they listened to anywhere within an order of magnitude or three of the frequency of whatever transmitter the put on that probe ship. And, here's the important part, if somehow they did, they could instantly tell the kind of gravity they're dealing with. They wouldn't have to bloody land to tell the problem.

Incidentally the same would apply to the light from its star, or the perceived rotation speed around it, or any light coming from the planet. You wouldn't go "hmm, that looks blue, it might be habitable." You'd go, hmm, only very long waves come from it... is it around absolute zero, or IS IT IN SOME KIND OF MASSIVE GRAVITY WELL?

But here's another problem: power is energy divided by time. That goes for any radio signal you send too. If the energy you put out in a minute, gets stretched over several years, the power of that signal is going to be negligible compared to the background noise even before inverse square law lowers it some more. I don't care how big an array of radiotelescopes you have, you're not really gonna get much of a reception there. (Not the least because see wavelength again. If it's bigger than the radiotelescope dish, that dish doesn't do much.)
 
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The captain in Star Trek giving the order "full stop." In space there is no such thing. Or two spaceships meet in space without arranging the meeting beforehand. Space is big. Really big. The only way for them to meet is to arrange beforehand or near a solar system.

Edit. Or how about a neutrino detector that does not weigh many tonnes.
 
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HansMustermann said:
3. Time dilation and other general (or even special) relativity effects. As seen in, for example, Interstellar.

Thing is, time effects tend to be oversimplified to the point of botching them, even when they ask a scientist. E.g., time dilation in Interstellar wouldn't just affect how long a time has passed since that probe ship landed, but also the wavelengths. If you sent your signal up even in the millimeter band, it would end up dilated to be higher wavelength than the cosmic background radiation. In fact, it wouldn't even end up in the microwave spectrum like that one, but as long wave at best. That kind of a difference. And any modulation you put on it to send a signal would end up stretched over months or years, so it wouldn't even look modulated.

Nobody would receive that signal if they listened to anywhere within an order of magnitude or three of the frequency of whatever transmitter the put on that probe ship. And, here's the important part, if somehow they did, they could instantly tell the kind of gravity they're dealing with. They wouldn't have to bloody land to tell the problem.

Incidentally the same would apply to the light from its star, or the perceived rotation speed around it, or any light coming from the planet. You wouldn't go "hmm, that looks blue, it might be habitable." You'd go, hmm, only very long waves come from it... is it around absolute zero, or IS IT IN SOME KIND OF MASSIVE GRAVITY WELL?

But here's another problem: power is energy divided by time. That goes for any radio signal you send too. If the energy you put out in a minute, gets stretched over several years, the power of that signal is going to be negligible compared to the background noise even before inverse square law lowers it some more. I don't care how big an array of radiotelescopes you have, you're not really gonna get much of a reception there. (Not the least because see wavelength again. If it's bigger than the radiotelescope dish, that dish doesn't do much.)
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Maybe I misunderstood, but I thought that they communicated through the wormhole.
 
That they did, but the wormhole (as they explain in the movie too) is just a shortcut between two points in space. It doesn't do any extra magic than that. Any signal you send will still have to go from source to the wormhole, and from the wormhole to Earth.

Most importantly, the wormhole doesn't undo time dilation effects. And that again is actually featured at lest twice in the movie. First when the scout ship had just crashed minutes ago in the planet's frame, although on Earth many years had passed. And second when they return from it, and on Earth a LOT of time had passed and now the guy has 20 years worth of messages from his daughter.

And really that is all that matters for what I wrote. If a minute on planet X is years for Earth, then that is all that's needed for wavelengths to be waaay longer from Earth's point of view, and for energy to be thousands of times less from Earth's point of view. It's just the fact that however many cycles you put out in a second, is exactly that many cycles over a month from Earth's point of view, so frequency is MASSIVELY shifted. And that however much energy you put out in a second, arrives over a month in Earth's frame, so the signal is that much weaker.

Now add the fact that you're within spitting distance of a black hole that's putting out a LOT of energy as it swallows its accretion disk, and you have the equivalent of someone smoking a cig next to the light of a lighthouse. And you're trying to spot the cigarette from a mile away. Yeah, it won't happen. The black hole will completely jam that weakened signal.
 
One of the things that annoys me (a bit) in sci-fi is the total disregard for scale and distances. e.g. in Star Trek (2009) in the opening scene someone asks if the anomaly could be of klingon origin. The answer is: "no, you're 75,000km from the klingon border" or something to that effect. 75 thousand? What the hell is the Kelvin doing that close to the border? Are they deliberately trying to cause an incident? They should stay billions of kilometers away from the border, if not more, just to avoid a misunderstanding! Hell, a light-year (9500 billion km) would probably be best.

Another is the idea that gravity is like a damned vacuum cleaner: if you don't actively push against it constantly, you just fall into the planet's or star's gravity well, and bye bye!

Both of those get combined in Into Darkness, when the Enterprise and Vengeance somehow drop out of warp a few kilometers from the moon's surface, fight a bit, and then as soon as the Enterprise loses power she starts tumbling down the Earth's atmosphere. What?
 
Aye, that one always bothered me too. Majorly.

And it's not just Star Trek (although it's like in every ST series at least once). KOTOR has it too, as well as several others. Ship loses power in orbit, bam, she starts to fall down. I mean, in TOS the shuttle with Spock and Scotty and the gang isn't even shot down or anything, it just has a finite amount of power left to stay in orbit, and then they'll fall and die. WTH? Then why not use that power (which was enough to take off from the planet, so not exactly some wimpy thruster) to get into a stable orbit?
 
A couple of times in Star Trek, where the ship was being pulled into (whatever).

"FULL REVERSE!" the captain yells.

I have a feeling the reverse thrusters/engines aren't as powerful as the main thrusters/engines.

I've always wondered why the ship doesn't pivot on its axis so its main thrusters/engines are pushing them away from (whatever)
 
Aye. I probably should give a kudos to The Expanse, where they actually do a flip and burn to reverse course.
 
HansMustermann said:
Aye. I probably should give a kudos to The Expanse, where they actually do a flip and burn to reverse course.
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They do it in the reboot of Battlestar Galactica - but only with the little fighter ships, not the big ships.

Whereas, in the first Star Trek movie, the little shuttlecraft have to do 3-point turns (Starting at about 5:50) to dock with the Entrprise.:confused:
 
It's simple .. spaceship mechanics are way different to what 'normal reader / viewer' is used to .. so unless you want tons of explaining, it wont make sense. Good idea would be at least not to depend heavily on such thing in the plot .. but then how do you scifi action without ship mechanics, right ?
One way is you simply don't give a frak. Like Starwars. All ships glow thrusters on the back, no matter where they are going. Also don't forget screaching sound passing ships make. Sometimes even good old Stuka bomber siren. But then .. it just works .. casuals are happy, Orbiter veterans will understand.
Indeed Expense does lot of things right, kudos for that.
 
rjh01 said:
The captain in Star Trek giving the order "full stop." In space there is no such thing....
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That part never bothered me. When a submarine officer of the deck gives out that order the main engine throttles are merely closed. The ship continues to coast while the shaft rotates; the sub slows though. If he wanted to slow down faster he would order the shaft stopped with steam, or a more likely, a backing bell.

Ranb
 
C_Felix said:
I've always wondered why the ship doesn't pivot on its axis so its main thrusters/engines are pushing them away from (whatever)
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crescent said:
They do it in the reboot of Battlestar Galactica - but only with the little fighter ships, not the big ships.
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Because there is the small matter of a principle of physics called "moment of inertia"

"a quantity expressing a body's tendency to resist angular acceleration. It is the sum of the products of the mass of each particle in the body with the square of its distance from the axis of rotation."

Put in simple terms, you can't flip big long heavy things end for end quickly. The simplest example is in boats. A 16ft Hamilton Jetboat can be flipped end-for-end in less than a second. Try that with the Queen Mary (and it has little to do with water displacement or air resistance, and being in space makes no appreciable difference).

The original series USS Enterprise is supposed to be about 725 metres long... that's 2½ times longer than RMS Titanic. Later models even longer. BSG-75 is supposed to a whopping 1440 metres... five times longer than Titanic. The moment of inertia for objects of that length is utterly enormous.

Anyone here who is around my age and is a keen sci fi reader is bound to have read Arthur C. Clarke's short story "Hide and Seek". It tells the story of a man on a very small moon (Phobos IIRC) in a spacesuit armed only with a pistol who is able to hold off a massive, heavily armed space cruiser basically because the space cruiser cannot chase him around the moon.
 
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I don't mind sci-fi movies with unrealistic asteroid belts, the asteroids as thick as a school of fish, but when the science documentaries show the asteroid belt that way it grates on my skeptical brain cells.
 
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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@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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@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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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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As seen through an atmosphere--and particularly from the surface of a planet having one decently enough dense--one cannot see the shadowed sides of objects outside that atmosphere as even the slightest bit darker than the sky.

Case in point: Pitch Black, with Vin Diesel. During the dramatic sequence when the once-in-a-thousand-year eclipse is getting underway, the nearby ringed planet that looms menacingly on the horizon has its shadowed side clearly 'black' as seen through a still reasonably bright sky. This is impossible. Seen in superposition, light sources always *add*. Check out our own Moon in a daytime sky. The night side and the darker maria, are always at least as bright as the immediately surrounding sky. And during the crescent phase the Earthshine becomes visible only once the twilight sky is sufficiently dark.

In the same vein, although unrelated to sci-fi, in the main. Older movies having scenes where films are projected onto screens in fairly bright rooms too often had the shadowed parts of images as much darker than the room lighting on the surrounding edge of the screen. Again, impossible, because light sources add in intensity. Those darkest shadows *must* be at least as bright as the ambient illumination, meaning the image is washed out and of poor contrast.
 
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