RE: A flaw in science fiction.

RE: A flaw in science fiction. (Full Version)

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MasterCaneman -> RE: A flaw in science fiction. (11/12/2013 7:38:49 AM)
quote: ORIGINAL: KYsissy quote: ORIGINAL: MasterCaneman quote: ORIGINAL: KYsissy quote: ORIGINAL: MasterCaneman I'm too busy to dig out the formula, but the deceleration is equal to their initial entry velocity when they enter the atmosphere. Some of the older Soviet capsules would go to six Gs coming back in. Humans can usually handle up to 9 for short periods of time. 10 meters per second squared is the gravitational constant for Earth. As for the Soviet capsules hitting 6 g's, that can only be when they hit the denser atmosphere and decelerated. In a vacuum, they would maintain 1 g acceleration and the feeling of weightlessness. If they maintained a 1G acceleration, they would have Earth-normal gravity aboard, not weightlessness. The space station and all the satellites have a 1 g acceleration and experience weightlessness. That is all the earth is capable of due to gravity alone. The moon is roughly 1/6 of g on earth. Acceleration can also be a change in direction of the velocity vector. Which is where the 6 gs jet pilots experience comes from. Anything in orbit is considered to be 'falling', as opposed to being under acceleration. If you had a vehicle undergoing constant 1G acceleration, you would have normal gravity. The reason they're weightless is because they're falling freely in their direction of travel. Now, if they were at a fixed point in relationship to a body, they would experience the same (or nearly so) of that body.

KYsissy -> RE: A flaw in science fiction. (11/12/2013 8:32:21 AM)
quote: ORIGINAL: MasterCaneman quote: ORIGINAL: KYsissy quote: ORIGINAL: MasterCaneman quote: ORIGINAL: KYsissy quote: ORIGINAL: MasterCaneman I'm too busy to dig out the formula, but the deceleration is equal to their initial entry velocity when they enter the atmosphere. Some of the older Soviet capsules would go to six Gs coming back in. Humans can usually handle up to 9 for short periods of time. 10 meters per second squared is the gravitational constant for Earth. As for the Soviet capsules hitting 6 g's, that can only be when they hit the denser atmosphere and decelerated. In a vacuum, they would maintain 1 g acceleration and the feeling of weightlessness. If they maintained a 1G acceleration, they would have Earth-normal gravity aboard, not weightlessness. The space station and all the satellites have a 1 g acceleration and experience weightlessness. That is all the earth is capable of due to gravity alone. The moon is roughly 1/6 of g on earth. Acceleration can also be a change in direction of the velocity vector. Which is where the 6 gs jet pilots experience comes from. Anything in orbit is considered to be 'falling', as opposed to being under acceleration. If you had a vehicle undergoing constant 1G acceleration, you would have normal gravity. The reason they're weightless is because they're falling freely in their direction of travel. Now, if they were at a fixed point in relationship to a body, they would experience the same (or nearly so) of that body. A velocity vector has a magnitude and a direction. Acceleration is a change in either or both of those. In orbit the magnitude of the vector is constant, the speed is not changing. But the direction of that vector is constantly changing, thus it is accelerating.

MercTech -> RE: A flaw in science fiction. (11/12/2013 10:17:07 AM)
quote: ORIGINAL: KYsissy 10 meters per second squared is the gravitational constant for Earth. As for the Soviet capsules hitting 6 g's, that can only be when they hit the denser atmosphere and decelerated. In a vacuum, they would maintain 1 g acceleration and the feeling of weightlessness. Um.... if you are accelerating you would feel normal weight not weightlessness. Force = mass x acceleration Now the force of acceleration felt on a re-entry is dependent on the velocity... But, save the Newtonian physics for another thread <grin>

MercTech -> RE: A flaw in science fiction. (11/12/2013 10:18:56 AM)
quote: ORIGINAL: MalcolmNathaniel The answer is far simpler: Drop rocks. This is covered very well in Niven and Pournelle's "Footfall." The basic idea is that if you drop something from orbit gravity puts all of the energy into the ensuing explosion. The asteroid belt has lots of really big rocks in it. A slight push and they fall out of orbit right into the path of the Earth. Big time boomies ensue. And if you use metallic rocks like nickle-iron asteroids the X-rays generated while passing through the magnetic field can sterilize a good chunk of a hemisphere.

KYsissy -> RE: A flaw in science fiction. (11/12/2013 11:16:08 AM)
quote: ORIGINAL: MercTech quote: ORIGINAL: KYsissy 10 meters per second squared is the gravitational constant for Earth. As for the Soviet capsules hitting 6 g's, that can only be when they hit the denser atmosphere and decelerated. In a vacuum, they would maintain 1 g acceleration and the feeling of weightlessness. Um.... if you are accelerating you would feel normal weight not weightlessness. Force = mass x acceleration Now the force of acceleration felt on a re-entry is dependent on the velocity... But, save the Newtonian physics for another thread <grin> For circular orbit, acceleration is found by a=V^2/r. , V is the magnitude of velocity, r is the radius.

SoulAlloy -> RE: A flaw in science fiction. (11/12/2013 11:27:53 AM)
quote: ORIGINAL: Moonhead quote: ORIGINAL: garyFLR quote: ORIGINAL: SoulAlloy Nope - they have a vent at the back which if you whack can stun them... No self destruct buttons though the only self exploding aliens I can think of are the Bomber Squigs from Warhammer 40k... Then why did they have a vent in the back of their spacesuits? Seems a bit daft to me. It's a recharge socket where they plug themselves into their spaceship: they just call it a vent. It was also to encourage them not to turn their back on an enemy :-P

MalcolmNathaniel -> RE: A flaw in science fiction. (11/12/2013 11:58:45 AM)
quote: ORIGINAL: MercTech Um.... if you are accelerating you would feel normal weight not weightlessness. Force = mass x acceleration Now the force of acceleration felt on a re-entry is dependent on the velocity... But, save the Newtonian physics for another thread <grin> This is not quite true. In order to feel weight you must be resisting against something. Weightlessnes is also known as freefall. For some fun, look up "The Vomit Comet."

Moonhead -> RE: A flaw in science fiction. (11/12/2013 12:06:44 PM)
quote: ORIGINAL: SoulAlloy quote: ORIGINAL: Moonhead quote: ORIGINAL: garyFLR quote: ORIGINAL: SoulAlloy Nope - they have a vent at the back which if you whack can stun them... No self destruct buttons though the only self exploding aliens I can think of are the Bomber Squigs from Warhammer 40k... Then why did they have a vent in the back of their spacesuits? Seems a bit daft to me. It's a recharge socket where they plug themselves into their spaceship: they just call it a vent. It was also to encourage them not to turn their back on an enemy :-P It's not a bug, it's a feature, then.

Moonhead -> RE: A flaw in science fiction. (11/12/2013 12:08:24 PM)
quote: ORIGINAL: garyFLR How come everyone's more knowledgeable than me [:(]? Probably because you have a life and don't sit around reading science fiction all day. [;)]

MarcEsadrian -> RE: A flaw in science fiction. (11/12/2013 12:37:47 PM)
quote: ORIGINAL: MalcolmNathaniel quote: ORIGINAL: MarcEsadrian Personally, I'm always annoyed by the idea aliens would attack us in conventional ways, using armadas of ships and exotic artillery. An alien invasion would most likely begin with a quick and efficient biological attack that would wipe us out completely and leave a silent earth ripe for the taking. The answer is far simpler: Drop rocks. This is covered very well in Niven and Pournelle's "Footfall." The basic idea is that if you drop something from orbit gravity puts all of the energy into the ensuing explosion. The asteroid belt has lots of really big rocks in it. A slight push and they fall out of orbit right into the path of the Earth. Big time boomies ensue. Clever! But the problem with that idea is that it would damage/alter the environment too much, destroying much of the existing ecosystem and polluting the atmosphere. If aliens could just remove the human problem on the planet without causing any further damage, that would clearly be optimal. The process would be quick, efficient, and not involve a single military action. I admit, however, that such a scenario would not involve much story drama, though I'm certain a plot could be developed involving some scattered humans who somehow managed to survive the biological attack.

MalcolmNathaniel -> RE: A flaw in science fiction. (11/12/2013 1:00:42 PM)
Have you ever really thought about how aliens would perceive life on Earth? Sure, we humans are the ones who make all the machines and electronic signals. But what does that mean? Another way to look at it is that there is a species who have servants who ensure their survival and propagation. These servants Make sure that the dominant species is free from predators, helps them to ensure hybrid vigor and even prepares nurseries for them on a massive scale. Yes, I am talking about corn.

epiphiny43 -> RE: A flaw in science fiction. (11/12/2013 1:03:26 PM)
From space there is only one species that requires immediate notice. Look at any night time image of the planet. Aliens would be most interested in the species that has the most control of and use of energy. And whatever tastes best. I don't think corn is even close to the most cultivated grain. RICE RULES

epiphiny43 -> RE: A flaw in science fiction. (11/12/2013 2:17:11 PM)
As for 'free fall', all objects in orbit are experiencing a 1G acceleration towards the nearby center of mass, Earth. or they wouldn't be in a curving path. (In orbit' is defined as falling towards the nearby mass at precisely a balancing acceleration to the inertia of the velocity. So you 'fall' at a constant radius (or constant average radius) from the mass. It's experienced as 'weightlessness' because the can they are in, spaceship or EVA suit is ALSO experiencing the same acceleration. Once encountering any sufficient atmosphere, the 'can' also is decelerated by the air's resistance and G's relative to the human's and their inertia is experienced as 'weight'. Gravitational acceleration (G's) doesn't 'feel' against inertia, it does from resistance or propulsion created vector change.

KYsissy -> RE: A flaw in science fiction. (11/12/2013 3:55:40 PM)
I think Porno for Pyros pretty much nailed the alien invasion. http://www.youtube.com/watch?v=FSOHO3GwEPg "Pets" Children are innocent A teenager's fucked up in the head Adults are even more fucked up And elderlies are like children Will there be another race To come along and take over for us? Maybe martians could do Better than we've done We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! My friend says we're like the dinosaurs Only we are doing ourselves in Much faster than they Ever did We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We'll make great pets! We will make great pets We'll make great pets! We'll make great pets! We'll make great pets! We will make great pets! We'll make great pets! We'll make great pets! We'll make great pets!

Zonie63 -> RE: A flaw in science fiction. (11/12/2013 7:40:41 PM)
quote: ORIGINAL: epiphiny43 From space there is only one species that requires immediate notice. Look at any night time image of the planet. Aliens would be most interested in the species that has the most control of and use of energy. And whatever tastes best. I don't think corn is even close to the most cultivated grain. RICE RULES I'm suddenly reminded of the old episode of The Twilight Zone, "To Serve Man." But they didn't really talk about what sort of side dishes they would use. In Star Trek IV: The Voyage Home, it suggested an intelligent group of aliens who were in contact with humpback whales. They weren't interested in humans at all nor which species used energy.

jlf1961 -> RE: A flaw in science fiction. (11/12/2013 8:02:12 PM)
Okay, my question about the gravitational constant has spread out to cover a lot of stuff. I used to have a book of sci fi short stories, Poul Anderson wrote short essays before each story discussing the technology. He suggested that with the advent of nuclear fusion, mankind could literally build rare elements to for industrial use. The book was released in the mid seventies, and he actually thought that by 2010 we would be using fusion power to generate electricity. As far as the discussion, it has proven interesting.

MasterCaneman -> RE: A flaw in science fiction. (11/12/2013 8:41:23 PM)
It's shown me I have to bone up on my math, for one thing.

Moonhead -> RE: A flaw in science fiction. (11/13/2013 5:39:45 AM)
quote: ORIGINAL: epiphiny43 From space there is only one species that requires immediate notice. Look at any night time image of the planet. Aliens would be most interested in the species that has the most control of and use of energy. And whatever tastes best. I don't think corn is even close to the most cultivated grain. RICE RULES Why stick to grains? We're removing the rain forests to provide grazing for cattle, so that gives cows a pretty decent claim to being the dominant species. At least rice and corn photosynthesise...

MarcEsadrian -> RE: A flaw in science fiction. (11/14/2013 3:17:11 PM)
quote: ORIGINAL: MalcolmNathaniel Have you ever really thought about how aliens would perceive life on Earth? Quite intelligently, no doubt. Whether their intent would be for good or ill is up to speculation, though the advanced intelligence will always have the upper hand.

garyFLR -> RE: A flaw in science fiction. (11/14/2013 8:53:06 PM)
quote: ORIGINAL: MarcEsadrian quote: ORIGINAL: MalcolmNathaniel Have you ever really thought about how aliens would perceive life on Earth? Quite intelligently, no doubt. Whether their intent would be for good or ill is up to speculation, though the advanced intelligence will always have the upper hand. To quote Monty Python, ' I hope there is intelligent life up there in the Universe, because there's bugger all down here'.

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