Question concerning space travel/speed.

I am pretty sure scientists can make a ship that in space can go very quick, maybe not light speed- but pretty close. Considering when something(a ship in this case, but the "law" applies to any object) in space is put in force to a certain speed via some sort of energy transmittion(gasoline, kerosene, plutonium, uranium, etc.) it will never stop going that speed until met with some gravitational force, runs into another object, or reverse thrusted- I imagine that there already is some type of ship that could be built right now with the right engine with the right fuel and/or other possible processes that will make this "imagianary" ship go incredibly fast... maybe not light speed, but incredibly fast. Whether by fusion, nuclear, hydrogen, or plain ol' oil, something could(and already can be built if you ask me[based on our current known technological ability]) be created that goes incredibly fast. But my question is this: Why is it stated that a man will die going a certain speed? It is said that light speed travel is impossible because a man would literally be smashed/"mushed" into his seat or whatever is behind him/her. I'm pretty sure this would happen at even sub-light speeds, such as 43,000 MPH. I do not expect to survive 43,000 MPH... nontheless 10,000 MPH. Well, every hour our solar system comes forty-three thousand miles closer to globular cluster M13 in the constellation Hercules. Considering the constellation Hercules is not the center of the universe, even it must be moving(?). .. in turn we are going even faster than 43,000 MPH. Take the fact that the Earth spins around the Sun and further yet- the Earth itself spins. Why would a man not be able to be pulled off of a spinning planet being spun around a Sun that is the center of our solar system that is headed somewhere at 43,000 MPH+[?] (+[?] because it is not estimated that the thing where we are headed is moving or not as well... the thing M13 might be headed toward something as well... and so on...) and survive? Because space must not be nothing but gravity. As such, everything is going towards the middle. if there was no middle a man-made object could get away from our Sun's gravity and then reverse thrust itself to 0 MPH and watch our solar system dissapear like a mother*explicit,* I mean, the thing going 43,000 MPH for christ's sake. Gone. Since wherever we are going is stronger than the Sun, I expect that ship never to reach 0 MPH. So plucked off of this planet, off of gravity and shot beyond the Sun's gravitational reach... uhhh, is there no such thing as 0 MPH? If there was 0 MPH in space or not, the whole solar system would shoot by a 0 MPH object like a mother*explicit!*

Where are we going y'all?

Sry to confuse you if I did(I'm terrible at conveying a cohesive thought in a logical and readable manner. Please read over it carefully). I welcome any possible response.

Originally posted by daisaison_x
I am pretty sure scientists can make a ship that in space can go very quick, maybe not light speed- but pretty close. Considering when something(a ship in this case, but the "law" applies to any object) in space is put in force to a certain speed via some sort of energy transmittion(gasoline, kerosene, plutonium, uranium, etc.) it will never stop going that speed until met with some gravitational force, runs into another object, or reverse thrusted- I imagine that there already is some type of ship that could be built right now with the right engine with the right fuel and/or other possible processes that will make this "imagianary" ship go incredibly fast... maybe not light speed, but incredibly fast. Whether by fusion, nuclear, hydrogen, or plain ol' oil, something could(and already can be built if you ask me[based on our current known technological ability]) be created that goes incredibly fast. But my question is this: Why is it stated that a man will die going a certain speed? It is said that light speed travel is impossible because a man would literally be smashed/"mushed" into his seat or whatever is behind him/her. I'm pretty sure this would happen at even sub-light speeds, such as 43,000 MPH. I do not expect to survive 43,000 MPH... nontheless 10,000 MPH. Well, every hour our solar system comes forty-three thousand miles closer to globular cluster M13 in the constellation Hercules. Considering the constellation Hercules is not the center of the universe, even it must be moving(?). .. in turn we are going even faster than 43,000 MPH. Take the fact that the Earth spins around the Sun and further yet- the Earth itself spins. Why would a man not be able to be pulled off of a spinning planet being spun around a Sun that is the center of our solar system that is headed somewhere at 43,000 MPH+[?] (+[?] because it is not estimated that the thing where we are headed is moving or not as well... the thing M13 might be headed toward something as well... and so on...) and survive? Because space must not be nothing but gravity. As such, everything is going towards the middle. if there was no middle a man-made object could get away from our Sun's gravity and then reverse thrust itself to 0 MPH and watch our solar system dissapear like a mother*explicit,* I mean, the thing going 43,000 MPH for christ's sake. Gone. Since wherever we are going is stronger than the Sun, I expect that ship never to reach 0 MPH. So plucked off of this planet, off of gravity and shot beyond the Sun's gravitational reach... uhhh, is there no such thing as 0 MPH? If there was 0 MPH in space or not, the whole solar system would shoot by a 0 MPH object like a mother*explicit!*

Where are we going y'all?

Sry to confuse you if I did(I'm terrible at conveying a cohesive thought in a logical and readable manner. Please read over it carefully). I welcome any possible response.

Yeah, you can make something that goes that fast. We need to discover plasma and its effects on the surrounding environment of the ship first. If we did make something, going sub-light speed, running into the ionized hydrogen would take a toll on the ship you're in. Not to mention the incredible amounts of radiation you would suffer. 43,000 MPH is quite slow... in fact its about 2 times as fast as the "low orbit" speed that the space shuttle uses. travelling at 43,000 mph would take 10 days to reach the moon, and 5379 days to reach mars when the earth and mars are closest together.

A few things, speed doesn't kill, acceleration does. LEO speed is about 8 kps, it will take less than two days to get to the moon starting at that speed. You're at escape velocity at that speed. The equations are pretty easy, but they're too complex to run in my head (square roots are a beotch). At an altitude of 6700 km, the speed is about 7.7 kps.

With current tech I'm pretty confident we could reach 1/100th c if we really busted @ss and had a lot of ingenuity. Now you can do gravity assists and other little things to get you a little more speed too. Things like ion propulsion (from what I've heard) can get you going pretty fast. Take gas and ionize it and accelerate it to about 1/2 c and fire it out the back. Nuclear propulsion is pretty cool too but there's irradiation problems with it. I'll try to find some sources and be back, don't be surprised if they're from my school though as they've got some cool stuff going on with this. Oh, solar sails too if they could ever launch them and not blow them up leaving the planet.

Edit: You'd have to make enormous amounts of electrical power to fling the stuff out that fast, but it may be possible. Damn you discovery channel and your lies. Thankfully, solar power harvesting is about 10x as efficient in space.

[edit on 5-8-2006 by LordOfBunnies]

Originally posted by LordOfBunnies
Things like ion propulsion (from what I've heard) can get you going pretty fast. Take gas and ionize it and accelerate it to about 1/2 c and fire it out the back.

LOB,
I read in Omni magazine, you know, before it went completely wacky it used to be a science mag, where NASA already has ion propulsion, this was decades ago.
The ion drive they'd developed back then only put out about one Newton of force. So, not much right? But it ran on solar cells. Given F=ma, you could get to lightspeed eventually, or at least the drive engine could, if you put it in orbit around the Sun.

I'd suggest a starting position slightly outside the Earth's solar orbital track though.

Harte

Originally posted by Harte

Originally posted by LordOfBunnies
Things like ion propulsion (from what I've heard) can get you going pretty fast. Take gas and ionize it and accelerate it to about 1/2 c and fire it out the back.

LOB,
I read in Omni magazine, you know, before it went completely wacky it used to be a science mag, where NASA already has ion propulsion, this was decades ago.
The ion drive they'd developed back then only put out about one Newton of force. So, not much right? But it ran on solar cells. Given F=ma, you could get to lightspeed eventually, or at least the drive engine could, if you put it in orbit around the Sun.

I'd suggest a starting position slightly outside the Earth's solar orbital track though.

Harte

What they could do, is if it was possible to have the ship gain speed while orbiting the sun from a distance where the escape velocity isn't too great, but close enough to be efficient. Once the ship reaches its targeted speed to reach wherever its going, just let inertia take it to the next star and have the ion's reverse thrust like an airplane would do when it lands. But you'd either have to have them on both sides or make them be able to go in any direction (which is probably what would end up happening if this tech ever takes off)

Ion propulsion engines are extremely efficient relative to chemical rockets such as we now use for most space missions. Thing is though they still expell mass to gain acceleration and the more mass you have to accelerate the slower you are going to be able to accelerate it with a given force. To use an ion propulsion engine on a manned spacecraft would not be very practical simply because the life support systems required would weigh an awful lot and current ion engine technology would only be able to accelerate such a huge mass at about 1/10,000 of a G. True, the ion engine could maintain that acceleration for several years, but the man inside would have long since expired. Now if you take the man out of the equation it gets better (much better) very fast. The less massive you can make the spacecraft the faster you can accelerate it. To make the engine run longer you again have to add mass (as propellent) and things start to slow down again. There is a point of diminishing returns for such engines even assuming you could be assured they would not fail for reasons other than lack of propellent. All in all, you might be able to accelerate a small spacecraft up to about 0.2C (2 tenths of lightspeed), but better reliability, etc. would be needed to go much beyond that. Still, we're talking about a velocity in excess of 130,000,000 MPH. Not bad for us ignorant savages here on earth.

Originally posted by XS207

What they could do, is if it was possible to have the ship gain speed while orbiting the sun from a distance where the escape velocity isn't too great, but close enough to be efficient. Once the ship reaches its targeted speed to reach wherever its going, just let inertia take it to the next star and have the ion's reverse thrust like an airplane would do when it lands. But you'd either have to have them on both sides or make them be able to go in any direction (which is probably what would end up happening if this tech ever takes off)

Well, as with all technology, it improves with time (unless you're talking about American car companies, but that's another issue). Actually what they use are called reaction wheels. You only need 1 main thruster because they use the reaction wheels to spin the ship. It's basically just a flywheel the ship can spin up to rotate the ship. The Conservation of Angular Momentum means the ship spins to counter the spin of the flywheel. It's a basic tech used in everything that goes into space pretty much, so you can use that to spin the ship to proper orientation as long as you don't gimble lock .

I'd be able to give you more information but I just moved out of my apartment and all my books are under a half ton of crap. To give you an idea, I've seen figures quoting the specific impulse of an Ion Drive to be 30,000,000 seconds. To compare, liquid hydrogen + liquid oxygen combustion that's used in a lot of boosters and thrusters is about 450 sec in a vacuum. From what Astronomer70 said, you'd need a big thruster to hit escape velocity (about 11 kps at 6700 km radius) then bust out the ion thrusters.

EVERYONE dont get your hopes up on this light speed travel fantasy. remember what einstein said, only light can travel at light speed because light is not matter there for only light is capable.

if you put a human in one of those tiny escape pods you see on star trek and they engage light speed almost instantly the craft and human would be incinerated. bcause if you jump from zero to light speed in one second thats like billions and billions of gforce acting on you and matter cannot travel light speed anyway.

maybe maybe maybe if we altered our dna so we look more like an insect maybe (insects were found to be more resilliant to g forces)

[edit on 6-8-2006 by worksoftplayhard]

I still believe in e=mc², but I can't believe that in all of human history, we'll never ever be able to go beyond the speed of light to reach where we want to go," said Clark. "I happen to believe that mankind can do it.

"I've argued with physicists about it, I've argued with best friends about it. I just have to believe it. It's my only faith-based initiative." Clark's comment prompted laughter and applause from the gathering.

Gary Melnick, a senior astrophysicist at the Harvard-Smithsonian Center for Astrophysics, said Clark's faith in the possibility of faster-than-light, or FTL, travel was "probably based more on his imagination than on physics."

www.wired.com...

Considering the post's Wesley Clark has held in military establishments so far i found this comment quite striking and the closest we will get to 'disclosure'.

Stellar.