speed of light,blackholes,timetravel,etc

[tpeezy]

ok here is another one of my silly questions so please dont flame me too bad. I know this is probably impossible but please try and bear with me. What if somehow maybe a little past the moon, we could make a black hole that is just large enough to make our ship rotate around it at the speed of light, but not destroy the solar system or earth. I know currently its impossible to do this, and im not even sure you can rotate around one that fast without getting sucked in, but please stay with me here, Im only using the black hole here so they can go the speed of light any way would work that keeps them near earth. and while we were going the speed of light, lets say we orbited for 200years earth time, I dunno how much time would have passed inside of the ship, but not very much. Would Nasa or whoever is talking to the crew be able to talk to the people in the ship while they are going lightspeed, so close to the earth? If so how can time be different for the people on the ship, and people on earth but how could they still talk if time was moving that far appart? Also when going the speed of light time on earth would have passed 200 years, and for the crew lets say 5years. Would their bodys age with the earth time or the real time in the space ship? It just seems like if u were going that fast your mind would still be working and time length would feel the same to you as it would on earth. If someone could look inside of the ship would you be moving in slow motion or something? Sorry if this is all hard to understand since its alot of different questions I just wanted to better understand the effects of light speed. Thanks and please keep an open mind and dont flame me to death lol

 

[SteveCNC]

the problem here is mass can never achieve light speed in normal space which is what you appear to want . The only way we will ever be able to achieve faster than light is if we can alter the space around us which right now is not possible however I can hope that some day it will happen . Too bad I will be long gone by the time that day comes . But if I were guessing I would say maybe in 200-500 years or so , assuming we haven't killed ourselves before that .

 

[tpeezy]

yah I know its prolly not possible in this lifetime, but what about my other questions? Like if it was possible, would they still age like on earth time, would they be able to communicate, and would they feel the time slow down? All of the other questions I asked in my first post?

 

[SteveCNC]

Lets see if I can explain , if you were to move a ship near the speed of light there would be a significant time dilation but in that case time is relevant . But the ship could never get to light speed no matter what because of the infinite amount of energy it would take to move it that fast in normal space . So even with the time dilation the ship never goes backwards in time but the people in the ship that's approaching light speed would experience a different time span relative to those on earth . The people on the ship might experience 1 year to earths 5 , exact numbers would depend on a few factors I couldn't explain if I knew . If the people on earth could observe the people on the ship they would seem like they were moving in slow motion . And conversly if the people on the ship could observe the people on earth they would seem to be moving very fast . But to each other everything seems normal.

If you were able to get a mass moving the speed of light (you have an infinite amount of energy) the mass itself would have to convert to energy if I understand physics right and once you convert it to energy I am thinking getting it back into recognizable mass would be beyond impossible .

As I mentioned before , it may be possible to alter the local space making it possible to move beyond light speed , although I am having serious doubts about time travel even under those circumstances , but that's several generations away .

 

[tpeezy]

Could the ship, and the earth based people communicate?? Lets say the ship is only 2 lightseconds away from the earth and its going the speed of light in a circle. Would they be able to talk to the people on earth? This is whats been bothering me is because the time would be different so what would the communication be like. I know like I said all this is probably impossible and if possible some time in the future, but just play along and act like all this could happen. How would they be able to talk if they are moving in light speed thus slowing time. Also lets say that they are not moving away from the earth when delivering this message.

 

[SteveCNC]

If they could actually achieve light speed I don't believe communication would be possible any longer since they are moving at the same speed as the signal there wouldn't be a detectable wave to pick up information from . However if they were just under light speed but still in a large time dilation they should be able to communicate though the decifering of the signal would be interesting . it would have severe red and blue shifts which might make it difficult to pull in and read but it should be possible , it just wouldn't exactly be in real time .

 

[csmyth3025]

the problem here is mass can never achieve light speed in normal space which is what you appear to want . The only way we will ever be able to achieve faster than light is if we can alter the space around us which right now is not possible however I can hope that some day it will happen . Too bad I will be long gone by the time that day comes . But if I were guessing I would say maybe in 200-500 years or so , assuming we haven't killed ourselves before that .

I'm not sure what you mean by "normal space". As far as I know the space between us and the most distant galaxies we can observe is normal. These distant galaxies are not only receding at the speed of light, they're receding (now) at speeds greater than the speed of light. The only reason we can see them at all is that they were receding from us at less than the speed of light some 12.88 Bly ago when they emitted the light we are now able to see.*

I know that this velocity is attributed to the expansion of the universe. I have difficulty reconciling this concept with the idea that it takes an infinite amount of energy to accelerate any massive particle or object to the speed of light.

* This statement seems to be in error. According to a paper by Davis and Lineweaver, some of these galaxies have always been receding from us at speeds greater than c. Their paper can be found here:

http://arxiv.org/PS_cache/astro-ph/pdf/ ... 1070v2.pdf

Chris