I mean, if you were on a spaceship moving at the speed of light, headed for the next star which is 4 light years away, would you arrive, having spent four years on your spaceship, or would the rest of the universe have aged 4 years, while it only took 4 months or so for you?\n\nWhich party observes the slower time is what I'm getting at?
129126
Neither Observer EXPERIENCES a change. The ONLY way any comparison can be made between the two unmentioned but essential clocks is to bring them together in the same rest frame again: then whichever clock ticktocked the least would be shown to be the one which accelerated and slowed down in their relative travel.
663877
Yes, in a way, looking at distant objects in our universe is like looking back in time.\nThe farther away we look, the older the image we are seeing is.\nAs fast as light travels, it still only travels at a finite speed and takes time to cross the VAST distances of interstellar (or even intergalactic) space.\nThings we wee in the sky could be billions of years old, we could be watching the formation of a new star (or for that matter, be receiving transmissions from an alien life form) that has since died long ago.
3404
O.K here is how it can happen. suppose u have a powerful torch whose light can travel through galaxy.u lit towards a star that is 10 lightyears away from u.u did this on 1-1-1980.\n Now on 1-1-89 u get onto ur spacecraft and reached that star on 1-1-1990 and found a light blinked onthe earth.u get an event that has ocurred in the past.
211982
Greetings,\n\nKinda outta my league, but perhaps the link I posted can be of some use to you.\n\nDiscover had an article last year about a couple of inflation cosmology theorists who believed the speed of light, while constant now, was not constant in the very early universe, it was in fact slower.  Not sure about all that, but thought you might want to go digging for the article.\n\n-matt
53202
I believe that warp speed is supposed to be significantly faster than the speed of light (given that they sometimes consider three light years a minor detour), and it's not possible to go faster than the speed of light.  The concept of manipulating space in such a way that they can essentially create worm holes it less unrealistic, but is still purely science fiction.
600608
Moving faster than light isn't really the real issue for space travel as traveling AT the speed of light solves all the distance problems(unless you are interested in time travel!). Of course that in itself is a big challenge. If one could demass the vehicle then surely one could achieve the speed of light!!! Afterall photons do travel at this speed.\nBut we would do very well even with speeds like .99999c because time dilation will reduce the time required drastically. Have the science, just need the technology!
211559
In theory, the faster you move, the slower time advances for you. If you were to move at a speed approaching the speed of light, you could slow time enough that you could "travel" forward. It isn't really time travel, but whatever works...\n\nAs far as I know, traveling backwards definitely is not possible; time is a construct, something that only exists in one's mind. It is really a rate of change; the change can only occur in the positive direction, so traveling backwards is out.
21104
As you travel faster and faster, time for you slows down, and length contracts. From your point of view, when you measure the speed of light, it will always be the same. An observer standing still with respect to you and the beam of light could measure your speed at 185000 mps and the speed of light as 186000 mps, and say the difference in speed is 1000 mps. But that is relative to them. The speed of light will always be the same for whoever measures it, no matter how fast they are moving.\n\nSee the website below for more about relativity.
312536
*sighs* Why can't people do any research on their own? Anyway... you are traveling through time right now, how else did you push those keys in sequence to form your question?\n\nI think that what you are attempting to refer to (lol I'm never gonna get a best answer replying like this) Is that as you travel faster and faster, closer and closer to the speed of light, time flow for you slows down, and the misconception of the public that if you go faster than light you will reverse time. WRONG!\n\nThat's not specifically what you asked though, so I will focus on teh misconceptions regarding the speed of light. First of all, accelerating mass to the speed of light is impossible as it would require an infinite amount of energy, so your question is meaningless. Second, since your question is meaningless tehre is nothing more to say except maybe a supporting and enlightening example. Third, I do not feel creative tonight so that example is gonna have to pass tis time, unless you email me and I will explain it better.\n\ndavid_lapierre@sbcglobal.net\n\nUnless this is just a school project, which I doubt since they are going donw the drain is sciences these days... you might wanna ask me a question, I can be very helpful when I know my time is not going to be wasted on a person who won't bother to take a few minutes to learn something... :-)
5754
There is this wonderful little thing called a "Rest mass", and should something have an imaginary rest mass (i.e. tachyons) its lowest speed possible is the speed of light.  However, this is one wacky hypothetical construct that has no proof nor anything to disprove it.\n\nAlso, the spacetime continuum itself can move faster than the speed of light; it has happened before, less than a second after the big bang.  This wonderful thing called inflation happened, and spacetime grew obscenely fast.  This is also why spacetime is mostly flat.
16024
It is definitely possible. However, we do not have the technology needed to reach the kind of speeds necessary to allow for travel to other solar systems, stars, etc. Here's something to consider, though. Einsteins Laws of Relativity, while not allowing travel at full light speed, do allow travel almost up to (and just short of) light speed. As you go closer to light speed, the traveler's clock would "slow down" as compared to an observer's clock on a "stationary" object. If you got close enough to light speed, you could travel across the galaxy (100,000 light years wide) in what might seem minutes or hours to you, and about 100,000 years to me. Great, great stuff. To learn more about this concept, google "twins paradox". Or go to http://media.nasaexplores.com/lessons/02-060/9-12_2.pdf and scroll down to page three. This will explain it more fully to you.
4921
Some distant galaxies appear to be accelerating away from us, not just moving at a uniform speed. \n\nAnd the most distant galaxies are probably expanding away from us at more than the speed of light. This does not violate the special theory since no information is being transferred (see reference).
358489
I dont think time travel is possible! Even if you were to go faster than the speed of light, it still takes time to get to where you are going. And that brings up another question, where do you go?? Do you zoom around the planet a few million times? Which direction? Does it matter, it still takes TIME to do it.\n\nJust for argument sake, lets say you could go back (or forward) in time. I dont know why you couldnt be seen, you just traveled to a different time and when you get there your there, just as if you were to travel to a different city.
615399
I remember Carl Sagan talking about this on one of his appearances on the Johnny Carson Show.  \nBecause the speed of light is always a constant to any observer, the information would still be reaching you at the speed of light.  Now, based on spatial compression and time dilation on your part possibly you would receive more than one of earth's second's worth of information in the time it takes one of your ship's seconds to elapse. But, bear in mind depending upon how close you got, you would need to slow down so as not to impact ar go by and be going away from earth, so you would eventually come back into synch with earth's space-time frame of reference.
40823
First of all, travelling at the speed of light is not possible, so don't even dream about travelling faster than it.\n\nBut, if it were theoretically possible, then no, you wouldn't be able to see the star reappear again. This is because light travels at the speed of light relative to everything. So when you're travelling billions of times faster than the speed of light, the light from the star will still be travelling away from you at the speed of light, so you can never catch up to it.
450654
well there r lot of major scienctists nowday ... working on it... for myself i do belive that time travels faster than light because we are living in alternate dimension.. inside vortex of time, we can be frozen in time and still time moves past us,the light travels is pretty slow.. when we look up in sky ans there r stars and next day same place, for about 3 days later it will be moved bit forward.. and that star is probably dead or giant black hole.. think about it
109682
The two key elements in this question are that the speed of the spacecraft is constant, and that you are at rest relative to the spacecraft.  In this situation, you will observe the beam of light moving forward and hitting the object just the same as if you were sitting in your living room.  This is in accordance with Einstein's Special Theory of Relativity.\n\nHowever, if the spacecraft were accelerating instead of moving at a constant speed, the same might not be true. As long as the spacecraft continues to accelerate, even at speeds below the speed of light, it is possible to set up a scenario in which the spaceship stays ahead of the beam of light forever!  This is in accordance with Einstein's General Theory of Relativity, which considers the effects of acceleration and gravity on light.