According to this article:
http://news.yahoo.com/s/livescience/20070309/sc_livescience/youcanttravelbackintimescientistssay;_ylt=AiyMyULk2M5M2TYpU7yADMMDW7oF
It says: "Build a spaceship. Go near the speed of light for a length of time—that I could calculate. Come back to Earth, and when you step out of your ship you will have aged perhaps one year while the Earth would have aged one million years. You would have traveled to Earth’s future.”
Is this possible? Has anyone done it before? Because if they did, they wouldn't be able to come back to our present, so we wouldn't know they did it in the first place....
What do you think?
2007-03-13 05:24:42 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Zoweee! What a bunch of different answers and opinions. That's the problem with trying to find out something on Yahoo!Answers. Unless you already know the answer, it can be difficult to figure out which of the answers is clued in and which is clued out.
That's why if you really need to know something, it's best to ask your teacher, or go to the library, or at the very least try an internet search.
AZ imagined is mistaken, and inappropriately opinionated. Same goes for the couple of other answerers who proposed that Einstein is wrong. So far, it appears that the real meaning of the statement "Einstein is wrong" is actually, "I don't understand Einstein," or "I don't want to do my homework."
So here: The mathematical relationship called "time dilation," which states that time appears to pass more slowly on a local level as the local frame of reference approaches the speed of light relative to some larger frame of reference, DOES appear to be valid, based on examinations of its mathematical orthogonality.
That is, it is true, as far as science can tell, that time dilates at very, very high velocities. We may be able to test the notion of time dilation within the next couple of hundred years, using particle accelerator technologies now under development.
The problem with the "build a space ship and fly off at 95 percent of the speed of light for a few years" idea is that it is not possible in practical terms to go that fast. The amount of energy needed to accellerate even a tiny space capsule to .95C would be thousands of times the amount of energy produced by the sun.
At today's gasoline prices, it's just not practical.
But that doesn't mean we can't have fun. Get out some!
And, see? I gave you some great vocabulary words, and showed you that you can do an internet search on "time dilation," and find out all kinds of neat stuff for yourself.
2007-03-13 14:42:12 · answer #1 · answered by aviophage 7 · 1⤊ 0⤋
According to the theory of relativity, it is possible. No no one has ever done it. They wouldn't have had time to do it yet. The farthest any human has gone is the Moon, a mere quarter million miles. But if they did do it, it's true, the world they returned to would be a different one, and they would definitely know it. It's not really "time travel", just a change in the experience of time passing.
To go a significant fraction of the speed of light takes a long, steady acceleration, and a lot of fuel, half of which will be needed to decelerate at the other end of your voyage. (And that's before you figure out how to come back.) To go even to the nearest star (4.3 light years away) would take many years even from the traveller's point of view, but it would be even longer from the point of view of an outside observer.
Time slows down in proportion to speed. We've never gone fast enough to make a noticeable difference, a few microseconds at most, but if we were to send people on a ship that spent some time at some significant fraction of light speed, say a tenth or a quarter, the difference would become obvious by the time we made contact with them again.
A million years difference is not likely, just because so much time and fuel would be taken speeding up and slowing back down, but a difference of, say, 10 to 1 is very possible. The travellers could survive easily, but most of the people they knew back home would have died in the meantime.
As I said, it's not really time travel. Objectively, the "real" time is kept by the folks back home. The travellers, if they could, would see the universe speeding up around them because their time slows down. So it only seems like they've travelled to the future. In fact, they've been in slow mode during the journey.
2007-03-13 05:50:46 · answer #2 · answered by skepsis 7 · 1⤊ 0⤋
No, it's not possible.
Everyone seems to worship at the altar of Einstein when it comes to time travel...but the man is either misinterpreted or was simply wrong. Time travel is impossible.
Laypeople always overlook the "relative" part of the theory of relativity. What Einstein decribes is what one observer would see compared to what another observer would see. It's complicated, but that doesn't mean you see what is REALLY happening. It is your view of reality that is distorted by relativistic effects.
If you take such a journey as you describe, when you return to Earth, exactly the amount of time you experienced will have passed. You will not have traveled into the future nor the past...though at various points along the way it may appear that you had.
Misinterpretations of the theory can make for great science fiction but the bottom line is that time travel is impossible.
2007-03-13 05:47:37 · answer #3 · answered by Anonymous · 1⤊ 1⤋
Einstein theorised that time decreases with velocity. The faster you travel the more time slows down compared to another person who is stationary.
The problem is that the closer you get to the speed of light the more the mass of the spaceship increases (E=mc^2 where energy equals mass multiplied by the speed of light squared). Thus more energy is required to move the spaceship. At the speed of light an infinite amount of energy is required which is impossible.
When you start off - at zero speed (0% of speed of light) your time is just regular. As you speed up your time runs slower . As you are approaching 100% of the speed of light your time slows more and more until it is infinitely slowed down. (You should realize that everything slows down including your heart beats, your thoughts, etc.) So for an example if your ship goes at 98% of the speed of light and you take a one year journey, when you return to Earth five years have gone by.
Mind boggling is it not?
2007-03-13 05:44:06 · answer #4 · answered by Spite.Fu 2 · 1⤊ 0⤋
In theory, it is possible. It's a result of Einstein's theory of special relativity, that clocks run slower in moving reference frames (and hence you age slower when you are moving). The effects are only noticable at speeds that a are a significant fraction of the speed of light. It hasn't been done before (as far as anybody knows) because attaining such speeds is impossible with the technology we have now.
2007-03-13 05:34:58 · answer #5 · answered by G M 2 · 1⤊ 0⤋
Yes in theory it would work. The only difficulty is going near the speed of light for a period of time. There's no technology even close to doing that.
2007-03-13 05:31:45 · answer #6 · answered by Gene 7 · 1⤊ 0⤋
According to Albert Einstein it's possible. Nobody has ever done this because we don't have the technology(yet) to achieve such high rates of speed.
2007-03-13 05:37:36 · answer #7 · answered by Tim C 4 · 0⤊ 0⤋
No.
No.
No.
Merely a theory. Not possible now or in the near future.
Einstein was wrong.
2007-03-13 07:05:54 · answer #8 · answered by Anonymous · 0⤊ 1⤋