Apparently time travel is possible. Let me exlain.?

Question

Atomic clocks left high in orbit around the earth have apparently slowed down. At such high speeds the clocks have been known to slow down. When brought back to Earth they are slower than they should be. Atomic clocks should remain accurate for millions of years. Also I've read that Astronauts living in space for a prolonged period of time are technically younger (I mean by fractions of millions of seconds but apparently this is true because of the massive speeds over such a long period). My question to you, is it true? I'm sorry if this sounds crazy but I read this recently and I was wondering if this is scientifically correct. Time travel has been asked about several times here and I'd like a professional opinion.

Your son is born in 2000. You are 20 years old. On that day you climb into a space craft and travel at 3/4 the speed of light for 20 years. After those 20 years you return to Earth at 40 years of age. Your son is also 40. I had physics friend explain this to me years ago. Is that really possible? I know my first question deals with ALOT less speed but the same principle applies, doesn't it?

Answer 1

I saw a lot of good answers out there that hit the answer pretty much on the head. I only wanted to point out one minor mistake in what you wrote (which you probably won't run into in most freshman courses in relativity). That the astronauts would actually be older than those who stayed on Earth. The special relativity people were explaining was correct. If you move => time slows down. The thing is that gravity has a greater effect in slowing down clocks and the gravitational field you experience in orbit is weaker than on the surface of the Earth (obviously it won't matter though if you are flying around space at speeds near the speed of light, then the special relativity part becomes dominant over the general relativity i.e. gravity).

Answer 2

This effect is well documented and evrything has been said about this that needs to be at this time. There is however another theory of the universe that allows for time travel, the supporting evidence for this theory is quite substantial. For example it starts to link together general relativity and quantum mechanics. The theory was arrived at back in 1951 by Burkhard Heim, the theory predicts a further 2 dimensions to Einsteins 4 and even goes so far as to surmise up to 12 dimensions.

There are many, many questions answered by this theory, including a few that didn't exist at the time of it's conception. It is a very radical theory and it would take too long to explain the supporting evidence. However a short list of things predicted by this theory:
Solves the energy distribution problem at conception of universe.
Unifies GRT and quantum mechanics, work in progress on this one.
Explains gravity and EM spectrum.
Predicts particle mass more accurately than quantum mechanics.
There is more evidence to support the theory and it even explains Zenos paradox, (Not much scientific importance but I thought it was interesting.)

So the implications of this theory are that by manipulating the 5th and 6th dimensions through the use of spinning electromagnetic rings, we can achieve super-luminal travel. This theory provides a basis for testing and as soon as the technology is available to produce strong enough magnets we will know one way or the other.

Should the theory be shown correct, it also predicts that time travel is possible. However the nature of time travel should be questioned, we have never seen future time travellers come back. I can envisage a situation for time travel as predicted by these theories whereby travelleing through time would require affecting different dimensions of the universe, however it cannot be clear whether it is possible to affect the dimensions we are currently aware of directly when we do travel in time.

Also how do we know history hasn't been re-written many times over, who says when we wake up tomorrow we won't all remember Robbie Williams having been President of the USA for the past few years. Paradox, AAAAAARRRRRGGGGGHHHHH!

Answer 3

No, because I believe time does not exist. Time does not exist because it is not constant all over the universe. For example, 24 hours of ours is a day, but in a large planet such Saturn 24 hours only equals to a fraction of a day. Experiments where scientists claim that time has slow down simply because clocks have slow down, are not correct. What's slowing down is the functioning of the apparatus, in this case a clock. What we actually have is what I call "space displacement" which is cause by movement which in return causes an event. All we have is movement and movement causes space to be displace and this displacement causes an event.

Answer 4

Your basic premise is right - as you reach speeds close to the speed of light, time doe's slow down (see Einsteins special theory or relitivity)

Basically, if you travelled at the speed of light to a distant planet 5 light years away (a light year being the distance travelled by light in a year - light travels at 300,000 Km per second) you would experience time slowing down to an almost full stop. This would make your journet seem to take almost no time at all. For an oberver watching from the Earth, they would have seen you blast off and reappear 10 years later (5 years there, 5 years back) So in effect, the traveller would have experienced a journey of minutes but the observer would have experienced a journey of 10 years.

All this is theoretical as light sped travel is impossible (at the moment) It also only relates to the slowing of time, mot the ability to travel to a specific point in time or to travel back in time.

There is a theory that if you were to travel faster than light to a point 200 light years away from earth and then look at the earth through a powerful telescope, you could witness the Battle of Trafalgar. This is based on the same basis as the light we see from distant stars is actually the light emited bythese stars hundreds of years ago - if a star is 100 light years away it will take 100 years for the light to travel from the star to your eyes making the light you see actually something from the past.

The real test of time travel is this - if it will ever be possible, why have we not met travellers from our future? Or have we????

Answer 5

Yes it is true. What you've read is correct. Atomic clocks and astronauts were affected by their motion in the ways you described.

Traveling close to the speed of light will slow down time noticeably (time dilation). However this is NOT time travel perse because it only allows the traveler to travel to the future (never the past) and it is a one-way trip.

So yes you can travel to the future to meet your son when you're both age 40.

Answer 6

Lets make it very simple. If you accelerate yourself to a significant fraction of the speed of light, then come back to visit, people on earth would have experienced 'more' time than you. This is the 'time travel' that is possible. However, you are not traveling in time. Time everywhere remained the same. It is just that time has a relationship to space. You are traveling on a manifold consisting of available paths in time and space.

Time travel, as in sci-fi, also has a serious problem. As conceived in numerous books and movies, you could jump to a different time. But think of the physics. The base velocity of the solar system is ~300 km/s. If you 'jumped' one minute ahead, you would also need to move 18,000 km in the same instant, as the earth would have gone that far in the minute you skipped. Space is very cold...

Answer 7

This is not time travel but the principal of relativity. Because the astronauts are orbiting the Earth at great speed they are moving through space faster than the people on the planet below. this puts them in a different frame of referance to those on the planet for the purposes of the universe. As they are travelling at higher speeds they seem to age more slowly to us ... but at the same rate to themselves. This is not time travel, but time dilation as it does not allow the astonauts to travel back and forth in time at all.

Time dilation did come under fire for a while due to the Twin Paradox but this was down to a bad assumption. To find out about this paradox and more about time dilation I'd recommend looking here:

http://en.wikipedia.org/wiki/Twin_paradox

Answer 8

yes this effect is know as time dilation when objects travel at different speeds they experiance differeing amounts of time, factor for time dilation = root of 1-v^2/c^2 where v is the speed of the object and c= is the speed of light, so if something is travelling 2x10^8ms-1 and the speed of light is 3x10^8 then this gives a factor of 75% this means that the person moving at this speed will experience 75% of the time comparred to a reletively still object. this remains the case at lower speeds althought the factor is much smaller. e.g closer to 100% both of these times is technically correct and there is no sense to give either of these times more significants than the other. however this is not really time travel its just more like experiencing differing amounts of time.

Answer 9

This is 100% true. The thing is, is that time feels the same for everyone everywhere. This comes out of Einstein's Special theory of relativity. The same theory that gives us E=mc^2. This theory is so well accepted that it is taught to undergraduates in college. What is being explained here is called time dialation and not time travel, as you do not travel anywhere in time. The math is not to hard either.

It all comes from the concept that the speed of light is constant from all observers and that all motion is relative. The relative amount of time difference for someone who is moving away from a "stationary reference is"

Elapsed time(moving) = Elapsed time(stationary) * 1 / sqrt (1 - v^2/c^2)

Answer 10

I have time shift on my DVB (Digital video broadcasting - freeview) - I can "go back in time" because it constantly records. Once back in time - or if I "make time stand still" I can go forward in time. Great for skipping advertising! Play with one of these - and it will maybe give you the idea that in the future virtual reality could work the same. Giving us a sort of time travel. Best I can do though. Your space theory has been put forward before - but has no practical application - not unless people from the future come a knocking!