weird space travel fact

[turbotim]

I might be wrong, but did you guys know if we flew a space ship to jupiter and fly around it as fast as we can for 1 year, and then come back to earth, we would be in the future!

[Capricorn]

If we sat here on earth doing nothing for a year watching telly we would also be in the future. One year in the future to be exact.

I am about 30 seconds in the future from when I started typing this.

Me thinks you need to supply more detail.

[Red Alert]

Has someone read The Forever War

[tobot]

yes i love the forever war and its sequels

[southernman]

The Forever War is a classic sci-fi book. Are any of the sequals as good ??

[brantuk]

The astronauts who walked on the moon all came back a few minutes younger as I recall. Or it could have been a few seconds lol

[yeti monster]

it's all relative...

[Dave S]

The astronauts who walked on the moon all came back a few minutes younger as I recall. Or it could have been a few seconds lol

A few seconds less older than us on earth beacuse they were travelling faster relative to us.

Same principal that applies to gps satellites. their internal clocks have to be set to compensate for the fact that at the speed they travel at time for them runs slower.

Dave...

[bcsman]

I might be wrong, but did you guys know if we flew a space ship to jupiter and fly around it as fast as we can for 1 year, and then come back to earth, we would be in the future!

i once listened to zeppelin's stairway to heaven backwards,i clearly heard a recipe for tomato and basil soup and a magic formula to turning dog s**t into toothpaste.

[Dave S]

and a magic formula to turning dog s**t into toothpaste.

Do you still have many friends?

Dave...

[Wurzil]

Ive always liked this story by Robert Heinlein. Its an enjoyable read and gives a good example of time dilation.

Time for the Stars - Wikipedia, the free encyclopedia

W

[RobH]

i once listened to zeppelin's stairway to heaven backwards,i clearly heard a recipe for tomato and basil soup and a magic formula to turning dog s**t into toothpaste.

Brilliant :D:D

[DrNeb]

A few seconds less older than us on earth beacuse they were travelling faster relative to us.

Same principal that applies to gps satellites. their internal clocks have to be set to compensate for the fact that at the speed they travel at time for them runs slower.

Dave...

i am usually quite good at grasping these sort of concepts... but this one has span my head..

Still don't get it.

[brantuk]

I wish Einstein could explain why commuting to London allways made me feel ten years older at the end of each week lol

[dmahon]

Excluding the very minor gravitation effects of Jupiter's mass, I thought that the time dilation was due to relative speed - if so, going round and round Jupiter (no matter how fast the angular velocity) won't have much effect with regard to an observer on Earth which remains in the same solar system.

Anyway - perhaps someone can explain this to me. I'll take a quote from Wikipedia, as this is the only place where it forgets to state that everything is relative:

Time dilation would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. That is, the ship's clock (and according to relativity, any human travelling with it) shows less elapsed time than the clocks of observers on Earth. For sufficiently high speeds the effect is dramatic. For example, one year of travel might correspond to ten years at home. Indeed, a constant 1 g acceleration would permit humans to travel as far as light has been able to travel since the big bang (some 13.7 billion light years) in one human lifetime. The space travellers could return to Earth billions of years in the future. A scenario based on this idea was presented in the novel Planet of the Apes by Pierre Boulle.

As everything is relative, which one is actually moving? Why wouldn't it be the Earth returning to the space craft billions of years in the future (ie the space craft is really old and time on Earth has hardly changed)?

Wouldn't [their] time just appear to pass slowly as something moves away from you at high speed, but if it moved towards you, it [their time] would appear to pass faster (doppler type effect)?

[Ronseal]

Did anyone see Stephen Hawkins series recently, I remember the last 2 hr (!) episode being all about this.

Time was stated as being the 4th dimension, and gravity has an effect on it slowing it down - hence the satellites clocks are faster or indeed putting a nuclear clock on a plane & a synchronised one on the runway, fly off then return & the clock on the plane is faster by billionths of a second.

He made several examples - satellites around earth, flying around the blackhole at the centre of our galaxy, travelling on a train around the earth at near the speed of light (7 times a second!) of which 1 week on the train equated to 100 years on the planet.....

Anyway, thats a bit deep, any more hidden messages in songs being played backwards??

[ollypenrice]

I might be wrong, but did you guys know if we flew a space ship to jupiter and fly around it as fast as we can for 1 year, and then come back to earth, we would be in the future!

Whose future? Not yours. You would be in your own present, but you would be in the future of those who had stayed at home.

This is routinely measured. Take 2 atomic clocks, put one in an accellerated environment (speed up, turn round, slow down) and it now runs slow by comparison with its partner clock.

There is the real and the false twins paradox. Two twins, one goes off into space to a distant star, comes back and finds him/herself younger than the home twin. That is the false paradox. The real paradox is why? In special relativity it is impossible to say that one twin was moving and one was not, since movement is relative. So if movement is relative, which twin should be younger than which? Paradox!!

It is resolved by general relativity which notes that the one who went off for a fly was accellerated by taking off, by turning and by slowing down to land again, so that one is the 'young' one.

Confused? Me too!!

Olly

[RobH]

Dmahon,

It's the speed of light which is the constant, everything else is relative to it.

You might think that, 'OK, if light travels at 186,282 miles per second, surely if I'm in my car going down the road at 50mph and I switch my lights on, then the light coming out of them will be going 186,000miles per second, plus 50mph.

Not so.

The light, if measured by you travelling at 50mph, will be travelling at 186,000 miles per second.

You and the car are in the same frame of reference.

If a person standing by the road, (who is in a different frame of reference because they are not travelling with you and the car), measures the speed of light from your headlights as you go past, it will be travelling at 186,000 miles per second for them too!

This is what relativity is about…. the speed of light is the only constant in the universe, and, in order for it to stay the same from all frames of reference, everything else must change around it, including time and space.

This gives rise to the time dilation effects that the OP has heard about.

It's all very odd and counterintuitive, but well proven.

Cheers

Rob

[James4]

I was recently trying to figure out by what factor does time slow down and at what speed? As Rob says 'time is the only constant'. As a result of this the answer is, if you travel at half the speed of light, time slows down to half normal time for you the traveller. If you could travel at the speed of light time would stop completely for you. However, because of problems with infinite mass, etc, etc, (I use etc, etc, to pretend I know lots more reasons, that really I don't - it always worked in exams!) you can't ever travel that fast - But! Photons do all the time. In fact its the only speed they can travel at. We often say to the public, 'just imagine, the light from Andromeda has taken 2.5 million years to travel to your eye'. And that's true, but it was only 2.5 million years on our watches. For the photon it took no time at all. It arrived here instantly - it's clock is still at 12.00 noon, the same instant that it left. The photon experiences no time passing and it travels anywhere instantly. What fun!

[Zapp]

A simple explanation I once heard, which helped to get my head around it a bit, was that it makes perfect sense for time and space dimensions to be related, after all, if you arrange to meet someone you have to specify a time and place

Sent from my HTC Desire using Tapatalk

[ollypenrice]

I was recently trying to figure out by what factor does time slow down and at what speed? As Rob says 'time is the only constant'. As a result of this the answer is, if you travel at half the speed of light, time slows down to half normal time for you the traveller. If you could travel at the speed of light time would stop completely for you. However, because of problems with infinite mass, etc, etc, (I use etc, etc, to pretend I know lots more reasons, that really I don't - it always worked in exams!) you can't ever travel that fast - But! Photons do all the time. In fact its the only speed they can travel at. We often say to the public, 'just imagine, the light from Andromeda has taken 2.5 million years to travel to your eye'. And that's true, but it was only 2.5 million years on our watches. For the photon it took no time at all. It arrived here instantly - it's clock is still at 12.00 noon, the same instant that it left. The photon experiences no time passing and it travels anywhere instantly. What fun!

The speed of light does vary dependng on the medium through which it is passing. This is quite important in making lenses work!

Olly

[Earl]

The speed of light through all this damn cloud might as well not exist !!!

How are you finding it olly.... actually i probably and other don't really want to know as well will probably cry

[ollypenrice]

The speed of light through all this damn cloud might as well not exist !!!

How are you finding it olly.... actually i probably and other don't really want to know as well will probably cry

It is mixed here. In the last couple of weeks we have had six good ones and one fake which was last night. I merrily got 4.5 hours on Orion thinking all was well but, when stacked, there were haloes due to high haze. Since the image is for a mosaic it is a scrapper. Oh well.

Sun has been good though, lots going on.

Back on the S of L, there is some evidence of instantaneous communication as in the entangled photons experiment and the research of Alain Aspect here in France. Very strange and murky...

Olly

[Zakalwe]

A few seconds less older than us on earth beacuse they were travelling faster relative to us.

Same principal that applies to gps satellites. their internal clocks have to be set to compensate for the fact that at the speed they travel at time for them runs slower.

Dave...

Hmm:icon_scratch:...IIRC their internal clocks run at a slightly different rate because they are further out of the Earth's gravity well due to gravitational time dilation, rather than due to the relative speed of the satellite.

Relative time runs at a different rate inside a gravity well in comparison to relative time outside the gravity well. An extreme example is that time will "stretch" as you approach the event horizon of a black hole, and will eventually stretch to the infinite as you cross the E.H.

[markophoto]

Dmahon,

It's the speed of light which is the constant, everything else is relative to it.

You might think that, 'OK, if light travels at 186,282 miles per second, surely if I'm in my car going down the road at 50mph and I switch my lights on, then the light coming out of them will be going 186,000miles per second, plus 50mph.

Not so.

The light, if measured by you travelling at 50mph, will be travelling at 186,000 miles per second.

You and the car are in the same frame of reference.

If a person standing by the road, (who is in a different frame of reference because they are not travelling with you and the car), measures the speed of light from your headlights as you go past, it will be travelling at 186,000 miles per second for them too!

This is what relativity is about…. the speed of light is the only constant in the universe, and, in order for it to stay the same from all frames of reference, everything else must change around it, including time and space.

This gives rise to the time dilation effects that the OP has heard about.

It's all very odd and counterintuitive, but well proven.

Cheers

Rob

Rob - excellent example - well explained