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# Is Time Travel Possible? Paul Davies Says "Yes".

23 replies to this topic

### #1Scorbing

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Posted 04 January 2013 - 14:00

The article is from 2010, but it is very interesting.

http://news.discover...l-possible.html

### #2Astra.Xtreme

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Posted 04 January 2013 - 14:14

Nothing really new since this is just the basic principle of relativity. The faster you go, the more time accelerates.
I believe it's something on the lines of if you travel at the speed of light for one year, 7 years here on Earth would elapse.
So technically that would be time traveling forward with respect to Earth. The key part is the time dilation.

Traveling backwards in time, on the other hand, is physically impossible.

### #3nik louch

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Posted 04 January 2013 - 14:22

Quote

Nothing really new since this is just the basic principle of relativity. The faster you go, the more time accelerates.
I believe it's something on the lines of if you travel at the speed of light for one year, 7 years here on Earth would elapse.
So technically that would be time traveling forward with respect to Earth. The key part is the time dilation.

Traveling backwards in time, on the other hand, is physically impossible.

I know very little on this, so bear with me...

What you say is the faster you travel, the faster time passes?

So the slower you travel the slower is passes? But that's not true, surely?

### #4Hum

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Posted 04 January 2013 - 14:25

May I say, DUH !

### #5Intrinsica

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Posted 04 January 2013 - 14:28

Astra.Xtreme, on 04 January 2013 - 14:14, said:

Nothing really new since this is just the basic principle of relativity. The faster you go, the more time accelerates.
I believe it's something on the lines of if you travel at the speed of light for one year, 7 years here on Earth would elapse.
So technically that would be time traveling forward with respect to Earth. The key part is the time dilation.

Traveling backwards in time, on the other hand, is physically impossible.
I agree with the first part, there's nothing particularly new in this article as we've known about the theory of relativity for a long time, and with it we've known and tested the time dilation effect.

However, the article points out that there is a possibility of traveling back in time by using wormholes. The only problem is that we can only speculate about the idea, which is as good as saying, "it's not yet possible." Even if wormholes were a portal for time traveling to the past, we've got no way to manipulate it so that it would send us back to a specific time. We'd just have to accept where the wormhole's end point in time is.

nik louch, on 04 January 2013 - 14:22, said:

I know very little on this, so bear with me...

What you say is the faster you travel, the faster time passes?

So the slower you travel the slower is passes? But that's not true, surely?
No. The theory of relativity states that the closer you get to the speed of light, the slower time passes for you. As the article points out, if you were on a train that got to 99% of the speed of light, you would perceive time as passing at a normal rate, but what is happening is that the time is passing slower on the train than it is for the people at the train station.

### #6+Crisp

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Posted 04 January 2013 - 14:30

Astra.Xtreme, on 04 January 2013 - 14:14, said:

Traveling backwards in time, on the other hand, is physically impossible.

Just because something seems impossible doesn't make it so.
I'm not saying I can prove you wrong, but in 1896 the Wright brothers would of thought it was "impossible" to put man in Space, let alone cross the Atlantic ocean.

### #7watkinsx2

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Posted 04 January 2013 - 14:31

nik louch, on 04 January 2013 - 14:22, said:

I know very little on this, so bear with me...

What you say is the faster you travel, the faster time passes?

So the slower you travel the slower is passes? But that's not true, surely?

No, basically the passage of time will be different for the person travelling close to the speed of light relative to someone standing still on earth, this is time dilation. So if you traveled around the earth at such speeds, for you only a week will have passed, but for everyone moving at relatively much lower speeds around you more time will have passed. The theory is that the closer you get to the speed of light the greater the effect.

edit: spent so long typing, someone beat me to it!

### #8XerXis

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Posted 04 January 2013 - 14:42

If you want to know more about spacetime, Brian Cox has a nice book that explains it in an easy to understand language.

The fun thing is, not only time changes if you go faster, but also space itself. For example, a lot of people think that travelling to a star that is 5 million lightyear away would take you more than 5 million years if you travel at 99% of the speed light, while in fact it would only take you a few hundred years. Very interesting stuff physics

### #9+Jdawg683

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Posted 04 January 2013 - 14:59

i just traveled back in time to read that article. good read.

### #10neufuse

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Posted 04 January 2013 - 15:24

send a message wirelessly around the world in under a 100th of a second is physically impossible...... oh wait we do that now... who knows what the future brings, to say something is impossible means you already gave up trying for new inventions...

### #11Astra.Xtreme

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Posted 04 January 2013 - 16:07

nik louch, on 04 January 2013 - 14:22, said:

I know very little on this, so bear with me...

What you say is the faster you travel, the faster time passes?

So the slower you travel the slower is passes? But that's not true, surely?

It's kind of an abstract idea, and it gets confusing pretty easily, but the time differential is only measurable when comparing two objects. For instance, if you are in a spaceship traveling at the speed of light away from Earth and then come back, the clock in your spaceship would he ahead of the time on a clock here on Earth. So depending on how you look at it, either time sped up in the spaceship, or time slowed down on Earth. It all comes down to reference.

Another example is that an astronaut in space will age slightly less while in space than people back on Earth. That's due to being further from the center of the Earth and essentially moving at a faster velocity than people on Earth. Gravity may have an effect too. That's pretty much "time dilation" in a nutshell.

### #12Hum

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Posted 04 January 2013 - 23:02

Astra.Xtreme, on 04 January 2013 - 14:14, said:

Traveling backwards in time, on the other hand, is physically impossible.

Why do you say that ?

Time, as it is usually thought of, is an illusion.

Many of the 'Alien' craft encountered, are in fact, from Earth's 'future'.

### #13+chconline

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Posted 04 January 2013 - 23:10

I don't think backwards time travel is possible. Forward, theoretically yes (Just basic relativity). if in an infinite amount of time from now that backwards time travel is possible, there should be evidence in the past of people from the future coming back. However, there is no evidence of it.

### #14Northgrove

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Posted 04 January 2013 - 23:14

Time travel in the sense that some objects travel slower in time than us happens all the time. GPS satellites regularly need their times corrected because they experience relativistic effects, and we want high accuracy from their clocks. Their clocks simply run slower than ours, but not because they are faulty!

If we didn't regularly correct for the GPS satellites travelling slower in time, the end result would be that navigational errors would accumulate with 10 km per day!

You can also read more on time dilation in general here: http://en.wikipedia....i/Time_dilation

So, in an extreme case, yes, it's both possible and proven that a person can in theory travel very fast around the Earth for a long time and age just 1 year while the entire Earth becomes 100 years older. His friends and relatives would be dead at the time he exits his spacecraft. In practice, though, the energy requirements for this would be absolutely immense and not really workable in any way we can understand today.

### #15Detection

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Posted 04 January 2013 - 23:18

I only have one thing to say: Prove it