Can Time Go Backwards?

[uscfanhawaii]

How would you like to time travel with Scarlett J.

The Time Machine, 2002, went back in time, then went WAY WAY into the future. It addressed a lot of the possible outcomes. In the end (spoiler alert!), he decided to stay in the future, which was actually an alternate remake of the past! Good brain food. :scratchchin: :smashfreakB: :boggled:

PS: a clip of The Time Machine can be accessed at the end of the Lucy clip.

 

[clester]

This may sound silly, but are you saying that any "time travel" would likely not extend life, so it may take generations to "travel" to new [actually old, in the past] worlds, in the "Star Trek" sense.

I think I messed up the video post, but the link is there to Superman.

Time Dilation and length contraction (Lorentz factor) come into play since the speed of light is constant. see Time Dilation and Length Contraction for a good explanation. It only really matters at very close to the speed of light or around massive gravity.

The thing is that its all about relativity. Meaning its all relative to which frame of reference you are in. If you're in the space ship everything appears normal inside the ship. Your clock ticks the same and the spaceships length doesn't change. But here on earth the ship appears to shorten and the ships clock will tick slower than the one here on earth. So, depending on the speed, if the ship is gone a year according to you on the earth and the ship travels near the speed of light the person on the ships clock will say he was only gone for say a month. He has gone into the future by 1 year and only aged 1 month.

But, this is the easy part. Of course we can't go fast enough yet to experience this. The hard part is backward time travel. No one's figured out if it can work.

 

[userque]

One can argue, and some do, that matter/energy is conserved.

The total amount of matter/energy remains the same, whether or not folks bounce around in time.

One problem I see is the law of the conservatation of matter( or energy). Einstein found that matter is energy as in E = mc^2.

If you were to travel to the past then your matter is added to the existing matter in the universe in the past and subtracted from the present. This causes an imbalance. So something would have to happen to equalize it. Like swapping equal matter or energy between times. You would cause something (energy or matter) in the past to swap places with you.

 

[dougscott]

...

But, this is the easy part. Of course we can't go fast enough yet to experience this. The hard part is backward time travel. No one's figured out if it can work.

Thanks ... but when we look through the telescope aren't we looking back into time, since the light is traveling toward us? Or are you talking (in the quote above) about going backward in time here on earth? Sorry for more questions ... this has always been an interest to me.

 

[clester]

Thanks ... but when we look through the telescope aren't we looking back into time, since the light is traveling toward us? Or are you talking (in the quote above) about going backward in time here on earth? Sorry for more questions ... this has always been an interest to me.

No problem. I love talking this stuff.

Yes for looking through telescope. Say you see alpha centari 5 light years away. So it takes 5 years for light to get here. So We see 5 year old light.

What I'm talking about is having a time machine to go into past here or wherever you are at that time.

 

[konakathy]

No problem. I love talking this stuff.

We can feel your enthusiasm from reading your answers. I find the whole subject very interesting and appreciate all the feedback from everyone.

A picture of "little clester" working on his first science project.

 

[konakathy]

Another perspective on time travel. I have always been a fan of Dr. Mitchio Kaku, he has a way of explaining the most difficult concepts of science so that a layperson can appreciate and understand the subject. I first heard him on a radio show (coast to coast am) over 20 years ago and still listen to the shows he appears on. He's a very interesting and funny man.

The Physics of Time Travel : Explorations in Science :: Official Website of Dr. Michio Kaku

 

[clester]

Another perspective on time travel. I have always been a fan of Dr. Mitchio Kaku, he has a way of explaining the most difficult concepts of science so that a layperson can appreciate and understand the subject. I first heard him on a radio show (coast to coast am) over 20 years ago and still listen to the shows he appears on. He's a very interesting and funny man.

The Physics of Time Travel : Explorations in Science :: Official Website of Dr. Michio Kaku

I agree, he is good and entertaining.

 

[dougscott]

No problem. I love talking this stuff.

Yes for looking through telescope. Say you see alpha centari 5 light years away. So it takes 5 years for light to get here. So We see 5 year old light.

What I'm talking about is having a time machine to go into past here or wherever you are at that time.

So if we could somehow [miracle happens here] place a mirror (or find a reflective object?) a million light years away ... we could watch some of the earths real history on the Discovery channel??

 

[clester]

The last few seasons of "Through the wormhole" got off track I think. But looks like they're back on track. I think quantum mechanics is where the answers lie. They mention it in the show that particles seem to travel back in time. Like the pigeons on the show. Depending on where you look a to particles they can travel back in time and change their behavior. In other words the future affects the past!

 

[clester]

So if we could somehow [miracle happens here] place a mirror (or find a reflective object?) a million light years away ... we could watch some of the earths real history on the Discovery channel??

I think so. If you place it there a million light years ago. You would be going back in time to place it. Now, if you could do it instantaneously then in a million years you could see our now

 

[k0nkuzh0n]

I think so. If you place it there a million light years ago. You would be going back in time to place it. Now, if you could do it instantaneously then in a million years you could see our now

I wonder what the tolerance on the angle would be for a mirror to reflect the image back from a million light years away and still be visible...

Lets call the earth 8k miles in diameter. inverse tan(4k/5.8785*10^18) ? ... 39 femtodegrees? :laugh: compass isn't gonna do it

 

[dougscott]

I wonder what the tolerance on the angle would be for a mirror to reflect the image back from a million light years away and still be visible...

Lets call the earth 8k miles in diameter. inverse tan(4k/5.8785*10^18) ? ... 39 femtodegrees? :laugh: compass isn't gonna do it

We could "instantly transport" a digital video camera. [the "instantly transport" part is still in work] Of course, we would also need "instant delivery" of the video feed.

 

[Frixxxx]

I think so. If you place it there a million light years ago. You would be going back in time to place it. Now, if you could do it instantaneously then in a million years you could see our now

Clester, If I ever have a chance to meet you, bring the abacus and the physics books, we'll knock out this time travel question, once and for all.....(I'll bring the drinks!) I believe that the matter question is an exchange between time instances.

 

[clester]

We could "instantly transport" a digital video camera. [the "instantly transport" part is still in work] Of course, we would also need "instant delivery" of the video feed.

Some sort of quantum entanglement mirror could be the answer. That's where two particles are "entangled " (I'm not sure how it's done but it's a real thing) and so affect each other's states immediately. There is no transmission mechanism needed. Distances don't matter.

 

[clester]

Clester, If I ever have a chance to meet you, bring the abacus and the physics books, we'll knock out this time travel question, once and for all.....(I'll bring the drinks!) I believe that the matter question is an exchange between time instances.

It helps to drink while contemplating!

 

[dougscott]

... In other words the future affects the past!

Some sort of quantum entanglement mirror could be the answer. That's where two particles are "entangled " (I'm not sure how it's done but it's a real thing) and so affect each other's states immediately. There is no transmission mechanism needed. Distances don't matter.

Ok, since we got this "looking into the past" thing all worked out ... how do we "look" into the future? How can the "future affect the past"? Sounds strange, but ... Does the future "exist"?

This is tough stuff for a Friday am ... no drinking yet. Now, you understand that some may be interested in future lotto numbers or wall street news, but I'm just interested in the science.:suspicious:

 

[rktect1]

As long as space is expanding, I would say no.

 

[Frixxxx]

Ok, since we got this "looking into the past" thing all worked out ... how do we "look" into the future? How can the "future affect the past"? Sounds strange, but ... Does the future "exist"?

This is tough stuff for a Friday am ... no drinking yet. Now, you understand that some may be interested in future lotto numbers or wall street news, but I'm just interested in the science.:suspicious:

Let's say a "matter exchange" has to occur when "traveling" through time. The matter of you in current state will be in a different state in the future. If you exchange the matter in the future state with the past state, then you have "altered" the past as well as the future. So the question becomes closed and open universe. More brain cells required.....going for more coffee.

 

[TSP-roulette]

You might consider my question stupid\dumb, regardless and hypothetically, if, if parallel dimensions do exist, are there exact duplicate of us living in those dimensions. Any good movies on the subject??