...looking back in time...

[Manifold]

Hi!

It is said that as we look deeper into space we look in the past...we see younger galaxies and objects, which formed at an early stage of development of our universe...and here is my question...

Does it mean that we could see "ourselves", our own galaxy when it was young...or follow its formation back in time?

[jordan]

That seems reasonable. At some point in our universe, the light that reflected off of the Earth during WWII (don't know why I picked that event) would still be visible to someone. The only catch to seeing that light ourselves is that we would have to move faster than the light to catch it and be able to view it.

 

If we were to take off today and travel for 1 light year at any speed, the light we would see when we got there would be from the Earth 1 year ago. But since we were traveling at speeds less than that of light, we would not have been on the Earth when that event happened. We would have been on our way to that point in the space shuttle. So seeing back in time isn't as much a problem as seeing ourselves back in time.

[Douglas]

Hi!

It is said that as we look deeper into space we look in the past...we see younger galaxies and objects' date=' which formed at an early stage of development of our universe...and here is my question...

Does it mean that we could see "ourselves", our own galaxy when it was young...or follow its formation back in time?[/quote']

Seems to me, if you were sitting on the Andromada galaxy today, which is 2 million light away, and you had a telescope that could see as far as 2 million light years, then you'd see us as we were 2 million years ago. You wouldn't see the dinosaurs, since they disappeared 65 million years ago. You'd have to be sitting on one of the further out galaxies

[RICHARDBATTY]

What about rotation of galaxies and their grav effect on the path of light. It may be that light from us set off one way and we the other, but, in the vast swirliness of space we may end up heading for the same light and it for us.

[[Tycho?]]

Being in other galaxies would be able to see it, but I dont think we would be able to see our own past.

[Manifold]

If we look at the Andromeda galaxy through a telescope, we see it as it was 2 million years ago...but if we look at it with a naked eye, then, according to my proposition, we must see it as it is at the moment...which is complete nonsense...it's clear, we zoom in the image of the object, in the information brought by light...though from the past...but we don't zoom in the object itself...I think I got it.

[Douglas]

If we look at the Andromeda galaxy through a telescope, we see it as it was 2 million years ago...but if we look at it with a naked eye, then, according to my proposition, we must see it as it is at the moment...which is complete nonsense...it's clear, we zoom in the image of the object, in the information brought by light...though from the past...but we don't zoom in the object itself...I think I got it.

I agree, we don't zoom in on an object as it is today, we see it as it was 2 million years ago.

 

Just as when we look at the sun, we see the sun as it was 8 minutes ago.

[jordan]

but if we look at it with a naked eye, then, according to my proposition, we must see it as it is at the moment

What was this proposition again?

 

it's clear, we zoom in the image of the object, in the information brought by light...though from the past...but we don't zoom in the object itself...I think I got it.

Yeah. If you're refering to using a telescope, the light hits the telescope at the same time it would hit our eyes so there is no difference there. It's just that the telescope makes things look closer, not sooner.

[Thales]

Correct. Zooming in changes the resolution of the image but not the time at which the photons hit the instrument. To see it from a different time you would have to travel some cosmically relevent distance (ie light years) towards or away from the object.

 

There is a theory in circulation that the overall shape of the universe is a 3-sphere. Light that has left the earth travels outward in all directions and since the universe is wrapped in on itself this light can take a multitude of different paths around the sphere but could, hypothetically, reach us again billions of years from the future. The main problem I see with this theory is the universe may be so finely balanced that in this regard it ends before light can traverse the cosmological sphere.

[Manifold]

For jordan:

Quote:

Originally Posted by Manifold

but if we look at it with a naked eye, then, according to my proposition, we must see it as it is at the moment

 

 

What was this proposition again?

 

...well...better to say, that was the question which implies what I had thought previously:

Does it mean that we could see "ourselves", our own galaxy when it was young...or follow its formation back in time?

I think what I said about Andromeda above would have been true if the answer to my question had been "yes"...

 

For Thales:

There is a theory in circulation that the overall shape of the universe is a 3-sphere. Light that has left the earth travels outward in all directions and since the universe is wrapped in on itself this light can take a multitude of different paths around the sphere but could, hypothetically, reach us again billions of years from the future. The main problem I see with this theory is the universe may be so finely balanced that in this regard it ends before light can traverse the cosmological sphere.

 

Yes...I thought about that yesterday...I think it follows in particular that observing "ourselves" at any moment in time is principally impossible, because we must then see our own image, but the light emitted by our galaxy would reach us again just when it has all ended...and it would be as old as the universe itself...am I right?

[Douglas]

For jordan:

 

 

...well...better to say' date=' that was the question which implies what I had thought previously:

Does it mean that we could see "ourselves", our own galaxy when it was young...or follow its formation back in time?

I think what I said about Andromeda above would have been true if the answer to my question had been "yes"...

 

[b']For Thales[/b]:

 

 

Yes...I thought about that yesterday...I think it follows in particular that observing "ourselves" at any moment in time is principally impossible, because we must then see our own image, but the light emitted by our galaxy would reach us again just when it has all ended...and it would be as old as the universe itself...am I right?

Some cosmologists claim that the universe is expanding at nearly the speed of light, this implies that the sphere is getting larger. It's like chasing your own tail.

Also, time stops at the speed of light, how does that figure in this hypothesis ? If anything.

[Thales]

There is also the point that if we could observe ourselves we could violate causality by contradicting what we see.

[RICHARDBATTY]

Some cosmologists claim that the universe is expanding at nearly the speed of light' date=' this implies that the sphere is getting larger. It's like chasing your own tail.

Also, time stops at the speed of light, how does that figure in this hypothesis ? If anything.[/quote'] I'm not a scientist but I have thought space may expand at c. I could be horribly wrong but even if its right it doesn't mean that the matter in space moves with it. So matter is a sub c.

[Sorcerer]

There is also the point that if we could observe ourselves we could violate causality by contradicting what we see.

 

Thats only if we see the future, not the past. We can look into the past and travel into the future, but we cannot see into the future and travel into the past.