Teslescopes see the past, but which?

[trini]

hey guys, ok so here's what's on my mind. we know that everything we see is in the past due to the finite speed of light, my question is, and this applies to everything but let's consider cosmological scales for simplicity:

when we zoom in on a star that is say 100000 light years away with a telescope and see it from a perspective that it would be if we were say 50000 light years away, do we see that star 50000 or 100000 years in the past.

In other words, does zooming in on something optically 'fast forward' you through its past?

 

[trini]

oops misspelt the title ^_^'

 

[Perfection]

No, it's just bigger.

 

[Nabeshin]

In other words, does zooming in on something optically 'fast forward' you through its past?

Nope.

 

[cepheid]

hey guys, ok so here's what's on my mind. we know that everything we see is in the past due to the finite speed of light, my question is, and this applies to everything but let's consider cosmological scales for simplicity:

when we zoom in on a star that is say 100000 light years away with a telescope and see it from a perspective that it would be if we were say 50000 light years away, do we see that star 50000 or 100000 years in the past.

In other words, does zooming in on something optically 'fast forward' you through its past?

You seem to be under the impression that zooming in on something actually somehow causes it to be closer to you. It doesn't. It just makes that object take up more of the field of view.

No matter what the magnification, you're seeing the object as it was at the time when the light from it was emitted. How long ago that was depends on how far away the object is.

 

[trini]

indeed, so if this is the case the photon emission densities of these stars must be massive because if what we are doing is essentially 'stretching' the received image radially outwards so as to magnify it then we should also be stretching the space in between the photons.

In other words, for us to be able to still resolve the image even after the kind of divergence(decreasing flux as distance increases) this light would have undergone on its journey to us, the photon flux must be massive at the source, right?

this was really the source of my confusion, how are we able to resolve very distant images if the flux from these objects has diverged so much on the way here.

 

[Redbelly98]

Yes, the photon flux when you are close to a star is incredibly large. That is why we are warned not to look at our sun, even though we are about 150 million km away.

 

[trini]

cool my mind is at ease ;)