Teslescopes see the past, but which?

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In summary, the conversation discusses the concept of seeing objects in the past due to the finite speed of light and the question of whether zooming in on an object optically "fast forwards" you through its past. It is clarified that zooming in does not actually move the object closer, it simply magnifies it in the field of view. The conversation also touches on the massive photon emission densities of stars and the ability to resolve distant images due to the high photon flux. Finally, it is mentioned that looking directly at the sun is not advised due to the incredibly large photon flux.
  • #1
trini
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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?
 
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  • #2
oops misspelt the title ^_^'
 
  • #3
No, it's just bigger.
 
  • #4
trini said:
In other words, does zooming in on something optically 'fast forward' you through its past?

Nope.
 
  • #5
trini said:
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.
 
  • #6
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.
 
  • #7
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.
 
  • #8
cool my mind is at ease ;)
 

Related to Teslescopes see the past, but which?

1. How can telescopes see the past?

Telescopes are able to see the past because light takes time to travel to Earth. When we look at distant objects in space, we are actually seeing them as they were in the past, since the light from those objects took a long time to reach us.

2. How far back in time can telescopes see?

The furthest back in time that telescopes can see depends on their capabilities and the distance of the object being observed. Some telescopes can see objects that are billions of light years away, meaning we are seeing them as they were billions of years ago.

3. Can telescopes see events that happened before Earth existed?

Yes, telescopes can see events that happened before Earth existed. Since light takes time to travel, we can see light from objects that are older than Earth itself. For example, we can see light from the Big Bang, which happened billions of years before Earth was formed.

4. Why is it important for telescopes to see the past?

Studying the past through telescopes allows us to gain a better understanding of the history and evolution of the universe. It also helps us to make predictions about the future and to learn about the origins of our own solar system and planet.

5. Are there any limitations to what telescopes can see in the past?

Yes, there are limitations to what telescopes can see in the past. The farther back in time we look, the fainter the light becomes, making it more difficult to observe. Additionally, some events may not emit any light, so telescopes are unable to see them in the past.

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