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Since our solar system is moving through the milky way galaxy, if we point our telescope to a certain point where we determine that the solar system was a certain time ago, will we see our solar system?

Qmechanic
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Sahil Sharma
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    See https://physics.stackexchange.com/q/221173/123208 – PM 2Ring Oct 07 '22 at 12:10
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    Why do you think this might happen? – ACuriousMind Oct 07 '22 at 14:49
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    Not what you are asking for... but it may help to think that "You constantly see the past image of the Sun" (the light takes ~8 minutes to reach our planet). Therefore, we always see our Sun "8 minutes in the past". To see "older stuff", you have to look even further (distant stars look "younger" than they are, some are already dead but still shine for us!), up to the "observable universe" horizon https://en.wikipedia.org/wiki/Observable_universe – Quillo Oct 07 '22 at 14:51
  • Stated in other terms: it is possible to rephrase your question in such a way that it "makes sense". Imagine you want to observe Neptune. Therefore, you have to point the telescope at the position where Neptune was ~4 hours ago (ignoring general relativistic corrections). In practice, you do not even have to worry about doing so, in the sense that no calculation is needed (just point the telescope up and search for a little shiny dot that is the image of Neptune, as it was 4 hours ago). – Quillo Oct 07 '22 at 15:11
  • Well guys, technically if there was a mirror placed afar we could see the earth back in time. – FriendlyLagrangian Oct 07 '22 at 21:59

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No. You don't see past versions of yourself as you walk around your house. Why would you expect to see past versions of the solar system ?

The finite speed of light means that when we look at other stars and other galaxies we see them as they were when the light that reaches us now was emitted - which can be thousands of years ago for stars in our galaxy, or millions or billions of years ago for other galaxies. But we don't see older versions of our own solar system.

gandalf61
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Another way to think about this:

In order to see an event from a thousand years ago, you need to look at locations that are a thousand light-years away. This is because light from that event must have been traveling for a thousand years. However, the Earth of a thousand years ago cannot be at any location that far away because it moves through space slower than the speed of light. This means that the light emitted from events on Earth a thousand years ago has already passed by the Earth's present location. All of that light is now moving away from us out into space, never to be seen by us.

There is one way light from the past could return to Earth. If there is a black hole 500 light-years away, then light from an event could make a U-turn around the black hole and be sent back to Earth's present location. See this article and the video within about light orbits around black holes to see what this looks like. It would be very difficult to disentagle the light from Earth from all the other light flung about by the black hole, but it would be in there.

Mark H
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