See far away objects in space in real time?

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Discussion Overview

The discussion revolves around the possibility of observing distant celestial objects in real time, addressing the implications of light travel time and the nature of time measurement in different frames of reference. Participants explore the conceptual challenges related to viewing the past of these objects and the potential for understanding time in relation to light emitted from distant sources.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether it is possible to see far away objects in space in real time, noting that telescopes show the past state of these objects based on their distance.
  • Another participant asserts that observing events from the past, such as a supernova, would require light to travel faster than the speed of light, which is not possible.
  • There is a discussion about the meaning of time measurement, with one participant suggesting that time should be measured according to a clock on Earth, leading to confusion about the nature of time and measurement devices.
  • One participant proposes that if there were a way to see light emitted at later times, it could imply a form of time travel or a contradiction to special relativity.
  • Another participant suggests that various clocks on Earth, including those based on radioactive decay or the Earth's orbit, could be used for time measurement, indicating flexibility in defining time reference frames.

Areas of Agreement / Disagreement

Participants express differing views on the implications of light travel time and the nature of time measurement. There is no consensus on the possibility of observing real-time events from distant objects or the interpretation of time in this context.

Contextual Notes

The discussion highlights uncertainties regarding the definitions of time and distance in different reference frames, as well as the implications of light speed limitations on observational capabilities.

robertito
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Hi,

I was asking myself if there is, or might be a way to see far away objects in space in real time? What I mean is that when we look even through the most powerful telescope we always see the past of the object we are looking at, and this past will depend on the distance the object is away from us, right?
So, if a planet is 1000 light years away from us and we have a telescope powerful enough to see its surface like, let's say, in google maps we will see how this surface looked like 1000 years ago. Then, maybe we see life on a planet, a supernova exploded 500 years ago and killed everything and we will see this in 500 years only.
Or maybe we don't see anything but there is life and the problem is that light still didn't reach us.
Is it like this or am I completely wrong?
Thanks!
 
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Yes, the only way to see what happened 500 years ago would be for the light that was emitted 500 years ago to travel at twice the speed of light which - more or less by definition - is not possible :)

For a rigorous discussion, we should probably think about what "500 years ago" means... 500 years on whose clock? :)
 
Thanks for your answer, you clarified something important!
About the clock, I don't know, because that's also something I never understood :) I guess, my clock here on earth? But it's a mechanical device, and this is what confuses me even more! (in the same way that the ruler you leave in the drawer is not measuring anything...)
By the way, you made me remember that I have to make a question about time, but in another place of the forum ;)
 
Yes, because you are saying that "the light is coming from a start 500 light years away", the distance is measured in your frame of reference, the time is measured in your frame of reference. In other words, by a clock sitting stationary next to you.
 
If there is any way to see light of later times (=not light emitted 1000 years ago for clocks on earth) here on earth, this allows time travel or completely ruins special relativity (or both).
I guess, my clock here on earth? But it's a mechanical device, and this is what confuses me even more! (in the same way that the ruler you leave in the drawer is not measuring anything...)
Well, you can use any clock here on earth, including radioactive decays, the orbit of Earth around the sun and so on. You are not limited to a specific clock.
 

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