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The Sun's rays hit our eyes around 8 minutes after they are emitted from the Sun. Does this mean that the Sun that we see is always the Sun as it was some 8 minutes before? I strongly think this must be happening; is it really a fact? Do we always see the Sun's past?

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    $\begingroup$ Down vote? I was just curious if i was thinking right. Anyway Thank you bro! $\endgroup$ – Deepeshkumar Feb 26 '15 at 3:52
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    $\begingroup$ The speed of light is finite. How could the answer be anything but yes? $\endgroup$ – Rob Jeffries Feb 26 '15 at 9:04
  • $\begingroup$ Hmm.. Well that is true but it is hard to digest that we are watching an object's past. When i had this argument with my pal and a teacher they made my fun. So i tried to verify. Now i can convince them n even have a debate. Thanks for answering! $\endgroup$ – Deepeshkumar Feb 26 '15 at 10:23
  • $\begingroup$ Light only travels about 11.8 inches per nanosecond. You have to be very close to an object to get real time information about it. $\endgroup$ – Wayfaring Stranger Mar 23 '17 at 19:49
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Yes, you are right. We don't only see the Sun 8 minutes in the past, we actually see the past of everything in space. We even see our closest companion, the Moon, 1 second in the past.

The further an object is from us the longer its light takes to reach us since the speed of light is finite and distance in space are really big.

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    $\begingroup$ In fact we see everything in the past, whether it's in space or not. If you see an object, say, 30 cm (~ 12 inches) away, you're seeing the light that left it about 1 nanosecond ago. At that scale, though, the delay in your own visual processing is much longer than the speed-of-light lag. $\endgroup$ – Keith Thompson Feb 25 '15 at 23:27
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    $\begingroup$ If we want to get even more complex, the photons from our sun that reach our eyes are actually much, much older than ~8 mins. They were created at the core of the sun something like 100,000 YEARS ago (I can't remember the exact estimate–someone pls correct me). It takes that long for the photons to travel from the immense pressure/gravity of the Sun's core and other layers before the light/photons finally escapes the Sun's corona on it's 8-minute journey to us. $\endgroup$ – iMerchant Sep 22 '16 at 15:26
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    $\begingroup$ @iMerchant Your latter point isn't true. The photons emitted in the core of the Sun were absorbed in the core of the Sun. The radiative energy takes a long time to diffuse outwards. The photons we see were emitted from the solar photosphere 8 minutes ago. $\endgroup$ – Rob Jeffries Mar 19 '17 at 19:16
  • $\begingroup$ @RobJeffries Good point indeed. We would not want the photons emitted in the core to hit us. $\endgroup$ – Peter - Reinstate Monica Sep 19 '17 at 12:27
  • $\begingroup$ I suppose one could add that most simple statements about space and time are to some degree bogus, if one fully considers general relativity. Fast moving objects -- say, neutrinos with mass -- would think that not much time passed since they left the sun. For the photons surely no time passed at all (and they didn't travel at all spatially, either). In a way one could probably say that everything we see at a given point in time, including GN-z11 and the microwave background, is almost contemporary -- from the view point of a very fast observer. $\endgroup$ – Peter - Reinstate Monica Sep 19 '17 at 12:35
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The speed of light in a vacuum is 299,792,458 meters per second, not infinite. Let's say, for example, particle of a beam of light, the photon, is emitted. It takes ~8 minutes to get to us; when it hits our eyes, we see it. This means that we see a photon that was emitted from the sun 8 minutes ago. We aren't, per se, looking "back in time", but we're looking at a photon that is ~8 minutes old.

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In fact past, present and future is still beyond of our consciousness. In reality they exist all together as spacetime. For example, when you say, we are seeing 10 years past of a star which is 10 light years away from our planet, similarly an alien right now is seeing our 10 years past earth. A nice video here https://youtu.be/vrqmMoI0wks can be helpful to understand how mind boggling reality we are living in.

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  • $\begingroup$ This does not prove that future is an illusion. $\endgroup$ – Anixx Mar 25 '17 at 13:12
  • $\begingroup$ What does it mean? What i mean the concept of time slicing is an illusion. @Anixx $\endgroup$ – Sazzad Hissain Khan Mar 25 '17 at 13:21

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