# When we see the Sun, do we actually see its past?

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?

• Down vote? I was just curious if i was thinking right. Anyway Thank you bro! Feb 26 '15 at 3:52
• The speed of light is finite. How could the answer be anything but yes? Feb 26 '15 at 9:04
• 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! Feb 26 '15 at 10:23
• 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. Mar 23 '17 at 19:49
• If you look at the person next to you, you also see an image of the past Apr 28 '20 at 5:22

## 3 Answers

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.

• 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. Feb 25 '15 at 23:27
• 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. Sep 22 '16 at 15:26
• @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. Mar 19 '17 at 19:16
• @RobJeffries Good point indeed. We would not want the photons emitted in the core to hit us. Sep 19 '17 at 12:27
• 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. Sep 19 '17 at 12:35

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.

Answer is Yes. Not only to sun and moon, we are seeing each and every distant object we are ever experiencing with certain delay. For example, if you are reading this text on a computer screen at 50 centimetres distant from your eyes, you are actually experiencing the past version of 1.66777852e-9 seconds.

One interesting thing to know is, in reality past, present and future exist all together as spacetime in the fabric of cosmos. For example, when you say, we are seeing 10 years past version of a star which is 10 light years away from our planet, similarly an alien right now is watching 10 years past version of our earth seating on that star.

An excellent explanation can be found here presented by Brian Greene to understand how mind boggling reality we are living in.

• This does not prove that future is an illusion. Mar 25 '17 at 13:12
• That's a very video link. Apr 28 '20 at 22:06
• @Jim what did you mean? Very old video link? Apr 29 '20 at 5:00
• Oh sorry, typo. I meant a very cool video. Apr 29 '20 at 9:06
• Yes. That’s actually a cut piece of original longer documentary which is about 50 minutes. Sharing for interested people youtu.be/Zuedaptw73w Apr 29 '20 at 9:38