Submitted by Seraph_Unleashed t3_10mum06 in space
[removed]
Comments
Seraph_Unleashed OP t1_j6587gt wrote
Yes, but does this mean obviously if there are other intelligences in space far enough away, they can see the light front the sun, but they’re seeing the sunlight as it was light years ago. Meaning they’re seeing it in the past.
WarWonderful593 t1_j658ygt wrote
Years ago. A light year is a measure of distance, not time. As the sun is about 5 billion years old, it's first light would be 5 billion lightyears away by now. In reality, it will be further than that because the universe will have expanded considerably in that time.
Seraph_Unleashed OP t1_j659auk wrote
Right exactly that’s that I meant to say. So 5 billion light years traveled. An alien race would see it billions of years later. The universe is expanding but into what exactly. If it is boundless and endless does that mean once it expands to a certain point will everything then fall back and collapse on it self like the Big Crunch theory?
beef-o-lipso t1_j65c6kp wrote
>Right exactly that’s that I meant to say. So 5 billion light years traveled. An alien race would see it billions of years later.
A being with a telescope that is 5 billion light years away today (in our frame of reference) would see the sun as it was 5 billion years ago. A being 1 light year away would see is as it was 1 year ago. That's what a light year is--the distance light travels in a year. You can't see something until the photons reach your eyes. Heck, we don't even see our Sun in real time. We see our Sun as it was about 8 minutes ago!
> The universe is expanding but into what exactly.
Unknown. Current think has it the univserse doesn't expand into anything. It simply gets larger and the distance between any two points (not matter, points) get larger.
> If it is boundless and endless does that mean once it expands to a certain point will everything then fall back and collapse on it self like the Big Crunch theory?
Also unknown. In addition, I don't think there is a known mechanism by which a reversal of the expansion could happen.
Odd_Republic5346 t1_j65m302 wrote
Isn't the sun 4.5 bn years old ? What would they see then
beef-o-lipso t1_j65r53i wrote
4.5 bn years then. The principle stands.
Not accounting for the universe expansion, someone X light years away would see another spot in the universe as it was X years ago cause that's own long it took light to travel from there to where ever the observer is.
Odd_Republic5346 t1_j67e2yh wrote
I know I was just wondering what was before the sun. I looked it up and it was a solar nebula
UmbralRaptor t1_j657vjy wrote
> I heard the Suns goes out to about 2 is that true?
About 2 what? In any case, the sun would be naked eye visible (6th mag) at ~17 pc (~56 ly). Farther away you'd need a telescope, but assuming you're not dealing with dust clouds, it should be visible from quite far away.
Seraph_Unleashed OP t1_j658b4w wrote
2 light years into space.
[deleted] t1_j656wko wrote
[removed]
space-ModTeam t1_j658kah wrote
Hello u/Seraph_Unleashed, your submission "How far out does the suns light travel into space?" has been removed from r/space because:
- Such questions should be asked in the "All space questions" thread stickied at the top of the sub.
Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.
Gorth1 t1_j66myhz wrote
The photons Wil keep on moving away from the sun forever until they hit something solid, like the eyes of an alien. They will wonder if there is life on that little speck of light and then continue with their day .
WarWonderful593 t1_j65808e wrote
Forever until the photons hit something. Same as radio and TV broadcasts. We can see the light from stars that left 15 billion years ago. Even after the sun burns out it's light will still be travelling out to the edge of the universe.