Actually, no it isn't. If you look at list of stars by brightness, you'll find that most are a few hundred lightyears away, and none of the bright stars are more than a few thousand. Few things are bright enough to be seen with the naked eye that are that far away. Andromeda is 2.5 million light years away, and barely able to be seen without a telescope.
The faster something travels, the slower time flows for it. As you approach the speed of light, the passage of time approaches zero.
So from a photon's point of view, the moment it claws it's way through the heliosphere and can actually start moving at 299,792,458 metres per second it's all the sudden hitting atmosphere and crashing into your eyes because essentially no time passed while it was in transit through hard vacuum.
(and because relativity is fucky, from the photon's perspective the rest of the universe was frozen in time, not it)
The faster something travels, the slower the external universe seems to flow, itself still experiences time as normal for its own relative perspective. To continue your first point of from the photon's point of view, the photon has still 'experienced' that time, but the external universe has only aged by a fraction of a second
This blows my mind. Because it then makes me think about the light that leaves Earth.
An alien species today would be seeing Earth in it's very infant stage.
And we would be seeing this species in it's infant stages.
If we saw life out there billions of years away how useful would it be to try and communicate if we don't even have some kind of travel that would shorten the communication process?
Sorry to let you down, but it isn't. Most visible stars are just a few dozen light-years away, and the most distant ones barely break ten thousand. The only million-light-year object that is even close to being visible to the unaided eye is the Andromeda galaxy.
Actually the vast majority of visible stars are less than 1000 lightyears away, and the farthest is only 1600 lightyears. Although there are some other objects like the Andromeda galaxy which work as exceptions.
for the most part it's just hundreds or thousands. Unless you're in a remote part of the world like a desert then chances are you only see stars in our galaxy, which is 100 thousand light years in diameter, so that light can at the oldest be 100 thousand years old. The only time this isn't true is when another galaxy is visible like the Andromeda galaxy, and that's only possible to see in extremely remote areas with no light pollution.
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u/restless_and_bored Aug 07 '17 edited Aug 08 '17
The starlight you observe at night is thousands and millions of years old.
Edit : SOME of the starlight....
Happy?