reply to post by Dr Expired
The fact that we are seeing light from many years ago has often been part of or the basis for many of my daily ponderings... Yes, scientifically, it
is true that if something caused the death of all other stars besides our own, and it happened simultaneously, we wouldn't know anything was wrong
for well over 100 years. Even after a star is gulped up by a black hole, there would still be a stream of light coming at us and the rest of the
universe surrounding the star. It would depend how far it is to tell how long before we notice it stops giving off light.
(1 light year away = it takes 1 year for its light, or absence thereof to reach us = we wouldn't notice for 1 yr)
I think our milky way galaxy is about 100,000 light years, side to side... But we are not located on the very rim, I think we are about 1/4 of the way
to the center, so if these figures are fairly accurate then
I would say it would take anywhere from 75,000 to 90,000 years before we saw the last one go out. Obviously we would know something was wrong within
the first 1,000. But maybe not before the first 100. This is all just my opinion as a guy who likes astronomy so that's all I have to offer, I'm
afraid. I don't know exactly how many stars ate within 100 light years so I don't know if it would be shocking to see them all go within 100 years,
but now that I think of it, someone would notice the stars dying in sequence by their distance and would eventually conclude that the process would
continue and thus the universe, or at the very least, our galaxy, was dying.
While this (post) is mostly my opinion, I can assure you, that light does take time to travel large distances, and that's actually how they
measure large distances in space. They look at how far light can get in 1 year and they said, ok, this is gonna be called a lightyear. So if a star,
say 12,528 light years away were suddenly to go out like a snuffed candle, we would continue seeing the light that has already left the star before it
met its fate. Light that is already on its way to us. The star dying or getting eaten by a black hole would have no effect on any light that escaped
the event horizon of the black hole and begun its journey toward us.
Of course, if you are assuming the stars all simply have lived out the course of their lives, and died on their own, without all being "shut off
for good" simultaneously, and many went supernova, then you have to remember that stars are also constantly being born out of clouds of gas and
minerals and stuff that came out of an exploding star. So even if all existing stars died, others are being "switched on" all the time from
existing.g clouds of gas, etc.. It will be so until either something like expansion causes the death of the universe, or all the lighter elements are
converted to heavier elements. Or I suppose in some cases, some of the gas might eventually be too far apart and drifting in the wrong directions to
be able to coallesce (sp) into a mass big enough to produce the sufficient pressure to cause nuclear ignition, creating a star.
PS, the elements that make up your body, the wooden coffee table in your living room, the device you are now using to access the internet, everything
was cooked up in the giant nuclear pressure cookers we call stars. Or you could call it "Gods kitchen" if you were so inclined.