? about speed of light ?

[Swane]

:confused: :confused: :tasdevil:
G'day all,
Would some knowledgable person be able to explain to me ,this question?
The images that we are looking at through our scopes are actually a slice in time. That means;what we are seeing has been travelling at the speed of light from where it originated from in the universe.
If the object is (say) a 1500 light years away from planet earth .We would be seeing what it looked like 1500 years ago.
(NOW FOR MY QUESTION)
" HOW DO WE KNOW THAT IS STILL THERE"?

[[1ponders]]

That's an easy one Swane. We don't. We can't know about anything happening anywhere until the light that comes from it reaches us. Whether it be the sun going out (about 8 1/2 minutes) or Andromeda collapsing into a supermassive black hole (2 1/2 Million years, never happen anyway :) ). So if eaither of these events happen we won't know about it til that last bit of light gets here

[ballaratdragons]

We don't.

An object we are looking at could have blown to smithereens hundreds or even thousands of years ago but the light of that catastrophe has not arrived yet!

Cool huh!

[Swane]

:einstein: [QUOTE='[1ponders]']That's an easy one Swane. We don't. We can't know about anything happening anywhere until the light that comes from it reaches us. Whether it be the sun going out (about 8 1/2 minutes) or Andromeda collapsing into a supermassive black hole (2 1/2 Million years, never happen anyway :) ). So if eaither of these events happen we won't know about it til that last bit of light gets here
:einstein: I've always reckoned that this is the case.Though; I also thought that the brainy ones would have a better answer than that. (I'm not insinuating that you have lack of brain) .I mean the astronimers at NASA and such.
Like something ,such as the colliding of the different systems gravitational fields impacting at the end of the chain at the same time as the first action happens.( Thats what supposed to happen with those execetive stress balls)
How does that sound?
I've always wanted to ask that question. Now that I'm getting into astronomy ,I I thought that I would throw it into the pool.
Also MY SCOPE ARRIVES ON TUESDAY!

[acropolite]

As the others said, we don't know for certain, but we can predict with a high degree of certainty that a situation exists based on our knowledge gained from observations over time. The very fact that astronomers can detect planets too small to image, orbiting far away stars, by the application of science gained through observation, shows that at least some of us have some intelligence. Unfortunately, most of the human race doesn't have the intelligence to realise that we are rapidly destroying our environment and most other living creatures that share it, despite the fact that the causes and effects are clearly visible.

[ballaratdragons]

No matter what happens out there it cannot be recorded any faster than the light getting here (gravitational shifts or effects on other sytems or whatever).
The only way to know any sooner is to get closer and you would have to go an awful long way (past Pluto) to know only a few days in advance of everyone else.
And by the time you saw it and radioed back to Earth they would have already seen it by then!!! Ain't science wonderful.

[Striker]

Their is 1 way.......use my Tardis.

[Robby]

Too throw another worm in.. Due to gravitational lensing, what we see is probably not what it actually looks like (rather looked like) anyway! It's all a big physics illusion!
Cheers