- #1
ChrisXenon
- 60
- 10
I guess I must be missing something obvious, but I've had this on my mind for a long time and can't see the error in my thinking.
Light travels at a fast, but finite speed, so we see things not as they are now, but as they were when the light left the object.
If follows from that, that the further an object is away, the further back in time we're looking at it.
So far, so good.
But we often hear astonomers talking about seeing back ever close to the origin of the universe - to the big bang.
And this is what bothers me. Please fault me reasoning for me:
Any event only happens once - and the instant and the instance of that event is never repeated.
An "event ripple" propogates outwards from that event at light speed, but if you miss that event - if it passes you before you started looking - you'll NEVER SEE IT.
So, for example, consider the the sun, which is 8 light minutes from Earth.
If it exploded NOW, and you slept for the next NINE minutes - you'd miss it forever (of course, you'd be dead so the point is practically moot).
Now unless the universe expanded faster than light speed for some of its history, the "event ripple" of the Big Bang will always be beyond anything in the universe, and so no one/thing will ever see it - and no one/thing ever did. In fact, it defines the limits of the universe - and if you're in it - you can't see it.
Where did I go wrong?
Thanks,
Chris
Light travels at a fast, but finite speed, so we see things not as they are now, but as they were when the light left the object.
If follows from that, that the further an object is away, the further back in time we're looking at it.
So far, so good.
But we often hear astonomers talking about seeing back ever close to the origin of the universe - to the big bang.
And this is what bothers me. Please fault me reasoning for me:
Any event only happens once - and the instant and the instance of that event is never repeated.
An "event ripple" propogates outwards from that event at light speed, but if you miss that event - if it passes you before you started looking - you'll NEVER SEE IT.
So, for example, consider the the sun, which is 8 light minutes from Earth.
If it exploded NOW, and you slept for the next NINE minutes - you'd miss it forever (of course, you'd be dead so the point is practically moot).
Now unless the universe expanded faster than light speed for some of its history, the "event ripple" of the Big Bang will always be beyond anything in the universe, and so no one/thing will ever see it - and no one/thing ever did. In fact, it defines the limits of the universe - and if you're in it - you can't see it.
Where did I go wrong?
Thanks,
Chris