If the universe is 13.8B years old, how can we see 46B light years away? (2018)
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Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#2What does it mean: "if we left today we could only reach one third of it"?
I couldn't find a the limiting factor... The stars would be dead before we arrived? My best guess. Of course, the qualification would be that we continue to be bound to the speed of light maximum.
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#3What does it mean: "if we left today we could only reach one third of it"? I couldn't find a the limiting factor... The stars would be dead before we arrived? My best guess. Of course, the qualification would be that we continue to be bound to the speed of light maximum.
The universe is expanding, at a rate which I believe is heading past the speed of light.
This limits our ability to reach galaxies further away from us as they are speeding away faster than we could conceivably travel since our engines would of course be bound by the speed of light.
Some more info: https://www.forbes.com/sites/startswithabang/2016/06/10/can-...
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#4What does it mean: "if we left today we could only reach one third of it"? I couldn't find a the limiting factor... The stars would be dead before we arrived? My best guess. Of course, the qualification would be that we continue to be bound to the speed of light maximum.
The limiting factor is the (according to current theories accelerating) expansion of the universe.
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#5It’s not that we can see that far, it’s that what we see has moved away from where it was when it produced the light we see now.
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#6What does it mean: "if we left today we could only reach one third of it"? I couldn't find a the limiting factor... The stars would be dead before we arrived? My best guess. Of course, the qualification would be that we continue to be bound to the speed of light maximum.
The limiting factors are the speed of light and the rate of expansion of the universe (same as the limiting factors of the observable universe).
"reach" is possibly the wrong phrase, since it is the corollary of the "observable universe", one might call it the "observing universe", which is the slice of the universe that light from our present day can ever reach due to the accelerating expansion of the universe and the limitation of the speed of light.
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#7What does it mean: "if we left today we could only reach one third of it"? I couldn't find a the limiting factor... The stars would be dead before we arrived? My best guess. Of course, the qualification would be that we continue to be bound to the speed of light maximum.
The universe is expanding, at a rate which I believe is heading past the speed of light. This limits our ability to reach galaxies further away from us as they are speeding away faster than we could conceivably travel since our engines would of course be bound by the speed of light. Some more info: https://www.forbes.com/sites/startswithabang/2016/06/10/can-...
That’s the case for the galaxies furthest away from us. Closer galaxies are receding less quickly and Andromeda is actually coming towards us.
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#8Simply put: We can see 46 Billion Light Years away now, b/c it wasn't that far away when it was created.
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#9What does it mean: "if we left today we could only reach one third of it"? I couldn't find a the limiting factor... The stars would be dead before we arrived? My best guess. Of course, the qualification would be that we continue to be bound to the speed of light maximum.
The universe is expanding, at a rate which I believe is heading past the speed of light. This limits our ability to reach galaxies further away from us as they are speeding away faster than we could conceivably travel since our engines would of course be bound by the speed of light. Some more info: https://www.forbes.com/sites/startswithabang/2016/06/10/can-...
Why would some things be bound by the speed of light and not others? I always thought of this limitation as an all-or-nothing law.
Re: If the universe is 13.8B years old, how can we see 46B light years away? (2018)
#10Earlier quoted context omitted.
The universe is expanding, at a rate which I believe is heading past the speed of light. This limits our ability to reach galaxies further away from us as they are speeding away faster than we could conceivably travel since our engines would of course be bound by the speed of light. Some more info: https://www.forbes.com/sites/startswithabang/2016/06/10/can-...
Why would some things be bound by the speed of light and not others? I always thought of this limitation as an all-or-nothing law.
Everything that moves is bound by the speed of light.
But when you create space between 2 points they can appear to move faster than the speed of light, despite not actually moving - it's just that there's new space created between them, so the distance between them grows faster than the speed of light.