Big bang and the hubble deep field?
Question by bashir n: Big bang and the hubble deep field?
Well i don’t know a lot about astronomy and cosmology but this is what i have been wondering about _if the bing bang happened 13.5 billion yrs ago _ and base on the hubble deep field the the farthest they could see in the universe is 43 billiom light yrs away form us ( which means depnding on where exactly the big bang happen they atleast traveled (i mean the galaxies ) for about half of that distance which is about 21.5 light yrs which i am not sure about then can we draw this conclusion that the cosmo must have expanded faster than the speed of light to get to the level of expansion that it’s at right now. thank you for answering i hope it’s clear
Best answer:
Answer by !Sticky!
It was my understanding that the hubble space telescope has only detected stars as far out as 14.5 billion light years, I don’t know where you got 43 billion light years from. And as scientists have been able to determine that it took approximately 1 billion light years for stars to form, we can observe stars out to that distance. And 1 light year is how far light travels in 1 year, considering that in 1 second the distance light travels is equivalent to 42 times around Earths equator, that distance is vast.
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The way astronomers measure distance is by the time light takes to get here from the object.
If the universe is 14 billion years old, then we cannot see anything that is more than 14 billion light-years away.
However, the universe is expanding. Any object that we see now at a distance x, is no longer that close (if it still exists). Galaxies live long enough that some people do worry about the “real” distance to that galaxy, IF we were able to see where it is now, instead of where it was when it emitted the light we see.
That is because the universe expands. Expansion adds distance between objects (the object could still be fixed relative to its local space).
For cosmologists, the important distance is this “comoving” distance: if we see a galaxy at 13 light-years away (counted the way astronomers do it), then how far is that galaxy “now”? Answer is roughly 40 billion light-years.
For cosmologist, this is the measure of the universe.
For astronomers, the “visible universe” is still only a radius of [almost] 14 billion light-years.
If you try to mix astronomical distances with cosmological distances, there will always be this difference (different definition of measurement).
maybe they used Doppler’s shift method to find the furthest star and assuming it was at the end of the universe calculate how the star is far by light years.
http://en.wikipedia.org/wiki/Doppler_shift
but i do not know what you really want the question is not clear