2006-10-25 21:27:02 · 6 answers · asked by sjibboleth 1 in Science & Mathematics ➔ Astronomy & Space
A quasar discovered in 2003, in the constellation Ursa Major, with a redshift of 6.4 (the highest yet found) which emitted its light when the universe was only 800 million years old, and the light has been travelling for almost 13 billion years. hence it is almost 13 billion light years away.
Hubble's Law (first formulated by Edwin Hubble and Milton Humason in 1929 after nearly a decade of observations) states that the redshift of a far-off stellar object is proportional to the distance away it is. The bigger the redshift, the further the object.
Having got accurate spectroscopic readings of the shift in the hydrogen and helium lines in its spectrum, it is a simple matter of multiplying by Hubble's constant to calculate the distance.
The most recent calculation of the constant, using the satellite WMAP began in 2003, yielding a value of 71±4 (km/s)/Megaparsec. As of the 2006 data, that figure has been refined to 70 (km/s)/Megaparsec, +2.4/-3.2.
The first link tells you the story of the quasar's discovery by the Sloan Digital Sky Survey and shows you a photograph of it: (the red dot in the middle of the picture).
2006-10-25 22:33:09 · answer #1 · answered by Anonymous · 15⤊ 0⤋
The furthest one we can see is about 13.7 billion light years away.
That's what we call the observable universe. Since the expansion of the universe appears to be accelerating, it could actually be much larger than that, but beyond 13.7 billion light years everything is receding at greater than light speed, so it's forever cut off from us.
That doesn't violate the rule you always hear that you can't go faster than light. Parts of the universe can move away from each other at greater than light speed because the space in between them is expanding at an accelerating rate.
2006-10-26 00:17:59 · answer #2 · answered by Nomadd 7 · 0⤊ 0⤋
A very long way. We can see for about 15 billion light-years and there are stars way out there.
2006-10-25 21:29:57 · answer #3 · answered by tgypoi 5 · 0⤊ 0⤋
Since the universe is 13.7 billion years, it is probably 13.7 billion light years away.
The furthest known galaxy is 13.2 billion light years away.
2006-10-25 22:13:52 · answer #4 · answered by Anonymous · 0⤊ 0⤋
We don't know. Since we don't know where the edges of the universe are, we can't know where the furthest star is.
2006-10-25 21:52:39 · answer #5 · answered by Sebille 3 · 0⤊ 0⤋
Just a moment, I'll get out my rule.
2006-10-25 21:31:40 · answer #6 · answered by Anonymous · 0⤊ 2⤋