All Questions
4
questions
3
votes
1
answer
503
views
What is mass-weighted age?
This seems to be a common term used in the field of stellar populations and galaxy evolution, but I can't find a good definition besides the fact that it is different from light-weighted age (a term I ...
42
votes
3
answers
7k
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How did Hubble know the red shift difference between "moving away" and "old"?
My 9yo daughter is very into space at the moment and asked a question that my physics knowledge (6th form college, 20 years ago) is way too poor to answer.
Her space book tells us that as stars age, ...
- 521
8
votes
1
answer
216
views
How far would EGSY8p7 be away now?
Apparently EGSY8p7 is the object with the longest light travel distance, 13.2 gly or a redshift of z = 8.68 (Wikipedia).
So the light took 13.2 billion years to travel to us from that object, but we ...
- 183
4
votes
1
answer
241
views
What have we learned from the observation of most distant galaxies [closed]
We have seen galaxies around 13 billion years old. Since these galaxies formed so early in the history of the known universe, are there observables about these galaxies that are apparently different ...
- 4,504