Questions tagged [age]
Questions about the temporal duration of a celestrial object.
46
questions
43
votes
5
answers
11k
views
Are photons aged?
If a star is at a distance of one lightyear, how old are its photons when they reach earth (from the photons’ perspective)? If time dilation is near zero at light speed, can we assume that the light ...
- 439
42
votes
3
answers
7k
views
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
11
votes
2
answers
521
views
Could a star closely orbit a black hole long enough for the star to have lost 0.5B+ years to time dilation?
I was wondering how stable a close star-black hole system could plausibly be, and thus how much time a star could plausibly miss out on (from an outside observer's perspective) due to being in an ...
- 387
8
votes
1
answer
2k
views
What would evidence of stars and galaxies significantly older than 13.8 billion years old look like? In what parts of space has it not been found?
The September 19, 2023 podcast with transcript Why the earliest galaxies are sparking drama and controversy among astronomers includes the following:
An article published earlier this year in the ...
- 30.7k
8
votes
2
answers
2k
views
Is the age of the universe relative to an observer's location in that universe?
According to Wiki the age of the universe is 13 billion years old, and I was taught that background radiation made the universe uniform in all directions.
Doesn't this define a sphere of space in the ...
- 927
8
votes
2
answers
3k
views
Age of a black hole
Is there a way to determine the age of a black hole. Suppose 100 Billion years from now, if two black holes have exactly the same mass(say 30 M☉). One of them formed 10 Billion years from now and ...
- 528
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
7
votes
2
answers
766
views
How do we measure the age of the universe?
As mentioned in wiki/Age_of_the_universe,
The current measurement of the age of the universe is around 13.8 billion years (as of 2015) – 13.799±0.021 billion years
When my friend who is not from ...
- 1,007
6
votes
2
answers
882
views
Is the age of the Universe really 13.8 billion years?
Ok, I know this has been asked by a lot of people, but my reason for asking this question is a bit different. Please read further.
I was watching a video by Fermilab (Start at 6:30, at 8:30 he ...
- 189
6
votes
2
answers
568
views
How to determine the age of a star using asteroseismology?
I keep reading that a standard way to determine the age of a star is asteroseismology, and I tried to learn more about it. I am wondering if somebody could help me to describe the method in simple ...
- 5,636
6
votes
1
answer
267
views
Do we know how old the matter that makes us is?
Last weekend, I had the pleasure of visiting an observatory where there was a series of lectures to cover up the fact that there was too much cloud cover to actually observe much at all.
One of these ...
user20278
6
votes
2
answers
277
views
Absolute model ages of lunar craters
I have been looking at several articles on the dating methods of craters, but I am wondering how exactly the "absoluteness" creeps into it. I came across several methods that link crater &...
- 1,105
6
votes
3
answers
350
views
Is there a stellar database that indicates how long ago stars in our Galaxy formed?
There are several ways of determining the age of a star: its position in the HR diagram, the presence of a protoplanetary disk, it belonging to a cluster...
When did the stars in our Galaxy form? Do ...
- 17.6k
6
votes
1
answer
499
views
Can someone calculate the age of the KOI-4878 star?
The star’s low metallicity and fairly high space velocity suggest that KOI-4878 is older than the Sun.
But I don't know how to calculate an estimation for the age.
KOI-4878 data on Simbad
user30548
5
votes
1
answer
2k
views
How to evaluate the fit of an isochrone to a stellar population?
Consider that I know the extinction, distance modulus, reddening, and metallicity for a particular star cluster.
I need to determine it's age from isochrone fitting.
After generating the required ...
- 333