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Salvador Sosa
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Since time is relative then what is the age of the universe (13.8 billion years) relative to?
Hey doesn't isotropic mean a bit more than that? Like for example, the laws of physics are invariant with respect to the direction you are facing? Or is the word just used to mean the uniformity of the CMB with respect to direction in the context of cosmology?Ibix said:It is the age measured by observers who see the universe as isotropic (who see the cosmic microwave background as the same temperature in all directions) and have always done so. This family of observers are called "co-moving" observers.
Ibix said:It is the age measured by observers who see the universe as isotropic
And just how would you decide how much time that is?Grinkle said:I have always thought of it as the amount of time GR says would have elapsed in rolling back expansion to the point where predictions of density go to infinity.
exactly. But the co-moving observer way is fundamental; your way is just a way of USING that amount of time.If I modify to 'amount of time GR says a co-moving observer would measure having elapsed in rolling ...' is that the same thing you are saying?
Would time be relative to the Big Bang?Salvador Sosa said:Since time is relative then what is the age of the universe (13.8 billion years) relative to?
Time in relativity behaves rather like distance in your every day experience. So if I asked you "would distance be relative to the corner of your house", what answer would you give? Does the question even make sense?Ivan Samsonov said:Would time be relative to the Big Bang?
The age of the universe is estimated to be around 13.8 billion years, relative to our present time.
The age of the universe is considered to be the time that has passed since the Big Bang, which is estimated to have occurred 13.8 billion years ago.
The age of the universe is not directly related to the speed of light. However, the speed of light is used to measure the distance of objects in the universe, which helps determine the age of the universe.
The age of the universe is the same for all galaxies, as they are all part of the same universe and formed at the same time.
The age of the universe is closely related to the expansion rate, as it is used to calculate the age of the universe. The expansion rate of the universe is currently estimated to be 69.32 ± 0.80 (km/s)/Mpc, which is used to determine the age of the universe.