Questions tagged [age]
Questions about the temporal duration of a celestrial object.
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Why is the main sequence often called 'zero age' main sequence?
The main sequence stage for a star begins after it stars burning hydrogen into helium. This is often referred to as the zero age main sequence.
This is confusing since stars have already lived ...
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Use of type-I a supernovae as standard candle
Why only type -Ia supernovae are used as standard candle to calculate age of universe and why not type II, type Ib, type 1c ?
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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 ...
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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 ...
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Is our universe flat?
I heard our universe is flat. Then one question is puzzling in my mind. If our universe is really flat, why we measure distance from any point across in a spherical way. In other words, why we say, ...
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How can we tell the age of a rogue planet?
Is it possible to find out how old is a planet, especially a rogue planet? I know that people measured the radioactive decays to determine Earth's age with some amazing accuracy, but what about ...
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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 ...
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Does the age of the universe take into account General Relativity / Special Relativity?
It is generally accepted that the age of the universe is approximately 12-15 billion years old based on the speed of the expansion of the universe. Since everything is moving very fast away from us, ...
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How can we explain high redshift numbers?
I just finished an introductory astrophysics course$^1$ and I have a lingering question that I can't seem to resolve.
We learned that for the first few hundred million years, the universe was pretty ...
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Redshift to calculate age of stars
In multiple articles I have seen the age of a star, within the milky way, referred to as its redshift (typically denoted by $z$). I know that $z$ can be calculated as $z=\frac{\lambda_{obsv} - \...
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Description of Henyey tracks on wikipedia incorrect?
So, if you search for Henyey tracks on wikipedia (I know, the shame of it!) you will come across this statement:
The Henyey track is characterized by a slow collapse in near hydrostatic ...
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Dating very old objects/events
After reading this space timeline, I have wondered how they managed to make these assumptions about various events like when the first black holes formed. This is obviously far beyond the good ol' ...
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Where are we in an approximate timeline of the possibly habitable universe?
Our universe is supposedly 13+ billion years old and our Sun is a third generation star. It seems to me that we are now in a relatively young stage of the universe. How many generations of stars will ...
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How is the Lithium Depletion Boundary used to determine the age of a stellar cluster?
According to my understanding of Soderblom et al. (2014), lithium ages of stars are determined as follows:
Determine lithium abundance from equivalent width measurement of Li$_{\mathrm{I}}$ ...
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Could we estimate the age of the universe based on the planar property of the Solar System?
The Big Bang scattered planets and stars everywhere in three dimensions.
But after billion years of moving and interacting with each others through gravity, planets moved on the same plane.
Given ...
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