Supernova frequency

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buckyburrows
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Supernova frequency

Post by buckyburrows » Sun May 31, 2015 10:53 am

How often, in the entire universe, do supernova occur?

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Ann
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Re: Supernova frequency

Post by Ann » Sun May 31, 2015 3:06 pm

Check out this page. A person posting there, Russ Watters, estimates that there are 82 million supernovas in the universe every Earth day. Personally I think that one of Watters' key figures is wrong, because he thinks that there is a supernova in an average galaxy every 5 years. I think that is wrong, and to the best of our understanding, there hasn't been a supernova in the Milky Way for about 400 years. I may be wrong about my estimation about the latest supernova in the Milky Way, but in any case, we are a far cry from a supernova every five years. I think that on average, there may be a supernova in an average "large" galaxy once every century. I don't think the figures are the same for the myriads of dwarf galaxies out there.

But divide 82 million by twenty, and you still get about four million supernovas every day in the Universe. Admittedly I have no idea if that estimate makes sense at all. For one thing, how large is the universe, and how many galaxies are there in it? We don't have an answer to the first question, and therefore, not to the second question, either.

Ann
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claramax600
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Re: Supernova frequency

Post by claramax600 » Wed Feb 10, 2021 11:11 am

I don't know but after reading the above comment I get Lil bit idea.

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Chris Peterson
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Re: Supernova frequency

Post by Chris Peterson » Wed Feb 10, 2021 2:59 pm

Ann wrote:
Sun May 31, 2015 3:06 pm
Check out this page. A person posting there, Russ Watters, estimates that there are 82 million supernovas in the universe every Earth day. Personally I think that one of Watters' key figures is wrong, because he thinks that there is a supernova in an average galaxy every 5 years. I think that is wrong, and to the best of our understanding, there hasn't been a supernova in the Milky Way for about 400 years. I may be wrong about my estimation about the latest supernova in the Milky Way, but in any case, we are a far cry from a supernova every five years. I think that on average, there may be a supernova in an average "large" galaxy once every century. I don't think the figures are the same for the myriads of dwarf galaxies out there.

But divide 82 million by twenty, and you still get about four million supernovas every day in the Universe. Admittedly I have no idea if that estimate makes sense at all. For one thing, how large is the universe, and how many galaxies are there in it? We don't have an answer to the first question, and therefore, not to the second question, either.

Ann
Latest work puts the supernova rate for the Milky Way at about one very 50 years. Most can't be directly observed from the Earth. The estimate is based on gamma ray observations of Al-26, which is produced in supernovas.
Chris

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