Quizzes & Puzzles0 min ago
Supernova
http://news.bbc.co.uk.../sci/tech/8382348.stm
In summary: massive star (up to 40X mass of Sun), 4500 lightyears away, could become a supernova at any time
When this happens, might it be bright enough to see during daytime?
In summary: massive star (up to 40X mass of Sun), 4500 lightyears away, could become a supernova at any time
When this happens, might it be bright enough to see during daytime?
Answers
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Erm, the light doesn't just stop, it will continue to infinity and beyond.
A comparison might be made with the supernova which give rise to the Crab Nebula. This occurred in 1054 and was definitely bright enough to be seen during the day because it was noted by Chinese and Arab astronomers. That progenitor star was probably about 10X the mass of the Sun and at a distance of 6,500 lightyears (these numbers I did get from Wikipedia), so both significantly less massive and further away.
All of which suggests, at first sight, that this impending supernova might be very bright, so I was wondering whether basing expectation solely on the numbers might be misleading.
A comparison might be made with the supernova which give rise to the Crab Nebula. This occurred in 1054 and was definitely bright enough to be seen during the day because it was noted by Chinese and Arab astronomers. That progenitor star was probably about 10X the mass of the Sun and at a distance of 6,500 lightyears (these numbers I did get from Wikipedia), so both significantly less massive and further away.
All of which suggests, at first sight, that this impending supernova might be very bright, so I was wondering whether basing expectation solely on the numbers might be misleading.
I'd think so.
We're way overdue for one - there hasn't been a supernova in our galaxy since the invention of the telescope - it was Keplers supernova http://en.wikipedia.org/wiki/SN_1604 that was 20,000 light years away and reached a magnitude of -2.5 so about as bright as Venus which you can certainly see at dusk.
As the brightness decreases with the square of the distance one similar supernova would by my calculation be about -5.7 which is brighter than any star or planet but not as bright as the full moon (about -12) - this is a logarithmic scale
Eta Carinae is another candidate - this is 100 solar masses so a real bruiser and very unstable
http://en.wikipedia.org/wiki/Eta_Carinae
We're way overdue for one - there hasn't been a supernova in our galaxy since the invention of the telescope - it was Keplers supernova http://en.wikipedia.org/wiki/SN_1604 that was 20,000 light years away and reached a magnitude of -2.5 so about as bright as Venus which you can certainly see at dusk.
As the brightness decreases with the square of the distance one similar supernova would by my calculation be about -5.7 which is brighter than any star or planet but not as bright as the full moon (about -12) - this is a logarithmic scale
Eta Carinae is another candidate - this is 100 solar masses so a real bruiser and very unstable
http://en.wikipedia.org/wiki/Eta_Carinae
THe aths isn't difficult but you have to know how - by assuming they are similar you just set the absolute magnitude to be the same for each and then the formula for appraent magnitude gives you how bright one is compared to the other.
Of course a big star like eta carinae will make a very very much bigger bang!
Yes I hope to see one in my lifetime too - it will be a very big event!
Of course a big star like eta carinae will make a very very much bigger bang!
Yes I hope to see one in my lifetime too - it will be a very big event!
Venus is currently quite near the Sun in the sky.
If you want a good planetarium program then may I suggest Stellarium http://www.stellarium.org/ - it's a lot better than those online versions.
If you want a good planetarium program then may I suggest Stellarium http://www.stellarium.org/ - it's a lot better than those online versions.
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