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picass
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what is the distance at which the explosion of a supernova could wipe out all life on Earth ?
Originally posted by LURCH
Current thinking generally puts the distance at about 25 light-years. At this distance, the gammaray bursts could strip the ozone layer from the earth, leaving the entire surface to be bombarded by solar radiation and sterilized.
Originally posted by LURCH
Current thinking generally puts the distance at about 25 light-years. At this distance, the gammaray bursts could strip the ozone layer from the earth, leaving the entire surface to be bombarded by solar radiation and sterilized.
Are there any candidates for supernovae anywhere around us? I hear that Beatle Juice is a red giant ready to do supernova. I also hear that Sirius (the dog star) has a strange history. Are there any candidates close enough not to wipe out all life but create, say, a world wide devastating earthquake?
Meteor;Originally posted by meteor
This page says that Sirius B will not likely undergo type IA supernova
http://www.astronomycafe.net/qadir/ask/a11207.html
Betelgeuse will go supernova, but is 600 ly away
The next star in our galaxy that is believed that will explode in supernova is Rho Cassiopeia, but luckily, is 10000 ly away
Originally posted by Labguy
Meteor;
Your posts, writings and links have always been helpful, but I have a terrible urge to blast the "Ask Astronomer" (certainly not you) who wrote that little link you gave. He is right about masses and distances of the Sirius system, but his info on what will and will not go supernova is so incomplete and flat-out wrong that anyone new to the subject would learn either nothing or learn it wrong.
Type I and Ia supernovae (Binary systems) have been discussed in detail several times on this forun and I would urge any reader to search back for some of the longer threads on PF for this subject. Please read this fast before Janus deletes it for being argumentative instead of informative. ..
Originally posted by meteor
This page says that Sirius B will not likely undergo type IA supernova
http://www.astronomycafe.net/qadir/ask/a11207.html
Here is just one post: https://www.physicsforums.com/showthread.php?s=&threadid=8073&highlight=labguyOriginally posted by Mike2
Perhaps you could give a summary of the conclusions of what will go supernova or not. That would be informative. Or perhaps you can find the thread you are talking about and give a link. Thanks.
I've often wondered if it were possible for a white dwarf or nuetron start to be so cool that we cannot detect it nearby. And could such a star be right on the edge so that if it passes through a dust cloud, it could accumulate enough mass to blow?
Welcome to Physics Forums picass!picass said:How do you come to that 25 ly ? Can you calculate that distance or did you come to that figure by observation of existing supernovae and their effects.
Another question : how can galaxies collide as they move away one from another because of the expanding universe
In our Milky Way galaxy, about 800 light years away and about 11,400 years ago, a supernova exploded in the constellation Vela.
The Distance to the Vela Supernova Remnant was measured by Cha, Sembach, and Danks, who reported in astro-ph/9902230 that "... The analysis of a significant sample of O and B stars in the direction of the Vela SNR has enabled a direct distance measurement of 250 +/-30 pc, with a conservative upper limit of 390 +/- 100 pc. ...". They also state the following attributes of Vela SNR at 250 +/- 30 pc:
Diameter: 32 +/- 4 pc Using angular size of 7.3 degrees (Aschenbach 1993).
Age of Remnant:
11,400 yr from Pulsar spin-down age (Reichley et al. 1970).
13,000 yr < t < 16,000 yr from Shock velocity considerations (Wallerstein & Silk 1971).
Energy of Remnant: 1 or 2 x 10^51 ergs See Jenkins & Wallerstein (1995).
Temperature Behind Blast: 4.5 x 10^6 K See Jenkins & Wallerstein (1995).
People on Earth saw the explosion about 11,000 years ago as a star of magnitude -10, as bright as a 7-day old Moon.
A supernova is a powerful explosion that occurs when a massive star reaches the end of its life cycle. It is one of the most energetic events in the universe and can release as much energy as the sun will in its entire lifetime.
If a supernova were to occur close enough to Earth, it could release harmful radiation and particles that could potentially damage our ozone layer and cause widespread extinction of species.
On average, a supernova occurs once every 50 years in our galaxy. However, the last supernova in our galaxy was observed more than 400 years ago, so we are not able to predict when the next one will occur.
While it is possible for a supernova to occur in our lifetime, the chances of one happening close enough to Earth to cause significant harm are very low. The nearest star that could potentially go supernova is Betelgeuse, which is about 642.5 light-years away.
Currently, there are no specific measures in place to protect us from a supernova. However, scientists are constantly monitoring space for any potential threats and developing ways to detect and potentially mitigate the effects of a supernova if it were to occur close to Earth.