What are the chances of a supernova or a gamma-ray-burst happening in the milkyway galaxy?

Question

what will happen if such things happen in our galaxy? What is the safe-distance (between the supernova or gamma-ray-burst and the Earth) to have no serious effects on the Earth?

Answer 1

Supernova? They happen all the time in our Milky Way; like 1 every million years or so, probably more. Just google up how vastly HUGE our "little" galaxy is. There are about one hundred million billion stars in here. (And about one hundred million billion OTHER galaxies, each with about one hundred million billion stars. But I digress...

A Gamma Ray Burst is impossible in the Milky Way. The black hole at the center of our galaxy is nowhere near massive enough to create gamma ray bursts.

If you WANT gamma rays, however; just allow a naturally radioactive atom to decay, and wala! Alpha, beta AND gamma!

Betegeuse will (already did) go HUGE supernova. Even with its "close" proximity, it will do no more than become very bright, even visible during the day.

Nothing to fear; except asteroids, 2012, nuclear war, global warming, and vacuum metastability!

Answer 2

theres no doubt it will happen but dude you will be dead by then live life to its fullest

Answer 3

Some good answers already.

In addition, there does seem to be a Wolf-Rayet star, WR 104, that may have one of it's poles pointed at us.  It's 8000 light years away.  It could be nasty.

Fortunately, Sagittarius only rises for a little bit from my vantage point in Michigan.  And the gamma ray burst, if it happens, is short, and will have the biggest impact on the side of the Earth facing it.

We may still have a million years or so.  In that time, we may discover that it isn't a threat, or can build a workable defense.  We're pretty smart, and getting smarter.

Answer 4

Supernovae have already occurred in our galaxy, and they shall again. It's not very rare. The tend to happen like once a century. As for a gamma ray burst, it might happen in our galaxy. It won't be a problem unless it's poles are aimed at us, as the vast majority of the energy is channeled to the poles.

"What will happen if such things happen in our galaxy".

If a supernova occurs, there will be a nebula created. See the "crab nebula". It was formed by a nova in 1054 A.D.  It was recorded by the Chinese, and I've heard that it may have been bright enough at night to allow you to be able to write. (in 1054 A.D., only the Japanese had internet, so the rest of the world still had to write).

If a supernova happens nearby enough to damage us, it will be in the form of heat. The energy of the object enters our atmosphere, heating up the planet. It'll be like having two suns. That's inconvenient. For Gamma-ray bursts, the ozone will get PWN3D, the atmosphere will undergo radical chemical changes due to the gamma rays splitting molecules in the air. All sorts of nasty stuff. No one on Earth will survive. Some bacteria might, and if so, they'll start to replenish the atmosphere and after a few hundred years the atmosphere will start to look like it did.

"What is the safe-distance ... to have no serious effects on Earth?"

For a supernova, perhaps 50 light years. Even then it's going to be bright. The star Alpha Orionis (often called "Betelgeuse" is near the point where it's going to go supernova, likely creating a black hole in the process. Yet even at 300 light years, it's too far to damage us).

As for gamma-ray-bursts, it depends on the orientation. If it's pole on, and we get the majority of the energy, the object needs to be a few thousand light years away. If we're not pole on, then I think it can be considerably closer, perhaps a few tens of light years.

If anybody sees an inaccuracy in my answer, please e-mail me and let me know =o.

Answer 5

In a galaxy the size of the Milkyway, I believe it's estimated to be one star will supernova about every 10 to 50 years; but most are so far away, the chances of it happening 'in the neighborhood' are about 1 in 20,000.

Gamma-ray bursts are fairly common;  we receive the indications of them about once per day, or once every couple of days, but (thankfully) they're so far away, a few stray gamma rays is all we receive.  This is a guess, but the gamma-ray sources are so violent that I would bet any planet with life in it's direct line out to, say, 10 or 20 thousand light years would be directly affected.  (Again, that's a guess.)

Answer 6

Read:

http://www.foxnews.com/story/0,2933,3351...

http://www.news.com.au/heraldsun/story/0...

http://www.physics.usyd.edu.au/~gekko/wr...

http://en.wikipedia.org/wiki/WR_104

Answer 7

  Gamma ray bursts happen at extreme distances,like 6 billion light years away.

  A super nova could occur in the milky way galaxy but it may be undetectable beyond the galactic center.