Betelgeuse is a red supergiant of spectral type M1-2Ia-lab located on the right shoulder of the constellation Orion. It is about 10,000 times as bright as the Sun. It is about 400 to 600 light years away. "Why bother about something so far away?",you may ask. Well, there are reports that Betelgeuse has shrunk by 15% lately. These changes may indicate that an explosion is about to happen. I'm not really familiar with the paradoxes of physics of red giants. You might think that if something is shrinking it means that it will simply burn out and disappear. But with a red giant a contraction could signal an explosive expansion. Could the gamma rays from this reach Earth? I can't say for sure. Keep watching and following reports.

It may have exploded already, because it is 400-600 light years away what we see is it 400-600 years ago. If we are viewing it through a telescope we'd see it a little closer to as it is now. The Gamma rays wouldn't reach earth until we can see the explosion, preferably unaided.

I highly doubt it could be dangerous, first of all the beams have been travelling for 400-600 years and spread out, what does hit us probably will be a minuscule compared to what the sun hits us with everyday.

Uh oh, I'm going to start building up my bomb shelter.