Arthur C Clarke: Beware of Gamma Ray Bursts

In June 2000, shortly after being knighted, Arthur C Clarke said:

"Some of the greatest threats to mankind's future, are global warming, pollution, gamma ray bursts and the threat of an asteroid hitting the earth.

...Gamma ray bursts are sudden outbursts of energy - several times more powerful than the sun - which may suddenly occur," he elucidated.

"If it happens during any of our lifetimes, we have all had it. I think that such a phenomenon may have affected evolution and if it happens again, there is nothing we can do about it."

Great Example of a Gamma Ray Burst's power

7.5 billion years ago, 7.5 billion light years from us, a star exploded.

The light from this gamma ray burst took until last month to be reach Earth. For a couple of hours this explosion was visible to the naked eye, making it the most distant thing a human has ever seen unaided.

Consider the power behind such a burst, to be visible from the other end of the universe. And wonder how much it could harm you if it occured much closer to home.

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Wolf-Rayet star aimed right at us!

The spinning wheel is generated by two massive stars, 8000 light years away, circling each other every eight months. Gigantic clouds of gas streaming off the stars are being stretched by the stellar dance into a spiral, much as water spirals from a rotating garden sprinkler.

Eight years ago Dr Tuthill's team, using Hawaii's huge Keck telescope, discovered that one of the objects is a highly unstable beast called a Wolf-Rayet star. They inevitably die in huge explosions that may sometimes produce deadly gamma ray bursts.

Now Dr Tuthill's team has made another discovery. Overlapping 11 time-lapse images of the 30 billion-kilometre-long gas spiral, they have concluded that Earth is almost directly above one pole of the doomed star, dubbed WR 104. When Wolf-Rayet stars explode, much of their energy is blasted from the poles.

"From our vantage point," said Dr Tuthill, "we are looking right down the gun barrel. That's what's got us worried."

Yet another space nasty to worry about. If the ancients were able to predict such things hitting us from space, then that could explain the 2012 end date.

Gamma Ray Burst from Nowhere!

The current theory holds that that gamma ray bursts like GRB 070125 are given off by super-jumbo-sized stars that run out of fuel and violently collapse to form black holes, explains Neil Gehrels, principal investigator of NASA's Swift telescope.

Such huge stars can only be created in very gas and dust-rich parts of galaxies where lots of other stars are also being born. So it makes no sense to find such a star living and dying in the empty space between galaxies.

Yet another space nasty to worry about. If it doesn't come from a star we can see, then the possibility exists that we can be zapped from one that is either a star we cannot see, or not a star at all. More at Discovery.com