Rates and Potential Effects On Life On Earth
All the bursts astronomers have recorded so far have come from distant galaxies and have been harmless to Earth, but if one occurred within our galaxy and were aimed straight at us, the effects could be devastating. Currently orbiting satellites detect an average of about one gamma-ray burst per day. The closest known GRB so far was GRB 031203.
Measuring the exact rate is difficult, but for a galaxy of approximately the same size as the Milky Way, the expected rate (for long GRBs) is about one burst every 100,000 to 1,000,000 years . Only a small percentage of these would be beamed towards Earth. Estimates of rates of short GRBs are even more uncertain because of the unknown degree of collimation, but are probably comparable.
Gamma-ray bursts are thought to emerge mainly from the poles of a collapsing star. This creates two oppositely-shining beams of radiation shaped like narrow cones. Planets not lying in these cones would be comparatively safe; the chief worry is for those that do.
Depending on distance, a gamma flash and its ultraviolet radiation could damage even the most radiation resistant organism known, the bacterium Deinococcus radiodurans. These bacteria can endure 2,000 times more radiation than humans. Life surviving an initial onslaught would have to contend with a potentially lethal aftereffect, depletion of the atmosphere's protective ozone layer by the burst.
Read more about this topic: Gamma-ray Burst
Famous quotes containing the words rates, potential, effects, life and/or earth:
“Good government cannot be found on the bargain-counter. We have seen samples of bargain-counter government in the past when low tax rates were secured by increasing the bonded debt for current expenses or refusing to keep our institutions up to the standard in repairs, extensions, equipment, and accommodations. I refuse, and the Republican Party refuses, to endorse that method of sham and shoddy economy.”
—Calvin Coolidge (1872–1933)
“While each child is born with his or her own distinct genetic potential for physical, social, emotional and cognitive development, the possibilities for reaching that potential remain tied to early life experiences and the parent-child relationship within the family.”
—Bernice Weissbourd (20th century)
“Oh that my Pow’r to Saving were confin’d:
Why am I forc’d, like Heav’n, against my mind,
To make Examples of another Kind?
Must I at length the Sword of Justice draw?
Oh curst Effects of necessary Law!
How ill my Fear they by my Mercy scan,
Beware the Fury of a Patient Man.”
—John Dryden (1631–1700)
“It is sweet to dance to violins
When Love and Life are fair:
To dance to flutes, to dance to lutes
Is delicate and rare:
But it is not sweet with nimble feet
To dance upon the air!”
—Oscar Wilde (1854–1900)
“But money, wife, is the true Fuller’s Earth for reputations, there is not a spot or a stain but what it can take out.”
—John Gay (1685–1732)