Death By Milky Ray
By Anne Pawsey
- 25/04/2007 - As if asteroids, climate change and volcanic eruptions weren’t enough, scientists have come up with yet another explanation for what killed the dinosaurs: cosmic rays.
The Earth gets clobbered with the cosmic stuff about every 62 million years, when it is furthest above the rest of the galaxy. The dinosaurs died out around 62 million years ago, which means… Oh dear.
Cosmic radiation is highly ionising and comes from outside our galaxy. It is mostly screened out by our atmosphere, but large amounts of these rays can cause real damage, disrupting DNA and possibly even causing climate change according to experts.
The amount of radiation that the earth is exposed to varies (slowly) with time. As the earth and the solar system go round the galaxy it wobbles up and down. At some points it is above most of the rest of the galaxy, at some points below. It takes about 225 million years to complete a circuit and the earth bobs up and down four times during this cycle.
When the earth is at its maximum, it is exposed to lots more cosmic rays, which come from the Virgo cluster of galaxies found to the “north” of our own. When it’s on the south side of the Milky Way, the rest of the galaxy shields us from the rays, a bit like a huge umbrella.
Scientists at the University of Kansas have studied a vast track of the fossil record and discovered that mass extinctions occur every 62 million years or so, corresponding with the peaks in the cosmic rays. The link requires more study but it’s another possible way for the end of the dinosaurs.
But forget the dinosaurs – what about us? Scientists seem to have calmly glossed over the fact that we stand to get zapped by these rays any time soon.
Don’t worry, The Null is on the case. Keep an eye out for our top tips for avoiding cosmic death.
Anne's a cosmic character. Check out her page.
For more galactic guff, check out:
- News - Space girls get astro-naughty
- Spoof - Terry the Microcosm
- Strange - Sinister shapes on Saturn
- Spoof - Custard seen from space
The Earth gets clobbered with the cosmic stuff about every 62 million years, when it is furthest above the rest of the galaxy. The dinosaurs died out around 62 million years ago, which means… Oh dear.
Cosmic radiation is highly ionising and comes from outside our galaxy. It is mostly screened out by our atmosphere, but large amounts of these rays can cause real damage, disrupting DNA and possibly even causing climate change according to experts.
The amount of radiation that the earth is exposed to varies (slowly) with time. As the earth and the solar system go round the galaxy it wobbles up and down. At some points it is above most of the rest of the galaxy, at some points below. It takes about 225 million years to complete a circuit and the earth bobs up and down four times during this cycle.
When the earth is at its maximum, it is exposed to lots more cosmic rays, which come from the Virgo cluster of galaxies found to the “north” of our own. When it’s on the south side of the Milky Way, the rest of the galaxy shields us from the rays, a bit like a huge umbrella.
Scientists at the University of Kansas have studied a vast track of the fossil record and discovered that mass extinctions occur every 62 million years or so, corresponding with the peaks in the cosmic rays. The link requires more study but it’s another possible way for the end of the dinosaurs.
But forget the dinosaurs – what about us? Scientists seem to have calmly glossed over the fact that we stand to get zapped by these rays any time soon.
Don’t worry, The Null is on the case. Keep an eye out for our top tips for avoiding cosmic death.
Anne's a cosmic character. Check out her page.
For more galactic guff, check out:
- News - Space girls get astro-naughty
- Spoof - Terry the Microcosm
- Strange - Sinister shapes on Saturn
- Spoof - Custard seen from space
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