Our solar system wades through the Milky Way not unlike mother Earth orbits the Sun. Every so often we come to a dense section of the spiral disc where comets and other space debris hurl towards us ten times more frequently. Is it time the dinosaurs went distinct again?
Scientists at the Cardiff Centre for Astrobiology built a computer model of our solar system’s movement and found that it “bounces” up and down through the plane of the galaxy. As we pass through the densest part of the plane, gravitational forces from the surrounding giant gas and dust clouds dislodge comets from their paths. The comets plunge into the solar system, some of them colliding with the earth.
The Cardiff team found that we pass through the galactic plane every 35 to 40 million years, increasing the chances of a comet collision tenfold. Evidence from craters on Earth also suggests we suffer more collisions approximately 36 million years. Professor William Napier, of the Cardiff Centre for Astrobiology, said: “It’s a beautiful match between what we see on the ground and what is expected from the galactic record.” Cardiff University
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