From New Scientist:
Last year Lisa Randall and Matthew Reece of Harvard University and their colleagues came up with a model that suggested there are thin, unseen discs of dark matter lurking within galaxies, or at a slight angle to them.
Our solar system orbits the galaxy every 70 million years, which would mean it passes through such a disc every 35 years. And comets spike at about that frequency. However,
The Chicxulub crater that has been linked to the extinction of the dinosaurs 66 million years ago does not completely coincide with the solar system passing through the disc – but Randall says there are enough uncertainties that there still could be a link. “It comes reasonably close, it’s not a perfect fit but it’s one possibility,” she says.
A further complicating factor is that craters are formed by comet and asteroid impacts, but only comets originate in the Oort cloud and so are far enough out to be diverted by dark matter. The team hopes to distinguish between the two types of impacts in future to hone their analysis.
Another one in the mix.
Smoking killed the dinosaurs? Well, the Chicxulub crater is called a “smoking gun,”and we had to get in our anti-smoking message for the year. 😉
Follow UD News at Twitter!