A thin disk of dark matter running through the Galaxy might be behind the large meteorite strikes that are thought to be responsible for some of Earth’s mass extinctions, including that of the dinosaurs, two theoretical physicists have proposed.
The model is based on a hypothetical form of dark matter described by the authors and their collaborators last year1, 2 as a means to solve a separate cosmic conundrum. The existence of such a 'dark disk' could be tested soon by astronomical observations.
Mario Livio, an astrophysicist at the Space Telescope Science Institute in Baltimore, Maryland, who was not involved in the research, says that the latest idea, which brings together two speculative and very different theories, is “very interesting”, even if the evidence supporting it is far from compelling.
Meteorites regularly pepper Earth's surface. Thirty years ago, physicists suggested that this bombardment intensifies cyclically, pointing to some underlying cosmic cause. One proposed explanation is that the Sun has an as-yet-undetected companion star, dubbed ‘Nemesis’ or ‘Death Star’, that regularly swings by, sending comets from the remote Oort cloud flying into the inner Solar System3, 4.
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