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Dinosaurs Done In By... Dark Matter?
bmahersciwriter writes "Theoretical physicists propose that the Sun periodically crosses into a dense layer of dark matter sandwiching the Milky Way. The gravitational push and pull that this creates disturbs debris in the Oort cloud sending deadly comets and asteroids ricocheting around the solar system. This passage happens, their admittedly speculative model suggests, every 35 million years, which jibes somewhat with evidence on impact craters. Take it with a dino-sized grain of salt."
Everything is science is "theoretical", that doesn't mean it's unlikely to be true.
Dark matter explains both galaxy rotation and the behavior of the early universe quite well. Until the CMBR data, dark matter was just one hypothesis among many for galaxy rotation, but only dark matter explained the observed pattern of mass distribution when the universe cooled enough to become transparent for the first time. And the numbers matched to a couple of significant digits, not in some hand-wavey way.
What dark matter is made of is still an open question, but it's pretty clear that about 4/5ths of the matter in the universe is dark.
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Except that to do this you first assume uniform distribution of impacts wrt time...