Dinosaurs Done In By... Dark Matter? 135
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."
Dark matter? (Score:2, Insightful)
I'm not a physicist but every description I've heard of dark matter more or less boils down to "we've noticed there is more gravity in areas where we don't see mass. And since only mass can generate gravity we have missing mass. We're going to call that missing mass dark matter."
Okay... fine... but that's entirely theoretical. No one has actually found dark matter... as in put it under a microscope or touched it. So... until then, lets not come up with any halfassed theories regarding it.
Re:magic (Score:5, Insightful)
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.
flawed (Score:3, Insightful)