Did a Disk of Dark Matter Cause the Dinosaurs to Go Extinct?
The scientific community widely accepts the notion that the extinction of dinosaurs was caused by a collision between the Earth and a massive object such as a meteor, the impact of which brought the Earth into an ice age that wiped out up to three-quarters of the species. We've never had a definitive answer, however, for the origin of said massive object. That might be about to change, as several scientists from Harvard theorize that a disk of dark matter at the center of our galaxy may have indirectly caused the collision.
The nature of dark matter remains under investigation by astrophysicists, but there is a near consensus among scientists that the majority of the universe consists of dark matter or dark energy. Dark matter refers to a hypothetical type of matter that accounts for observed phenomena that appear to be the result of mass where mass cannot be seen. Astrophysicists believe that dark matter is matter composed of particles that do not emit or absorb light and that interact only through gravity and the weak force (weakly interacting massive particles, or WIMPS).
Credit: The Daily Galaxy
Recently, theoretical physicists Lisa Randall and Matthew Reece suggested that a hypothetical type of dark matter could form a sort of disk that runs through the center of the Milky Way. If the solar system were to move through this disk, then the gravitational effects of the dark matter could potentially dislodge comets and meteors from orbit.
"Those objects are only weakly gravitationally bound," Randall said. "With enough of a trigger, it's possible to dislodge objects from their current orbit. While some will go out of the solar system, others may come into the inner solar system, which increases the likelihood that they may hit the Earth."
According to the model created by Randall and her team, the solar system would pass through the disk of dark matter every 35 million years, which is consistent with evidence from impact craters that demonstrates an increase in meteor strikes that occurs periodically on approximately that timetable.
If this model is correct, then scientists would not only need to re-evaluate the mass extinction event, but many other scientific mysteries as well, such as the mechanism by which the massive black holes at the center of galaxies form.
"One possibility is that it may 'seed' black holes at the center of galaxies," Randall said. "This is a work in progress. It's an entirely new scenario we're working out, so I don't want to overstate anything, but it's a very interesting possibility."