Could dark matter cause some mass extinctions?
In Earth’s path around and through our Galaxy’s disc, dark matter may perturb the orbits of comets and lead to additional heating in the Earth’s core, both of which could be connected with mass extinction events, according to a research finding by New York University Biology Professor Michael Rampino.
Writing in an open-access paper published today, Feb. 19, in Monthly Notices of the Royal Astronomical Society, Rampino notes that the Galactic disc is the region of the Milky Way galaxy where our solar system resides. It is crowded with stars and clouds of gas and dust, and also a concentration of elusive dark matter, hypothesized small subatomic particles that can be detected only by their gravitational effects.
Previous studies have shown that Earth rotates around the disc-shaped Galaxy once every 250 million years, with the Sun and planets weaving through the crowded disc approximately every 30 million years.
Analyzing the pattern of the Earth’s passes through the Galactic disc, Rampino notes that these disc passages seem to correlate with times of comet impacts and mass extinctions of life. The famous comet strike 66 million ago that led to the extinction of the dinosaurs is just one example.
While traveling through the disc, the dark matter concentrated there disturbs the pathways of comets typically orbiting far from the Earth in the outer Solar System, Rampino suggests. This means that comets that would normally travel at great distances from the Earth instead take unusual paths, causing some of them to collide with the planet.
But even more remarkably, with each dip through the disc, the dark matter can apparently accumulate within the Earth’s core. Eventually, the dark matter particles annihilate each other, producing considerable heat. The heat created by the annihilation of dark matter in Earth’s core, which also show peaks every 30 million years, could trigger events such as volcanic eruptions, mountain building, magnetic field reversals, and changes in sea level,
Rampino therefore suggests that astrophysical phenomena derived from the Earth’s winding path through the Galactic disc, and the consequent accumulation of dark matter in the planet’s interior, can result in dramatic changes in Earth’s geological and biological activity.