Galactic dark matter may trigger extinctions on Earth

Science : Mass extinctions tend to occur on Earth about every 30 million years. They appear to result either from impacts by extraterrestrial objects or from geological events such as volcanic eruptions. Both types of catastrophes may be caused by dark matter, proposes Michael Rampino, whose research has been published in the Monthly Notices of the Royal Astronomical Society. Rampino notes that as the Sun orbits the center of the Milky Way galaxy, it oscillates vertically with a similar periodicity through the galactic plane. Not only might the presence of dark matter in that plane disrupt the orbits of comets and asteroids, causing them to impact Earth, but dark matter particles might also get trapped by Earth’s gravity and sucked into the planet’s core, where they could fuel geological upheavals. Although what dark matter is remains unknown, its gravitational effect on visible matter indicates that there’s a lot of it.