A team of scientists from Harvard University believes that dark matter is capable of affecting the movement of massive asteroids and comets. They said this mysterious substance could cause major impact events on Earth and trigger mass extinctions.
According to scientists, dark matter is an unseen substance in space that accounts for about 80 percent of the universe's entire mass. It is also believed that its strong gravitational pull is what prevents galaxies from spinning apart.
Causing Extinction Events On Earth
Many scientists believe that a dense disk of dark matter that's about 35 light-wide exists within the central region of Milky Way. Occasionally, the Sun passes through this region as it orbits the center of Milky Way.
According to a study first published in 2014 in the journal Physical Review Letters, the gravitational pull from the dark matter could disturb the massive space rocks residing in the outer regions of the Solar System, such as the Oort Cloud. If this happens, dark matter could cause giant asteroids and comets to collide with Earth.
Since the Oort Cloud is inhabited by mountain-sized asteroids, the resulting impact would have a huge effect on the planet. Aside from the blast, the impact event would trigger extreme environmental conditions that would kill off almost all life on Earth.
How Dark Matter Can Affect Asteroids
As explained by the authors of the study, the possibility of dark matter hurling asteroids toward Earth is based on the theory regarding the Sun's cycle. According to the theory, the Sun passes Milky Way's central region every 35 million years. After analyzing the data of major impact events on Earth for the past 250 million years, the scientists learned that most of the asteroid strikes matched the cycle.
They explained that as the Sun goes through the galaxy's central plane, the Solar System gets exposed to the dangers posed by dark matter in this region. The scientists noted that the major impact event that killed off the dinosaurs might also be related to this cycle.
"The cycle is slightly off for that mass extinction, but we have an incomplete data set regarding impact craters, so maybe with more information the cycle might fit what we know better," the study's co-author Lisa Randall, a theoretical physicist at Harvard University, told Space.com. "Even if it's a remote possibility that dark matter can affect the local environment in ways that have noticeable consequences over long periods of time, it's still incredibly interesting."