Dark Matter May Cause Mass Extinctions and Geologic Upheavals on Planet Earth

How much does dark matter impact our planet? It could have massive effects on Earth, according to a new study. Scientists have concluded that Earth's infrequent but predictable path through our galaxy's disc may have a direct effect on geological and biological phenomena occurring on Earth, and that movement through dark matter may perturb the orbits of comets and lead to additional heating in the Earth's core, which could be connected with mass extinction events.

The galactic disc is the region of the Milky Way Galaxy where our solar system resides. It's crowded with stars and clouds of gas and dust, and also a concentration of elusive dark matter-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. However, the Earth's path is wavy, with the sun and planets weaving through the disc about every 30 million years.

Now, scientists have analyzed the pattern of the Earth's passes through the galactic disc. They've found that these disc passages seem to correlate with times of comet impacts and mass extinctions of life on Earth. As an example, the famous comet strike 66 million years ago led to the extinction of the dinosaurs.

So what causes this correlation between Earth's passes and the impacts and extinctions? 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. This means that comets that would normal travel at great distances from Earth instead take unusual paths that may make them collide with the planet.

That's not all the researchers found, though. With each dip through the disc, dark matter can accumulate within Earth's core. Eventually, the dark matter particles annihilate each other, producing considerable heat. This heat in Earth's core could trigger events such as volcanic eruptions, mountain building, magnetic field reversals and changes in sea level; these events also show peaks every 30 million years.

"We are fortunate enough to live on a planet that is idea for the development of complex life," said Michael Rampino, one of the researchers, in a news release. "But the history of the Earth is punctuated by large scale extinction events, some of which we struggle to explain. It may be that dark matter-the nature of which is still unclear but which makes up around a quarter of the universe-holds the answer. As well as being important on the largest scales, dark matter may have a direct influence on life on Earth."

The findings are published in the journal Monthly Notices of the Royal Astronomical Society.

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