Throughout the history of the Earth, more than 99 % of that living species that ever walked on its surface were wiped out. Ecological reasons and tragic calamities hitting the Earth, for instance in the form of comets, are said to have led to the mass extinction of those species. A recent study has suggested a new possibility involving dark matter, the mysterious invisible subatomic particles that might account for much of our universe make-up.
The large-scale disappearances of species of the Earth seem to have happened in cycles of around 26 to 30 million years – or so indicate the fossil records. This time lapse fits with the amount of time that our planet takes to pass through the galactic disk of the Milky Way. This region of the Milky Way consists of clouds of dust and gas, and perhaps high levels of dark matter.
Dark matter has not been witnessed by humans. But, scientists purport it indeed exists. They argue that it causes gravitational effects on other heavenly bodies. The scientists have suggested that each square light-year of the region constituted by the galactic plane has about one solar mass of dark matter.
The author of the new study concluded in his paper that the dark matter present in the galactic disk of the Milky Way might disturb comet orbits, rendering the conditions conducive for collisions involving the Earth and comets, annihilating most of the life on the planet. Furthermore, the dark matter is said to heat the core of the Earth such that geological events might be stimulated, like volcanic eruptions that have the potential to destroy life.
Our solar system rotates around the Milky Way – a process taking approximately 250 million years. Furthermore, it also oscillates vertically through the galactic disk, going through the galactic plane in periods of 30 millions years or so. This time limit is where the mass extinction fits: the events that have led to the destruction of life on Earth, including those involving comet impacts, have happened during these time intervals.
The researcher new study argues that the dark matter contained in that region might be shifting orbits of space debris, changing their directions such that they are flung towards the Earth. The collision resulting from this would successfully annihilate life. Dinosaurs, for instance, might have died out as a consequence of this.
Dark matter could also be accumulating in the core of the Earth after having been caught in the latter’s gravity. The particles are said to destroy each other over time, releasing much energy that would heat the core by several hundred degrees Celsius. This heat might eventually reach the surface of the planet, killing all that exists.