Dark matter may have helped end the age of dinosaurs, new research reveals.
Our solar system revolves around the Milky Way Galaxy once every 250 million years. During its journey, the Sun and its attendant planets weave up-and-down through the central disk of stars ever 30 million years or so. Regular matter, such as stars, planets, and asteroids, are concentrated within this disk, along with exotic dark matter, which cannot be seen by telescopes.
Dark matter affects normal material through the influence of gravity. New analysis shows that gravitation could perturb the Oort Cloud surrounding the Solar System, sending comets to rain down on the inner solar system, and could also affect the behavior of the Earth's core. Either of these influences could result in mass extinctions, researchers theorize. It is possible that the asteroid strike that ended the age of dinosaurs may have been sent to Earth during one of these passes through the central disk of the Milky Way.
"We are fortunate enough to live on a planet that is ideal for the development of complex life. 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," Michael Rampino of New York University said.
It is possible that dark matter can accumulate in the core of the Earth. There, these particles would, eventually, annihilate each other, producing heat. This extra energy could alter the behavior of the molten cores of the Earth, potentially leading to catastrophic volcanic eruptions, magnetic field reversals, and subsequent extinctions. Average sea levels show a correlation with the 30 million-year cycle of movement through the galactic disk, which could also have an effect on wildlife.
This new research could provide biologists with information regarding possible causes of extinctions in the geological past of the Earth. It could also help astronomers chart the concentration of dark matter throughout the Milky Way.
Dark matter has never been directly observed by astronomers, but rotational rates of galaxies suggest that an unseen form of matter must exist throughout the Universe. There is simply not enough normal matter to account for observed rotational rates.
Although the presence of dark matter could explain some mass extinctions on Earth, the process is unlikely to be responsible for all such events.
Analysis of extinctions and their possible tie in with Earth's orbit around the Milky Way was profiled in the Monthly Notices of the Royal Astronomical Society.