Earth may be in great danger as the sun’s path through the galaxy sends comet flying towards our planet, scientists have warned.
Researchers have identified a 26 million-year cycle of meteor impacts that coincides with the timing of mass extinctions over the past 260 million years.
The doomsday events are linked to the motion of the sun and its family of planets through the dense mid-plane of the Milky Way.
Researchers have identified a 26 million-year cycle of meteor impacts that coincides with the timing of mass extinctions over the past 260 million years. Pictured is a graph showing how the rate of cratering has changed on Earth over time. The arrows indicate the dates of mass extinctions
Gravitational disturbance of the Oort Cloud – a shell of icy objects on the outer edge of the solar system – is believed to lead to periodic showers of comets pouring through the inner region where the Earth resides.
The last of these events is said to have occurred about 11 million years ago, roughly the same time as the Middle Miocene mass extinction.
But according to geologist Professor Michael Rampino, it might be wrong to assume that we are living in a completely safe era, millions of years away from the next danger period.
‘There is evidence that the comet activity has been high for the last one to two million years, and some comet orbits are perturbed, so we may be in a shower at the present time,’ he said.
Earth may be in great danger as the sun’s path through the galaxy sends comet flying towards our planet, scientists have warned. The doomsday events are linked to the motion of the sun and its family of planets through the dense mid-plane of the Milky Way
‘That would agree with our position near the galactic mid-plane, where perturbations from dark matter etc. would be expected.’
WHAT IS DARK MATTER?
Dark matter surrounds galaxies across the universe, and is invisible because it does not reflect light.
It cannot be seen directly with telescopes, but astronomers know it to be out there because of the gravitational effects it has on the matter we can see.
The European Space Agency says: ‘Shine a torch in a completely dark room, and you will see only what the torch illuminates.
‘That does not mean that the room around you does not exist.
‘Similarly we know dark matter exists but have never observed it directly.’
Scientists are fairly sure it exists and is crucial to the universe, but they do not know what it looks like or where to find it.
Dark matter is the mysterious invisible substance that surrounds galaxies and can only be detected from its gravitational effects.
It is believed to account for more than 80 per cent of all the matter in the universe.
Professor Rampino, from New York University, and colleague Professor Ken Caldeira, from the Carnegie Institution, carried out an analysis of meteor impacts and extinctions using newly available data providing more accurate age estimates.
They found that six mass extinctions linkedwith the timing of heightened periods of impact cratering on Earth.
One of the impacts studied was caused by the large comet or asteroid that struck the Earth 65 million years ago off the Yucatan coast of Mexico and is said to have wiped out the dinosaurs.
Five of the six largest impact craters coincided with mass extinction events, said the scientists writing in the journal Monthly Notices of the Royal Astronomical Society.
‘The correlation between the formation of these impacts and extinction events over the past 260 million years is striking and suggests a cause-and-effect relationship,’ said Prof Rampino.
‘This cosmic cycle of death and destruction has without a doubt affected the history of life on our planet.’
Dark matter clustered within the dense disk of the Milky Way (shown above) could trigger extinction events by sending comets on a collision course with our planet and sparking geological disruption on the Earth