Scientists have analyzed the stars around us and concluded that nearby supernova explosions occur at a frequency similar to the frequency with which mass extinctions occur on our planet. That could be their explanation.
Mass extinctions in Earth’s history
In the history of our planet there have been cases when whole groups of living beings disappeared in the shortest possible period of time. Biodiversity on a planet-wide scale was declining by tens of percent. And a group of researchers from Keele University recently suggested that the cause of these events should be sought in space.
In general mass extinctions, in the history of our planet can be identified up to a dozen, although much more often called the number 5. It all depends on the limit beyond which we consider species extinction to be mass extinction. So the authors’ new paper focuses primarily on two such events. They occurred in the Late Devonian and Ordovician periods 372 and 445 million years ago, respectively.
So far, the specific cause of exactly these two extinctions has not been named. According to the authors of the study, published in Monthly Notices of the Royal Astronomical Society, their cause was the explosions of supernovae very close to the Solar System. This idea was suggested decades ago, but now new arguments have been found to support it.
Frequency of supernova explosions
Supernovae are catastrophic events that release incredible amounts of energy in all parts of the electromagnetic spectrum, including what we commonly call radiation. At the same time, a huge number of atoms of elements heavier than helium are ejected into space. They become the basis for earth-like planets and life on them.
However, if the planet and life on it have already had time to form, a nearby supernova explosion could be fatal to it. Radiation will simply destroy life on the planet partially or completely. But how often this situation occurs is hard to say.
The stars in the galaxy are always moving, periodically moving closer and farther away, and in order to impact the Earth, a large luminary would have to be very close to us. In a new study, scientists have calculated the number of bright blue stars in the radius of kiloparsec, that is, a little more than 3000 years from us, and on this value calculated how often in our neighborhoods occur such events, and this value turns out to be very close to that which separates the mass extinctions in the history of the Earth.
Based on this very information, it was concluded that it was supernova explosions that may be behind the mass extinctions. But at the same time, it became clear that in the next hundreds of thousands, or even millions of years, such events will not threaten us.
According to phys.org
