Science has many scenarios for the apocalypse. Air & Space talks about one more thing – this is a supernova explosion. In the past, it was supernova explosions that were one of the causes of mass extinctions on our planet. During one such extinction, 70% of all terrestrial vertebrates died.
Betelgeuse is harmless, but other stars turning into supernovae can doom the Earth to death.
In a recent publication on The Astronomer’s Telegram, Edward Guinan and Richard Wasatonic of Villanova University reported a mysterious darkening of the bright star Betelgeuse, which makes up the right “shoulder” of the constellation Orion.
Ginan and his student Vasatonic began to observe this star in 1981, and Vasatonic continues this work since 1995. The red super giant Betelgeuse never shone as dimly as now. In terms of brightness in the starry sky, Betelgeuse occupied eighth or ninth place, but by the beginning of February it dropped to 21 or 22 places, which is why Orion looks rather strange. Since September, the temperature of this star has also fallen by about 100 degrees Celsius, and the brightness has dropped by about 25%.
The question is whether this is a prelude to a supernova explosion, or is it just a natural wobble. Located 700 light years from Earth, Betelgeuse is one of the closest stars to us from among those that may become supernovae. If it explodes, then in brightness it will almost equal the full moon. The expected explosion can occur both tomorrow and after 100 thousand years.
Supernova explosions are one of the causes of mass extinctions on Earth such as what happened 2.6 million years ago, or the Permian mass extinction that happened 252 million years ago. It was the most disastrous disaster for the terrestrial flora and fauna of that time, destroying about 96% of all marine species and 70% of all terrestrial vertebrates.
Fortunately, Betelgeuse does not pose any danger to the Earth. Whenever it explodes, its deadly radiation will spread evenly in all directions, and by the time it reaches us, the level of this radiation will be very weak, without causing any concern. But there are other supernova candidates, such as the Wolf-Rayet stars, which are much more dangerous. Some of them can emit gamma radiation streams that emit radiation in a narrow direction along the axis of rotation of the star. If the Earth is on the line of fire, the consequences will be disastrous. The most notorious example of this kind is the star WR 104, which is too far from our planet to pose a threat to it. But other, closer Wolf-Rayet stars such as the one found in the Gamma Sails system can be much more dangerous.
That is why the study of stars turning into supernovae can save our lives in the future. In the case of Betelgeuse, we will know about a bright explosion in about an hour. This will be known to us by neutrinos and gravitational waves, which will come to us before the impact reaches the surface of the star, and visible light begins to rapidly increase.
It would be nice to follow Betelgeuse this summer, when she comes too close to the Sun, and it will be impossible to observe it from the Earth. The amateur astronomer Walter Webb has one suggestion in connection with this: let our spacecraft located near Mars help us in this matter.