A new study suggests thatpowerful flashes of radiation could destroy life on other planets and became the cause of mass extinction on Earth. Physicists have calculated that the gamma-ray bursts observed in the Universe inhibit the development of complex life forms in 90 percent of galaxies. This explains the long search for extraterrestrial intelligence.
Intense high energy radiation,released as a result of such explosions is known to be fatal even for most of the most radiation-resistant organisms. Research can help explain why we still have not found any signs of a complex life elsewhere in our galaxy. It follows that finding extraterrestrial life will be much more difficult than many people think.
Scientists have discovered that in the past the Earth was exposed to gamma-ray bursts. His strength was enough to cause the mass extinction of species on our planet.
The researchers found that the chances of sucha fatal explosion occurred about 500 million years ago, accounting for 50 percent. Recent calculations of gamma-ray bursts show that most of our galaxy - the Milky Way - may become unsuitable for life.
In the Milky Way, the probability of occurrencelethal gamma-ray burst much more. This creates adverse living conditions. The probability decreases only on the outskirts of the galaxy, at a distance of 32,616 light-years from its center, ”says Professor Zvi Piran of the Hebrew University of Jerusalem, who led the study with colleagues from the University of Barcelona (Spain).
According to the expert, life can only be found in10 percent of galaxies. Gamma-ray bursts occur almost daily, and they can be observed using telescopes tuned to detect powerful and bright bursts of energy.
Gamma-ray bursts can last from a few seconds to minutes. They are associated with supernova explosions as a result of the collapse of a rapidly rotating star into a black hole.
Multiple fraction flash radiationseconds near the Earth can damage the thin ozone layer of the planet, protecting its surface from the effects of ultraviolet radiation from the Sun. Gamma rays trigger a chain of chemical reactions that lead to the binding of oxygen and nitrogen to an ozone-depleting substance - nitric oxide.
According to scientists, a flash with a brightness of about 100kilojoules per square meter can destroy 91 percent of ozone in a month. This is enough for the mass extinction of species. Presumably, something similar happened on Earth about 450 million years ago, when more than 80 percent of the species were destroyed - the second largest extinction in the history of our planet. At that time, mollusks and arthropods dominated the Earth, and the first vertebrates were just beginning to appear.
The results of the study were published in the journal Physical Review Letters.