まず、ベテルギウスのことは忘れてこの距離(600光年以内)でII型超新星が観測できる頻度について考えてみよう。銀河系に於けるII型の超新星の発生頻度として、(Capellaro et al. 1997)を採用するなら、80万年に一度のイベントとなる。我々が特別に運がいい時代に生きていると仮定しなければ、この距離での超新星観測には数十万年の待ち時間を期待すべきだ。
ガンマ線バーストがかつて地球上で大量絶滅を引き起こしたという研究がある。
カンザス大学とNASAの共同研究による発表なので、トンデモ説ではなさそうだ。 (NASA - Explosions in Space May Have Initiated Ancient Extinction on Earthによる)
<Two Suns? Twin Stars Could Be Visible From Earth By 2012>
Earth could be getting a second sun, at least temporarily.
Dr. Brad Carter, Senior Lecturer of Physics at the University of Southern Queensland, outlined the scenario to news.com.au. Betelgeuse, one of the night sky's brightest stars, is losing mass, indicating it is collapsing. It could run out of fuel and go super-nova at any time.
When that happens, for at least a few weeks, we'd see a second sun, Carter says. There may also be no night during that timeframe.
The Star Wars-esque scenario could happen by 2012, Carter says... or it could take longer. The explosion could also cause a neutron star or result in the formation of a black hole 1300 light years from Earth, reports news.com.au.
But doomsday sayers should be careful about speculation on this one. If the star does go super-nova, Earth will be showered with harmless particles, according to Carter. "They will flood through the Earth and bizarrely enough, even though the supernova we see visually will light up the night sky, 99 per cent of the energy in the supernova is released in these particles that will come through our bodies and through the Earth with absolutely no harm whatsoever," he told news.com.au.
In fact, a neutrino shower could be beneficial to Earth. According to Carter this "star stuff" makes up the universe. "It literally makes things like gold, silver - all the heavy elements - even things like uranium....a star like Betelgeuse is instantly forming for us all sorts of heavy elements and atoms that our own Earth and our own bodies have from long past supernovi," said Carter.
UPDATE: To clarify, the news.com.au article does not say a neutrino shower could be beneficial to Earth, but implies a supernova could be beneficial, stating, "Far from being a sign of the apocalypse, according to Dr Carter the supernova will provide Earth with elements necessary for survival and continuity."