Given that astronomical observations made between 1996 and
2011 have shown that the star Betelgeuse shrank by 15%, is it soon going to
become a supernova?
By: Ringo Bones
Back in 1996 and even more recent astronomical observations
made in 2011 have shown that the star Betelgeuse shrank by 15%, and given what
astronomers have learned over the years observing stars, it is very likely that
Betelgeuse could go supernova in 500-million years’ time. But should all of humanity
be worried?
Given that one of the hypothesized causes of the Permian
Mass Extinction of 250 million years ago was a supernova or stellar explosion
that was much closer to planet Earth than the 100 light-year minimum safe
distance for such events to not disrupt the ozone layer or fry the Earth’s
surface with lethal amounts of ionizing radiation, we should all be a little
worried about the star Betelgeuse going supernova. But there are some very
important factors to consider before anyone gets carried away by the hoopla
over a repeat of the Permian Mass Extinction in our near future.
First, the minimum 100-light-year safety distance for
supernovas is, in truth, but an arbitrarily set safety distance on what
astronomers know so far for supernovas not disrupting our planet’s ozone layer
or frying Earth’s surface with lethal amounts of gamma radiation given that
some stars with weird magnetic field configurations that go supernova can still
wreak havoc to the ozone layers of Earth-like planets 500-light-years from
them. Second, given that Betelgeuse is about 700-light-years away from us, and
assuming the star had gone supernova back in 1996, we – and Earth’s astronomers
- would only know that Betelgeuse went supernova in 1996 only after 683 years
into the future given it would take light and other information pertaining to
Betelgeuse going supernova 700 years to get to Earth. So it might only be a
problem – or an astronomical wonder – for humanity’s future generations hence.
Going supernova or not, Betelgeuse is quite a fascinating
star in itself. As a red supergiant in the constellation of Orion, Betelgeuse
is a very peculiar over-bright star. In spectral type, Betelgeuse is only a red
M-star, shedding its ruddy light from a surface only half as hot as our sun’s.
Normal M-stars are 10-times smaller in diameter and 1,000 times dimmer in light
than our sun. But Betelgeuse equals 800 suns in diameter and 14,000 suns in
brightness.
Another more fascinating aspect of this star is that the
outer edges of Betelgeuse contains huge curtains of billowing gas that rise and
fall quicker that the whole globe of the star’s rotational period. And in these
convection currents, the atoms are more loosely packed than the most perfect
vacuum that our own scientists have so far been able to create on Earth!
