The next supernova
nthenearfuture,thefullMoon
willhavealuminousrivalasa
cataclysmicevent 650 lightyears
awaywillmomentarilyshinewith
thebrightnessof 10 billionSuns.Theafter-
effectswillhanginourskyformanymonths,
andpermanentlyalterournightskyinawaynot
witnessedinrecenthumanhistory.Betelgeuse
isoneofourmostrecognisablestars.Forming
partoftheOrionconstellation,itsbright-red
appearance,duetoitsvastsize,hasbeennoted
bystargazerssinceantiquity.
PlaceBetelgeuseintheexactlocationof
ourSunandthestar’sequatorwouldextend
outtotheorbitofJupiter,withalltheinner
rockyplanetsmovingalonginsideitsfiery
outeratmosphere.Forthemajorityofpeople
livingunderlight-pollutedcityskieswithouta
telescope,Betelgeuseislikelythelargestobject
theywilleversettheireyeson.I
In recent months, however, it has been
trickier to spot. The star described by the
ancient Greek astronomer Ptolemy and named
by medieval Islamic astronomers has started to
fade from view. A notice posted in December
by astronomer Edward Guinan at Villanova
University described it as about half as bright as
it was in September. Subsequent measurements
by the same team have shown it has rapidly
become the faintest, dimmest and reddest it has
been in at least 40 years. It was off their charts.
“We changed the graph scale because I was
plotting points in open space,” says Guinan.
However, any reports of Betelgeuse’s demise are
much exaggerated... or at least premature. One
thing we know for certain about this supergiant
star is that it won’t be going out with a whimper.
In fact, our models of stellar evolution show it
will end its life in a huge supernova that is due
anytime in the next 100,000 years. And somehave speculated Betelgeuse’s winter retreat
might actually be preparation for an imminent
grand finale.
When Betelgeuse does go supernova, whoever
is around to see it will witness one of the greatest
astronomical events of that decade, century and
perhaps even millennium. If human civilisation
is still going, the star will write its name in
our astronomical history in a way that only a
few others have. One example can be found in
ancient Chinese manuscripts. These describe the
appearance of a ‘guest star’ in the year 1054, an
event since linked to the supernova that formed
the famous Crab Nebula. Its appearance as a new
light in the night sky, six-times brighter than
Venus, was also noted in the Arab world, and
more controversially has been linked to cave art
in North America.