Betelgeuse is flustering astronomers once again, as it is now shining 50% brighter than usual.
This dying red giant had only recently mysteriously dimmed its shine after an enormous explosion.
It is expected to explode into a supernova visible from Earth, though likely not for thousands of years.
Betelgeuse, one of the most visible stars in the Earth's sky, is behaving very weirdly.
The red giant — a star not far from death — is now shining about 50% brighter than it usually would, scientists said.
Scientists later found out that Betelgeuse was not yet collapsing. But it had experienced an enormous explosion that affected its brightness.
More recently astronomers have noticed Betelgeuse returning to its brightest state about twice as quickly as usual, in about 200 days, per a study published on the pre-print server arXiv on May 18.
It's not uncommon for Betelgeuse to get dimmer and brighter — but that tends to happen following a 400-day-long cycle. This cycle shortening is likely linked to the Great Dimming of 2019, experts have said.
Your friendly neighborhood giant dying star
Scientists are keeping a close eye on Betelgeuse, as this red giant is a dying star that is close to turning supernova. However, given the huge timescales in the life of stars, this last step may still take thousands of years.
Betelgeuse (pronounced like the Tim Burton character Beetlejuice) is a relatively young star in the Earth's backyard, located in the Milky Way about 640 light-years away.
It is about 10 million years old, much younger than our sun, which has been around for about 5 billion years. But this star is so big, about 700 times the size of the sun, that it is already starting to die.
"One of the coolest things about Betelgeuse is that we're watching the final stages of big-star evolution play out almost in real-time for us, which we've never really been able to study in this much depth before," said Sara Webb, an astrophysicist at the Swinburne University of Technology in Australia, in an interview with the Guardian.
The explosion is still being felt
Betelgeuse's weird behavior is likely linked to the Great Dimming of 2019 and 2020.
Scientists started raising alarm bells when they spotted Betelgeuse had lost its brightness in no time at all in 2019. When massive stars abruptly lose brightness, it can be a warning sign that they are ready to explode.
But later analysis suggested something else — an explosion. Betelgeuse had released an enormous amount of its plasma into space in the blast, seen in the artist's impression here:
The explosion was so massive that it created a dense cloud of cosmic dust that stood between the Earth and Betelgeuse, obscuring the star.
Andrea Dupree, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics who tracks the star told Scientific American that the star's weird behavior is likely a consequence of this massive explosion.
"Just imagine if you take a hunk of the material out. Then everything else is going to swish in, and it's going to slosh around," he said.
Betelgeuse could burst into a supernova visible from Earth — one day
When it finally explodes, Betelgeuse is far enough that it won't be dangerous for our planet, but near enough that it will be a spectacular show for anyone watching.
On the day, the sight will be momentous. The explosion will be so bright that, for about a week, it could be visible during the day, The Guardian reported. The last time such a supernova exploded in our galaxy was in the 17th century, Insider previously reported.
That is, if humans are still around to see it. Experts are quick to explain that this is unlikely to happen for at least another 10,000 years.
That being said, stars are very unpredictable, so a supernova within our lifetimes is not completely impossible.
Read the original article on Business Insider