In the zoo that is the universe, there is a thing called a magnetar…a vicious beast. Even at a distance of 1,000 kilometres away one would kill you with it’s colossal magnetic field, ripping your flesh due to the diamagnetism of water. At a distance half way to the Moon, a magnetar would wipe your credit card. They are a rare type of neutron star left over from the death of a large mass star in a supernova, and have a very high gravitational field. They are only tens of kilometres across, spin faster than a kitchen blender, and have the mass of the Sun squeezed down tightly into something the size of your town or city. Their magnetic field is colossally powerful, millions of times more intense than any electromagnet humankind can ever make. Star quakes can happen on their surface, disrupting the magnetic field and releasing lethal gamma rays…the most deadly form of electro-magnetic radiation
But astronomers using ESO’s Very Large Telescope have found one of these magnetic monsters in a cluster of hundreds of very heavy weight stars, 16,000 light years away. The magnetar’s home is a cluster called Westerlund 1, with some of the stars in the cluster at 2,000 times the diameter of the Sun. But this one particular magnetar has really thrown a spanner in the works, and messed about with what astronomers thought they knew about those other beasts of the universe, black holes.
Now it all comes down to mass, the mass of a star usually dictates what it’s eventual fate will be when it gives it’s last choking gasps at the end of it’s life. If it’s a stellar specimen around the size of the Sun it will result in a red giant and eventually a pretty planetary nebula. If it’s something heavier, say ten to twenty times the mass of our Sun, then a neutron star would result such as what powers the famous Crab Nebula. A neutron star is extremely dense, but not quite a black hole. Any star tipping the scales at over 25 times the Sun’s mass would definitely result in a black hole.
But here’s where the fly in the ointment is…as you know this magnetar is of course a type of neutron star, but it has formed from the demise of a massive star that was a whopping 40 times the mass of the Sun…at least. By all accounts this should really be a black hole and nothing else, definitely not a neutron star! Obviously the rules that govern the birth of black holes are not as cut and dry as astronomers thought. It now seems much more complicated than that, and has astronomers going back to the drawing board.