In space everything is inhumanly large, heavy and far. The earth is an insignificant planet, the gigantic sun a modest star. Distances are measured in light years, because the cosmos is only somewhat manageable at the dizzying speed of light. Sometimes it almost seems like it’s on purpose. Anything to hammer in that one message: you, dear people, are totally negligible cosmically.
That same feeling comes over you with the latest addition to the space record books, one that astronomers described this week in the trade magazine The Astrophysical Journal Letters: the most massive neutron star ever measured.
Now neutron stars are already quite extreme phenomena. They form from massive stars when they die with a catastrophic explosion called a supernova. In that ultra-violent event, the remnant of such a star is compressed with unimaginable force. What remains is nothing like the ordinary: a single tablespoon of neutron star weighs as much as the entire Mount Everest.
Neutron Paste
To get a little grip on those bizarre stars, some astronomers turn to – no, really – comparisons with Italian food.
That starts already below the surface, where hundreds of neutrons close together form so-called ‘gnocchi’. Further inwards, where the pressure is higher, these become long strings. That’s right: neutron spaghetti. Even more deeply, those wisps fuse into a plane (neutron lasagna) until a uniform mass of holes is formed, as if they contained elongated tubes: neutron penne, neutron bucatini or, if you prefer, the anti-spaghetti phase. Right.
So much for theory, now for practice.
The star that astronomers discovered is called PSR J0952−0607 and is a so-called pulsar. That is to say: a neutron star that spins like a kind of cosmic lighthouse and sends radiation into the universe. That spinning is going at record speed, but more important is that other record: the star is about 2.35 times as massive as our sun. A mass that he, incidentally, amassed by using his gravity to chew the material from his partner star, something that earned him the nickname ‘black widow’, after the female spider that eats her partners.
The same particles as humans
Because physicists know that there is a point at which a neutron star can no longer withstand the pressure of its own gravity and then collapses into a black hole, it is useful to know where that upper limit is. Then you know how firmly the star props up itself, and that reveals something about the properties of that densely packed interior.
If PSR J0952−0607 is about the heaviest possible neutron star, then it consists of ‘ordinary’ particles inside, the researchers write: neutrons and up and down quarks, for those in the know. The same particles that make up humans, planets and ordinary stars. But if a much heavier variant is discovered in the future, they may contain more exotic particles, which you can only find on Earth in particle accelerators.
And then say goodbye again, with that human touch.