Space researchers have observed what is believed to be the heaviest known neutron star — a highly dense object formed after a supernova explosion. The star, officially named PSR J0952-0607, is nicknamed the "Black Widow" due to its violent origin and mass-gaining process from a companion star.
It spins over 700 times per second and has a mass approximately 2.35 times that of our Sun, making it nearly dense enough to collapse into a black hole.
This neutron star is a type of pulsar — highly magnetized, rotating neutron stars that emit beams of electromagnetic radiation. Only one other neutron star spins faster.
According to Roger Romani of Stanford University, “The heavier the neutron star, the denser the material in its core.” If this star had any more mass, it would cross the event horizon threshold and become a black hole.
Romani added, “As the heaviest neutron star known, this object presents the densest material in the observable universe. Any denser, and it would be beyond detection, trapped within a black hole’s event horizon.”
The object was studied using the Keck I Telescope in Hawaii and is located about 20,000 light-years from Earth. The term "Black Widow" also refers to a spider species where females consume males after mating — a parallel to the neutron star that has consumed much of its partner’s mass.
The companion star now has just 2% of its original mass, making it more massive than Jupiter but much less than an average star.
This extraordinary discovery pushes the boundaries of astrophysics and gives scientists a deeper look at how matter behaves at such extreme densities.