The remnants of the nuclei of stars that exploded in supernovae, known as neutron stars, are one of the most dense objects in the universe. In them, twice the mass of the Sun is equivalent to a city, dozens of kilometers in diameter, in an incredibly small space.

Due to the intense gravity of the surface of neutron stars, Thin crust of hydrogen and helium, Is incredibly smooth, although minor deformation may occur due to stellar activity. New modeling has shown that this variant is 100 times smaller than expected.

“Neutron stars are incredibly circular objects,” says Fabian Gittins of the University of Southampton in the UK. “It’s really impressive.”

Gittins and colleagues modeled the various forces acting on a neutron star, and found that any surface irregularities were less than 0.1 mm in height, otherwise the surface would shrink.

“We’ve found a lot of misconceptions,” Gittins said. “Previous work has given the stars a physically impossible appearance.”

Astronomers thought that changes in the surface of neutron stars would distort the space-time needed to detect the gravitational waves, but this latest work suggests that they are more difficult to detect than expected.

As in the case of the Einstein underground telescope in Europe, “we can only do this with third-generation gravitational wave detectors,” says Gittins.