Neutron Stars Are So Dense They Warp Light

Neutron stars pack more mass than the Sun into a sphere just 20 km (12 miles) wide. That insane density creates gravity strong enough to bend light around the star. If you could see one up close, its immense gravity would bend light from the far side around to you, so you could see more than half of its surface at once. This effect, called gravitational lensing, means a neutron star doesn’t look like a normal sphere—it looks distorted, like something out of a funhouse mirror.