Neutron stars, the dense remains of massive stars that have exploded in supernovae, are some of the most fascinating objects in the universe.
These dead stars are incredibly compact—about a trillion times denser than lead. Despite their importance in astrophysics, much about their surfaces remains a mystery.
Scientists now believe these stars may have “mountains,” and these features could reveal exciting new details about the universe.
On Earth, mountains form through geological processes like tectonic activity. Nuclear theorists have explored whether similar mechanisms could create “mountains” on neutron stars.
However, these mountains would be far more extreme than anything on Earth.
Neutron star mountains are tiny compared to Earth mountains, but their immense mass could create ripples in the very fabric of space-time, known as gravitational waves.
Gravitational waves are distortions in space-time predicted by Einstein’s theory of relativity. When neutron stars rotate with these mountain-like features—called non-axisymmetric deformations—they release gravitational waves in a specific and continuous way.
Detecting these waves could provide direct evidence of neutron star mountains and offer a deeper understanding of the universe.
Interestingly, scientists have drawn comparisons between neutron star surfaces and the crusts of moons in our solar system.
For example, Jupiter’s moon Europa and Saturn’s moon Enceladus have thin icy crusts over deep oceans, and Mercury has a thin crust over a metallic core.
These surfaces show unique features: Europa has long, linear ridges; Enceladus displays tiger-like stripes; and Mercury’s surface has curved, step-like formations. Similarly, neutron stars may have distinct patterns on their crusts, potentially revealed through gravitational wave signals.
The height of these mountains on neutron stars could also be influenced by their crust material. If the crust is anisotropic (meaning its strength varies depending on direction), the mountains could grow taller as the star spins faster.
This could help explain the fastest spin rates observed in neutron stars, particularly those known as millisecond pulsars.
The Laser Interferometer Gravitational Wave Observatory (LIGO) is currently searching for these faint gravitational waves.
The signals are so weak that they require highly sensitive instruments and carefully tuned analysis methods to detect. If successful, these discoveries would mark a major milestone in science, providing unique insights into neutron stars—the densest objects in the universe short of black holes.
Detecting continuous gravitational waves would not only deepen our understanding of neutron stars but also test the fundamental laws of physics.
This research could open a new window into the universe, allowing us to explore its secrets in ways never before possible.
