Celestial bodies within our Solar System, such as Europa and Enceladus, exhibit characteristics of possessing tenuous outer layers encasing vast subsurface oceans. Concurrently, the planet Mercury presents a thin crust overlying a substantial metallic dense core. Analogous to these planetary phenomena, thin envelopes on celestial objects can deform through universally consistent patterns. Europa is marked by linear geological formations, Enceladus displays distinctive patterns referred to as ‘tiger stripes,’ and Mercury features curved, stepped geological structures. It is posited that neutron stars might harbor comparable surface irregularities. Emerging scientific inquiry suggests that any such undulations on neutron stars could engender detectable ripples in spacetime, commonly known as gravitational waves.
An artist’s impression of a neutron star. Image credit: Sci.News.
Neutron stars are objects of extraordinary density, surpassing that of lead by a trillionfold, and the nature of their surface topography remains largely enigmatic.
Theoretical physicists specializing in nuclear matter have investigated the mechanisms responsible for the formation of such topographical features on solar system moons and planets.
Certain of these investigated mechanisms indicate a high probability of neutron stars possessing mountainous formations.
Any such mountains on neutron stars would possess magnitudes far exceeding terrestrial elevations, being so immense that their inherent gravitational pull would be sufficient to generate gravitational waves.
The Laser Interferometer Gravitational Wave Observatory (LIGO) is presently engaged in the detection of these specific cosmic signals.
“The magnitude of these waves is so infinitesimal that their detection necessitates highly refined and sensitive observational techniques, meticulously calibrated to anticipated frequencies and other specific signal attributes,” stated Indiana University nuclear astrophysicist Jorge Morales, alongside Professor Charles Horowitz.
“The initial detection of continuous gravitational waves will unveil novel perspectives on the cosmos, furnishing invaluable insights into neutron stars, which are the most compact celestial entities aside from black holes.”
“Furthermore, these detected signals may offer stringent validation of the fundamental principles governing the universe.”
The researchers drew parallels between the hypothetical mountains on neutron stars and the surface features observed on bodies within our solar system.
“Both neutron stars and certain moons, such as Jupiter’s moon Europa or Saturn’s moon Enceladus, are characterized by thin outer shells overlaying profound internal oceans, while Mercury features a diminutive crust above a substantial metallic nucleus. The deformation of thin layers can manifest in a universal manner,” they elaborated.
“Europa exhibits linear geological features, Enceladus is distinguished by its ‘tiger stripes,’ and Mercury is characterized by curved, staircase-like formations.”
“The presence of mountains on neutron stars could result in analogous surface features, potentially detectable through the observation of continuous gravitational wave emissions.”
“The innermost region of the Earth’s core exhibits anisotropy, with a shear modulus that is dependent on the directional orientation.”
“Should the crustal material of a neutron star also possess anisotropic properties, a mountain-like deformation would ensue, and its elevation would escalate proportionally to the star’s rotational velocity.”
“Such a surface irregularity could provide an explanation for the maximum observed rotation rates of neutron stars and a potential minimal deformation in radio-emitting neutron stars known as millisecond pulsars.”
The scientific publication detailing this research has been featured in the esteemed journal Physical Review D.
