Imagine celestial objects so odd they could be likened to cosmic Russian dolls, where one mysterious body is hidden inside another. This is precisely what researchers from Goethe University in Frankfurt have recently proposed with their theory on "nestars."
For over a century, black holes have captivated and intrigued us. These points of no return, where anything that ventures into them vanishes forever, pose serious puzzles for physicists. The first photograph of a black hole in 2019 was revolutionary, providing us with a direct glimpse into these elusive phenomena.
Artistic rendition of a nestar, inspired by the idea of Russian dolls, where one gravastar is nested within another.
Credit: Goethe University Frankfurt
But what if black holes were not the sole actors in this cosmic play? In 2001, an alternative theory introduced gravastars: objects as dense as black holes but without their most problematic features, such as the central singularity that defies the laws of physics. These gravastars would have a solid surface and a core filled with exotic energy that repels all matter, thus avoiding the unfathomable trap of black holes.
It is in this context that nestars come into play, thanks to the innovative work of Daniel Jampolski and Professor Luciano Rezzolla. These theoretical objects would be like gravastars nested within one another, offering a complex structure. Although this might seem straight out of a science fiction novel, this idea helps scientists explore new ways to understand the Universe.
Exploring nestars and their unique characteristics could shed light on still-unknown aspects of general relativity and the Universe itself. Even if these objects did not actually exist, studying them enriches our understanding of extreme phenomena, like black holes, and the very structure of our cosmos.