Inside a black hole, the spacetime curvature is so large that light cannot escape, nor can particles, under any circumstances. A singularity, based on our current laws of physics, must be an inevitability. Image credit: Pixabay user JohnsonMartin.

Black Holes Must Have Singularities, Says Einstein’s Relativity

Unless you can make a force that travels faster than the speed of light, a singularity is inevitable.

The more mass you place into a small volume of space, the stronger the gravitational pull gets. According to Einstein’s general theory of relativity, there’s an astrophysical limit to how dense something can get and still remain a macroscopic, three-dimensional object. Exceed that critical value, and you’re destined to become a black hole: a region of space where gravitation is so strong that you create an event horizon, and a region from within which nothing can escape. No matter how fast you move, how quickly you accelerate, or even if you move at the ultimate speed limit of the Universe — the speed of light — you can’t get out. People have often wondered whether there might be a stable form of ultra-dense matter inside that event horizon that will hold up against gravitational collapse, and whether a singularity is truly inevitable. But if you apply the laws of physics as we know them today, you cannot avoid a singularity. Here’s the science behind why.

The very slowly-rotating neutron star at the core of the supernova remnant RCW 103 is also a magnetar. In 2016, new data from a variety of satellites confirmed this as the slowest-rotating neutron star ever found. More massive supernovae can create a black hole, but neutron stars may be the densest physical objects nature can create without a singularity. Image credit: X-ray: NASA/CXC/University of Amsterdam/N.Rea et al; Optical: DSS.