black holes

LIGO's first gravitational-wave detection confirmed a century-old prediction of general relativity and opened a new way to observe the universe.

The most massive black holes challenge galaxy formation models. This article explains ultramassive black holes, how mass is measured, and why records change.

Stephenson 2-18 is a star so large that if it replaced the Sun, its surface would engulf Saturn's orbit. The black hole at the center of galaxy TON 618 contains 66 billion solar masses — more than the combined mass of every star in the Milky Way. The Hercules-Corona Borealis Great Wall spans 10 billion light-years, a structure so enormous that its very existence challenges the standard cosmological model. Mass in the universe operates at scales that have no human analogy, and each record reveals a different physical constraint — or its violation.

Four million solar masses packed into a region smaller than our solar system, sitting 27,000 light-years from Earth. For three decades, astronomers tracked stars swinging around it at nearly 3% of the speed of light. Then, in 2022, they photographed it.

When physicists say a singularity exists at the center of a black hole, they do not mean a point of infinite density crammed into zero volume. They mean that the equations of general relativity stop making predictions, and that something beyond those equations is needed. The distinction matters enormously for what singularities are and whether they are real.

Black holes come in sizes that span 10 orders of magnitude, from a few solar masses to tens of billions — but the range between roughly 65 and a few hundred solar masses appears nearly empty. A 2020 gravitational wave event punched straight through that forbidden zone, and nobody fully agrees on how.

On September 14, 2015, LIGO detected a ripple in spacetime from two merging black holes a billion light-years away. Here is how the instrument works and what it measured.

Black holes explained: how they form from stellar collapse, what happens at the event horizon, why Hawking radiation matters, and what the information paradox means for physics.

Roger Penrose won the 2020 Nobel Prize for proving black holes must exist. He also drew the impossible triangle that inspired Escher and argues quantum effects in microtubules produce consciousness.

Subrahmanyan Chandrasekhar's life, the Chandrasekhar limit, and verified quirks: humiliated by Eddington, derived the limit at 19 on a ship, taught 2 students who both won Nobels.

Stephen Hawking's life, discoveries, and verified quirks: betting against his own theories, running over Prince Charles's toes, and flying weightless at 65.

Wormholes: theoretical tunnels through spacetime. Einstein-Rosen bridges, exotic matter, traversability, ER=EPR, and time travel paradoxes explained.