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# Physics

## Latest Articles

### Black Hole Echoes Would Reveal Break With Einstein’s Theory

Gravitational waves have opened up new ways to test the properties of black holes — and Einstein’s theory of gravity along with them.

### Why Stephen Hawking’s Black Hole Puzzle Keeps Puzzling

The renowned British physicist, who died at 76, left behind a riddle that could eventually lead his successors to the theory of quantum gravity.

### How Einstein Lost His Bearings, and With Them, General Relativity

By 1913, Albert Einstein had nearly completed general relativity. But a simple mistake set him on a tortured, two-year reconsideration of his theory. Today, mathematicians still grapple with the issues he confronted.

### Why the Tiny Weight of Empty Space Is Such a Huge Mystery

The amount of energy infusing empty space seems too small to explain without a multiverse. But physicists have at least one alternative left to explore.

### To Test Einstein’s Equations, Poke a Black Hole

Two teams of researchers have made significant progress toward proving the black hole stability conjecture, a critical mathematical test of Einstein’s theory of general relativity.

### Physicists Find a Way to See the ‘Grin’ of Quantum Gravity

A recently proposed experiment would confirm that gravity is a quantum force.

### Elusive Higgs-Like State Created in Exotic Materials

Two teams of physicists have created the “Higgs mode” – a link between particle physics and the physics of matter. The work could help researchers understand the strange behavior of deeply quantum systems.

### Physicists Mourn Joe Polchinski, Developer of Deep Ideas and Paradoxes

The theoretical physicist Joe Polchinski, who died February 2, left a tremendous professional and personal legacy, says a friend and collaborator.

### Neutron Lifetime Puzzle Deepens, but No Dark Matter Seen

Two methods of measuring the neutron’s longevity give different answers, creating uncertainty in cosmological models. But no one has a clue what the problem is.