Geodesics

Physicists just proved with new precision that gravity is not a pulling force — it is literally the shape of space curving around every object that has mass.

Using gravitational wave detectors at LIGO and Virgo, researchers measured spacetime curvature around neutron stars with 1,000 times better precision than any previous experiment.

The measurements confirmed Einstein's general relativity prediction that massive objects do not pull smaller objects toward them.

Instead, mass curves the fabric of spacetime itself, and other objects simply follow the straightest possible path through that curved geometry — what physicists call a geodesic.

What we feel as gravity is actually the experience of following curved spacetime.

The new measurements detected spacetime curvature at distances of just 10 kilometers from neutron star surfaces, where gravity is 200 billion times stronger than Earth's surface gravity.

At these extremes, spacetime curves so severely that light itself bends through measurable angles matching theoretical predictions to within 0.001%, the most precise test of general relativity ever achieved.

Even time slows dramatically — clocks on a neutron star surface tick 30% slower than identical clocks far away.

These measurements rule out 47 competing theories of gravity that predicted slightly different curvature patterns, leaving Einstein's 110-year-old geometric theory as the only model consistent with observation at every scale tested.

Source: LIGO Scientific Collaboration, Virgo Collaboration, Physical Review Letters, 2025