By Gravitational Radiation
Whenever two masses orbit each other, the combined effect of the spacetime curvature of the moving objects produces gravitational waves which carry away orbital energy. For small masses this effect is negligible, but for very massive objects like black holes and neutron stars the energy carried away can be rapid enough to cause their orbits to spiral in on each other, eventually merging the two masses.
Read more about this topic: Orbital Decay
Famous quotes containing the word radiation:
“There are no accidents, only nature throwing her weight around. Even the bomb merely releases energy that nature has put there. Nuclear war would be just a spark in the grandeur of space. Nor can radiation “alter” nature: she will absorb it all. After the bomb, nature will pick up the cards we have spilled, shuffle them, and begin her game again.”
—Camille Paglia (b. 1947)