White dwarf pair will trigger a supernova — in 700 million years

Two white dwarfs, dense remnants of stars, are set to spiral together and explode in about 700 million years. With a combined mass about 1.76 times that of the sun, this is the first pair known to be massive enough to generate a powerful explosion known as a type 1a supernova, researchers report in the February 9 Nature.

The duo sits inside the Henize 2-428 nebula, about 4,600 light-years away in the constellation Aquila. When they collide, they will combine into a single star that will be too massive to support its own weight, triggering a collapse that will destroy the star.