By examining gas lit up by an exploding star, astronomers have obtained new insight into how a common type of supernova erupts.
According to a widely accepted model, the stage is set for a type 1a supernova when a dense, Earthsize star called a white dwarf steals gas from a bloated companion star. When the gas-guzzling white dwarf tips the scales at more than 1.4 times the mass of the sun, it blows to smithereens.
That's the theory, but astronomers aren't sure that they've got it exactly right. Getting the model correct is critical because researchers rely on type 1a supernovas to measure the distance and expansion rate of the universe.