Why is the universe ripping itself apart? A new study of exploding stars shows dark energy may be more complicated than we thought

The remains of a Type Ia supernova – a kind of exploding star used to measure distances in the universe. NASA / CXC / U.Texas, CC BY

What is the universe made of? This question has driven astronomers for hundreds of years.

For the past quarter of a century, scientists have believed “normal” stuff like atoms and molecules that make up you, me, Earth, and nearly everything we can see only accounts for 5% of the universe. Another 25% is “dark matter”, an unknown substance we can’t see but which we can detect through how it affects normal matter via gravity.