For 10 years, scientists had been observing one of the largest known stars in the universe, located in a galaxy 75 million lightyears away.
Then one day, it disappeared — and no one knows why. Read more.
Scientists used to wonder whether these split-second bursts of radio waves bombarding Earth might be from aliens.
Now, they know it’s more likely from a massive object like a black hole or neutron star. Read more.
When neutrinos seemed to be traveling through Earth, scientists were left without answers. Some got excited about a potential parallel universe, but that’s more a science-fiction dream.
More likely, scientists discovered a new kind of particle. Read more.