quasar

Quasars emit a light as bright as that of one trillion stars. Scientists think they get their energy from supermassive black holes.

When astronomers look at the universe on a grand scale—when they step back to view the arrangement of galaxies on a scale of billions of light-years—they see that galaxies are aligned in a web formation.

A comet carrying enough water to fill a small lake provided astronomers with the first tangible evidence to support a controversial theory that Earth’s water may have arrived on comets billions of years ago.