Andromeda Galaxy

100 Years after the “Great Debate”: How Edwin Hubble Expanded the Cosmos

In 1924, Edwin Hubble found proof that the Milky Way isn't the only galaxy in the Universe.
Anaxagoras

Anaxagoras and the Eclipse: The First to Get It Right

Scholars sometimes credit Thales or Empedocles of Acragas with the first correct theory of solar eclipses, but it was Anaxagoras who had the science right.

The Hunt for Life in Alpha Centauri

This oddball system of three stars might be our best chance at finding nearby life in the Universe.
Aerial view of Barringer crater in Arizona

The Eight Best Hidden Impact Craters on Earth

Many impact craters on Earth have been erased thanks to wind, water, and plate tectonics. But scientists have clever ways to find them.
An active sun

The Carrington Event of 1859 Disrupted Telegraph Lines. A “Miyake Event” Would Be Far Worse

We don't know what causes Miyake events, but these great surges of energy can help us understand the past—while posing a threat to our future.
The IceCube Laboratory just before South Pole Dawn

“Ghostly” Neutrinos Help Us See Our Milky Way as Never Before

As Marcel Proust said, “The real voyage of discovery...consists not in seeking new landscapes, but in having new eyes.”
The view south from Viking 2, one of two probes sent to investigate the surface of the planet Mars for the first time, September 6, 1976

We Might Have Accidentally Killed the Only Life We Ever Found on Mars Nearly 50 Years Ago

In one experiment, the Viking landers added water to Martian soil samples. That might have been a very bad idea.