For a brief time in 1976, it seemed as if NASA's Viking landers had found microbes on Mars! Those results have been vigorously disputed in the years since, but the original experiment's principal investigator, Gilbert Levin, still maintains they really did detect Martian microbes.

A new study from Brown University suggests that different deposits of ice at the moon's south pole not only originated from different sources, but also vary greatly in age.

Astronomers in Poland have just published the 1st peer-reviewed paper on the 2nd interstellar visitor, now officially labeled as a comet, 2I/Borisov. Plus check out the new Hubble Space Telescope image of this object.

Nebula IC 63 - in the direction of our constellation Cassiopeia - is slowly dissipating under the influence of ionizing ultraviolet radiation from a hot, luminous variable star known as Gamma Cas.

These images from the Mars Express spacecraft show an ancient, dried-up river system, one of the longest valley networks on Mars.

Watch 2 NASA astronauts aboard the International Space Station (ISS) make history by performing the 1st ever all-female spacewalk on Friday.

Exoplanets - worlds orbiting distant suns - are very, very far away. Astronomers are learning what some might look like, and what's in their atmospheres. Soon - for the first time - a new telescope will be able to "see inside" some exoplanets.

The Cassini mission to Saturn is over, but scientists still pore over its data. The newest discovery is of organic compounds - the ingredients of amino acids, the building blocks of life - in water vapor plumes from Saturn's moon Enceladus.

Scientists working with the Curiosity rover have found salt-enriched rock at a place called Sutton Island on Mars. The rocks suggest ponds with briny water on Mars, billions of years ago.

Astronomers have found 20 new moons orbiting Saturn, bringing the planet's total number of moons to 82. That surpasses Jupiter, which has 79.