We know of Mars as the red planet, for its surface and atmosphere is caked in endless swirling dust of rusted iron, the rusting action provided by the always-eager oxygen. But this was not always so.

The Solar System is home to a remarkable range of planets, from tiny rocky worlds to massive gas giants. But just how big are these planets really? To put it into perspective, we can run some ...

Since then, astronomers around the world have been studying the planet’s composition through a range of techniques including ...

LOS ANGELES — At least one in every four stars like the sun have planets about the size of the Earth circling them in very close orbits, according to the first direct measurement of the incidence of ...

The three planetary candidates highlighted in this study are Kepler Object of Interest (KOI) 1422.02, which is 90 percent the size of Earth in a 20-day orbit; KOI-2626.01, 1.4 times the size of Earth ...

Somewhere beyond Neptune, the Kuiper Belt is bent. Not by much, and not in a way any known planet can account for. A study ...

Scientists have discovered over 4,000 exoplanets outside of our Solar System, according to NASA’s Exoplanet Archive. Some of these planets orbit multiple stars at the same time. Certain planets are so ...