Exoplanet hunters Christopher Watson and Annelies Mortier explain the long search for a 'twin Earth' capable of sustaining life.

Mercury is tiny, barely bigger than the Moon. Its metallic core makes up 70% of the planet’s mass, vastly exceeding Earth’s 32% and Mars ’ 25%. It’s unlikely that the core actually formed like this.

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and Earth. The authors dubbed it Planet Y.

A recent theory has emerged suggesting that the answer to Mercury’s unusually large metallic core may lie in the early history of our solar system. This theory proposes that a soft collision between ...

Scientists have shown that Earth’s basic chemistry solidified within just three million years of the Solar System’s formation. Initially, the planet was barren and inhospitable, missing water and ...

It’s especially puzzling since Venus is a terrestrial world much like Earth, so much so that it’s considered to be our planet’s “twin,” at nearly the same size and density. We’re also neighbors, ...

On October 6 1995, at a scientific meeting in Florence, Italy, two Swiss astronomers made an announcement that would transform our understanding of the universe beyond our solar system. Michel Mayor ...

The timing of Earth's early formation points to a planet that started out dry. So, life’s essential building blocks arrived later, but how?

NASA has gone silent just hours before humans get their most detailed look at the mysterious object traveling through the solar system.

A respected Harvard astrophysicist believes one of the most famous signals ever sent to Earth could have been sent by the object rapidly approaching our planet.

Forty-three years ago, in March 1982, humanity received its last direct visual postcard from the surface of Venus.

A detection of phosphine in the atmosphere of a brown dwarf 54 light-years from Earth deepens the mystery of phosphorus chemistry throughout the Milky Way.