The solar system consists of eight planets, several dwarf planets, hundreds of moons, and billions of asteroids, comets and meteoroids. The exact boundaries of the solar system ar ...

Sound is a constant presence for most organisms on Earth, but throughout the rest of the solar system, sound is often entirely absent. Mercury, for example, has no atmosphere for sound waves to ...

A rare magnetic signal revealed lithium on Mercury, showing the planet is still being reshaped by meteoroid strikes.

Mercury, Venus, Earth and Mars are known collectively as the rocky planets, in contrast the Solar System’s gas giants—Jupiter, Saturn, Uranus and Neptune. (Pluto is an ice dwarf, which makes ...

Some scientists think Mercury formed farther from the Sun and moved inward later in the solar system’s history. This inner world’s proximity to the Sun makes it difficult to observe and study.

The Mercury-bound BepiColombo spacecraft recorded the sound of the solar wind at Venus as it flew just 340 miles (550 kilometers) above the planet's surface during a maneuver designed to adjust ...

Mercury is getting smaller. Over its roughly 4.5 billion years of existence, the dense little planet’s diameter could have shrunk by as much as 14 kilometers, a study published today in Nature ...

With a total volume little more than the Moon, it is the smallest planet in the Solar System and is situated the closest to the Sun. Mercury has no atmosphere to retain heat, meaning that the ...

Mercury is the smallest planet in the solar system — it is only slightly larger than Earth's moon. Since it has no significant atmosphere to stop impacts, the planet is pockmarked with craters.

Mercury is also the smallest planet in the solar system, measuring just 3,032 miles wide at its equator. That makes it only slightly larger than Earth’s moon.

An image of the planet Mercury created by NASA’s Messenger spacecraft in 2008. The planet is the smallest in our solar system and closest to the sun.