Rocky bodies called protoplanets were thought to have formed slightly earlier in the inner solar system than those beyond the ...

Mercury is by far the smallest planet in the solar system, with only around 5.5% of both the mass and volume of Earth.Despite that diminutiveness, Mercury manages to be the second-densest planet ...

Close stellar encounters could change the structure of our planetary system, potentially dooming Earth or other worlds to ...

In the remote outer reaches of planetary systems, far beyond the orbit of known planets, enormous and mysterious worlds silently loop around their stars. Some drift as far as 10,000 times the distance ...

When the Sun expands into a red giant, it will swallow the inner solar system and raise the temperature in the outer regions. Skip to content Introducing the all-new Astronomy.com Forum!

The planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. If you include the ...

How did the Solar System's giant planets form? The Solar System formed from a collapsing gas cloud, with the vast majority of it becoming part of the Sun.The remaining 0.1% of matter formed a ...

The location of the solar system's outer boundary is a point of contention among astronomers. There are three possible candidates, which "all have merit." But which one is best?

The solar system continues to intrigue scientists and space enthusiasts alike, with each discovery unfolding new secrets about our cosmic neighborhood. While we’ve acquired substantial knowledge ...

Our Solar System is full of mysteries, but if the inner planets are a puzzle, the boundary between the Solar System and interstellar space is a secondhand puzzle with half the pieces missing.