There are a couple of ways that scientists can date planets, so which planets formed first in our solar system?

About 4. 6 billion years ago, the Solar System formed from a cloud of dust and gas collapsing in on itself due to gravity.

Did you know our solar system might have had an extra planet? Scientists believe a mysterious ninth planet once existed but got kicked out long ago! This "lost" planet could have been tossed into deep ...

A recent research paper suggests that a planet may exist far beyond Neptune — less than 20 years after the previous ninth planet, Pluto, was demoted. That research paper, accepted last month for ...

The shocking findings were part of a recent study in which astronomers effectively peered back in time to discover what Jupiter was like in its early years. Jupiter is not only the largest in the ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...