Our solar system has eight planets but in recent years, astronomers have theorised there could well be a ninth planet that's hiding in our solar system we've not been able to see yet.

Everyone's favorite dwarf planet, Pluto, was discovered just 95 years ago. Here's the story of how the once-ninth planet was ...

Our solar system is probably on the mild side compared ... mission called New Horizons that will send an unmanned probe past Pluto and its five known moons in July 2015. From there Stern hopes ...

Once, a gassy envelope of hydrogen and helium surrounded our infant world. Over millions of years, that atmosphere escaped into space. Pluto is the only place in the solar system where we can ...

Planets' temperatures are largely influenced by their structural characteristics and proximity to the Sun, however, Venus ...

New Horizons principal investigator Alan Stern says, "Pluto is showing us a diversity ... the fascinating dwarf planet at the edge of our solar system. Produced by Alex Kuzoian and Jessica Orwig.

and Vesta as full-fledged members of our planetary system. Today, when tens of thousands of minor planets have been discovered (most residing in an "asteroid belt" between Mars and Pluto), not ...

Narrator: Serious scientists, like myself, believe our solar system was formed by the collapse ... moons and dwarf planets such as Pluto. What's this? Oh noooo… Stella: You should know where ...