Some planets are extremely big—so huge that 1,300 Earths could fit inside one.

Some planets are extremely little—smaller than Earth's moon.

Some planets are extremely fast—speeding through space at 104,000 miles an hour.

Some planets may not be planets at all!

Extreme Planets Q&A has answers to questions such as: What makes up a planet? Why is Earth the only known world where life exists? How can a planet's day actually be longer than its year?

So buckle up as you blast off for an extreme voyage through the solar system, from Mercury to Neptune and beyond!