Solar System Exploration: Kids: EXTREME Space

There are worlds out there cold enough to instantly freeze an explorer into a human popsicle. And others hot enough to boil a person into a wisp of steam in seconds flat. There's also poisonous air, steel-crushing atmospheric pressure and winds that make Earth's most intense tornados seem tame. Pick a planet and read on to find out more amazing facts about our extreme solar system.

Far Out
The band of icy objects that make up the Kuiper (say Ki-Per) Belt is more than 12 to 15 billion kilometers (2.8 billion to 9.3 billion miles) from our Sun - more than twice as far away as Pluto, the most distant planet.

Solid Science
In 1951, astronomer Gerard Kuiper suggested that there was a belt of comet-like debris at the edge of our solar system. But his theory wasn't confirmed until 1991 - more that 20 years after his death.

Little Rock
Quaoar is one of the largest known Kuiper Belt Objects, but it is still much smaller than even the United States. America is about 4,800 km (3,000 miles) across while Quaoar is only about 1,290 km (800 miles) in diameter. No wonder it was so hard to spot.