Question: why is pluto so far away

Douglas Blane answered on 24 Jun 2010:

Poor old Pluto, which was demoted recently from a full planet to a dwarf, is a long way away.

It’s almost 40 times as far from the sun as Earth. And we’re 92 million miles from the sun.

So why? Well all the planets, moons, asteroids and comets formed at the same time as the sun, from a huge cloud of gas and dust in space.

This gradually got smaller because of its own gravity pulliing it in. But the cloud was spinning at the start, and when something shrinks it spins faster. (Think of a skater pulling her arms in.)

So some of the gas and dust ended up spinning too fast to fall into the centre to form the sun – although most of it did.

So you get a big mass at the centre, the sun, and a whole load of planets, moons, asteroids and comets stretching out into space.

Pluto is far away but it isn’t the furthest part of our solar system. There are other dwarf planets and comets beyond.

Even out there though, it’s still a very long way to the nearest star, Alpha Centauri.