How Far Away is Pluto From the Sun?

By Fraser Cain - November 14, 2009 at 10:27 PM UTC | Planetary Science

[/caption] How far away is Pluto from the Sun? Pluto's average distance from the Sun is 5.9 billion km or 3.7 billion miles.

But Pluto actually follows an elliptical orbit around the Sun. Sometimes it's much closer to the Sun, and other times it's further away. At its closest point, Pluto measures only 4.4 billion km from the Sun. This is close enough that a thin layer of frost evaporates from its surface, becoming a thin atmosphere around the planet. And then as it continues its journey around the Sun, Pluto gets colder again and this atmosphere refreezes onto the planet. It continues to travel out to a distance of 7.4 billion km from the Sun.

Astronomers use another method of measuring distances in the Solar System called the astronomical unit. 1 astronomical unit or AU is the average distance from the Earth to the Sun; approximately 150 million km. So we can use this to describe Pluto's distance from the Sun. At its closest point, Pluto measures 29.7 AU. And then at its furthest point, Pluto is 49.3 AU.

We have written many articles about Pluto for Universe Today. Here's an article about

why Pluto isn't a planet any more

, and here are some

pictures of Pluto

.

If you'd like more info on Pluto, check out

Hubblesite's News Releases about Pluto

, and here's a link to

NASA's Solar System Exploration Guide to Pluto

.

We've also recorded several episodes of Astronomy Cast about Pluto. Listen here,

Episode 64: Pluto and the Icy Outer Solar System

.