iD Ideas Discoveries March 2017

In 1930, American astronomer Clyde Tombaugh discovered

the ninth planet in the solar system. However, Pluto remains a

mystery even 87 years later. These three blurry images below

were the best ones ever taken of the former planet before New

Horizons began its voyage. Are the colorful patches seen on the

surface impact craters? Or are they mysterious eruptions from

the interior? One thing’s for certain: Hardly any other object in

the solar system has such a diverse surface— Pluto even seems

to have seasons because, over the course of one year there

(248 of Earth’s years), its surface gets redder. And why does

Pluto rotate in the opposite direction with regard to most of the

other planets and moons? The Sun, which is 3.67 billion miles

away, rises every 6.4 days in the west— not in east, as on Earth.

Perhaps therein lies the secret of Pluto’s birth: It and its fi ve

known moons were likely formed by a huge collision with another

Pluto long ago. The New Horizons data should lift the veil a little.

THE ANATOMY OF PLUTO

PLUTO

CHARON

MOON

90° 180° 270°

PLUTO

AT

PLUTO

AT

PLUTO

AT

PLUTO

7% OF

EARTH’S

GRAVITY

165 f t

HIGH

10 ft

HIGH

EARTH

PLUTO

DOUBLE DWARF
Charon is the innermost of Pluto’s
fi ve known moons, and it’s more
than half as large as Pluto itself.
Charon takes six days to orbit Pluto.

SNOWBALL
Frozen nitrogen and methane
constitute the “shell” of the
dwarf planet, below which
lies a thick layer of water ice.
But an ocean of flowing water
could surround its rocky core.

COSMIC PIPSQUEAK

With a diameter of around 1,470 miles,

Pluto is only about two-thirds the size of

Earth’s Moon, and it’s also six times lighter.

Unlike the moon, Pluto has a signifi cant

atmosphere, in which wind even blows.

ideasanddiscoveries.com 79 Mar 2017