DK - WOW! The Visual Encyclopedia of Everything

143

Tail shapes

blue and straight, and the The gas tail is

dust tail is white and curved.

The nucleus of Halley’s

Comet is 15.3 km

(9.5 miles) long

Sun’s bright disc

has to be masked

so that the comet

can be imaged

One of more than 30

separate fragments of Comet

Schwassmann Wachmann 3

Several dozen

mini-fragments trail

behind the main one

Jets of dust and gas

stream out of the nucleus

BREAKING UP

▶

As a comet passes a massive body,

such as the Sun or Jupiter, it may be

pulled apart by its gravity. Comet

Schwassmann Wachmann 3 orbits the

Sun every 5.4 years and astronomers

have observed that it is disintegrating.

Closest to the Sun

are longest when closest to The tails

the Sun, then shrink as the

comet moves away.

142_143_Comets.indd 143 03/01/19 12:10 PM