Asteroids are the chunks of rock and metal,
while comets are frozen balls of dirty ice.
A comet's orbit is from outer space ,
then into our solar system,
around the Sun and back to outer space.
When a comet comes close to the Sun
it is lit up and has a long bright tail.
Halley's Comet is the most famous comet.
It returns once every 76 years .
Halley's comet orbits from beyond Neptune
then comes close to the orbit of Venus.
The comet was seen as far back as 240 B.C.
This regular visitor to our solar system is named
for Sir Edmund Halley who plotted
the comet's orbit. He predicted when it would return,
but he did not live to see it happen.
web page by J.Giannetta