who's ready to explore more space if
you've joined squeaks and me here
recently then you already know about the
biggest object in the solar system which
is made up of the Sun the earth and
seven other planets the four planets
that are closest to the Sun including
Earth are smaller solid rocky worlds
those are called the rocky planets and
the floor planets farther away from the
Sun are much bigger they are made mostly
of gases those are the gas giants but
there's a lot more in our solar system
than just those eight planets there are
also things like comets and asteroids
there are a lot smaller but they're just
as interesting and they both have one
main thing in common they're basically
flying space rocks let's talk about
comets first the word comet comes from
the Greek word for hairy because some
astronomers once referred to comets as
hairy stars but why a comet isn't a star
at all and it doesn't have hair it's
really a chunk of ice dust and rock
think of it as like a big dirty snowball
in orbit around the Sun as a comment
gets closer to the Sun it's frozen gases
and dust begin to warm up and thaw out
the gas and dust start to break apart
and stream behind the comet making it
look like it has well a big hairy tail
our solar system's most famous comet is
probably the one known as Halley's Comet
it's named after English astronomer
Edmund Halley who figured out what it
really was he had read reports about
three comets that were seen flying by
the earth many years apart but how he
figured out that these three comets were
actually the same comet flying past us
over and over again based on when the
comet had passed by the earth in the
past he predicted when it would come by
again and he was right Halley's Comet
has been spotted from Earth every 75
years or so the last time it came close
was 1986 meaning we'll probably see it
again in 2061 how old will you be then
now comets have really big orbits and
spent a lot of their time in the far
outer reaches of our solar system so
let's talk about rocks that come a
little closer to the earth asteroids
most asteroids are found between the
planets Mars and Jupiter in an area
called the asteroid belt there are a lot
of asteroids cruising around and
belt but most of them are spaced really
really far apart asteroid sort of look
like comets but they don't have
outlines or tails actually they look a
lot more like tiny planets in fact one
famous asteroid named Ida even has its
own moon called dactyl asteroids are
basically broken pieces of unfinished
planets left over from the time when the
solar system first formed they're mostly
big chunks of rock with metals in them
too and as they fly around out there in
the asteroid belt they often crash into
each other sometimes an asteroid will
get bugged clear out of the asteroid
belt they can even get knocked in our
direction if a flying space rock enters
the Earth's atmosphere which is what we
call the layer of gases that surround
our planet it'll start to burn up then
it's called a meteor a really fast drink
of light that flies through the sky you
might have heard this called a shooting
star but now you know it's not a star at
all most meteors burn up completely
before they reach the surface of the
earth but if a hunk of rock is big
enough then some of it might still be
left by the time it reaches the ground
what happens if one of these flying
space rocks hits our planet if that
happens then it's called a meteorite
most meteorites are still pretty small
you could probably hold an average-sized
meteorite in your hand but very rarely
earth can get hit by a rock that's
pretty big in fact most scientists think
that a really big meteorite that hit the
earth millions of years ago led to the
extinction of the dinosaurs but don't
worry most flying space ought to stay
where they are in space now who wants to
go in the backyard and watch for meteors
me too
see you next time for more scishow kids
and remember if you have a question for
any of us here at the fort let us know
by leaving a comment below or emailing
us at kids at the scishow calm