Transcript Dwarf Planets - Cloudfront.net

The Small Stuff
Meteoroids, Asteroids
Dwarf Planets
And Comets
Five types of objects orbit the Sun:
1. Planets, that have enough mass to be spherical
and clear their orbits of other objects of similar
size. (they are also “differentiated” or layered)
2. Dwarf Planets, which have enough mass to be
round but haven’t cleared their orbits
(also differentiated)
3. Comets, Icy objects that melt as they near the Sun
forming “tails”
4. Minor Planets or Asteroids, rocky objects that
have too little mass to make themselves spherical.
5. Meteoroids, even smaller rocky objects
Meteoroids, Meteors & Meteorites
Meteoroids often have orbits that cross that of
Earth.
When they are in space they are called Meteoroids
When they fall through the atmosphere they heat
up and glow…
A “falling star” or Meteor
The largest meteors are known as “Fireballs”
Most burn up before they hit the surface.
Those that hit the Earth (or other planet or moon)
are called Meteorites
Three Kinds of Meteoroids
Meteoroids are divided
into three kinds by
content:
1. Iron, made of metal,
mostly iron-nickel.
2. Stony, made of
silicates
3. Stony-Iron, of mixed
composition
Chondritic Meteoroids
Most stony meteoroids are made of smaller rounded chunks
called chondrules
These “chondritic” meteoroids are 4.5 billion years old.
They probably are some of the first objects to condense out
of the solar nebula
Carbonaceous Chondritics
Some chondritic meteoroids have a high carbon content.
These carbonaceous chondritic meteoroids often contain
organic compounds including
amino-acids!
So the building blocks of proteins and thus life have been
around since before the solar system formed.
Origin
Most meteoroids are fragments of asteroids
or comets.
Some have been blasted off of planets or
moons during collisions.
Some may have condensed in the early solar
system and just never became part of a
larger object.
Meteor Showers
Meteors fall toward Earth all the time.
Meteoroids that came from comets often orbit in
groups near the path of the comet’s orbit.
When the Earth passes through one of these “clouds”
of meteoroids the number of meteors per hour
goes up significantly
A Meteor “Shower”
They are predictable.
And are named for the constellation they seem to
come from