Parts of Our Solar System Notes
Our Solar System consists of many objects including the Sun, planets, Moons, dwarf planets, comets,
asteroids, meteors, meteoroids, & meteorites. All of these objects revolve around our sun due to gravity. T
Everything in our solar system revolves around the Sun because it has the most gravitational pull in our solar
system due to its immense size.
Moons
Moons are natural satellites that revolve around something larger like a planets and asteroids. Most moons
are usually made of rock. In our solar system every planet has moons except for Mercury and Venus. The
Earth’s moon causes the Earth to experience tides. Finally, because of the Earth’s moon is tidally “locked” to
the Earth only one side of the moon is visible to the Earth. The moon undergoes moon phases as it revolves
around the sun.
Planets
Planets are celestial bodies that revolve around the sun in an elliptical shape. They are grouped into inner and
outer, based on distance from the sun and common characteristics. The 4 inner planets are considered rocky
planets and are smaller than the outer planets. The outer planets (Jupiter, Saturn, Uranus, Neptune) are much
larger in comparison and are considered “gas giants” because of their size and their primary make up of gases.
Planets are big enough to other some smaller objects to revolve around them (moons) and to clear other
larger objects from near their orbit. The Earth is the only planet/space object in our solar system known to
have life.
Asteroids
Asteroids are metallic, rocky bodies without atmospheres that orbit the Sun but are too small to be classified as planets.
Known as "minor planets," tens of thousands of asteroids orbit in the main belt: a vast, doughnut-shaped ring located
between the orbits of Mars and Jupiter. One scientific theory is that many asteroids are leftover pieces that did not form
into planets with the solar system formed.
Meteors, Meteoroids, & Meteorites
1. Meteorites = A stony or metallic object from interplanetary space that impacts a planetary surface like
Earth.
2. Meteor = A small rock in space that orbits the sun.
3. Meteoroids - when a space rock enters the atmosphere, commonly known as a shooting star.
Meteoroids glow because of pressure from the Earth’s atmosphere heating and melting the gases on
the meteoroid.
Our Sun
Our Sun is much larger than a planet and is composed of hot, glowing gases (mostly hydrogen & helium) that
are continually undergoing nuclear fusion. The Sun does not have a solid surface. The sun is currently about 5
billion years old and has enough helium to “burn” for another 5 billion years. Because of the sun’s immense
size it has enough gravitational pull to cause everything in our solar system to revolve around it.
Comets
A small celestial body composed at least partially of ices and rock. Comets either orbit the Sun or pass through
the Solar System on hyperbolic orbital paths sometimes taking 50-1000+ years to travel around the sun.
Comets have sometimes have tails that trail behind them. Comets also have temporary atmosphere called a
coma.