Our solar system is made up of a star - the Sun - eight planets, 146 moons, a bunch of comets, asteroids and space rocks, ice and several dwarf planets, such as Pluto.
The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
The solar system is made up of two parts:
The inner solar system contains Mercury, Venus, Earth and Mars. These four planets are closest to the Sun.
The outer solar system contains Jupiter, Saturn, Urenus, and Neptune.
The inner plates are seperated from the outer planets by the Asteroid Belt..
Mercury is closest to the Sun.
Neptune is the farthest. Remember the order of the planets like
this:
My Very Educated Mother Just Showed Us Neptune.
Planets, asteroids and comets orbit our Sun. They travel around in our Sun in a flattened circle called an ellipse. It takes the Earth one year to go around the Sun. Mercury goes around the Sun in only 88 days. It takes Pluto, the most famous dwarf planet, 248 years to make one trip around the Sun.
Moons orbit planets. Right now, Jupiter has the most named moons - 50. Mercury and Venus don't have any moons. Earth has one. It is the brightest object in our night sky. The Sun, of course, is the brightest object in our daytime sky. It lights up the moon, planets, comets and asteroids, too.
Remember everything here is "Kid-friendly" so lets get started.
Scientists believe that the Solar
System evolved from a giant cloud of dust and gas. They believe
that this dust and gas began to collapse under the weight of its
own gravity. As it did so, the matter contained within this could
begin moving in a giant circle, much like the water in a drain
moves around the center of the drain in a circle.
At the center of this spinning cloud, a small star began to form.
This star grew larger and larger as it collected more and more of
the dust and gas that collapsed into it.
Further away from the center of this mass where the star was
forming, there were smaller clumps of dust and gas that were also
collapsing. The star in the center eventually ignited forming our
Sun, while the smaller clumps became the planets, minor planets,
moons, comets, and asteroids.
Once ignited, the Sun's powerful solar winds began to blow. These winds, which are made up of atomic particles being blown outward from the Sun, slowly pushed the remaining gas and dust out of the Solar System.
With no more gas or dust, the
planets, minor planets, moons, comets, and asteroids stopped
growing. You may have noticed that the four inner planets are much
smaller than the four outer planets. Why is that?
Because the inner planets are much closer to the Sun, they are
located where the solar winds are stronger. As a result, the dust
and gas from the inner Solar System was blown away much more
quickly than it was from the outer Solar System. This gave the
planets of the inner Solar System less time to grow.
Another important difference is that the outer planets are largely
made of gas and water, while the inner planets are made up almost
entirely of rock and dust. This is also a result of the solar
winds. As the outer planets grew larger, their gravity had time to
accumulate massive amounts of gas, water, as well as
dust.
Asteroids are rocky, airless worlds that orbit our sun, but are too small to be called planets. Tens of thousands of these minor planets are gathered in the main asteroid belt, a vast doughnut-shaped ring between the orbits of Mars and Jupiter. Asteroids that pass close to Earth are called near-earth objects.
Little chunks of rock and debris in space are called meteoroids. They become meteors -- or shooting stars -- when they fall through a planet's atmosphere; leaving a bright trail as they are heated to incandescence by the friction of the atmosphere. Pieces that survive the journey and hit the ground are called meteorites.
Comets are cosmic snowballs of frozen gases, rock and dust roughly the size of a small town. When a comet's orbit brings it close to the sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the sun for millions of kilometers.
The Kuiper Belt is a disc-shaped region of icy objects beyond the orbit of Neptune -- billions of kilometers from our sun. Pluto and Eris are the best known of these icy worlds. There may be hundreds more of these ice dwarfs out there. The Kuiper Belt and even more distant Oort Cloud are believed to be the home of comets that orbit our sun.
