Solar System. The solar system is a planetary system of objects that exists in an ecliptic plane. These objects orbit around and are bound by gravity to a star called the sun.
The solar system is a system of objects that orbits around the sun, which is the star, that’s in the middle of the solar system. All the other objects orbit around it, because they are pulled in by the sun’s gravity.
The next lesson: The Sun, both lessons are included in Practice Tests.[divider]The following transcript is provided for your convenience.[divider]
Now objects that orbit around the sun – there are lots of them and they include planets, dwarf planets, moons, asteroids, meteoroids, cosmic dust, and comets. All of these are caught in the sun’s pull of gravity and they orbit around the sun. They do not all orbit at the same rate and so they have different paths that they trace around the sun.
The definition of planets has changed. At one time there were nine plants, so nine objects classified as planets in the solar system. Now there are only eight, so nothing happened to the ninth one, it just is no longer classified as a planet, it is classified as a dwarf planet instead. Of our planets, there are four inner terrestrial planets, which means that they are closer to the sun, they are inner, they are closer to the sun, they orbit closer than the other planets. These four are the inner planets orbiting closer to the sun. They’re terrestrial which means they have more land to them or mass and they are Mercury, Venus, Earth, and Mars.
They’re relatively small, dense rocky, they lack rings and have few or no moons, so Earth has a moon, but not all of the inner planets have moons and we don’t have that many of them. Now, these planets are relatively small, but they are dense and rocky, they are land planets.
Next, we have the four outer or Jovian planets including Jupiter, Saturn, Uranus, and Neptune. Jovian means coming from Jupiter, so they’re the ones Jupiter and outward. Their orbits are further out from the sun than the inner planets. These are large, these planets are larger and they have low densities. They are not as dense as the inner planets. They do have rings and they have many moons. They’re also known as gas giants. These planets are made up of more gas, which makes sense since they have lower densities even though they are very large.
These are made primarily of gas and are known as gas giants, where the four inner planets are made more of land, they’re made more of solid things instead of gas. Between the inner and outer planets, so you’ve got your four inner planets and then you’re four outer planets, between those two is the asteroid belt. This is also in the sun’s orbit and so you’ve got your four orbiting planets and then you’ve got this belt of asteroids orbiting around in between those inner planets and then the outer planets orbits that start after that. Between Mars and Jupiter’s orbits, you’ve got Mars as the farthest inner planet and Jupiter as the closest outer planet. Between Mars and Jupiter, you’ve got this asteroid belt orbiting and beyond Neptune is the Kuiper belt, which is another belt of asteroids.
Within these belts are five dwarf planets, so they’re bigger than your normal asteroids, but they are not classified as a planet and these include, Ceres, Pluto, Haumea, Makemake, and Eris. These are the five objects that have been classified as dwarf planets and you’ve got your outer planets, your inner planets and they’re all orbiting around the sun to make up the solar system.
The next lesson: The Sun, both lessons are included in Practice Tests.