Solar System

Scientists are learning more about our Solar System every day. As we send new missions out into space, we are gathering information that is added to our knowledge. The words “Solar System” relate to two things: Any celestial body that is “of the Sun,” and a collection of objects that work together to form the entire whole.

Solar systems contain an immense amount of objects. The Sun or star is at the center and are surrounded by planets, dwarf planets, moons, asteroids, gas, comets, and dust. To date, our Solar System contains:

Our Sun contains 99.8% of the mass of the entire Solar System, with the gas giant planet, Jupiter, containing almost all of the remaining mass.

The formation of our Solar System has been outlined and studied, and many offer explanations that are debated through to today. Thus far we believe that our Solar System developed in the following way:

Facts about The Solar System

  • Around 4.6 billion years ago a force, possibly a supernova, disturbed a large cloud of dust and gas that resulted in energy being sent to the cloud to make it move.
  • The movement of the cloud caused its own gravity to make the cloud collapse in on itself, creating a rotation and heat buildup.
  • As the temperature and rotation of the cloud increased, the cloud began to flatten out into a kind of disk-shape with almost all of the mass in the middle.
  • When the temperature and pressure at the center of the cloud became so great, nuclear fusion occurred, which caused the creation of the Sun.
  • Dust and gases that were farther away from the Sun started to cool and then condense into small particles, eventually colliding with each other and sticking together to become bigger and bigger.
  • When these particles got as large as boulders, they also collided and stuck together. These are known as planetisimals, and when enough of these joined together they formed what is called planetary embryos.
  • The planetary embryos are large enough to begin exerting their force of gravity on surrounding objects, pulling more debris, boulders, and particles in to become part of them until they were large enough to create a planet.
  • Any materials that didn’t collide or join to form either the planets or the sun were left to form asteroids, moons, and comets.
  • Over long periods of time, the gravitational pull of the Sun caused the various planets to stabilize and rotate around the Sun, creating the Solar System that we see today.

The objects in our Solar System interact with each other. One way is that they move around the Sun in elliptical paths and since they exist on around the same plane, they interact in an ecliptic plane.

The interaction that causes the objects to orbit is gravity, and the Sun exerts so much gravitational pull on all of the objects in our Solar System that it “bends” the path of each object from a straight path into a curved path.

Other objects, such as the planets, also have significant gravitational pull so that they maintain the orbit of moons around them.

Information about our Solar System has drastically changed in the 20th century.

Where we once thought the Solar System ended at the orbit of Pluto, we now know that there are many celestial bodies beyond that area.

Currently, our Solar System is thought to be around two light years, which is around 125,000 times the distance of the Earth to the Sun. However, beyond Pluto we have an area of asteroids called the Kuiper Belt as well as a spherical area called the Oort Cloud that contains many comets.

Solar System Quiz

  • Astronomy for Kids