Formation of the Solar System
Although there is some debate as to the Solar System's formation, the following outline is currently the best known explanation of how the Solar System developed.
- Approximately 4.6 billion years ago a large cloud of gas and dust was disturbed by some force. (Scientists have theorized that this force was a nearby supernova.)
- As a result of this disturbance and the energy introduced to the cloud, the cloud began to move.
- Once the movement began, the cloud started to collapse in on itself due to its own gravity.
- During the process of collapsing, the cloud began to rotate and heat up.
- As the cloud continued to collapse, the cloud's temperature continued to rise and its rotation became faster and faster. As a result, the cloud eventually began to flatten out into a disk shape with most of the mass located at its center.
- At some point the pressure and temperature became so great at the cloud's center that nuclear fusion began to take place. It was then that the Sun was born.
- After the Sun was born, the gases and dust further out from the disk's center began to cool and condense into tiny particles.
- As more and more particles formed they began to collide with one another and stick together, thus creating particles as large as rocks and boulders.
- Like the smaller particles that collided, the boulder-sized particles began to impact and join together. These larger bodies are known as planetisimals.
- Eventually, enough planetisimals joined together to form planetary embryos. However, unlike the small particles, boulders, and planetisimals, planetary embryos were massive enough to exert significant gravitational force on surrounding objects. Hence, instead of random collisions between objects, planetary embryos pulled objects in the surrounding area to itself.
- Once all of the material in the area of each planetary embryo was pulled in, the planets were born.
- All other significant material in the solar system that did not join to form the Sun or the planets condensed to form the moons, asteroids, or comets.
- Over time, the orbits of the planets and other bodies stabilized into the solar system that we know today.