Solar System Creation In a 10 Minute Read.

Wouldn’t it be good to know how you got here? Well unfortunately the answer to that is unknown. It has been thought about for a long, long time and one day we will probably know the answer. What we do have good idea about though is how the solar system formed.

Throughout the galaxy gigantic clouds of dust and gas exist known as a nebula. It is within these nebulas that the Sun and planets were formed. Something such as the shock from a supernova explosion could have started the gas cloud rotating.

The particles attracted each other having large mutual gravitational attraction. As the gas and dust got pulled in the cloud of dust and gas sped up. If you can think of an ice skater with her arms out and then slowly bringing them down to both sides she speeds up (I hope you are into ice skating). Around the sun, the gas and dust cloud starts to speed up in the same way. This eventually causes a flat disk circling around the sun at the centre. This process, if you are interested, is called a protoplanetary disk or solar nebula. The protoplanetary disk has been seen around other stars by the Hubble space telescope.

Planetary Nebula

The dust cloud that we have been talking about is actually made out of mostly hydrogen. This hydrogen and some dust (ices, Carbon, metallic and silicate substances) formed the sun. Nuclear reactions in the sun caused the sun to shine producing heat (quite a lot of heat!). The dust remaining in the solar nebula was vaporised due to the heat of the sun.

The solar nebula started to cool, as they do, and the dust grains condensed into different types of dust grains. It merely means grains and particles of Rocky and icy material stuck together quite nicely and obviously this made it grow larger. This process took some time but when you think that the universe has been around for 14.6 billion years the mere 10,000 years that it took to create 10mm particles isn’t so long after all.

Each 10 mm particle mainly consisted of silicon materials and these clumps formed in the orbits of the planets of the solar system today. But, as we know, the accretion process didn’t stop there and bigger and bigger clumps were formed. The clumps increased to about 10 m in size.

Helix nebula

The process continued and planetesimals were formed after about 100,000 years. Planetesimals are the name given to tiny planets which are about 0.1 to 10 km across. Gravitational focusing started to occur when their bodies got bigger and all the particles were attracted to the particles with a larger gravitational force. Unfortunately this meant curtains for the smaller clumps as they joined the larger clumps and made the planetesimals. This crashing together of the larger particles all into one caused heat, if you want to be technical the kinetic energy turned into potential energy. Their heating and collisions caused different types of minerals to be formed in the resulting planetesimals.

Planetary embryos were now formed because of the planetesimals colliding together and forming larger bodies. These larger bodies were a few thousand kilometres in diameter. After a while these planetary embryos would have used most of the remaining smaller planetesimals but some were left over creating satellites and asteroids etc.

Orion Nebula

Now, planetary creation would have slowed because of the fewer fragments to collide with. Some planetary embryos may have collided together causing massive collisions and so much heat that the body could have formed a molten mantle called a magma ocean. As the surface began to cool a thin crust would have been born. The debris formed from the initial collision of the two planetary embryos would have formed debris and the debris would have formed impact collisions on the surface of the remaining planetary embryo. Other factors such as convection currents would have changed any solidified areas.

Giant, massive impacts would have continued to occur until the terrestrial planets were half their size today. This would have taken about 10 million years and then they would have reached full size full size at about 100 million years. The moon probably exists today because of a massive impact between two planetary bodies leaving a ring of debris around the Earth. Accumulation of debris produced the moon by continual impacts over the years.

Certain elements of the dust cloud would not exist closest to the sun because of the sun’s heat but they did exist further out. This is why we have gas giants further out and the rocky terrestrial planets further in toward the sun (Mercury, Venus Earth and Mars).

This is the best guess that we have today and it’s widely accepted. If anyone does manage to find a time machine and go back and have a look at how the solar system was formed then please let me know.

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