All information below, unless otherwise stated, was taken from the television documentary series How the Universe Works. If you question the information below, conduct your own research and tell me about it in the comments. (Be sure to cite your sources!) All information comes from the television series How the Universe Works, specific episodes listed in the section headers.
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Alien Solar System
Our Solar System was a very interesting place during its creation. For instance, both Uranus and Neptune were created closer than their current orbits. The composition of both planets suggests formation around Saturn. For every one rotation around the Sun Saturn took, Jupiter took two. The gravitational force of such a combination flung Uranus and Neptune further away from the Sun. But that’s not all! As they were relocating orbits, Uranus traded spaces with Neptune, becoming the seventh planet from the Sun instead of the eighth.
Scientists have not yet figured out how Uranus was turned on its side. As a gas giant, any impact from an asteroid or forming rocky planet wouldn’t have had an affect.
Because of their proximity to the Sun, the rocky inner planets (Mercury, Venus, Earth, and Mars) have less water than the outer planets. During formation, the Sun’s heat and the constant collisions sent water flying away from the planets. Meanwhile, the gas giants (Jupiter, Saturn, Uranus, and Neptune) were able to keep their water — not necessarily in liquid form.
Collisions played a huge part in the formation of the rocky inner planets. Mercury’s crust was blown completely off by a giant asteroid during formation. That is why Mercury doesn’t have an atmosphere. It’s not the proximity to the Sun, it was literally blown away. Meanwhile, the Earth suffered a huge collision itself. The debris of said collision coalesced and formed our Moon.
Jupiter, being the biggest planet in the Solar System, acts as a body to Earth and the other inner planets. It’s gravitational pull effects comets and asteroids and often redirects them away from a collision course with Earth. One such incident was documented in 1994 when a space probe caught images of a stray comet running into the atmosphere of Jupiter. If Jupiter had not caught the comet, it would have continued on and hit Earth.
When you see a star in the night sky, unless it’s a planet, you are looking at the past. This is because the stars we see are hundreds, thousands, even millions of lightyears away from Earth. Because it takes hundreds, thousands, even millions of years for that light to travel to us, the light we see is hundreds, thousands, even millions of years old. Heck, it takes eight minutes for light from the sun to reach us.
(Because of this phenomena, the further into the galaxy we look, the further into the past we can see, and the more information we can gather about the origin of the Universe. You can find more information on this subject in the episode “The Big Bang”).
Stars, like our own Sun, create their energy through nuclear fusion, which is the combining of atoms to create new atoms. Their main source of energy is hydrogen, or at least that’s what our Sun is doing, making hydrogen into helium. When it starts to run out of hydrogen, it will start to fuse other elements. As soon as a star makes iron, it has only seconds to live.
During nuclear fusion, the star maintains balance of the energy it generates and the gravity produced by its mass. When iron starts to form, this balance is disrupted. Iron does not give off energy very well, and it gets crushed under the gravity. The force of the imbalance is enough to cause a supernova.
Supernovas are how the elements of the universe are spread from one part of the universe to the other. Professor Michio Kuka speculates that the atoms that make up your left hand probably came from a different star than the atoms in your right. Kinda makes your head spin, doesn’t it?
Comment Question: What are some other fun facts about the planets and the solar system? (no need to cite sources)