Theories about the Moon and the Solar System By: Rania Tabunot

Where did the Moon come from, and how was it formed and what happened? The GIANT Impact Theory A theory that explains the origins of Earth's moon, postulating that an asteroid roughly the size of Mars impacted the Earth during its formation. This impact resulted in rocky surface material being blown outward from the Earth, some of which accreted to form the Moon. This theory explains the similar oxygen isotope ratios between the Earth and the Moon as well as the Moon's lack of an iron core. It also accounts for the angular momentum that was necessary for the Moon to reach its current position.

Why do scientists believe in this theory and When was the Moon formed? Junjun Zhang is the scientist who discovered the theory of the Giant Impact in Chicago. He came up with this theory after he studied the Fission theory (the theory about the Moon joined to the earth). He studied the rocks on the moon and the compared them to the Earth rocks- which were very different. He said that the Moon must’ve been formed elsewhere, quite close to earth on another planet and came crashing towards earth. The probable main reason why the Moon circles the Earth is because after the Giant Impact, the moon got caught up with the rotation of the Earth, and it too, started to orbit the earth. The moon was formed about 4.5 billion years ago, elsewhere in the universe. –After reading through some research about this theory, I re-wrote the information in my own words.

How was the Universe created? The Big Bang theory states that the universe was formed about 14 billion years ago as the result of a giant explosion of very dense and hot matter. This matter expanded and started to cool down, going through different transitional phases. The universe has been expanding ever since. The first scientist to come up with the idea of a 'big bang' was the astrophysicist Friedrich Franz Friedmann who used relativity field equations to prove that the universe is expanding. Edwin Hubble's observations later proved this theory. Hubble discovered the red shift of galaxies. He measured their distances from Earth by observing variable stars called Cepheids. The red shift distance law of galaxies is now referred to as Hubble's Law. The discovery of cosmic microwave background radiation in 1965 made the Big Bang theory the best theory of the origin and evolution of the universe. Radio astronomers Arno Penzias and Robert Wilson discovered the cosmic microwave (high frequency radio wave) background which is thought to be leftover radiation from the initial explosion of matter - the 'Big Bang'. Apparently this theory was called 'The big bang' by a radio commentator who was mocking it. Initially the theory was called 'The primeval atom'. Today astrophysicists with a sense of humour sum up the Big Bang theory as the following: First there was nothing, then there was the bang and then there was everything.

Why do scientists believe this theory and When did it happen? Some scientists believe that the big bang theory has a relation to the first story in the Bible (when he created light etc.) Scientists believe that the big bang theory is a proper way to explain the actual happening. Some scientists, however do not believe the theory is related to the Bible story; as they do not associate with the religion. The Big Bang theory happened about 14 billion years ago, according to scientists. Ever since the great explosion, the universe has been expanding since (as said on the slide before). -Written by Rania Tabunot (put in own words)