AST101H1 Lecture Notes - Lecture 13: The Frost, Correlation Does Not Imply Causation
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AST101H1 Full Course Notes
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The universe recycles: when stars reach the end of their lives, they explode (supernova explosion) The interstellar medium: the gas between the stars is called the interstellar medium, most of it is invisible, but there are isolated de(cid:374)se (cid:862)(cid:373)ole(cid:272)ular (cid:272)louds(cid:863) of gas and dust. Formation of the planets: tiny small objects stick together to form planetesimals. These are the seeds (cores) of what will become planets. The frost line: disc is 98% hydrogen and helium; 2% other atoms and molecules. Inner parts of the disc are warmer than the outer parts. Planets inside the frost line are terrestrial, since they form only from rocks and metal. Planets outside the frost line are jovian: they are made from rocks, metal and ice (but mostly ice, larger cores use gravity to accrete large gas envelopes, each planet has its own disk, which then form moons.