The Solar System From the Big Bang to Planets, Asteroids, Moons. and eventually humans!
SOLAR SYSTEM A SUN, AND ALL THE OBJECTS ORBITING IT
But First! The Uncertainty Clause
Big Bang! First Generation Stars Hydrogen is the first (simplest) form of matter created. Some Helium (and Lithium) also form. Giant clouds gather together, condense, and get heavy. The intense heat and pressure ignites NUCLEAR FUSION (atoms combining to form heavier elements) Result: First Generation Stars are born!!! Time: 250 Million Years
After fusing Hydrogen into heavier elements, the stars EXPLODE and throw their guts (brand new elements!) out into space.
Star Guts Star Guts Second Generation Stars The star guts (new, heavier elements) then start the process of clumping and condensing again. The new clumps get heavy enough to ignite their own fusion. Result: Second Generation Stars are formed! This process can keep on repeating
We think our own Sun is a second or third generation star.
Major Ideas: ALL MATTER COMES FROM STARS COOKING UP HEAVIER ELEMENTS AND THEN SPEWING THEM OUT.
Major Ideas: OUR SUN (AND SOLAR SYSTEM) IS NOT A *DIRECT* RESULT OF THE BIG BANG.
We started as a cloud fragment An older star s guts were swirling around and started to clump together. The heavy clump in the middle of the cloud was the PROTOSUN It started to collect more matter, getting heavier and spinning. The spinning caused the cloud to flatten into a disk.
Protoplanetary Disk - The disk of gas and dust now spinning around the protosun. - Also known as a proplyd
In the disk Clumps of heavier matter start to form in the disk: planetesimals Over 100 s of millions of years, they gob together into larger clumps: protoplanets
Eventually, the protosun accumulates enough mass to ignite fusion! A star is born! The intense exhaust of solar wind pushed the lighter elements to the outer edge, while the heavier elements stayed closer. (this is why the close planets are rocky and dense, while the outer planets are gassy and light!)
This whole process took many 100s of Millions of years to complete. The Solar System finished forming around 4.5 Billion years ago.
Orbital Inclination Thanks to angular momentum, the disk was pretty flat. The planets all rotate around the sun more or less on a flat plane (counter clockwise). The angle at which a planet orbits (with respect to OUR orbit)
Orbital Inclination Earth: 0 degrees! All 7 other planets fall within 7 degrees of orbital inclination. Pluto: 17 degrees!
LEFTOVERS: Moons Most moons are gravitationally captured planetesimals.
LEFTOVERS: Asteroids Chunks of rock & metal Size range from kilometers to Volkswagens Millions in the Asteroid Belt, elsewhere Largest: Ceres (900 km)
LEFTOVERS Meteoroids Same as asteroids, just smaller Volkswagen to pebbles and dust grains When falling through the atmosphere: - Meteor If it strikes the Earth: -Meteorite
LEFTOVERS Kuiper Belt Elongated ring of dust, ice, and gas Home to over 60 Dwarf Planets including: - Pluto - Sedna - MakeMake - Quaoar
LEFTOVERS Oort Cloud A shell/sphere of icy debris encapsulating the entire solar system. Source of most comets Mind-blowingly huge and far away. (about 1 Ly)
BTW: Comets! Chunks of rock & ice Orbit the sun in very eccentric ellipses Their tails always face AWAY from the Sun!
The Main Characters:
Mercury Namesake: fastest messenger of the gods Fastest orbit (88 days!) Small & rocky, no moons Roman week: Wednesday French: Mercredi Italian: Mercoledi Spanish: Miércoles English: Norse god Odin (Wodan)
Venus Extremely thick atmosphere of CO 2 Hottest temperatures in the solar system Namesake: goddess of love & beauty Brightest planet in the sky Roman week: Friday French: Vendredi Italian: Venerdi Spanish: Viernes English: Norse god Frigg (Odin s wife)
Mars Red Planet due to iron in soil Largest mountain, Olympus Mons Two moons: Phobos (fear) & Deimos (panic) Namesake: god of war Roman week: Tuesday French: Mardi Italian: Martedi Spanish: Martes English: Norse god Tyr (god of combat)
Jupiter Largest & most massive planet Giant red spot huge hurricane! 4 major moons, dozens of others Namesake: king of the gods (Jove) Roman week: Thursday French: Jeudi Italian: Giovedi Spanish: Jueves English: Norse god Thor
Saturn Huge rings!!! Largest moon in solar system: Titan Second-largest planet Namesake: god of the harvest (father of Jupiter) Roman week: Saturday! French: Samedi Italian: Sabato Spanish: Sábádo
Uranus First discovered planet William Herschel, 1781 Rolls sideways around the solar system! Moons are named after Shakespearian characters Namesake: Sky deity Ouranos (father of Saturn)
Neptune Accidentally discovered with math in 1846 due to variations in Uranus orbit Very windy, stormy atmosphere Has a great dark spot, sort of like Jupiter Named for the god of the sea (deep blue)