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Earth & Space Unit 1
Earth & Space Unit 1 - Universe
| Term | Definition |
|---|---|
| Elliptical | the shape of Earth's orbit |
| Asteroids | small rocky object; smaller and closer than comets |
| Retrograde Motion | apparent motion of a planet in a direction opposite to other bodies within its system |
| Galaxy | Milky Way; center is super massive black hole |
| Planet | orbit sun, nearly round shape, cleared neighborhood in orbit; 8 major ones |
| Astronomical Unit | average distance from Earth to Sun |
| Dwarf Planet | planets in our galaxy that have not cleared the neighborhood around orbit |
| Oort Cloud | marks boundary of our solar system |
| Kuiper Belt | where comets are found |
| Epicycles | planets do loop in orbit and appear to move backward in the sky when viewed from Earth |
| Comets | farthest away; "dirty snowball" found in Kuiper Belt and Oort Cloud |
| Meteoroids | piece of asteroid; in void of space |
| Meteorites | meteoroids that land on Earth |
| Meteor | meteoroid burning in the atmosphere; shooting star |
| Heliocentric | sun-centered |
| Geocentric | earth-centered |
| Aristotle | found that Earth was round by observing lunar eclipses; geocentric |
| Ptolemy | used epicycles to explain why Mars seem to periodically move backwards in the sky; geocentric |
| Aristarchus | sun much farther away from Earth than moon is; sun much larger than both moon and earth; all planets must revolve around sun; heliocentric |
| Copernicus | correctly explained retrograde motion; heliocentric |
| Galileo | phases of Venus; 4 moons of Jupiter; discovered Sun spots; mountains and craters on moon (Sea of Tranquility); heliocentric |
| Kepler's 1st Law | orbits are ellipses with sun at the focus |
| Kepler's 2nd Law | planets travel faster when they are closer to the sun and slower when further away |
| Kepler's 3rd Law | closer the planet is to the sun, the shorter its orbital period (year) |
| Hubble | nearly all galaxies are moving away; universe is expanding |
| Brown | discovered Eris in Kuiper Belt, leading to Pluto's demotion |
| Red Shift | galaxies moving away from us; universe is expanding |
| Plank Epoch | gravity separates from 4 main forces; first event of Big Bang Theory |
| Formation of Exotic Particles | inflation period, cooling; theoretical |
| 4 Separate Forces Established | gravity, weak, electromagnetism, strong |
| Particle Zoom | protons and neutrons form |
| Nucleosynthesis | formation of atomic nuclei form from protons and neutrons |
| Transparent Universe | hydrogen, helium and lithium are first elements created; universe no longer opaque |
| Formation of First Stars and Galaxies | cooled clumps of gas contract due to gravity; last event of Big Band Theory |
| Olber's Paradox | sky should be as bright as the sun at all times; light hasn't reached us or it's redshifted beyond what we can see |
| Hubble's Constant | the ratio of the speed of recession of a galaxy to its distance from the observer; not an agreed value |
| Light Year | distance that light travels in one year |
| Hubble's Law | all galaxies are moving away; redshifted; universe is expanding |
| CMB | microwave radiation left from Big Bang; cosmic microwave radiation |
| Dark Matter | makes up most of mass of galaxies and galaxy clusters; not related to dark energy |
Created by:
golden_wonwoo
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