ASTRO 5 UCLA MIDTERM (HANSEN) TEST
LATEST UPDATED
Geocentric Model - ANSWER -earth at center of celestial sphere
-problem: retrograde motion
Heleocentric Model - ANSWER -originally considered, but then rejected
-should have predicted stellar parallax (could not detect it with their level of
precision)
Epicycles - ANSWER -addressed retrograde motion
-each planet revolves around a deferent as it orbits
Copernican Principle - ANSWER -revived heleocentric model
-states that we occupy no special place or time in universe
Keplers 3 laws - ANSWER -orbits are elliptical around the sun at one focus
-the closer you are to the sun, the faster you go
-mathematical relationship between period of orbit and distance from the sun
Discovery science - ANSWER -exploring and gathering data
Hypothesis-driven science - ANSWER -propose ideas to be tested
Theory - ANSWER -a model that describes the underlying principles which
give rise to observed phenomena
Occam's Razor - ANSWER -usually the simplest explanation is the correct one
Nuclear burning/fusion - ANSWER -fusing lighter elements into heavier
Spectroscopy - ANSWER -each element has a characteristic spectral
fingerprint corresponding to absorption/emission at particular wavelengths
, -provides info about the temperature and composition of a radiating body
Astronomical background - ANSWER -universe began much hotter and denser
than today
- expanded and cooled to current state through 14 Ga
Galaxy creation - ANSWER -originally a nebula (cloud of dust and gas)
-created by clumps of material falling together under mutual gravity
-the collapsing galaxy contains both dark matter and gas
-gas cools and clump together, eventually collapses to form stars
-composition of original gaseous material: 75% H, 25% He
-formation of a star requires contraction which results of spinning of material to
form a disk
Planet formation - ANSWER - formation of a star leaves a disk of gas and dust
orbiting it
-the dust grows by accreting other durst; forms pebbles which become large
bodies
- if planet is large enough, it can gravitationally capture gas from surrounding
nebula
Origin of elements - ANSWER -stars are like nuclear reactors; their energy
comes from fusing hydrogen and helium, and then helium with itself and so on
-stars end their lives by losing mass
-nuclear processed material is ejected back into the interstellar medium
-then swept up and takes part in the collapsing of material to form a new star
Mercury - ANSWER - much smaller than earth
- but much higher density
- MUCH hotter surface
- no atmosphere
Venus - ANSWER - similar size to earth
- Too dense of an atmosphere which keeps the surface very hot
Earth - ANSWER - habitable because of presence of liquid water
Mars - ANSWER - 10% mass of earth
LATEST UPDATED
Geocentric Model - ANSWER -earth at center of celestial sphere
-problem: retrograde motion
Heleocentric Model - ANSWER -originally considered, but then rejected
-should have predicted stellar parallax (could not detect it with their level of
precision)
Epicycles - ANSWER -addressed retrograde motion
-each planet revolves around a deferent as it orbits
Copernican Principle - ANSWER -revived heleocentric model
-states that we occupy no special place or time in universe
Keplers 3 laws - ANSWER -orbits are elliptical around the sun at one focus
-the closer you are to the sun, the faster you go
-mathematical relationship between period of orbit and distance from the sun
Discovery science - ANSWER -exploring and gathering data
Hypothesis-driven science - ANSWER -propose ideas to be tested
Theory - ANSWER -a model that describes the underlying principles which
give rise to observed phenomena
Occam's Razor - ANSWER -usually the simplest explanation is the correct one
Nuclear burning/fusion - ANSWER -fusing lighter elements into heavier
Spectroscopy - ANSWER -each element has a characteristic spectral
fingerprint corresponding to absorption/emission at particular wavelengths
, -provides info about the temperature and composition of a radiating body
Astronomical background - ANSWER -universe began much hotter and denser
than today
- expanded and cooled to current state through 14 Ga
Galaxy creation - ANSWER -originally a nebula (cloud of dust and gas)
-created by clumps of material falling together under mutual gravity
-the collapsing galaxy contains both dark matter and gas
-gas cools and clump together, eventually collapses to form stars
-composition of original gaseous material: 75% H, 25% He
-formation of a star requires contraction which results of spinning of material to
form a disk
Planet formation - ANSWER - formation of a star leaves a disk of gas and dust
orbiting it
-the dust grows by accreting other durst; forms pebbles which become large
bodies
- if planet is large enough, it can gravitationally capture gas from surrounding
nebula
Origin of elements - ANSWER -stars are like nuclear reactors; their energy
comes from fusing hydrogen and helium, and then helium with itself and so on
-stars end their lives by losing mass
-nuclear processed material is ejected back into the interstellar medium
-then swept up and takes part in the collapsing of material to form a new star
Mercury - ANSWER - much smaller than earth
- but much higher density
- MUCH hotter surface
- no atmosphere
Venus - ANSWER - similar size to earth
- Too dense of an atmosphere which keeps the surface very hot
Earth - ANSWER - habitable because of presence of liquid water
Mars - ANSWER - 10% mass of earth
