My Notecards 1051-1100
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- Neptune has
- -internal energy -periodically shows cyclonic storms
- Asteroids:
- small bodies orbiting Sun between Mars and Jupiter – Mostly rock and metal, irregular shapes
- Jupiters Moons
- – Io: volcanically active thanks to tidal effects – Europa: may have a liquid ocean below ice – Closer in, mostly rock, farther out more ice – Youngest surfaces close in due to geologic activity
- Saturn's one giant moon
- Titan – Has a Nitrogen atmosphere and a methane “water cycle†– Also suffers from a photochemical “smog†problem
- Uranus has no
- -internal heat -no weather or obvious features
- Ice Giants are..
- Uranus and Neptune
- Jupiter has giant cyclonic storm
- The Great Red Spot
- Jupiter Has extremely large
- Magnetic Field
- Saturn’s bright rings made of
- orbiting chunks of ice and rock
- Jupiter’s ring is faint, composed
- of fine dust
- Gaps in rings maintained by paired
- Shepard Moons
- All.....have ring systems
- Jovian Planets
- Mars
- Least dense of the terrestrial planets • Thin, dry CO2 atmosphere – Low gravity – Can’t retain much heat due to thin atmosphere • Liquid water at some point? – Freezes out as Mars cools, polar ice caps – Flow channels • Cratered highlands (South), plains (North) • Once volcanically active, but no longer
- Kuiper Belt
- flat disk of Trans-Neptunian Objects – Plutinos in 3:2 orbital resonance with Neptune – Source of short-period comets
- Gas Giants
- Jupiter and Saturn -rocky core, H/He atmosphere
- Moon
- Young, dark maria • Light heavily cratered highlands • Extent of cratering indicates surface ages • Theorized origin: Parts of Earth’s mantle knocked off in a collision, Moon formed from the debris
- Mercury
- Heavily cratered, little geologic activity • Virtually no atmosphere – Small gravity – High temperature (because so close to Sun) – Extreme temperature variations • Unusually large iron core
- Venus
- Hot, dense CO2 atmosphere – Runaway greenhouse effect • Surface mapped with radar • Geologic activity: – Volcanoes – Tectonics due to high temperatures (but not plate tectonics) – Few craters
- Wartime manpower losses
- WWI violent; other people to work in factories and wartime industries
- Earth's Atmoshpere
- Composition: nitrogen, oxygen, argon, water vapor ⬢ Greenhouse effect keeps Earth liveable ⬢ Carbon dioxide locked up in rocks, dissolved in oceans ⬢ Oxygen from life
- Earth's Interior
- Solid inner and liquid outer iron cores ⬢ Thick rocky mantle ⬢ Thin rocky crust ⬢ Differentiation: heavy stuff sinks, light stuff floats ⬢ Plate Tectonics, Continental drift ⬢ Seismic analysis
- Uranus and Neptune appear bluish-green because
- The methane in the atmosphere
- Aristarchus
- Measured (incorrectly) the distance to the Sun
- Aristotle
- Uniform circular motion – Earth a perfect unmoving sphere
- Daily Motion
- Earth rotates west to east about its axis – Objects rise in east, set in west -Circumpolar stars: always above your horizon
- Solstices
- Sun at maximum northern or southern declination
- Equinox:
- Sun crosses Celestial Equator – Lengths of day and night the same
- Solar day
- One local noon to the next, 24 hours
- Sidereal day:
- Time between successive transits of a given star, 23h56m
- Comets
- dirty snowballs – Sun sublimates ice, creating gas and dust tails – Long, elliptical orbits from either Kuiper Belt or Oort Cloud
- Sideral Month
- 27.3 days, time to orbit Earth and return to starting constellation
- Synodic Month
- 29.5 days, time between New moons, longer because need to factor motion around Sun
- Moon Phases
- New Moon, Waxing Cresent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Cresent, New Moon
- Lunar:
- Moon passes through Earth’s shadow aka -full moon, visible everywhere
- Solar Eclipse
- Earth passes through Moon’s shadow aka new moon, only visible on small spot on earth
- Copernicus
- - heliocentric theory -Earth rotates on axis, revolves around Sun – Explained retrograde motion – Kept epicycles to have uniform circular motion
- Tycho Brahe
- -greatest astronomer before telescope
- Kepler: Laws of Planetary Motion
- 1st-Orbits are ellipses – 2nd Law: Equal Areas in Equal Times – 3rd Law: P2=a3
- Galileo
- Telescope! – Moon craters – not a perfect sphere – Sunspots – not perfect, rotating – Moons of Jupiter – Earth not only center of motion – Phases of Venus – Venus orbits Sun – Milky Way – Individual stars
- Newton
- 1st Law: Objects in motion remain in motion unless acted upon by an outside force – 2nd Law: F=ma – 3rd Law: To every action there is an equal and opposite reaction – Law of Gravity
- Gravity
- Force is proportional to the masses and inversely proportional to the square of the distance between them F=GM1M2/d2
- Spring Tides
- Extra High tides when Moon and Sun work together (Full, New Moon)
- Neap Tides
- Extra Low tides when Moon and Sun interfere (Quarter Moon)
- Speed of Light constant
- 300,000 km/sec
- Inverse Square Law
- Brighteness= 1/dxd
- Wavelength
- (λ): distance between crests
- Frequency
- (f): number of crests per second
- Electromagnetic Spectrum
- – Gamma Rays – X-rays – Ultraviolet – Visible – Infrared – Microwaves – Radio
- Blackbody
- absorbs all light, emits continuous spectrum
- Hotter objects are
- Bluer
- Emission Lines
- electron falling to lower orbit emits a photon
- Refracting
- Lenses
- Reflecting
- mirrors
- Terrestrial Planets
- Mercury, Venus, Earth, Mars -small surface, rocky/metallic
- Neptune one giant moon
- Triton – Geysers of N2 gas repave surface – In a circular, retrograde orbit; probably a captured TNO
- Meteoriods
- Chunks of rock or metal orbiting Sun, smaller than asteroids – Meteor: streak of light when enters Earth’s atmosphere
- Find planets around other stars using a variety of techniques
- Velocity wobble, transits, gravitational microlensing