Flashcards

Astronomy Final

o.ensley Inglês 141 flashcards

Flashcards do conjunto (141)

1light-yearthe distance light travels in a vacuum in one year
2Parsecsa unit of distance, 3.26 light-years
3AUsastronomical unit; the semimajor axis of Earth’s orbit, the average distance between Earth and the Sun
4Parallaxthe apparent displacement of an object due to the motion of the observer
5Celestial Spherean imaginary sphere of very large radius centered on an observer; the apparent sphere of the sky
6Altitudethe angular distance from horizon to star
7Azimuththe perpendicular measurement from horizon to star
8Declinationlatitude measurer
9Right ascensionmeasures longitude, given in a time
10Winter solsticesun’s rays lowest below equator
11Summer solsticesun’s rays highest above equator
12WeatherSummer sunrise above celestial equator, so hot
Winter sunrise below celestial equator, so cold
It is the angle the earth is tilted that gives us seasons.
13Phases of the Moon
14Eclipses• Eclipses happen when the earth, moon, and sun line up together exactly (the moon must be a full or new moon)
- The moon is tilted by 5°, so it’s very rare that the geometry lines up perfectly which is why we don’t have an eclipse every full or new moon
- Lines up about twice a year for lunar eclipse and twice a year for solar
15Ptolemygeocentric view of solar system, explained retrograde motion
16Copernicusheliocentric model, circular orbits
17Brahedetailed notes about everything in the solar system which Kepler used, saw a supernova and showed that the heavens weren’t fixed (questioned the geocentric model of the universe)
18Galileonot the center of the universe- moons that orbit Jupiter, Venus has phases
19Keplerlaws about rotation: (1) elliptical orbits (2) equal areas covered close and far from sun (3) set relationship for how long something takes to get around and how big the radius is between planet and solar system T2=R3
20Newtongravity, laws of motion: law of inertia, force=ma, every force has an equal and opposite reactionary force
21Edwin Hubbleobserved Andromeda and realized that there were other galaxies; first to think about Big Bang; observed spectrometry of galaxies and saw that they were red-shifted- discovered that galaxies were moving away from us
22Einsteinspatial theory of relativity—a quantity m of mass can in principle be converted into an amount of energy E according to a now famous equation E=mc^2 (c=speed of light); thermonuclear fusion
23Geocentric model of the UniverseEarth at center
24Heliocentric model of the universesun at center of the universe
25Electromagnetic SpectrumLong to short wavelengths: Radio Microwave Infrared Visible Ultraviolet Gamma rays (Rarely Must I Venture Under Xenon’s Gate)
26Visible lightRed is longer wavelength; purple shorter (we can see 400 to 700 nm → 4x10^ -7 to 7x106 -7
27Opacity of Earth's atmosphereatmosphere absorbs infrared and ultraviolet wavelengths
28Electromagnetic wave of Light
29Wavelengththe distance between two different wave crests, measured in lambda
30Frequencythe number of crests or troughs of a wave that cross a given point per unit time; the higher the frequency, the shorter the wavelength
31speed of wavewavelength x frequency
32Black body radiation
33Black body radiationHotter objects are brighter and “bluer” than cooler objects
34Wien's lawA relationship between the temperature of a blackbody and the wavelength at which it emits the greatest intensity of radiation
Continuous spectra for different temperatures; at higher temperatures, there is more energy at all wavelengths and the peak of the spectrum shifts to smaller wavelengths
35Bohr atom
36Absorption and emission of light by atoms—Kirchhoff’s laws
37Doppler Shift
38Refraction Telescopebends the light
39Refraction Telescope $Refraction Telescope$
40Reflection telescopethe redirection of light
41Reflection Telescope
42KeckGround-based telescope, Hawaii, giant optical telescope on a mountain made up of smaller hexagons
43SALTSouthern African Large Telescope, largest optical telescope in southern hemisphere
44LBTlarge binocular telescope, Arizona
45Areciboradio; Puerto Rico, largest radio telescope
46VLAradio; Very Large Array, New Mexico
47SpitzerOuter space telescope, CalTech
48Chandralayers; x-rays
49Solar System Formation
50Terrestrial Planetshigh-density worlds with solid surfaces, including Mercury, Venus, Earth, and Mars
51Jovian Planetslow-density planets composed primarily of hydrogen and helium, including Jupiter, Saturn, Uranus, and Neptune
52Definition of Planetmust orbit the sun DIRECTLY, has enough gravity that it formed in the shape of a sphere (cuts out things like asteroids), “cleared the neighborhood” rule: swept up all of the mass in its own orbit and secreted that mass onto itself
53Extrasolar Planeta planet orbiting a star other than our Sun
54Earth's AtmosphereTop to bottom: Ionosphere Mesosphere Stratosphere Troposphere (I Met Sarah Tuesday)
55Greenhouse EffectIncoming visible light from the Sun (short wavelength) is either reflected back to space by clouds of liquid droplets or solid particles or makes it to the ground to heat it up. Visible light passes through H20 and CO2 gases. Since the ground is much cooler than the hot Sun's surface, it reradiates the energy in the form of infrared light (long wavelength) instead of visible light. Greenhouse gases (like H20 and CO2) and clouds reflect some of the infrared light back to the ground trapping the heat close to the surface. Some infrared light does escape back to space-otherwise the surface would continually get hotter and hotter.
56Van Allen Radiation Beltwhere particles from the sun are stopped by the magnetic belt of the planet; Outer Belt- negative electrons; Inner belt- positive protons → when field enters atmosphere, it causes particles to glow which creates the Northern lights (or Aurora)
57Escape Velocitythe velocity it takes to exit from atmosphere; on Earth the escape velocity is approximately 11.2 km/sec
58Mariadark spots on the moon from volcanic processes
59Highlandswhitish spots on the moon
60Ejecta blanketlayer of dust that covers the surface of the Moon
61Scarpsurface feature of Mercury; cliff that is formed by extreme heating and cooling-cracks like an eggshell
62Mercury's AtmosphereNone, too hot, all the gases have left
*Note: Atmosphere or lack of depends on temperature and gravity
63Venus• Venus is 850°F because it’s atmosphere is greater than that of Mercury, so it holds onto more of the heat. Atmosphere is 96% carbon dioxide whereas on Earth it’s only a few percent. The clouds are made of sulfuric acid.
• Gaseous because so hot, immense pressures so could never send something in and land it, the closest planet to the size of Earth
64Mars's Atmosphere90% carbon dioxide
65Olympus MonsHuge ass volcano on Mars
66Marinerison Mars; similar to Grand Canyon except deeper and wider
67Dust DevilMini tornadoes on Mars that just move the fucking dust around like a dumb ass hoe
68Mars's Moonsmore like asteroids, look like big rocky potatoes
69Mars (why red)covered in rust from amounts of Iron and Oxygen
70Why do we explore planets?to look for signs of life or signs that a planet could sustain life; to gather information about our universe
71Jupiter• The movement of the bands is what causes so much turbulence and so many storms. The different colors of the bands mean one is going up and one is going down (conflicting temperatures)
• Has a magnetic field that is 14 times stronger than the Earth’s field, strongest magnetic field in the solar system other than the Sun
• Rings come from tiny rocks that get caught in gravity of planet and get broken up and turned into ring.
• Big red spot: a storm that has been going on for at least 300 years, twice the size of Earth
72Galilean Moons4 closest moons to Jupiter first observed by Galileo; Innermost to outermost- Io Europa Ganymede Callisto (I Eat Good Cookies)
*Note: All have solid surfaces
73Io• Io is the only other known object in the solar system that has ACTIVE volcanoes. On Io, the tidal forces tear up the moon. Can calculate the gravity by observing how high the spray of the volcano is.
74Europa• Europa has a lot of cracks caused by the tidal forces. It is entirely covered in frozen water ice. Has some liquid water underneath because of the tidal forces. This is one of the few places in our solar system that could support life.
75Ganymede• Ganymede and Callisto are a little bit bigger than Earth’s moon
• Ganymede is very similar to Earth’s moon, has Maria, and is largest moon in our solar system.
76Callistoa little bit bigger than our moon; has water ice
77Saturn• Rings are made mostly of ice and rock. Moons that tried to form or were successful in forming but then the tidal forces broke them up.
• The rings are very thin and are located right at the equator
• The gaps between rings are where the bigger moons are that can resist the tidal forces.
• Saturn has 62 known moons- mostly small and rocky and icy
• Cassini launched in 1997
78Titanlargest moon of Saturn- first moon we found that has a really thick atmosphere- 90% Nitrogen, also has other gasses like Methane (a hydrocarbon which means that it’s a building block of carbon based life form as we know it)- very cold- around the poles of Titan there are what appears to be lakes which are not water lakes but probably methane or hydrocarbon lakes
79Uranus2-3% Methane, no Ammonia → makes the blue color
27 moons
80Why isn't Pluto a planet?Hasn't cleared its neighborhood
81Asteroids versus Meteoroids• Asteroids and meteors are both rocks in space. Asteroids are bigger than 100 meters across. Meteors are smaller than 100 meters across. Most of the asteroids and meteors reside between Mars and Jupiter in the asteroid belt. They can also exist (and be stable gravitationally) at the LaGrange point (Trojans).
82Meteoroid, Meteor, MeteoriteMeteoroid: in space
Meteor: trail of light that we see in the sky
Meteorite: lands on planet's atmosphere
83Meteor Showerwhen we pass through an area in our orbit where there’s debris from asteroids, comets, or meteoroids
84Oort cloudthought that most of the comets have come from this Oort cloud, on the outskirts of the solar system
85Kuiper beltinhabited by Pluto-like objects, small moon-sized ice and rock
86Parts of a comet• Nucleus: dry ice held together by water ice plus dust and organic compounds
• Blue tail: ion tail
• Tail pointed away from the sun because solar wind
• White Tail: dust tail; see reflected sunlight from the dust
• Hydrogen Envelope: starts to form when the sun starts to defrost ice
87Luminositymeasures the intensity of light, proportional to R2T4
88Parts of the SunInner to Outer: Core, Radiation Zone, Convection Zone, Photosphere, Chromosphere, Corona (Corn Reproduction Company Produces Chewy Corn)
89Corefusion, hydrogen and helium, hydrogen turned into helium
90Convection Zonewhere heat rises and colder creates a circular motion
91Photosphereappearance of the sun, surface, once it reaches this really small layer the photons are released
92Chromospherehas absorption lines
93Coronaouter layer, really thin, heats up particles so that they become faster than the sun’s escape velocity and this creates solar wind (nobody knows why the corona is so hot)
94Sunspotsregions of intense magnetic fields, low temperature, in the photosphere, frequently found in groups but can be by themselves as well, umbra core and penumbra brighter outer core
95Sun Flaresejects clouds of electrons, ions, and atoms through the corona of the sun into space; increases when the sun is active
96Prominencesloops, go to corona
97Coronal Mass Ejectionspasses the corona into space, massive burst of solar wind and magnetic fields
98Solar Windan outward flow of particles (mostly electrons and protons) from the sun, the speed needed to reach escape velocity is what causes the wind
99Quiet Sunthe processes of the sun that put out 99.9% of the sun’s light/heat/energy, steady, doesn’t really change (fusion in the core, convective zone, released at the photosphere)—occurs when the magnetic fields are not tangled
100Active Sunrapid change, lots more flares and ejections, occurs when the magnetic fields are tangled
101Fusionpulling objects together and creating them into a larger object, happens when you take two nuclei and bring them together into a reaction to form a larger or heavier element (loss in mass which is released as energy which creates the light)
102Neutrino Problemonly found a third of the neutrinos they thought there would be, discovered there were three types of neutrinos
103Spectral ClassesOBAFGKM (Oh Boy A Fine Guy Kissed Me)
*Note: Our sun is a G2 star
104Apparent and Absolute BrightnessApparent: how bright a star appears to us on Earth
Absolute: the apparent brightness that a star would have if it were at a distance of 10 parsecs
*Note: The lower a star is on the magnitude scale, the brighter it actually is if it seems bright from Earth
105Temperaturehotter stuff on left side, cooler stuff on right side
106Distancecan find if you know how bright a star is
107HR diagram
108Trends of Main Sequence Starsmass gets smaller as spectral class gets cooler, luminosity decreases
109Main Sequence Stars
110Reflection nebulaeblue (same reason our sky is blue—methane)
111Planetary Nebulaforms at the end of a medium star’s life, releases outer layers of itself, forms a circular cloud around where the dead star will be
112Dark Nebulasometimes referred to as stellar nurseries
113How we find nebula if dust is blockingDust often blocks visible light, but not infrared light from these luminous stars (so we know they exist)
114Nebula 21 cm radiationmost reliable way to find star birth area, hydrogen spin (the proton and the electron want to be different because it takes lower energy, so the electron usually flips up and down)
115Death of sun-like star
116Novaa star that experiences a sudden outburst of radiant energy, temporarily increasing its luminosity roughly a thousandfold
117Type 2 Supernovadeath of all high mass stars
118Type 2 Supernovadeath of all high mass stars
119Type I Supernovawhen you have a low mass star with a binary star; the low mass star becomes a white dwarf and steals material from its binary star forming an accretion disk. If it gets too much mass then it explodes.
120Cepheid Variable Stara type of yellow, supergiant, pulsating star
121Neutron Stara very compact, dense star composed almost entirely of neutrons
122Pulsara pulsating radio source thought to be associated with a rapidly rotating neutron star
123Formation of Black Holes
124Schwarzschild Radiusthe radius from the center of the black hole at which point equals speed of light, once you’re in the Schwarzschild radius you’re stuck in the black hole no getting out, constantly changing as mass gets added into the black hole- gets bigger
125Event horizonthe outside circle of the black hole, nothing physically there, just a location
126Spiral galaxya flattened, rotating galaxy with pinwheel-like spiral arms winding outward from the galaxy’s nucleus
127Barred Spiral Galaxya spiral galaxy in which the spiral arms begin from the ends of a “bar” running through the nucleus rather than from the nucleus itself (what our galaxy is)
128Elliptical Galaxya galaxy with an elliptical shape and no conspicuous interstellar material, no longer making stars
129Irregular Galaxyan asymmetrical galaxy having neither spiral arms not an elliptical shape
130Milky WayOur galaxy, can see the spiral arms; the band of faint stars seen from Earth in the plane of our Galaxy’s disk
131Active Galaxya galaxy that is emitting exceptionally large amounts of energy; Seyfert galaxy, radio galaxy, or quasar
132Gravitational Lensing
133Dark matternonluminous matter that is the dominant form of matter in galaxies and throughout the universe; may account for the movement of the stars
Candidates: weakly interacting massive particles (wimps); faint, red, low mass stars; dim objects with small masses such as brown and white dwarf stars; black holes
134Dark energya form of energy that appears to pervade the universe and causes the expansion of the universe to accelerate, but has no discernible gravitational effect
135Hubble Constanta constant proportion between how far away a galaxy is and how fast it’s traveling away
136Hubble's LawEquation: Ho=v/d, where v=speed away from us and d=distance
137Universe ExpansionEdwin Hubble—put light from galaxies into a spectrometer—discovered that almost every galaxy is red shifted—moving away from us
-The farther away it gets, the faster it’s moving away from us
-1st one to think about the big bang: the universe is expanding
138Cosmic background radiationan isotropic radiation field with a blackbody temperature of about 2.725 K that permeates the entire universe
139Cosmic background radiationan isotropic radiation field with a blackbody temperature of about 2.725 K that permeates the entire universe
140Fate of the Universe
141Fate of the Universe (Open, Closed, Critical)Density greater than the critical density-closed universe;
Density equal to the critical density-critical universe;
Density less than the critical density-open universe