Flashcards
Astronomy Exam 2
Cards in this deck (59)
- 1Copernicussun-centered heliocentric model 1543
used model to determine layout of solar system
no more accurate than the Ptolemaic model,
still used perfect circles - 2Tycho Brahe (1546-1601)compiled most accurate naked eye measurements
could not detect stellar parallax, thought earth must be at the center of the universe
hired Kepler - 3Galileoobjects in air would stay with a moving earth
heavenly perfection: tycho's observation of comet and supernova already challenged this idea
first to use telescope (saw sunspots and mountains and valleys on the moon) (not perfect sphere)
parallax: accurate observations (galileo showed stars must be much farther than Tycho thought - in part by using his telescope to see Milky Way is countless individual stars
not all objects orbit earth
saw phases of venus - 4Kepler's first laworbit of each planet around sun is an ellipse with the sun at one focus, nothing lies at the other focus (perihelion is closest distance between sun and planet/aphelion is largest distance between sun and planet)
- 5Kepler's second lawas planet moves around its orbit, it sweeps out equal areas in equal times
this means that a planet travels faster when it is closer to the sun and slower when it is farther - 6Kepler's third lawmore distant planets orbit the sun at slower average speeds obeying the relationship
- 7How did galileo overcome the objections to the copernican view? How did galilioe solidify the heliocentric model?earth could not be moving because objects in the air would be left behind (noncircular)
1. objects in air would stay with a moving earth
2. heavenly perfection: tycho's observations of comet and supernova already challenged this idea
first to use telescope (saw sunspots and mountains and valleys on the moon) (n - 8phases of venus in geo and heliocentricgeo: new and crescent
helio: goes through all phases - 9hallmarks of sciencedefining science can be difficult
science comes from latin word scientia, meaning knowledge
1. modern science seeks explanations for observed phenomena that rely on natural causes
2. science progresses through the creation and testing of models that nature explain the observations as simply as possible
3. a scientific model must take testable predictions about natural phenomena that would force us to revise or abandon the model is the predictions do not agree with observations - 10occam's razortheory
- 11what is science? contrast and pseudosciencescience: the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment
pseudoscience: a collection of beliefs or practices mistakenly regarded as being based on scientific method - 12speedrate at which object moves
speed=distance/time - 13velocityspeed and direction
- 14accelerationany change in velocity either in speed or direction
- 15what means free fall motionacceleration of gravity
objects moving under sole influence of gravity - 16acceleration of gravityg is about equal to 10m/s^2
keeps squaring the farther it drops - 17distinguish mass from weightmass: amount of matter in an object
weight: the force that acts upon an object - 18why are astronauts weightless in space?there is gravity in space
weightlessness is due to a constant state of freefall - 19Force of gravityUniversal law of gravitation
1. every mass attracts every other mass
2. attraction is directly proportional to product of their masses
3. attraction is inversely proportional to the square of the distance between their centers
closer together=attracts more
farther=attracts less - 20How did Newton generalize Kepler's laws?Kepler's laws are a natural consequence of the three laws of motion and the universal law of gravity
Newton generalized Kepler's laws in order to apply to any two bodies moving under the influence of their mutual gravity (moon orbiting earth)
Newton 1: each of two bodies follows an orbit around the common center of mass, located in one focal point of the orbital path
ellipses are not the only orbital paths (bound: ellipses, unbound: parabola and hyperbola) - 21define escape velocityif an orbit gains enough orbital energy, it may escape (change from a bound to unbound orbit)
escape velocity from earth is about equal to 11km/s from sea level
escape and orbital velocities do not depend on mass - 22conservation of angular momentumangular momentum=mass x velocity x radius
explains why objects rotate faster as they shrink in radius
think of ice skater pulling arms in to spin faster - 23What causes tides?moon's gravity pulls harder on near side of earth than far side
the difference in the moon's gravitational pull stretches earth - 24When are tides the strongest and weakest?strongest: new and full
weakest: first and third quarter - 25how are they related to the moon's phasessize of tides depends on phase of moon
- 26light as a wave: wavelength, frequency, and energyparticles of light are photons
each photon has a wavelength and frequency
light is an electromagnetic wave - 27wavelengthwavelength and frequency are inversely related
- 28gamma-raysmost powerful, frequency and energy are at its highest
- 29x-raysfrequency and energy are high
- 30ultravioletblue
- 31visiblecolors we see, ROYGBIV
- 32infraredred, red is longer wavelength
- 33radioleast amount of energy and frequency, wavelength is the longest with this
- 34Visible portion of spectrum: ROYGBIV - order by wavelength, frequency, energyactually goes backwards (VIBGYOR)
red is longer wavelength
blue/violet is shorter - 35compare energy, wavelength, frequency and speed of different kinds of light (EM) wavesthey all move at the same speed, so they will get places at the same time
- 36What means doppler shift?using change in frequency of a wave to observe how object is moving (think radar)
- 37redshiftreceding (observer sees a longer wavelength)
- 38blueshiftapproaching (observer sees a shorter wavelength)
- 39structure and constituents of an atomatoms: consists of nuclei and electrons
molecules: consists of two or more atoms - 40atomic numbernumber of protons
- 41atomic mass numbernumber of protons and neutrons (a neutral atom has the same # of electrons as protons)
- 42isotopedifferent isotopes of a given element contain the same number of protons, but different number of neutrons
- 43mariadarker
smoother
younger
lava helped form it - 44highlandslighter
more cratered
older - 45what is the most accepted theory that explains the formation of the moon?planet-sized object collided with earth to form moon
- 46Why does the moon's surface appear more heavily cratered compared to the Earth's surface?it is more cratered because the moon has no atmosphere
- 47objects in solar systemsun
mercury
venus
earth
mars
asteroid belt
jupiter
saturn
uranus
neptune
kuiper belt - 48structure of the solar systemtwo major types of planets
planets are very tiny compared to spaces between them - 49what features of our solar system provide clues on how it formed?1. motion of large bodies (planets and their moons)
2. two major planet types (terrestrial and jovian)
terrestrial planets are closer to the sun
jovian planets are farther from the sun
3. swarms of smaller bodies (asteroids and comets)
4. exceptions to trends stand out (some planets have unusual axis tilt, venus has extreme tilt of 180 degrees, goes clockwise, uranus orbits sun on its side, tilts 90 degrees - 50composition of the solar nebulacloud of interstellar gas
nebular theory: solar system formed from a giant - 51how does the nebular theory explain the patterns of motion in the solar system?the rotation of speed of the cloud from which our solar system formed must have increased as the cloud contracted
- 52how was the solar nebula formed?galactic recycling
- 53how were the planets formed?accretion
terrestrial: small particles of rock and metal were present inside frost line, planetesimals of rock and metal built up as these particles collided
gravity assembled planets
accretion: formation of assembly - 54how were the planets formed?jovian: ice could also form small particles outside the frostline
larger planetesimals and planets were able to form
the gravity of these larger planets was able to draw in surroundings
the gravity of rock and ice in Jovian draws together Hydrogen and helium
moons of jovian planets form in miniature disks
radiation and outflowing matter from sun and solar wind blew away leftover gasses - 55where did asteroids and comets come from?leftovers from accretion process
rocky asteroids inside frost line
icy comets outside frost line - 56when did planets form?the oldest moon rocks are 4.4 billion years old
use rocks from places to tell how old something is - 57refractorsas light passes from one medium to another is bent
light is gathered and focused by a curved lense - 58reflectinga curved mirror is used to collect and focus the light
- 59main functioning of a telescopelight gathering
resolving power (or resolution)
magnification
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- Astronomy Flashcards on Astronomy Exam 2, created by Sophia H on 30/10/2022.
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