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43 Cards in this Set
- Front
- Back
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Who was Aristarchus?
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First to suggest that earth went around the sun
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Who is Copernicus?
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-From Poland (1473 - 1543)
-First class education -Discovered simple geometric relationships that allowed him to calculate each planets orbital period around sun, and distance. -Sun centered idea -Didn't work because of "perfect circle" orbits. |
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Who is Tycho?
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-1546-1601
-Took most accurate naked eye observations -He didn't know how to explain stellar parallax, which made him conclude that the earth remained stationary. |
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Who was Kepler?
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-1571-1630
-Discovered planets orbit in elipses |
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What was Kepler's 1st Law?
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The orbit of earth planet around the Sun is and ellipse with the sun at one focus. Closest at perihelion, and farthest at aphelion.
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What is Kepler's 2nd Law?
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As a planet moves around its orbit, it sweeps out equal areas in equal times.
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What is Kepler's 3rd Law?
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More distant planes orbit the sun at slower average speeds obeying a precise mathematical relationship (p2 = a3)
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What is Newton's 1st law of motion?
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An object moves at constant velocity if there is no net force acting upon it.
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What is Newton's 2nd Law of motion?
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When object net force is present, net force will change an object's momentum. F = m X a
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What is Newton's 3rd Law of motion?
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For any force there is always an equal and opposite reaction force.
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What is the Universal Law of Gravitation?
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-Every mass attracts every other mass through the force called gravity
-The strength of the gravitational force attracting any two objects is directly proportional to the product of their masses. For ex. doubling the mass of one object doubles the force of gravity between objects. -Strength of gravity between 2 objects decreases with the square of the distance between centers. Gravitational force follows an inverse square law with distance. (fg = G M, M2) G = 6.67 x 10 -11 d2 |
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What is Tidal force?
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Difference in attraction creates stretching, stretches the entire earth to create 2 tidal bulges - one facing moon and one opposite.
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How many daily high tides are there?
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2
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Why does the earth orbit the sun?
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Because of the sun's tidal force. Distance makes the pull on earth relatively small.
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How do Jupiter's moons rotate? What are Jupiter's moons?
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They rotate synchronously. Jupiter's moons are IO, Europa, Ganymede etc.
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What are wavelengths?
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Distance from one peak to the next
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What is frequency?
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The number of peaks passing by any point each second.
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What is speed (in light waves)?
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The speed of waves tells us how how fast their peaks travel across the pond.
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What is Infrared?
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Light with wavelengths somewhat larger than red light, because it lies beyond the red end of the rainbow.
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What are radiowaves?
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The longest wavelength light
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What are microwaves?
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The region near the border between infrared and radio waves.
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What is ultraviolet light?
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Lies beyond blue or violet end of the rainbow.
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What are X-rays?
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Short wavelength
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What are gamma rays?
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Shortest wavelength
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What is a continuous spectrum?
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Spectrum of a common (incandescent) light bulb is a rainbow of color. Because the rainbow spans a broad range of wavelengths without interruption.
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What is an Emission line spectrum?
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A thin or low density cloud of gas does not provide a continuous spectrum. Instead, it emits light only at specific wavelengths that depend on its composition and temperature. The spectrum consists of bright emission lines that we see against a black background.
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What is an Absorption line spectrum?
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If the cloud of gas lies between us + a light bulb, we still see most of the continuous light emitted by the light bulb. However, the cloud absorbs light of specific wavelengths, so that the spectrum shows dark absorption lines over the background rainbow from the light.
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What is Doppler Shift?
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If an object is moving towards us, the light waves bunch up between us and the object, so that its entire spectrum is shifted to shorter wavelengths. Because shorter wavelengths of visible light are bluer, the doppler shift of an object coming towards us is called a blueshift. When it goes away, it is shited to longer wavelengths, redder.
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What is a refracting telescope?
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Transparent glass lenses to collect and focus light.
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What is a reflecting telescope?
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Uses primary mirror to gather light. This mirror reflects the gathered light to a secondary mirror that lies infront of it. Secondary mirror to a focus.
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What are radio telescopes?
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The most common type are satellite dishes. Angular resolution, unimportant. These are extremely big. Biggest - Arecibo (?)
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What are x-ray telescopes?
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Have sufficient energy to penetrate materials. Grazing incidence mirrors deflect x rays towards focal point.
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What are adaptive optics?
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Makes telescope mirror do opposite jiggle, to cancel out atmospheric turbulence.
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Where did the Solar System come from?
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Came from an interstellar cloud of gas.
- Hydrogen + helium |
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(What processes did the Solar Nebula go through?) What is heating?
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Temperature of it increased as it collapsed
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(What processes did the Solar Nebula go through?) What is Energy Conservation?
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As cloud shrank, gravitational potential energy turned into kinetic energy.
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(What processes did the Solar Nebula go through?) Spinning?
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Nebula rotated faster and faster as it shrank in radius. Collapsed into center.
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(What processes did the Solar Nebula go through?) Flattening?
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This flattening is a natural consequence of collisions between particles in a spinning cloud.
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(What processes did the Solar Nebula go through?) Frost line?
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Hydrogen compounds could condense into ices only beyond this line. Which lay between orbits of mars and jupiter.
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(What processes did the Solar Nebula go through?) Solar Wind?
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Vast majority of hydrogen + heliu gas in solar nebula. Never became part of a plane, swept away by a stream of charged particles. Strong in young stars.
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How was the moon formed?
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A giant impact, accretion ring of debris formed moon.
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What is radiometric dating?
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-It measures the age of a rock.
-Measurement of isotopes in rock -Radioactive isotope has a nucleus that can undergo spontaneous change. -Radio active decay, breaking apart or having one of its protons turn into a neutron. |
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What is half-life?
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Time it would take for half of the parent nuclei in the collection of decay.
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