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69 Cards in this Set
- Front
- Back
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Celestial object |
any object in outer space ie stars, planets, nebula etc |
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astronomer |
a scientist that studies outer space |
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revolution |
an orbit around an object such as a star example, the earth orbits the sun and takes 365 days to complete a full revolution |
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rotation |
a turn around an axis the earth takes 24 hours to fully rotate on its axis |
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constellation |
a collection of stars that appear to create an image if one was to connect the dots |
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light year |
the distance uninterrupted light can travel in one year roughly 10 trillion kilometers |
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apparent magnitude |
the brightness of an object as seen from earth the sun has a -27 apparent magnitude |
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asterisms |
a constellation inside of a larger constellation |
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pointer stars |
stars that when drawn a line from one to another point at Polaris, the north star |
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circumpolar |
a star that never dips below the horizon or 'sets' they are always visible year round for certain locations |
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zenith |
an imaginary point directly above the observer |
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tides |
times of heightened sea levels because of the moons gravitational |
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phases of the moon |
the different apparent shape of the moon when earths shadow is cast upon it |
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lunar elipse |
when the shadow of the earth completely covers the moon, causing the appearance that it disappears temporarily |
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solar eclipse |
when the moon comes in between the earth and sun and causes the sun to look blocked by the moon on earth |
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Why do we have seasons? |
Because the earth is on a 23.5 degree tilt, when a hemisphere of the earth is tilted towards the sun, it receives more sunlight due to its tilt which in turn heats that hemisphere up more |
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planet |
a body that orbits a star could be gaseous or rocky |
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solar system |
a collection of asteroids, comets planets and their moons that all fall in orbit of a star or star system |
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retrograde motion |
the apparent motion of an object from the view point of another object for example mars' retrograde motion is different than its actual orbit |
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astronomical unit |
a unit of measurement that is equivalent to the distance from the sun to the earth 149,598,000 km |
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orbital radius |
the length of radius of an orbiting object |
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geocentric model |
a model of the solar system that places the earth at its center with the sun, moon and planets orbiting around it |
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heliocentric model |
the correct model of the solar system with the sun at the center of the solar system and the planets and other objects orbiting around it |
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comet |
a piece of rock and ice that when comes near the sun starts to evaporate and a tail of gases from facing away from the sun as a result of solar winds pushing them away ` |
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Asteroid |
a piece of rock that orbits the sun |
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meteroid |
also a piece of rock that orbits the sun and is in outer space |
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meteor |
a meteoroid that has entered earth's atmosphere |
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meterorite |
a meteor that has landed on the earths surface |
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trans-neptunium object |
an object that orbits the sun outside of the orbit of neptune ie, pluto and the oort cloud |
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solar nebula theory |
the leading theory for how stars form clouds of gases or nebula, start to clump together to form protostars. This cloud of gas starts to spin and clump together more to form planets eventually the protostar will become massive enough that its gravity condenses the gases inside that so much pressure is created that nuclear fusion starts |
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star |
a body of plasma that combines hydrogen nuclei through the process of nuclear fusion to release energy and photons |
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nebula |
the remnants of a supernova gases and bits of matter that are a result of a dying star |
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protostar |
a collection of gas that has almost enough mass to be a star but not enough that it has started nuclear fusion |
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nuclear fusion |
the process of combining lighter atomic nuclei to create heavier nuclei and in the process creating energy in the form of radiation |
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photosphere |
the 'surface' of the sun where trapped photons from the fusion process are released into space |
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sunspot |
a darker spot on the sun that is extremely magnetically charged |
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solar wind |
a stream of charged particles that are ejected from a solar flare |
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solar flare |
when multiple sunspots group together, trapped amounts of charged particles and radiation are released into space |
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Importance of the sun |
the suns ultraviolet radiation is the highest energy radiation that can pass through the earth's atmosphere it provides energy for plants which convert solar energy into chemical energy it also is reflected off of the earth's surface where it loses some of its energy and becomes infrared radiation where it reflects back off of the greenhouse gases in the atmosphere and warms the earth |
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luminosity |
the brightness of an object |
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absolute magnitude |
the luminosity of an object from a distance of 1 parsec (3.26 light years) |
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spectroscope |
a device that splits the light of a light source into a spectrum of light so stripes in the light can be detected to identify different elements from the light source |
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spectral lines |
the black lines that show up in the spectrum when light is split by a spectroscope the patterns that they create are used to identify elements that the light has passed through |
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HR Diagram |
a diagram that shows the absolute magnitude of a star compared to its color |
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main sequence |
a star in the main part of its life where it is fusing hydrogen gas to create energy |
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white dwarf |
a low to medium mass star runs out of hydrogen gas to burn and becomes a white dwarf. It is extremely takes a long time to burn out and cool down. |
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supernova |
when a large mass star dies, it collapses in on itself and sheds the outer layers of gas and releases huge amounts of radiation |
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neutron star |
after a large star has shedded its outer layers through a supernova, the remaining super dense core has so much gravity that the remaining protons and electrons combine to form neutrons |
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how low mass stars evolve |
start as a small protostar, is a main sequence star for 100 billion years, sheds its outer layers to become a planetary nebula and a white dwarf, which cools to be a black dwarf |
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how intermediate mass stars evolve |
start as a small protostar, is a main sequence star for 10 billion years, swells to become a red giant, sheds its outer layers to become a planetary nebula and a white dwarf, which cools to be a black dwarf |
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how high mass stars evolve |
burns for 100 million years, then swells to become a red supergiant which continues to fuse until it has an iron core, the core collapses inwards to create a supernova. It then condenses to a neutron star or if its massive enough a black hole |
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black hole |
an infinitely small point in space where its matter is so dense its gravity is so strong that light cant escape |
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milky way |
the galaxy in which we belong |
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galaxy |
a collection of stars and star systems that influence each others gravity and hold each other together as one object |
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star cluster |
a group of stars and star systems that are tied into each others gravitational fields |
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open cluster |
a loosely tied group of stars |
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globular cluster |
a spherical collection of stars that orbits the galactic core |
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local group |
the star cluster that we belong to |
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supercluster |
a cluster of galaxies |
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shapes of galaxies |
spiral: has a round core with arms that spiral off of it, our galaxy is a spiral galaxy elliptical: comprised of older stars and new stars rarely form lenticular: a mix of both with vaguely defined arms and a elliptical center irregular: cant fit into any catergory based on shape |
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cosmology |
the study of the universe |
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doppler effect |
the blue or redshift as a result of a moving light source if the object is moving away the waves are stretched out and are red shifted the opposite is true with blue shifting |
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redshift |
the process of waves being streched out when an object moves away from the observer causing a more red apperance |
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blue shift |
the opposite of a red shift |
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Big bang |
the leading theory on how the universe was created from an infinitely massive point |
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cosmic background radiation |
the leftover radiation from the big bang |
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radiation |
waves of light with varying amounts of energy ie radio, infrared, visible, gamma |
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dark matter |
an un-observable source of mass that is needed to explain the mass of galaxies as they are 6 times more massive than they appear |
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dark energy |
a unknown energy that expands the fabric of space at an accelerating rate |
