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26 terms

grade 9 astronomy

STUDY
PLAY
Apparent Magnitude
the brightness of a star as seen from Earth. Our Sun = -26
Asteroid
rock debris of various sizes, orbits Sun. Found in belt between Mars and Jupiter.
Aurora Australis/Borealis
a shimmering light in Earth's Polar regions, which is a result when high-energy-charged particles from solar wind are carried past Earth's magnetic field, generating electrical currents that flow toward the poles. Electric currents charge the gases in upper atmosphere.
Comet
a flying ball of dust, ice, gas and rocks. The tail is a reflection of sun's light (white) or gases ionized by radiation (blue). It will always orbit until it dissipates (dies out)
Corona
area of highly ionized gas surrounding the Sun.
Eclipse
when one celestial body is directly in front of another.
Galaxy
collection of stars, dust, gas, and planets held together by gravity.
Lunar Eclipse
sun casts a shadow of Earth that completely covers moon. No light from sun can reflect off moon, therefore moon disappears.
Meteor
meteoroid colliding with Earth's atmosphere. Burns up during atmospheric friction.
Meteorite
meteoroid that falls to Earth.
Meteoroid
rock in space.
Nebula
vast cloud of gas and dust. The beginning of a star.
Planet
object that orbits one or more stars, but is not a star itself. It does not share its orbit with another object.
Planetisimal
the result of collisions that build rock debris. Eventually will combine into a planet after enough rock debris.
Photosphere
surface of the sun.
Protostar
hot condensed object at the centre of a nebula.
Retrograde Motion
direction opposite to movement of something else. Since the orbits of the planets are of different sizes, they take different amounts of time to revolve around Sun. From Earth, their apparent motion resembles a loop.
Satellites
objects that orbits a celestial body. Moon, man-made radar satellites.
Solar Eclipse
when moon is between Earth and sun, casting shadow onto earth. Sun's light is blocked out, but it is still harmful to watch.
Solar Flares
magnetic fields explosively eject intense streams of charged particles into space.
Solar Prominence
large eruptions of luminous hydrogen gas that rise thousands of km above chromosphere.
Solar System
group of planets that orbit around a star.
Solar Wind
a stream of fast-moving charged particles ejected by Sun into solar system.
Sunspot
area of strong magnetic fields on photosphere. It has a different temperature than the Sun.
Tides
moon orbits earth, gravity pull makes high and low tide.
Universe
all stars, planets, moon, dust, gas, energy, solar system, galaxies.