one word
two words
100
comet
celestial body that catches fire when it passes the sun
100
milky way
the galaxy that contains our solar system
200
universe
everything that exists from outerspace to substance particles
200
astronomical unit
distance from the Earth to the Sun, unit of length
300
atmosphere
layer of gases, surround a planet, kept in place by gravity
300
star system
a small number of stars that orbit each other
400
exoplanet
Orbits other star not the sun
400
geomagnetic storm
disturbance of planet's magnetic field
500
meteorite
solid pieces of debris from asteroids or comets
500
solar flare
flash of brightness of the sun's surface
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