solar system Flashcards
nebula
a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.
solar nebula
a large cloud of gas and dust from which the sun, planets, and other solar system bodies formed.
nuclear fusion
a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
sunspot
a spot or patch appearing from time to time on the sun’s surface, appearing dark by contrast with its surroundings
terrestrial planets
a planet having a compact rocky surface like the Earth’s; the four innermost planets in the solar system
prograde rotation
having a rotational or orbital movement that is the same as most bodies within a celestial system. In our solar system, prograde movement for both rotating and orbiting bodies is in a counterclockwise direction when viewed from a vantage point above the Earth’s north pole.
retrograde rotation
all eight planets in the Solar System orbit the Sun in the direction of the Sun’s rotation, which is counterclockwise when viewed from above the Sun’s north pole. Six of the planets also rotate about their axis in this same direction. The exceptions – the planets with retrograde rotation – are Venus and Uranus.
gas giant
a large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune.
satellite
an artificial body placed in orbit around the earth or moon or another planet in order to collect information or for communication.
new moon
the phase of the moon when it is in conjunction with the sun and invisible from earth, or shortly thereafter when it appears as a slender crescent.
waxing crescent
the moon is less than one-half illuminated by the sun but less than one quarter illuminated. Occurs when the moon’s illumination is increasing, First Quarter. The moon is one-half illuminated by the sun.
quarter moon
the moon is one-half illuminated by the sun. Occurs when the moon’s illumination is decreasing, Waning Crescent. The moon is less than one-half illuminated by the sun but less than one quarter illuminated.
waxing gibbous
the gibbous moon is either the last phase before the moon reaches fullness or the first phase after the full moon.
full moon
the phase of the moon in which its whole disk is illuminated.
waning gibbous
waning means that it is getting smaller. Gibbous refers to the shape, which is less than the full circle of a Full Moon, but larger than the semicircle shape of the Third Quarter Moon.
