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24 terms

Science astronomy

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axis
the center around which something rotates
rotation
the act of rotating as if on an axis
revolution
the movement of an object around another object
orbit
the path described by one celestial body in its revolution about another
solstice
either of the two times of the year when the sun is at its greatest distance from the celestial equator
equinox
either of two times of the year when the sun crosses the plane of the earth's equator and day and night are of equal length
Phases of the moon
the progression of changes in the moon's appearance during the month
New moon
the time at which the moon appears as a narrow waxing crescent
crescent moon
the phase of the moon in which only a curved edge of the moon's side that faced earth is illuminated
Gibbous moon
when the size of the illuminated portion of the moon is greater than half but not a full moon
full moon
the time when the moon is fully illuminated
waning
a gradual decrease in magnitude or extent
waxing
pertaining to the period during which the visible surface of the moon increases
solar eclipse
occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth
lunar eclipse
the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon
umbra
a region of complete shadow resulting from total obstruction of light
penumbra
a fringe region of partial shadow around an umbra
total eclipse
an eclipse as seen from a place where the eclipsed body is completely obscured
partial eclipse
an eclipse in which the eclipsed body is only partially obscured
nebula
an immense cloud of gas (mainly hydrogen) and dust in interstellar space
Gravity
the force of attraction between all masses in the universe
Nuclear fusion
a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
universe
All matter and energy that exists in space
big bang
the cosmic explosion that is hypothesized to have marked the origin of the universe