Astronomy Review 18-19


Terms in this set (...)

sun-centered model of the universe
earth-centered model of the universe
oval orbit
a ball of ice and dust that becomes lit as it travels close to the sun
a group of stars that is imagined to look like a picture of a person, thing, or animal
a large ball of burning gas in space mostly composed of oxygen and helium
an object in space that orbits a star, is large enough to have become rounded by its own gravity, and has cleared the area (neighborhood) of its orbit
a streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere
an object that orbits a planet
an object at rest will stay at rest, and an object in motion will stay in motion
A force that pulls objects toward each other
A measure of the force of gravity on an object
Each of the two times of the year when days and nights are of equal length
Time when the Sun is farthest from the equator.
All of space and everything in it (planets, stars & galaxies)
The path of an object as it revolves around another object in space
the spinning motion of a planet on its axis
an imaginary line that passes through the poles of a planet and its center
The movement of an object around another object
the darkest part of a shadow
The part of a shadow surrounding the darkest part
lunar eclipse
an eclipse that occurs when the Earth passes between the sun and the moon.
solar eclipse
an eclipse that occurs when the moon passes between the sun and Earth, making the sun appear dark.
neap tide
the tide with the least difference between low and high tide; has low high tides and high low tides.
spring tide
the tide with the greatest difference between high and low tides has high high tides, low low tides.
one of the different shapes of the moon as seen from Earth.
the lit portion is getting larger
becoming less bright, intense, or strong
there are billions in our galaxy & their light takes millions of light-years to reach us
the distance light can travel in a year; used to measure light from stars
Date of Winter Solstice
December 21st
Date of Summer Solstice
June 21st
Milky Way
the name of our galaxy, a spiral galaxy that contains about 400 billion stars
Day (24 hours)
the time required for Earth to rotate once on its axis
Month (29-31 days)
the time it takes for the moon to rotate around the Earth once
Year (365 days)
The time it takes the Earth to go around the sun once
Sunlight on earth during Summer Solstice (Northern Hemisphere)
Northern Hemisphere is tilted towards the sun (direct sunlight)
Sunlight on Earth during Winter Solstice (Northern Hemisphere)
Northern hemisphere is tilted away from the sun (indirect sunlight)
Nicolaus Copernicus
Devised a model of the universe with the Sun at the center, and not earth. (heliocentric model)
Claudius Ptolemy
He believed that the Earth was at the center of the Universe, and that the sun and other planets revolved around the Earth. (geocentric model)

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