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50 Cards in this Set

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  • Back
The name of the satellite that orbits the Earth.
blue moon
The second full moon in the same calendar month.
The path of a planet or other heavenly body as it revolves around another body in space.
A straight line that an object or body rotates, or seems to rotate around.
To send or give out.
Chunks of rock that vary in size from very large to quite small. They orbit the sun between Mars and Jupiter. About 3000 have been discovered.
A six class scale used to measure the brightness of stars. Brightest in the sky are of the 1st magnitude.
The study of the Universe and all of the bodies that appear in the skies.
waxing moon
When the Moon grows gradually more illuminated when passing from new to full moon.
The distance a heavenly body appears above the horizon as measured in degrees.
Bright stars grouped according to the patterns they make in the sky. There are 99, many of their names coming from characters in ancient mythology.
annual motion
The Earth's orbital motion around the Sun every year.
light year
The distance light travels in a year. Used to measure distances in space. On light year is about 9.5 trillion km.
A layer of air between the Earth and outer space.
A hole created on the surface of an object or body, made by falling meteorites or by erupting volcanoes.
asteroid belt
The area between the inner and outer planets that is filled with asteroids.
The motion of a planet satellite, or the Sun around its north-south axis. It takes 24 hours for the Earth to rotate once on its axis.
binary stars
When two relatively close stars revolve around each other, often appearing as single stars because they are so far away from the Earth.
The closest star to the Earth, measuring more than a million kilometers across.
black hole
An intense gravitational field created when a star runs out of fuel and collapses. Nothing, not even light can escape its pull.
A spiral island of stars in space. Our galaxy is called the Milky Way.
celestial equator
An imaginary line in the sky directly above the Earth's equator.
A man made or heavenly body (moon) that orbits around a larger object.
A large ball of ice, dust, rock and gas that orbits the Sun, circling the dark edges of the Solar System.
When a meteoroid enters the Earth's atmosphere, creating a bright streak of light, it is called a meteor or a shooting star.
A device that uses shadow to tell time.
solar system
The Sun and all of the bodies - planets, satellites, asteroids, comets, etc. that orbit around it.
A phase in the Moon's cycle when more than half of the moon, but not the entire face of the Moon is illuminated.
lunar eclipse
When the moon moves into the Earth's shadow, preventing sunlight from falling onto the moon's surface.
Once a year the Sun reaches it highest and lowest points in the sky at noon. (Dec. 21, June 21)
Either the north or the south half of the Earth divided by the equator, or the east or west half divided by the prime meridian.
Large bodies that can only be seen by reflected light, as they revolve around the sun. Greek word meaning "wanderer".
During the Sun's annual path in the sky it crosses the celestial equator at two points (equinox points). The day is divided between twelve hours of sunlight and twelve hours of darkness. (March 21, September 23)
These rocks, usually not much bigger than grains of sand, may have been swept off asteroids and comets. They also orbit the Sun.
A gaseous body that produces its own energy, releasing it as light and heat.
inner planets
The four hard rocky planets - Mercury, Venus, Earth, Mars - closest to the Sun.
solar eclipse
A solar eclipse is when the moon passes in front of the Sun, covering some or all of the Sun's disk.
Larger meteors that fall to the surface of the Earth.
pole star
A bright star, also known as North Star or Polaris that appears in the northern hemisphere sky. It always stays in the same position.
An imaginary circle around the centre of the Earth, perpendicular to the axis of rotation.
Nicolaus Copernicus
(1493-1543)A Polish scientist. First to re-introduce the idea that the Sun and not the Earth, was the center of the solar system.
moon phases
A cycle in which the Moon appears in different forms as it orbits the Earth.
outer planets
The four giant, gaseous planets - Jupiter, Saturn, Uranus, Neptune - that orbit the Sun.
The motion of a planet along its orbit around the Sun. For example, the Earth takes one year to "revolve" around the Sun.
solar noon
The time of the day when the Sun casts its shortest shadow and shadows face true north.
A force that attracts and holds the universe together. It gives objects weight.
The surface look or feel of something.
Everything that exists: the Earth, the Sun, the Moon, satellites, stars, asteroids, all the galaxies and the space in between them.
waning moon
When the Moon grows gradually more illuminated when passing from new to full moon.
The time it takes for a planet to go all the way around the Sun. On Earth a year is 365 days, on Uranus one year is 84 Earth years.