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48 Cards in this Set
- Front
- Back
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List the planets, by distance from the Sun
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Mercury, Venue, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
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What is the largest dwarf planet
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Eris
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Name the dwarf planets
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Ceres, Pluto, Eris
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Satellite
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A body orbiting a planet.
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Star
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A massive, gaseous body held together by gravity and generally emitting light.
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Solar System
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The Sun, planets, their moons, and other bodies, such as meteors and comets.
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Astronomical Unit
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A distance unit based on the average distance of the Earth from the Sun.
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Big Bang
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The event that began the universe.
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Local Group
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The small group of three spiral galaxies and several dozen small galaxies, to which the milky way belongs.
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dark energy
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A form of energy detected by its effect on the expansion of the universe.
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Milky Way Galaxy
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The galaxy to which the sun belongs.
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dark matter
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Matter that emits no detectable radiation but whose presence can be deduced by its gravitational attraction on other bodies.
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galaxy
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A massive system of stars, gas, and dark matter held together by their mutual gravity.
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galaxy cluster
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A set of hundreds or thousands of galaxies held together by their mutual gravitational attraction.
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galaxy group
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A system of from two to several dozen galaxies held together by their mutual gravitational attraction.
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light-year
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A unit of distance equal to the distance light travels in one year.
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stellar evolution
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The gravity-driven changes in stars as they are born, age, and finally run out of fuel.
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supercluster
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A cluster of galaxy groups and clusters.
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universe
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The largest astronomical structure we know of.
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Virgo Cluster
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The nearest large galaxy cluster.
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horizon
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The line separating the sky from the ground.
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MKS system
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The form of the metric system using meters, kilograms, and seconds to measure length, mass, and time.
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parsec
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A unit of distance equal to about 3.26 light-years.
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asterism
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An easily identifiable grouping of stars, sometimes a part of a larger constellation.
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celestial equator
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An imaginary line on the celestial sphere lying exactly above the Earth's equator.
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celestial pole
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An imaginary point on the sky directly above the Earth's North, or South Pole.
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celestial sphere
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An imaginary sphere surrounding the Earth.
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circumpolar
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Close enough to a celestial pole that always remains above the horizon.
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constellation
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An officially recognized grouping of stars in the night sky.
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declination (dec)
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One part of a coordinate system for locating objects in the sky. North/South
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nadir
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the point on the celestial sphere directly below the observer.
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Polaris
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A moderately bright star in the constellation Ursa Minor. The north star.
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right ascension (RA)
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Used to locate objects in the sky. East-West
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zenith
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The point on the celestial sphere that lies directly above the observer.
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rotation axis
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An imaginary line through the center of a body about which the body spins.
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solstice
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The beginning of winter and summer. The solstice occurs when the sun is at its greatest distance north or south.
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Tropic of Cancer
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The latitude line of 23.5 degrees north, marking the distance farthest north where the Sun can pass directly overhead.
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Tropic of Capricorn
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The latitude line of 23.5 degrees south, marking the distance farthest south where the Sun can pass directly overhead.
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vernal equinox
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Spring in the Northern Hemisphere begins on the vernal equinox, which is on or near March 20.
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year
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The time it takes the Earth to complete its orbit around the Sun.
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zodiac
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A set of 12 constellations along the ecliptic, in a band around the celestial sphere.
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apparent noon
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The time at which the sun crosses the meridian as seen from a particular location.
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leap second
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A time adjustment added every few years to clocks around the world to adjust them to account for Earth's slowing speed.
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sidereal day
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The length of time from the rising of a star until it next rises.
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sidereal time
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A system of time measurement referenced to the motion of stars.
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solar day
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The time interval from sunrise to the next sunrise.
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tidal braking
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The slowing of one body's rotation as a result of gravitational forces exerted on it by another body.
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universal time
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The time kept at Greenwich, England, at the Prime Meridian.
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