Science
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61 terms
Terms | Definitions |
|---|---|
 absolute magnitude | a measure of the amount of light that a star actually emits. |
| apparent magnitude | a measure of the amoundt of light from a star that is received on earth |
| asteroid | a piece of rock similar to the material that formed into planets. |
| axis | imaginary vertical line that cuts through the center of earth and around which earth spins. |
| big bang theory | states that approximately 12 to 15 years ago, the formation of the universe began with a fiery explosion. |
| black hole | remnant of a star that is so denxe that nothing, not even light, can escape it's gravity field. |
| chromosphere | lalyer of the sun's atmosphere found above the photosphere and below the transition zone and corona. |
| comet | a mass that travels through space and in composed of rock particles and dust mixed wiht frozen water, methane, and ammonia. |
| constellation | a group of stars that forms a pattern resembling a familiar object, character, or animal, and that changes position throughout the year because earth moves. |
| corona | largest layer of the sun's atmosphere from which charged particles continually escape into space. |
| earth | third planet from the sun, its atmosphere protects life and its surface temperatures allow water to exist as a solid, liquid, and gas. |
| electromagnetic spectrum | arrangement of electomagnetic radiation, including radio waves. |
| ellpse | elongated, closed curve that describes earths yearlong orbit around the sun |
| equinox | twice-yearly time, each speing and fall, when the sun is dirctly over the equator and the number of daylight and nighttime hours are equal worldwide. |
| full moon | phase that occurs when all of the moon's surface facing earth reflects lgiht. |
| galaxy | a large group of stars, dust and gas that is held together by gravity and can be ellipticall, spiral, or irregular. |
| giant | late stage in a stars life cycle where its hydeogen is used up, its core contracts, and its outer layers expand and cool. |
| Great Red Spot | a giant, high-pressure sontinuous storm on Jupiter. |
| impact basin | a hollow left on the surface of the moon caused by an object striking its surface. |
| Jupiter | largest planet and fifth planet from the sun, has faint rungs, seventeen moon,and atmoshphere formed mostly of hydrogen and helium, and its surface has continuous storms. |
| light-year | distance light travels in one year, the unit of measure used by a astronomers to determine distances in space. |
| lunar eclipse | occurs when earths shadow falls on the oon |
| maria | dark-colored, relatively flat regions of the moon formed when ancient lava reached the surface and filled craters on the moons surface. |
| Mars | fourth planet from the sun, appears reddish because of iron oxide in weathered rocks, ahs polar ice caps, a thin atmoshere, and two moons. |
| Mercury | planet closest to the sun, has a thin atmosphere with temperature extremes, and iron core, and man craters and high cliffs. |
| meteor | a metoriod that burns up in earths atmosphere. |
| meteorite | a meteoroid that does not completely burn up in the atmosphere and strikes the surface of a moon or planet. |
| Moon phase | changein appearance of the moon as viewed from the earth, due to the relative positions of the moon, earth, and sun. |
| nebula | a large cloud of dust and gas that can break into smaller pieces and from stars. |
| Neptune | large, gaseous planet with rings, dark-colored storms, and eight moons, has a distinctive blue-green color. |
| neutron star | collspsed core of a supernova that shrinks to about 20km in diameter and whose dense core ahs only neutrons. |
| new moon | moon phase that occurs when the moon is between earth and the sun,at which point the moon connot be seen because its lighted half is facing the sun and its dark side faces earth. |
| observatory | building that can house an optical telescope; often has a dome-shaped roof that can be opened for viewing |
| orbit | curved path followed by a satellite as it revolves around an object |
| photosphere | lowest layer of the Sun's atmosphere and the layer that gives off light |
| Pluto | smallest planet and usually considered to be the ninth planet from the Sun; has a thin atmosphere and a solid, icy-rock surface |
| Project Apollo | final stage of the U.S. space program to reach the Moon, with Apollo II landing on the Moon's surface on July 20, 1969 |
| Project Gemini | early U.S. space program where one Gemini astronaut team connected with another spacecraft in orbit; also studied the effects of space travel on the human body |
| Project Mercury | first U.S. space program that orbited a piloted spacecraft around Earth and brought it back safely |
| radio telescope | an instrument that collects and records radio waves traveling through space and can be used day or night under most weather conditions; provides information to map the universe and look for life on other planets |
| reflecting telescope | an optical magnifying instrument that uses a concave mirror in the base of the telescope to focus light from an object and form an image at the focal point |
| revolution | Earth's yearlong elliptical orbit around the sun |
| rocket | a motor that does not require air to burn either liquid or solid propellant and can carry objects into space |
| rotation | spinning of Earth on its imaginary axis, which takes about 24 hours to complete and causes day and night to occur |
| satellite | Any natural or artificial object that revolves around another object in space |
| Saturn | second-largest and sixth planet from the Sun; has a complex ring system, at least 31 moons, and a thick atmosphere made mostly of hydrogen and helium |
| Solar eclipse | occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth |
| solar system | the sun with the celestial bodies that revolve around it in its gravitational field |
| solstice | twice-yearly point at which the Sun reaches its greatest distance north or south of the equator |
| space probe | an instrument that carries datagathering equipment deep into space and sends information back to Earth |
| space shuttle | A reusable spacecraft designed to make many trips and that carries astronauts, satellites, and other cargo to and from space |
| space station | a large structure with living quarters, work and exercise areas, and equipment and support systems for humans to live and work in space; can provide the opportunity to conduct research not possible on Earth |
| sphere | a round, three-dimensional object whose surface is thesame distance from its center at all points; Earth is a sphere that bulges somewhat at the equator and is slightly flattened at the poles |
| sunspot | an area of the Sun that is cooler and not as bright as surrounding areas and that is caused by the Sun's intense magnetic field |
| supergiant | Life cycle stage of a massive star where the core reaches extremely high temperatures, heavy elements form by fusion, and the star expands. |
| Uranus | seventh planet from the Sun; is large and gaseous, has a distinct bluish-green color, and rotates on an axis nearly parallel to the plane of its orbit |
| Venus | second planet from the Sun; similar to Earth in mass and size; has a thick atmosphere and a surface with craters, faultlike cracks, and volcanoes |
| waning | describes phases that occur after a full moon, as the visible lighted side of the Moon grows smaller |
| waxing | describes phases following a new moon, as more of the Moon's lighted side becomes visible |
| white dwarf | Stage in which a star has used up its helium and its outer layers escape into space, leaving behind a hot, dense core that contracts |
| refracting telescope | an optical magnifying instrument in which light from an object passes through a double convex lens and is bent to form an image at the focal point |
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