Chapter 3 Solar Energy And Earth-sun Relationships Flashcards
What is a galaxy?
A large system of stars, gas, and dust bound together by gravity.
What is a light-year?
The distance that light travels in one year.
What is a solar system?
A collection of planets and other celestial bodies orbiting a star.
What is gravity?
The force that attracts two bodies towards each other.
What is mass?
The amount of matter in an object.
What is a planet?
A celestial body that orbits a star and is large enough to be rounded by its own gravity.
What is a terrestrial planet?
A planet that is composed primarily of silicate rocks or metals.
What is a giant planet (gas planet)?
A large planet that is not primarily composed of rock or other solid matter.
What is an asteroid?
A small rocky body that orbits the sun, primarily found in the asteroid belt.
What is a comet?
A small celestial body made of ice, dust, and rocky material that, when close to the sun, displays a visible atmosphere and sometimes a tail.
What is a meteor?
A small particle from space that burns up upon entering Earth’s atmosphere.
What is a meteorite?
A meteor that survives its passage through the atmosphere and lands on Earth.
What is the habitable zone?
The region around a star where conditions may be right for life.
What is a fusion (thermonuclear) reaction?
A reaction in which two light atomic nuclei combine to form a heavier nucleus, releasing energy.
What is solar wind?
A stream of charged particles released from the sun’s atmosphere.
What is an aurora?
A natural light display in the sky, typically seen in high-latitude regions.
What is the aurora borealis?
The northern lights, a natural light display in the Arctic region.
What is the aurora australis?
The southern lights, a natural light display in the Antarctic region.
What is a sunspot?
A temporary phenomenon on the sun’s photosphere that appears as a spot darker than its surroundings.
What is the solar constant?
The amount of solar energy received per unit area at the top of the Earth’s atmosphere.
What is a calorie?
A unit of energy defined as the amount of heat needed to raise the temperature of one gram of water by one degree Celsius.
What is electromagnetic energy?
Energy that is propagated through space by electromagnetic waves.
What is the electromagnetic spectrum?
The range of all types of electromagnetic radiation.
What is the visible spectrum?
The portion of the electromagnetic spectrum that is visible to the human eye.
What is shortwave radiation?
Radiation with a short wavelength, typically emitted by the sun.
What is longwave radiation?
Radiation with a long wavelength, typically emitted by the Earth.
What is galactic movement?
The motion of galaxies through space.
What is rotation?
The spinning of an object around its own axis.
What is revolution?
The movement of one object around another in an orbit.
What is the circle of illumination?
The dividing line between the day and night sides of a planet.
What is perihelion?
The point in the orbit of a planet where it is closest to the sun.
What is aphelion?
The point in the orbit of a planet where it is farthest from the sun.
What is the plane of the ecliptic?
The imaginary plane that contains the Earth’s orbit around the sun.
What is the angle of inclination?
The tilt of a planet’s axis in relation to its orbital plane.
What is parallelism of the axis?
The concept that a planet’s axis maintains the same orientation throughout its orbit.
What is the North Star (Polaris)?
A star located nearly directly above the North Pole, used for navigation.
What is insolation?
The amount of solar radiation received by a given area.
What is a solstice?
The time when the sun is at its greatest distance from the equator, occurring in summer and winter.
What is an equinox?
The time when day and night are of equal length, occurring in autumnal and vernal.
What is the Arctic Circle?
The latitude approximately 66.5° North, marking the southern limit of the polar day.
What is the Antarctic Circle?
The latitude approximately 66.5° South, marking the northern limit of the polar night.
What are direct (vertical) rays?
Sun rays that strike the Earth at a 90-degree angle.
What is the Tropic of Cancer?
The latitude approximately 23.5° North, marking the northernmost point of the sun’s direct rays.
What is the Tropic of Capricorn?
The latitude approximately 23.5° South, marking the southernmost point of the sun’s direct rays.
What is solar declination?
The angle between the rays of the sun and the plane of the Earth’s equator.
What is the subsolar point?
The point on the Earth’s surface where the sun is directly overhead.
What is an analemma?
A diagram showing the position of the sun in the sky at the same time of day throughout the year.
What is zenith?
The point in the sky directly above an observer.
What is the tropical zone?
The region of Earth between the Tropic of Cancer and the Tropic of Capricorn.
What is the midlatitude zone?
The region of Earth between the tropics and the polar circles.
What is the polar zone?
The region of Earth within the Arctic and Antarctic Circles.
