The trapping of heat near a planet's surface by certain gases in the planet's atmosphere:

A total kinetic and potential energy of all the particles of an object:

The transfer of thermal energy by the movement of fluid:

The transfer of thermal energy from one particle of matter to another:

The transfer of energy by electromagnetic waves:

The horizontal movement of air from an area of high pressure to an area of lower pressure:

The flow of cooler air from over an ocean or lake toward land:

The flow of air from land to a body of water:

The effect of Earth's rotation on the direction of winds and currents:

Band of high-speed winds about 10 kilometers above Earth's surface:

A large stream of flowing water that flows through the oceans:

An abnormal climate event that occurs every two to seven years in the Pacific Ocean causing changes in winds, currents, and weather patterns for one to two years:

A climate event in the eastern Pacific Ocean in which surface waters are colder than normal:

The average annual conditions of temperature, precipitation, winds, and clouds in an area:

A gas in Earth's atmosphere that absorbs heat leaving Earth's surface:

The trapping of heat leaving a planet's surface by certain gases in the planet's atmosphere:

A sudden or gradual change in Earth's climate:

A gradual increase in Earth's average temperature:

Energy-rich substance formed from the remains of organisms:

An unforeseen chain of events caused by a disturbance in a system:

Clean energy sources that do not come from fossil fuels:

An object that orbits a planet:

A ball of hot gas, primarily hydrogen and helium, that undergoes nuclear fusion:

An object that orbits a star, is large enough to have become rounded by its own gravity, and has cleared the area of its orbit:

A streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere:

A loose collection of ice and dust that orbits the sun, typically in a long narrow orbit:

A pattern or grouping of stars that people imagine to represent a figure or object:

Term describing a model of the universe in which Earth is at the center of the revolving planets and stars:

Term describing a model of the solar system in which Earth and the other planets revolve around the sun:

An oval shape which may be elongated or nearly circular; the shape of the planets' orbits:

An imaginary line that passes through the Earth's center and its north and south poles, about which the planet rotates:

The spinning motion of a planet on its axis:

The movement of an object around another object:

The path of an object as it revolves around another object in space:

Either of the two days of the year on which the sun reaches its greatest distance north or south of the equator:

Either of the two days of the year in which neither hemisphere is tilted toward or away from the sun:

The attractive force between objects; the force that moves objects downhill:

The scientific law that states that every object in the universe attracts every other object:

The tendency of an object to resist a change in motion:

One of the different apparent shapes of the moon as seen from Earth:

The partial or total blocking of one object in space by another:

The darkest part of a shadow:

The part of a shadow surrounding the darkest part:

The periodic rise and fall of the level of water in the ocean:

The tide with the greatest difference between consecutive low and high tides:

The tide with the least difference between low and high tide:

The system consisting of the sun and the planets and other objects that revolve around it:

A unit of distance equal to the average distance between Earth and the sun, about 150 million kilometers:

A large gaseous body at the center of the solar system:

An object that orbits a star, is large enough to become rounded by its own gravity, and has cleared the area of its orbit:

A natural satellite that orbits a planet:

One of the rocky objects revolving around the sun that is too small and numerous to be considered a planet:

A chunk of rock or dust in space, generally smaller than an asteroid:

A loose collection of ice and dust that orbits the sun, typically in a long, narrow orbit:

The energy transferred through space by electromagnetic waves:

Electromagnetic radiation that can be seen with the unaided eye:

The range of wavelengths of electromagnetic waves:

The distance between two corresponding parts of a wave, such as the distance between two crests:

An optical instrument that forms enlarged images of distant objects:

A large cloud of gas and dust in space:

A contracting cloud of gas and dust with enough mass to form a star:

The blue-white hot core of a star that is left behind after its outer layers have expanded and drifted out into space:

The brilliant explosion of a dying supergiant star:

The brightness of a star as seen from Earth:

The brightness a star would have if it were at a standard distance from Earth:

A huge group of single stars, star systems, star clusters, dust, and gas, bound together by gravity:

All of space and everything in it:

The distance light travels in one year, 9.46 trillion kilometers:

The initial explosion that resulted in the formation and expansion of the universe: