BJU Earth Science Chapter 22

astronomical unit

The average distance between Earth and the sun, about 150 million kilometers

solar spectrum

the entire span of electromagnetic wavelengths that the sun emits; includes radio waves, microwaves, infrared light, visible light, ultraviolet rays, x-rays, and gamma rays.

nuclear fusion

The process by which two or more small nuclei fuse to make a bigger nucleus

photosphere

the visible surface of the sun

chromosphere

The lowest layer of the sun's atmosphere, starting at the photosphere and extending out to 2000 km from the sun's surface.

corona

The hot outer atmosphere of the sun that extends far out into space to become solar wind. It is the location of solar prominences.

prominence

a stream of solar plasma that rises into the corona from the chromosphere then gradually falls back.

solar wind

A stream of electrically charged particles produced by the sun's corona

sunspot

a cooler darker spot appearing periodically on the sun's photosphere

solar flare

A sudden eruption of intense high-energy radiation from the sun's surface

ray

a bright streak that radiates from some moon craters

mare

a broad, lowland plain on the moon made of hardened lava

rille

a long, narrow valley on the surface of the moon

ecliptic

Path the sun takes across the sky

revolution

Earth's yearlong elliptical orbit around the sun

rotation

the spin of an object around an imaginary axis that passes through its center

terminator

the line or edge separating the light and dark sides of any astronomical body

lunar eclipse

Earth blocks sunlight from reaching the moon

lunar phase

Changes in the visible portion of the Moon caused by its revolution about the Earth allowing us to see more or less of its lit up visible portion.

solar eclipse

Occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth