ASTRONOMY Unit Review (Defenitions)

the sun and all the objects in the orbit around it.

a large collection of matter that is generally spherical and revolves around the sun.

the study of the origin of the universe

a very large collection of matter that emits on the intense amount of energy (light and heat)

star groupings

the north star

measured from east to west from the 0 degree line that crosses Greenwich, England

measured from the Equator to either the North Pole or the South Pole

Earth was the center of the universe

sun-centered system

A medium sized star composed of 75% hydrogen and 25% helium.

Core that collapses and explodes.

Very cool in temp. and ends their life span by forming a cool, dim, star called white dwarf

Fuels hydrogen into helium for energy

emits extremely large amounts of energy for a short period of time

the brightness of the star that we see

the actual brightness of the star

splits light up into a pattern of colours, like a rainbow

consists of a visible spectrum of energy that we can see, as well as other energy that we cannot see.

When light shifts are compressed, the light emitted appears more purple in colour

when light waves are spread out (or further apart), the light emitted appears more red in colour.

huge collections or gas, dust, and billions of stars. The force of gravity attracts the tars in a galaxy to each other.

Looks like a small star, limits up to 100 times more energy than our galaxy, emits radio waves.

contain 10 000-1 000 000 stars that are fairly close to each other and travel together.

the distance that light travels in a year

the distance between the sun and the earth

measurement for distance that is equal to 3.26 light years

smaller than stars, and do not emit light

chunks of rock/metal that orbit the sun but are too small to be called planets. (minor planets)

asteroids with orbits that cross paths with earth

chunks of ice/dust that orbit the sun

lumps of rock that can be trapped by earth's gravity and can be pulled into earth's atmosphere.

meteoroids that enter earth's atmosphere

the streak of light produced across the sky as the meteor burns up.

meteoroids that do not completely burn up as meteors in the earth's atmosphere may strike the earth's surface.

bowl shaped holes on the earth's surface, made by large meteorites

when earth passes through debris left behind from an old comet, there may be a swarm of visible meteors in the night sky.

collections of 100 000 to 1 000 000 stars held together by gravity, arrnged in spherical shapes.

formed by very high mass stars, contracting even further.

the study of all objects in the universe.