Astronomy Unit Final Review

Nebula

Baby Stars-Cloud of gas and dust where stars form. The material collects until it gets big enough to burn in the core. Nuclear fusion creates heat and light.

Main Sequence

Adult Stars-This is the longest stage in the life cycle of a star. These stars can be big or small, hot or cool. They create energy by fusing hydrogen into helium in their cores. This is where our SUN is found!

Red Giant Star

Senior Citizen Stars- a very LARGE star of high luminosity and low surface temperature. These stars are starting to run out of fuel. They burn their outer layers so they expand-get BIG and COOL

Red Supergiant Star

Senior Citizen-A red supergiant is an aging giant star that has consumed its core's supply of hydrogen fuel. (It is the same as the red giant except BIGGER!

White Dwarf Star

Death of a giant star-small, hot star that is the leftover center of an older star; has no hydrogen left and cannot generate anymore energy; can shine for billions of years before completely cooling off.

Black Dwarf Star

A white dwarf star that has been cooled to such a low temperature that it emits no detectable light.

Supernova

the brilliant explosion of a dying supergiant star

Neutron Star

A star that has collapsed under its own gravity.

Black Hole

An object in space whose gravity is so strong not even light can escape. Death of the most massive stars

Which color are the hottest stars?

blue

Which color are the coolest stars?

red

how will our sun end its life?

white dwarf

phases

the different shapes of the moon you see from Earth

One half

the portion of the moon that is always in darkness

New Moon

Moon phase that occurs when the Moon is between Earth and the Sun, at which point the Moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth.

Full Moon

moon phase when the entire side facing Earth is illuminated.

first quarter moon

The moon is a quarter of the way around the Earth. You can see the right half of the moon. This is in its waxing cycle.

third quarter moon

The phase of the moon when it is three-quarters of the way through its orbit, and we see the left half of the moon. It is in its waning cycle

Waxing

You SEE more of the moon each night. Seen on the right side

Gibbous

Moon phase in which more than half of the Moon appears to be illuminated.

Waning

You SEE less of the moon each night. Seen on the left side

total solar eclipse

A solar eclipse during which the Sun becomes fully blocked by the disk of the Moon

lunar eclipse

an eclipse in which the moon appears darkened as it passes into the earth's shadow.

Maria

Dark, flat areas on the moon's surface formed from huge ancient lava flows.

crater

A large round pit caused by the impact of a meteoroid.

rays

the white lines that extend in all directions from some craters

Rillies

structures that look like narrow canyons or stream courses

highlands of moon

bright rugged areas pitted with craters

large-impact hypothesis

The theory that the moon formed from debris ejected during a collision between Earth and a large planetesimal.

planet

A large body in space that orbits a star and does not produce light of its own

Moon or Satellite

A body in space that orbits around a planet

Rotation period of the moon

29.5 days

Gravity on the moon

1/6 of earths

Size of moon compared to earth

1/4 the size

Far side of the moon

The side of the moon facing away from the earth

How often does the moon rotate

only 1 time during its 29.5 day revolution around the earth

crescent moon

Shape of the Moon that is less than a quarter moon.

How many days pass between the New Moon to the Full Moon

15 days

Solar System

sun, planets, and all the other objects that revolve around a star

galaxy

a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.

planet

A large body in space that orbits a star and does not produce light of its own

moon/satellite

an object that orbits a planet

star

A ball of hot gas, primarily hydrogen and helium, that undergoes nuclear fusion. It produces it own heat and light. Our sun is a star

meteor

A small piece of debris that is floating around in the universe and if enters the earths atmosphere will burn up and create a streak of light called a "shooting star". It is not a star at all.

asteroid

a small rocky body orbiting the sun. Many found in the asteroid belt. Located between Mars and Jupiter

Rotation

The spinning of Earth on its axis

orbit

The path an object follows as it moves around another object

Polaris

North Star

23.5 degrees

The tilt of the Earth's axis

counterclockwise

the direction that earth spins on its axis

Axis

An imaginary line that passes through Earth's center and the North and South poles, about which Earth rotates

Revolution

The movement of an object around another object, like the Earth moving around the Sun

solar angle

the angle at which light from the Sun strikes the surface of Earth

Summer Solstice

Day with the most hours of sunlight and the fewest hours of darkness. June 21

Winter Solstice

December 21, when the sun is at its southernmost point

Equinoxes

The two days of the year on which neither hemisphere is tilted toward or away from the sun. 12 hours of equal sunlight and darkness

Seasons are caused by

the tilt of the earth's axis & the revolution around the sun

The Sun is lowest in the sky at __________.

Winter Solstice: Sun hits the earth at the Tropic of Capricorn

The Sun is highest in the sky at __________.

summer solstice: Sun hits the earth at the Tropic of Cancer

What would happen if the earth stopped rotating?

We would be stuck in either day or night forever.

What would happen if the earth stopped revolving but continued to rotate.

We would still have normal day and night but we would be stuck in whatever season it was at that time.

Arctic Circle

The area by the North Pole that may receive 24 hours of daylight or darkness depending on the season

Antarctic Circle

The area by the South Pole that may receive 24 hours of daylight or darkness depending on the season

Which hemisphere do we live in?

Northern Hemisphere

If it is summer for us in the Northern Hemisphere what season is it in the Southern hemisphere?

Winter (always the opposite)