Chapter 16

Repeated events such as seasons, phases of the Moon, rising/setting of Sun

Helped people to know when to plant crops or hold festivals

were thought to have special meanings

The Moon blocks the Sun's light

Earth casts a shadow on the Moon

Rare events; people in ancient cultures thought something bad would happen

left records of their observations/predictions of eclipses

left behind buildings and structures that show movements of the Sun, Moon, & stars 

Giant circle of stones in Southwest England which scientists believe is linked to astronomy

Pyramid in Mexico built 700 years ago; shows that people were clever sky watchers

Tool used from 200 B.C.-1700 A.D. to help people better understand the stars

Tool that replaced the astrolabe; had more movable attachments

Inventor of the first telescope (1608)

First person to use a telescope in astronomy, but he didn't invent the telescope

scientific genius born the year Galileo died; developed the reflecting telescope

Used a curved mirror; allowed people to see dimmer & farther away objects in sharper detail

they gather light and concentrate it to make objects seem brighter.

invisible types of electromagnetic radiation

Twin telescopes; largest in the world; work together; used to see very distant stars

detect radio waves; look like satellite dishes; collect radio waves given off by distant objects

must view stars through air currents of the atmosphere; causes some images to look fuzzy

Space telescopes that provide better pictures of stars due to clear and dark conditions

Gigantic balls of very hot gases that give off electromagnetic radiation

A medium-sized star; hydrogen & helium gas react together to make the Sun shine

are the stars that give off the most energy.

also depends on the star's size, temperature, and distance from Earth.

are the coolest stars.

are the second hottest stars.

are the hottest stars.

innermost layer of the Sun; the part that gives off the light energy we see. 

the distance light travels in one year.

A cloud of gas and dust that new stars form in.

a gigantic explosion that occurs when a massive star's core runs out of fuel.

a point in space containing a strong gravity force that pulls in everything close to it.

a huge system of stars, dust, and gas held together by gravity; there are billions in the universe

the galaxy containing the Sun, Earth, and other planets

Look like pinwheels with bright, bulging middles & wispy arms that fan out from the center

Round or more oval, like a football; these are the largest galaxies we know of

have no real shape; are probably young galaxies in which stars are still forming

groups of stars that form a pattern; scientists divide the night sky into 88 constellations

people "connected the dots" formed by the stars; reminded them of different creatures

see different sections of the sky & different constellations.

Can only be seen from the Southern Hemisphere; named after an anicent Greek myth

Another constellation from Greek mythology; contains clusters of stars

stars do not always appear to be in the same position.

the stars that can be seen in the sky change.

in various directions & speeds; nothing stands still.