When Giovanni Riccioli used a telescope like this one to observe a star in the handle of the Big Dipper, he discovered two stars that orbit each other. Red Sea

A constellation -

Star Systems How are stars distributed in space?

Most stars occur in groups of two or more. Star Systems Most stars occur in groups of two or more. A star system is – A binary star is –

Star Clusters What are the characteristics of each type of star cluster?

Star Clusters The Pleiades are – 47 Tucanae is –

Star Clusters A globular cluster is –

Galaxies What are the types of galaxies?

Galaxies A galaxy is –

Galaxies Spiral galaxies –

Galaxies Barred-spiral galaxies is –

Galaxies Elliptical galaxies are-

Galaxies Irregular galaxies is –

Galaxies A spiral galaxy in the constellation Coma Berenices A barred-spiral galaxy in the Fornax cluster

Galaxies Elliptical galaxy M87 An irregular galaxy with many areas of star formation

In a side view, the Milky Way appears as a – Galaxies In a side view, the Milky Way appears as a – Location of solar system Central bulge Nucleus Overhead View of Our Galaxy Disk of spiral arms containing mainly young stars Central bulge containing mainly older stars Nucleus Halo containing oldest stars Side View of Our Galaxy About 100,000 light-years

Galaxies The Milky Way’s flattened disk shape is – The sun takes about 220 million years – . Recent evidence suggests that there is – Stars are forming-

Galaxies quasars are –

Assessment Questions A constellation is two stars that orbit each other. a star system with more than two stars. an open cluster of stars that are close to one another. a group of stars that appear to form a pattern.

Assessment Questions A large group of older stars without sufficient gas and dust to form new stars is a(n) open cluster. galaxy. association. globular cluster.

What type of galaxy is the Milky Way? Assessment Questions What type of galaxy is the Milky Way? spiral galaxy barred-spiral galaxy elliptical galaxy irregular galaxy