THE STARS AND THE STARS AND CONSTELLATIONSCONSTELLATIONS

STARSSTARS

Stars form when Stars form when clouds of gases clouds of gases (mainly hydrogen) are (mainly hydrogen) are pulled together by pulled together by gravitational forces.gravitational forces.

Atomic explosions Atomic explosions occur inside stars.occur inside stars.– They are so hot inside They are so hot inside

that they emit heat and that they emit heat and light.light.

STARS CONTINUEDSTARS CONTINUED

Stars can have Stars can have planetary systems planetary systems made up of planets made up of planets and satellites.and satellites.

An enormous cloud of An enormous cloud of gas and dust, a gas and dust, a nebula, surrounds the nebula, surrounds the stars.stars.

STARS AND THEIR SIZESSTARS AND THEIR SIZES

Stars can have Stars can have different sizes. different sizes.

Some stars are similar Some stars are similar in size to the earth, in size to the earth, they're called dwarf-they're called dwarf-stars. stars.

When stars are bigger When stars are bigger than earth, they're than earth, they're called giant-stars. called giant-stars.

STARS AND THEIR COLORSSTARS AND THEIR COLORS

The color of stars is variable:The color of stars is variable:– red starsred stars

– yellow starsyellow stars

– blue starsblue stars

Red stars are the coldest and blue stars are the hottest.Red stars are the coldest and blue stars are the hottest.

CONSTELLATIONSCONSTELLATIONS

Constellations are Constellations are imaginary patterns of imaginary patterns of bright stars.bright stars.

The ancient Greeks The ancient Greeks invented the invented the constellations we call constellations we call the twelve signs of the the twelve signs of the zodiac.zodiac.

CONSTELLATIONS CONT.CONSTELLATIONS CONT.

There are eighty There are eighty eight official eight official constellations.constellations.

Some examples Some examples are: Big dipper, are: Big dipper, Orion, Gemini, Orion, Gemini, Little dipper.Little dipper.