The Night Sky

Learning Goals I will be able to explain the criteria required to be called a planet. I will be able to name and group the planets as a gas giant and terrestrial. I will distinguish between the terms: galaxy, star and moon.

Astronomy The scientific study of what is beyond Earth Celestial Object: any object that exists in space Universe: everything that exists, including all energy, matter, and space

Stars Any object in space is a celestial object. Most we see at night are stars. A star is a massive collection of gases. Stars produce and emit (give off) their own light, which makes them luminous.

Our Star … the Sun compared to other stars, the Sun is medium-sized. mass almost 340 000 times and a volume that is 1.3 million times Earth located about 150 million km from Earth. The next-closest star is about 300 000 times farther from us

Planets A planet is a large, round celestial object that travels around a star in a closed or continuous path called an orbit. To be classified as a planet, a celestial object must: orbit a star and no other celestial object, contain enough mass so that its gravity pulls it into a round or spherical shape be able to clear other celestial objects out of its orbit. There are eight planets travelling around the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Two Types Mercury, Venus, Earth, and Mars are all made of solid material. called the “terrestrial planets.” Jupiter, Saturn, Uranus, and Neptune are made up mostly of gases, and possibly have small rocky cores. called “gas giants.” planets appear bright, like stars, but are not luminous. Five planets are visible from Earth with the unaided eye: Mercury, Venus, Mars, Jupiter, and Saturn

Moons Any celestial object travelling in orbit around a larger celestial object is called a natural satellite. The planets are natural satellites of the Sun, and moons are natural satellites of the planets. moons are not luminous. Planets can have different numbers of moons. Mercury and Venus do not have any moons, while Jupiter and Saturn each have more than 60 moons.

Galaxies gigantic collections of gas, dust, stars, and planets contain billions of individual stars! All of the millions of galaxies together, indeed everything that exists, are part of the Universe Earth is part of Milky Way

Movement in the Sky Most of the movement due to Earth spinning in space and orbiting the Sun. The Sun appears to rise and set because our side of Earth is facing the Sun during the day, but is turned away from the Sun at night. We call this optical illusion of movement apparent motion. the Sun, the stars, and the other planets appear to move across the sky. Earth rotates in counterclockwise direction, from west to east. the Sun and stars appear to travel from east to west.

Learning Goals Revisited I will be able to explain the criteria required to be called a planet. I will be able to name and group the planets as a gas giant and terrestrial. I will distinguish between the terms: galaxy, star and moon.

Complete… Crossword P308 #2-5,7,8 Please read section 8.2 on the Sun BRING YOUR SCIENTIFIC CALCULATORS THE NEXT FEW DAYS!!!