Earth Science - Overview PDF

I.THE EARTH A. The Universe 1. Galaxies: - Collection of nebulae and millions of stars. - Our galaxy name: The Milky Way. 2. Nebulae: Huge clouds of gas and dust. 3. Stars: Are very large, hot balls of gas. 4. Other celestial bodies: Planets: Are spherical, rocky, and gaseous....

I.THE EARTH A. The Universe 1. Galaxies: - Collection of nebulae and millions of stars. - Our galaxy name: The Milky Way. 2. Nebulae: Huge clouds of gas and dust. 3. Stars: Are very large, hot balls of gas. 4. Other celestial bodies: Planets: Are spherical, rocky, and gaseous. Dwarf planets: Are spherical. They are smaller than planets. Satellites: - Revolve around a planet. - The Earth´s satellite: The Moon. Asteroids: Rocky object. They travel through space or revolve around a star o a planet. Meteorites: - Asteroids that collide with planets or satellites. - Shooting stars: Are small meteorites that disintegrate in the Earth´s atmosphere. Comets: - Balls of dust and ice. - Have got tails of steam. - Most famous: Halley´s Comet. B. The Solar System 1. Solar System: Definition: A star and the celestial bodies that revolve around it. The Sun: - Our Solar system star. - Is medium in size. - It produces a lot of energy and provides light and heat to the planets. C. The planets: 1. Names: There are 8 planets in our solar system. Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune 2. Satellites in planets: Jupiter and Saturn: - More than sixty satellites each. - Are different sizes. - Different orbits. The Earth: - One satellite: The Moon. Orbits: Are the paths that celestial bodies take around the planets. 3. Dwarf planets: Revolve around the Sun, past Neptune´s orbit. Pluto: Is the most well-known dwarf planet. C. The layers of the Earth 1. Earth characteristics: Rocky and spherical body. Is slightly flat at the poles. It has 3 different parts. 2. Parts of the Earth The Atmosphere: - Is the layer of air that surrounds the Earth. The Hydrosphere: - Is all the water on the Earth. - It covers about 70% of the surface. The Geosphere: - Is the solid, rocky, part of the Earth. - It has got 3 layers: ✓ The crust: o Forms the continents and the seabed. ✓ The mantle: o Is between the crust and the core. o It is made up of very hot rocks. ✓ The core: o Is in the center of the Earth. o It is made up of metal. D. The Moon 1. The Moon: Definition: - The Earth´s only satellite. - It rotates on its axis as it revolves around the Earth. This takes 29 twenty-nine and half days. Characteristics: - It is rocky and spherical. - It has not atmosphere or hydrosphere. - It has craters, that are caused by meteorite collisions. 2. Light: The Moon doesn´t produce light. It reflects light from the Sun. The phases of the moon: how we see the Moon each day from the Earth (bigger or smaller). 3. Tides: Tides: - Are the rise and fall of sea level. - The Moon pulls on Earth´s water with gravity. 4. Solar eclipses: Solar eclipse: When the Moon moves between the Sun and the Earth, part of the Sun´s light is blocked, and the sky slowly gets dark. E. How the Earth moves. 1. Revolve: The Earth revolves around the Sun. Takes 365 days and 6h: One year. 2. Rotates: The Earth rotates on its axis. It takes 24h: One day. Causes: Day and night. F. The seasons in the Northern Hemisphere. 1. The seasons in the Northern Hemisphere: The Sun´s rays reach the Northern Hemisphere at different angles, depending on the time of the year. This happens due to the Earth´s position change during the year with rotation. 2. Seasons: Season Summer Autumn Winter Spring Dates June 21st- September 23rd- December March 20th- June 21st. September 23rd. December 21st. 21st- March 20th. Days / Nights Longer Days Same Length (Days Longer Same Length (Days and Nights) Nights and Nights) Temperature Hot Mild Cold Mild