Our Solar System

Our Solar System Consists of the sun, eight planets, their moons, asteroids, comets, and The planets are all unique and differ in terms of their: Size Surface temperature Chemical elements (e.g. H, He, O2 and C) Gravitational field strength (surface gravity)

The planets orbit the sun in the following order: M V E M J S U N P “My very elderly mother just sent us nine pizzas”

The Inner (Terrestrial) Planets The four planets closest to the sun Mercury Venus Earth Mars They are: Small High density Mainly composed of rocks/metals

The Outer Planets or Gas Giants The four planets farthest from the sun Jupiter Saturn Uranus Neptune They are: Large Low density Mainly composed of gases such as hydrogen and helium

Pluto **Pluto is in a category by itself. Due to its strange orbit and tiny size it is no longer classified as a planet. It has been re-classified as a minor or dwarf planet.

Other Objects in our Solar System Asteroids (aka:Minor Planets) Small rocky objects There is a ring of asteroids between Mars and Jupiter known as the “Asteroid Belt” http://antwrp.gsfc.nasa.gov/apod/ap950630.html Explanation: An asteroid with a moon! The robot spacecraft Galileo whose primary mission is to explore the Jupiter system, has encountered and photographed two asteroids during its long journey to Jupiter. The second asteroid it photographed, called Ida, was discovered to have a moon which appears as a small dot to the right of Ida in this picture. The tiny moon, named Dactyl, is about one mile across, while the potato shaped Ida measures about 36 miles long and 14 miles wide. Dactyl is the first moon of an asteroid ever discovered. The names Ida and Dactyl are based on characters in Greek mythology. http://www.jpl.nasa.gov/images/ds1/borrelly_caption.html In this highest resolution view of the icy, rocky nucleus of comet Borrelly, (about 45 meters or 150 feet per pixel) a variety of terrains and surface textures, mountains and fault structures, and darkened material are visible over the nucleus's surface. This was the final image of the nucleus of comet Borrelly, taken just 160 seconds before Deep Space 1's closest approach to it. This image shows the 8-km (5-mile) long nucleus about 3417 kilometers (over 2,000 miles) away.

Comets Aka “Dirty Snowballs” Made up mainly of dust and ice Travel in a very long orbit around the Sun

Comets As the comet approaches the Sun, it is warmed. Frozen material begins to melt and then evaporate from its surface becoming gases. These gases are pushed outward by the solar wind to produce a bright tail. A comet’s tail can be MILLIONS of kilometers long and always points away from the Sun. http://www.windows2universe.org/comets/comet_model_interactive.html

Meteors (aka Shooting Stars) A meteoroid is a small rock or particle of debris in our solar system. They range in size from dust to around 10 metres in diameter (larger objects are usually referred to as asteroids). A meteoroid that burns up as it passes through the Earth’s atmosphere is known as a meteor. Most never reach the earth. http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=789 Barringer Meteor Crater, Arizona Meteor Crater is one of the youngest and best-preserved impact craters on Earth. The crater formed roughly 50,000 years ago when a 30-meter-wide, iron-rich meteor weighing 100,000 tons struck the Arizona desert at an estimated 20 kilometers per second. The resulting explosion exceeded the combined force of today's nuclear arsenals and created a 1.1-kilometer-wide, 200-meter-deep crater. http://www.youtube.com/watch?v=D8DPrVSmjwI ..\..\..\My Videos\grade nine science\Spaced Out- Meteors, Meteorites and Shooting Stars.mp4

Meteorites A meteor that hits the Earth before it completely burns up. Produce large craters http://www.youtube.com/watch?v=dBvotWfR3j4 ..\..\..\My Videos\grade nine science\Meteorite Explosion - Russia Chelyabinsk 2_15_2013 - Asteroid expected to pass close by Earth.mp4

Planetary Moons (aka. Natural Satellites) Large natural objects that revolve around the planets Each moon is a different size and has a different surface Contain useful minerals

Luminous vs. non-luminous Luminous objects are seen because they give off their own light. Examples are stars. Non-luminous means objects can only be seen because light from the sun reflects off of them. Examples are planets, moons, asteroids and comets.

Homework Read pg 430  433 Questions p. 433 # 3 - 5