1. Take up worksheets -other objects in solar system -solar system chart

2. PlanetOrbital Radius (AU) Radius (Km) Mass (relative to Earth) Average Surface Temp (C) Period of rotation (relative to Earth 1 day) Period of Revolution (relative to 1 Earth Year) Number of Moons Mercury0.3924400.0517958.900.240 Venus0.7260520.82467244.000.620 Earth1.0063731.00171.00 1 Mars1.5233960.11-631.031.882 Jupiter5.2071 490317.8-1500.4111.8661 Saturn9.5460 27095.2-1700.4529.4660 Uranus19.1825 56014.5-2150.7284.0127 Neptune30.0624 76517.1-2350.67164.813

3. Measuring distance from Space Why do we need special units for astronomy -we are dealing with a lot of space, large distances (hard to relate to) Astronomical Units (AU); is a unit of measure created by astronomers for measuring distances in the solar system, it is equal to the ORBITAL distance between the EARTH and SUN, about 150 million km Orbital Radium: The average distance between the STAR (SUN) and the object orbiting the SUN, it is expressed in AU ’ s

4. Light-Year: the distance that light travels in a year, about 9.5 x 10 12 km Trans-Neptunian Objects: Objects that circle the sun beyond the orbit of Neptune are called trans-Neptunian objects: they are located in the KUIPER BELT, which is a disc- shaped group fo millions of small objects orbiting the Sun. Astronomers theorize that the Kuiper Belt is composed of leftovers from the formation of the Solar System, think of it as the dust around the edges of a patio after you sweep it.

5. Why is Pluto considered a trans ’ Neptnian object? Sometimes it ’ s orbit crosses over Neptune ’ s orbit. Pluto has 3 moons that orbit it however it is also smaller than the largest Kuiper Belt object which also has a moon orbiting it, so Pluto was demoted to Dwarf Planet The Oort Cloud is a spherical cloud of small icy fragments of debris at the farthest reaches of the Sun ’ s gravitational pull. It is between 50000 AU and 100 000 AU from the Sun and roughly 1/4 of the distance between the sun and Proxima Centauri, the nearest star.

6. Comets: Most comets originate in the Kuiper Belt and the Oort cloud at the farthest reaches of our solar system. Comets are composed of ICE, Frozen Gases and Dust particles. When a comet is pulled inward by the gravitational force of the SUN, it either collides with the planet or is pulled into the inner solar system and begins to orbit the Sun. AS the comet approaches the Sun it melts as the Suns radiation releases the gas and particles in the comet and the wind from the sun pushes the gas and particles away creating the tail. The comet has two tails and these two tails do not always point in the same direction because the dust tail is often slightly curved, it follows the orbit of the comet, while the gas or ion tail is more strongly affected by the solar winds and is pushed away from the sun.

7. Asteroids: Most asteroids originate in the asteroid belt, which is found between mars and Jupiter. They are small, non-spherical objects that are believed to be debris left over from the formation of the universe They range in size from a tiny speck, like a grain of sand to about 500 km wide. Some asteroids are so large they have been promoted to a dwarf planet and some even have their own moon.

8. Meteoroids, Meteors, Meteorites A meteoroids is a piece of rock moving through space, they are thought to be rocky chunks that have broken off asteroids and planets. When meteoroids collide with Earth’s atmosphere they burn up due to the atmospheric friction and form meteors. Many people mistake meteors for shooting stars and in certain times of the year Earth passes through an areas where there is a lot of excess material, such as debris left over from a comet and a meteor shower results. Meteor showers often seem to come from certain constellations and are therefore named for those constellations, such as the Lenoid meteor shower, seen in November and the Perseid meteor shower seen in August (image is of the Perseids) If a meteor survives impact on Earth and reaches the ground it becomes a meteorite, scientists estimate that about 100 000 tonnes of material from meteorites reach Earth’s surface annually.

9. Approximately 65 million years ago an asteroid the size of a mountain struck Earth the result was a catastrophic change to Earth’s atmosphere. Some scientists hypothesize that these changes are responsible for global mass extinctions of thousands of species, including the dinosaurs. Approximately 39 million years ago, an object 2 km in diameter hit Devon Island; Nunavut. The crater left is known as Haughton Crater. A second impact occurred approximately 40 000 to 50 000 years ago in Arizona. Most recently still, on June 30, 1908 in Tunguska, Siberia an area the size of Kingston Ontario was destroyed when an object entered Earth’s atmosphere. The object flattened nearly 100 million trees and killed tens of thousands of forest mammals, including several large herds of reindeer. Scientists believe that the object was about 50 km in diameter-no remnants of the object were found.

10. Questions Meteor to Meteorite: Comet and Asteroid: Difference between an Asteroid and Meteoroid: