Galaxies: enormous collections of gases, dust and stars held together by gravity Our galaxy is called the milky way

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1 Celestial bodies are all of the natural objects in space ex. stars moons, planets, comets etc. Star: celestial body of hot gas that gives off light and heat the closest star to earth is the sun Planet: celestial body that orbits a star, is large enough that its own gravity holds it together and is the only body occupying its orbital pa Moon: celestial body that revolves around a planet Galaxies: enormous collections of gases, dust and stars held together by gravity Our galaxy is called the milky way Every star that you see at night is part of this galaxy approximately 200 billion galaxies exist in the observable universe Types of Galaxies: Type Description Sketch Spiral Has many long arms spiralling out from centre core Elliptical Ranges in shape from a perfect sphere to an elongated flattened ellipse Irregular Has neither spiral arms or an obvious centre core

2 Movement of Celestial Bodies Rotation Revolution

3 Solar System: _an arrangement of planets and / or other bodies orbiting a star Our solar system Is in the Milky Way galaxy orbits around the closest star (The Sun) Contains 8 planets Inner Planets Planet Details Sketch Mercury Venus Earth Mars

4 Outer Planets Planet Details Sketch Jupiter Saturn Uranus Neptune

5 Compare and contrast the Terrestrial (Inner) and Jovian (outer planets) Size Motion Composition Terrestrial (Inner) Small Slow spinning, small orbits Solid, rocky Jovian (Outer) Large Faster spinning, larger orbits gaseous Distance from the sun closer further Temperature Warmer, but temperatures vary Colder, but temperatures vary Density greater less Brainstorm possible pneumonic devices that you could use to remember the order of the planets: ex. My Very Excited Mother Just Served Us Nuggets Pluto is no longer considered a planet and is now referred to as a Dwarf planet. What is a Dwarf planet? a celestial body resembling a planet but which has not cleared it s orbit of all other material

6 Asteroid: large, rocky, usually irregularly shaped, bodies in the inner solar system, believed to be leftover from the formation of the solar system Asteroid Belt: Area between the orbits of Mars and Jupiter where most asteroids are found Kuiper Belt: Area beyond Neptune containing many comets, asteroids and other small bodies made largely of ice -similar to the asteroid belt but much _larger Sketch our solar system including the asteroid belt and the Kuiper belt Comet: a celestial body composed of ice, rock, & gas Originate from outer solar system Develop a coma (fuzzy outline) and sometimes a long, bright tail when passing near the sun Period: amount of time it takes an object to make one complete orbit Meteoroid: small rocky or metallic objects in space Up to 10 m wide Most are fragments from comets or asteroids Meteor: a meteoroid that passes into Earths atmosphere Burns up and is seen as a shooting stars Meteorite: When a meteor survives passing through the earth s atmosphere and lands on the surface large meteorites and produce indentations called crators

7 Compare and Contrast Comets Asteroids Meteoroids Origin Kuiper belt and Oort cloud Between orbits of Jupiter and Mars (Asteroid belt) Comets or Asteroids Size Centre ~ 10 km Usually less than 1 km, some up to 300 km Less than 10 m wide Composition Ice, dust, small rocky particles Rock Rock Units of Measurement Special units are used because the distances discussed in astronomy are so large Astronomical Units (Au) Unit of distance 1AU = 150 million km (based on the distance between the sun and earth) Light years (ly) Unit of distance_ Distance a photo would travel in 1 year Used because light is the fastest known thing in the universe