Human Understanding of both Earth and Space has Changed Over Time Unit E: Topic One

1.4 Our Solar Neighbourhood

How did our solar system get here? Ideas?

Nebular Hypothesis The theory of how solar systems are formed

Evolution of solar system Many moons have formed from circling discs of gas and dust around their parent planets Other moons are thought to have formed independently and later been captured by their planets Still others, such as Earth's Moon, may be the result of giant collisions. Collisions between bodies have occurred continually up to the present day and have been central to the evolution of the Solar System. The positions of the planets often shifted due to gravitational interactions

The Sun Made up of mainly Hydrogen and Helium 110 times wider than Earth Surface temperature = 5500ºC Core temperature = 15 000 000ºC Releases a steady flow of charged particles that flow out in every direction, this is called solar wind.

If our Sun was the size of a beach ball, Jupiter would be as small as a golf ball and Earth would be as tiny as a pea. 

Why Do Planets Move in an Orbit? Answer: Universal Gravitation Explanation: There is a gravitational force between all objects that pulls them together. When no forces act on an object, it will move in a straight line at a constant speed. Since the sun has gravity to pull the planets inwards, they move in an elliptical orbit.

The Planets Each has its own unique features and characteristics. Divided into inner planets (terrestrial) and outer planets (Jovian). Inner – tend to be smaller and rockier, close to sun Outer – large and gaseous, far away from sun

Planet Presentations Each group will be responsible for a different planet in the solar system. Each group will collect important information about their planet. Each group will present to the class.

The Planets Inner Planets (Terrestrial Planets) Mercury, Venus, Earth, Mars Outer Planets (Gas Giants) Jupiter, Saturn, Uranus, Neptune

Mercury Smallest planet Closest to the sun No moons The most cratered planet

Venus The hottest planet Its thick atmosphere traps heat with a greenhouse effect Rotates clockwise, rather than counterclockwise Very close to Earth’s size. Sometimes called Earth’s sister No moons Second brightest object in the night sky, after the moon

Earth The largest of the terrestrial planets Only planet not to be named after a Greek or Roman deity The densest planet Only one natural satellite Most of the Earth is covered in water

Mars The red planet because of iron oxide Second smallest planet Has polar icecaps Signs of liquid water

Jupiter Largest planet Has thin rings Has a great red spot, which is a huge storm At least 67 moons Heavier than all the other planets combined

Saturn Second largest planet Known for its rings Has about 150+ moons! Only 53 given official names

Uranus Not visible to the naked eye Orbits on its side, nearly perpendicular to the sun Hits the lowest temperatures Has thin rings Rotates clockwise, rather than counterclockwise

Neptune Farthest planet Not visible to the naked eye On average, the coldest planet Has thin rings

Trends? Patterns?

Other Bodies in the Solar System Asteroids Between the orbits of Mars and Jupiter lies a narrow belt of small, rocky or metallic bodies traveling in space. They range in size from a few meters to hundreds of kilometers Origin of asteroids: scientists are uncertain

Other Bodies in the Solar System Comets Made of dust and ice that travels through space When they get close to the sun, they heat up and gases are released. As the comets move, the streaming gases are visible as a “tail” Comets usually stay in the outer edges of the solar system, but sometimes they’re thrown into the inner solar system and regularly rotate around the sun.

http://www.esa.int/Education/Teach_with_Rosetta/Paxi_animations Scroll down to comet video http://www.esa.int/spaceinvideos/Videos/2014/08/Philae_s_mission_at_comet_67P

Images from the Rosetta spacecraft show Philae drifting across the surface of its target comet during landing Nov. 12, 2014. Credit: ESA/Rosetta/MPS for OSIRIS Team

Other Bodies in the Solar System Meteoroids Small pieces of rock flying through space Meteor When a meteoroid is pulled into our atmosphere, atmospheric friction causes it to light up These are shooting stars Meteorite If the meteor lasts long enough to hit the earth, it is called a meteorite Two impact craters left by a meteorite in Quebec