Download day 2 - The Solar System Presentation

THE SOLAR SYSTEM
Measuring Distances in the Solar System
 1 AU is the average distance between the Sun
and the Earth (150 000 000 km)
 1 AU = 150 000 000 km
o Jupiter is 780 million km from the Sun,
therefore, Jupiter is 5.2 AU from the Sun
Planets
Planets must:
 Be in orbit around a star (such as the Sun)
 Have enough mass to be pulled into a stable
sphere shape by gravity
 Dominate its orbit (mass must be greater than
anything else that crosses its orbit)
INNER PLANETS (Terrestrial plants): Mercury,
Venus, Earth, and Mars
 located closest to the sun
 composed primarily of rock and metals; have
solid surfaces
 have high density
 slow rotations
• no rings and few satellites (moons)
OUTER PLANETS (Gas Giant planets):
Jupiter, Saturn, Uranus, and Neptune
 located further from the sun
 composed mostly of gases (“gas giants”)
 low densities
 have rapid rotation
 have rings and many satellites (moons)
Dwarf planets: orbit the Sun and have spherical shape but do not
dominate their orbits. For example, in 2006 it was determined that
Pluto was NOT a true planet because it does not dominate its orbit.
Other Objects in our
Solar System
Asteroids
 small celestial objects in the Solar System
composed of rocks, minerals and metals
 smaller than planets, range in size, have no
definite shape
 lots located in the asteroid belt between
the orbits of Mars and Jupiter (this asteroid
belt also separates the inner and outer
planets)
Satellites
 small celestial bodies that orbit a larger one
(planet) in a fixed path (example – moons)
Meteoroids
 celestial objects even smaller than asteroids composed of rock
and iron or dust – many are asteroid fragments
 can vary in size, from the size of dust particles to the size of
buildings
 When they are caught in the Earth’s atmosphere, friction causes
them to burn up, creating a streak of light across the sky. They are
then referred to as Meteors or A SHOOTING STAR!!! (Which occur
once every 15 minutes on average).
 If the meteor does not burn up completely, small pieces may land
on the surface of the Earth, which is referred to as a Meteorite
Comets
 large chunks of ice, dust and rock that orbit the Sun (the orbit can take a few
years to a hundred thousand years) (nicknamed “Dirty Snowballs”)
 can be 100m to 40 km in diameter
o Short-period comets: originate from just beyond Neptune and orbit the
Sun in less than 200 years (for example, Halley’s Comet which takes 75-76
years to orbit)
o Long-period comets: originate from a spherical cloud of debris further
than Pluto and orbit the Sun in more than 200 years (for example, HaleBopp Comet which takes 2380 years to orbit)
 When comets come close to the Sun, the surface sublimates (changes from
solid to gas) and the icy nucleus heats up; therefore, gases and dust escape
in cloud called a “coma”. Radiation and solar wind from the Sun exert a force
on the coma causing a gaseous tail.