The Solar System

SUNSUN75% hydrogen and 25% helium by mass75% hydrogen and 25% helium by mass

Sun converts hydrogen to helium using nuclear Sun converts hydrogen to helium using nuclear fusion in its core.fusion in its core.

Differential rotationDifferential rotation– equator the surface rotates once every 25.4 daysequator the surface rotates once every 25.4 days– near the poles it's as much as 36 daysnear the poles it's as much as 36 days

Core conditionsCore conditions– temperature is 15.6 million Kelvintemperature is 15.6 million Kelvin– pressure is 250 billion atmospherespressure is 250 billion atmospheres

The solar system consists of: The Sun Eight planets 3+ "dwarf planets" 130+ satellites (moons & rings) Small bodies ( comets and asteroids) Interplanetary medium (dust, gas, etc…)

DefinitionsThe IAU resolved in 2006 that planets and other bodies in ourSolar System, except satellites, be defined into three distinctcategories:

1) “Planet” -bodies that: a. Orbit the Sun b. Assume round shapes (hydrostatic equilibrium) c. clear their neighborhood.

2) “Dwarf planet” -bodies that:a. orbit the Sun b. Assume round shapes (hydrostatic equilibrium)c. have not cleared the neighborhood around their orbits.

3) “Small Solar System Bodies” a) All other objects orbiting the Sun

Classifying PlanetsThe eight planets are classified in several ways: The eight planets are classified in several ways: by by compositioncomposition: :

– terrestrialterrestrial or or rockyrocky planets: Mercury, Venus, planets: Mercury, Venus, Earth, and Mars: Earth, and Mars: • The terrestrial planets are composed The terrestrial planets are composed

primarily of rock and metal and have primarily of rock and metal and have relatively high densities, slow rotation, solid relatively high densities, slow rotation, solid surfaces, no rings and few satellites. surfaces, no rings and few satellites.

– jovianjovian or or gasgas planets: Jupiter, Saturn, planets: Jupiter, Saturn, Uranus, and Neptune: Uranus, and Neptune: • The gas planets are composed primarily of The gas planets are composed primarily of

hydrogen and helium and generally have hydrogen and helium and generally have low densities, rapid rotation, deep low densities, rapid rotation, deep atmospheres, rings and lots of satellites.atmospheres, rings and lots of satellites.

Terrestrial planets (Interiors)Terrestrial planets (Interiors)

Jovian Planets (Interiors)Jovian Planets (Interiors)

Classifying Planets (con’t)By By SIZESIZE::

Terrestrial planets (Size)Terrestrial planets (Size)

MercuryMercury Venus Venus Earth Earth Mars Mars

Small planets:Small planets: Mercury, Venus, Earth, Mars. Mercury, Venus, Earth, Mars. diameters < 13000 km.diameters < 13000 km.

Jovian Planets (Size)GIANTGIANTS: Jupiter, Saturn, Uranus and Neptune. S: Jupiter, Saturn, Uranus and Neptune.

diameters > 48000 km. diameters > 48000 km. Sometimes called Sometimes called gas giantsgas giants..

Classifying Planets (con’t)Classifying Planets (con’t)by position relative to the Sun: by position relative to the Sun: • innerinner planets: Mercury, Venus, Earth and Mars. planets: Mercury, Venus, Earth and Mars.

• outerouter planets: Jupiter, Saturn, Uranus, Neptune. planets: Jupiter, Saturn, Uranus, Neptune. • The asteroid belt between Mars and Jupiter forms the The asteroid belt between Mars and Jupiter forms the

boundary between the inner solar system and the outer boundary between the inner solar system and the outer solar system.solar system.

Terrestrial planetsTerrestrial planets (Orbits)Terrestrial planets (Orbits)

Jovian Planets -Gas Giants (Orbits)Jovian Planets -Gas Giants (Orbits)

The Planets (Spin)The Planets (Spin)

Terrestrial Bodies – Scaled Size

(Beyond Neptune’s Orbit)

Which one of these is from Star Wars?