Overview of the Solar System Solar system contents one star, - PowerPoint PPT Presentation

Overview of the Solar System Solar system contents – one star, several planets, lots of debris.

Most of it is the Sun! 99.8% of the mass of the Solar System resides in the Sun. A hot ball of mostly hydrogen and helium held together by gravity. – In bulk composition it resembles an unbiased scoop of galactic material. –

Most of it is the Sun! 99.8% of the mass of the Solar System resides in the Sun. A hot ball of mostly hydrogen and helium gas held together by gravity. – In bulk composition it resembles an unbiased scoop of galactic material. – 3/4 Hydrogen 1/4 Helium 1% other elements

Eight Major Planets Maybe one or two more depending on semantics and future discoveries.

Four Jovian Worlds Jupiter, Saturn, Uranus and Neptune – “Gasballs” constituting 99.9% of the planetary mass

Four Jovian Worlds Jupiter, Saturn, Uranus and Neptune – Hydrogen and helium, under high pressure, become dense liquids – more appropriately these are spinning liquid droplets.

Four Terrestrial Worlds Mercury, Venus, Earth, and Mars – Small rocky/metallic worlds hugging the Sun with thin or non-existent atmospheres.

Jovian vs. Terrestrial Characteristics Terrestrial: Mercury, Venus, Earth, and Mars – Small relatively speaking – Solid rocky cratered surfaces with significant iron cores – Three satellites between them all

Jovian vs. Terrestrial Characteristics Jovian: Jupiter, Saturn, Uranus, Neptune – The “Gas Giants” – about 10 times bigger than the terrestrial worlds – Gaseous with no solid surface, resembling the Sun in composition (mainly Hydrogen and Helium) . – Clouds of Methane, Water, Ammonia, and other molecules provide an apparent “surface” – More than one hundred satellites – most made mainly of water/ice.

Jovian vs. Terrestrial Characteristics Jovian: Interiors of compressed liquified gas

Jovian vs. Terrestrial Characteristics Jovian: Cloudtop “surfaces”

Jovian vs. Terrestrial Characteristics Jovian: Many satellites

Jovian vs. Terrestrial Characteristics Jovian: Icy satellites

Jovian vs. Terrestrial Characteristics Jovian: Satellites as big as planets, some with atmospheres.

Minor Constituents: Asteroids, Comets, and Dust Asteroids: Millions of small rocky objects mostly between the orbits of Mars and Jupiter

Minor Constituents: Asteroids, Comets, and Dust Asteroids: Millions of small rocky objects mostly between the orbits of Mars and Jupiter http://www.daviddarling.info/encyclopedia/A/asteroid.html

Minor Constituents: Asteroids, Comets, and Dust Asteroids: Millions of small rocky objects mostly between the orbits of Mars and Jupiter

An Outer Icy Asteroid Belt Another group of asteroid-sized bodies orbit beyond Neptune in the “Kuiper Belt” – Pluto is one of the largest of these.

A Cloud of Cometary Nuclei Trillions of small iceballs, most only a kilometer in size, orbit as far out as ½ way to the nearest star. – only a small fraction make it into the inner solar system to be heated by the Sun to become a comet.

A Cloud of Cometary Nuclei Trillions of small iceballs, most only a kilometer in size, orbit as far out as ½ way to the nearest star. – only a small fraction make it into the inner solar system to be heated by the Sun to become a comet.

Interplanetary Dust The grinding of asteroids and evaporation of comets populates the inner solar system with fine dust. http://www.astrophoto.com/images.htm

Interplanetary Dust The grinding of asteroids and evaporation of comets populates the inner solar system with fine dust.

Interplanetary Dust The grinding of asteroids and evaporation of comets populates the inner solar system with fine dust.

Regular Features of the Solar System All of the planets orbit the Sun in the same plane See orbits All planetary orbits are nearly circular All planets orbit the Sun in the same “direction” Most planets rotate in the same sense as the orbit.

Regular Features of the Solar System The Jovian and Terrestrial planets are well sorted in terms of distance from the Sun. – rocky worlds close – gaseous/icy worlds far away

Regular Features of the Solar System All of the planets orbit the Sun in the same plane See orbits All planetary orbits are nearly circular All planets orbit the Sun in the same “direction” Most planets rotate in the same sense as the orbit.

Regular Features of the Solar System The Giant Planet satellite systems resemble the Solar System

Regular Features of the Solar System Exposed solid surfaces are heavily cratered throughout the Solar System. – The process was messy and produced lots of leftovers.

Regular Features of the Solar System Exposed solid surfaces are heavily cratered throughout the Solar System. – The process was messy and produced lots of leftovers.

Building a Solar System through “Accretion” These regular features are “fossilized” memory of the conditions that gave rise to the Solar System. – In sum, they suggest the planets grew within a rotating flattened disk and, today, their orbits reflect the structure of that disk.