Age of our solar system is 4.6 billion years old. The Solar System Section I The Solar System Age of our solar system is 4.6 billion years old. The solar system is made up of 8 planets since Pluto has been denoted to and many smaller objects that orbit the sun.

Ideas about the night sky have changed over time Earth-centered model ( Geocentric theory)– early Greeks thought planets, Sun, Moon, and stars revolved around Earth

Sun-Centered model (Heliocentric) Nicholas Copernicus and Galileo Galilei observed that the moon revolved around Earth and that Earth and other planets revolved around the Sun

Modern View solar system includes Sun, eight planets, many small objects.

NEBULA THEORY (origin of solar system) a nebula of gas, ice, and dust slowly formed in space

A cloud of material in the nebula slowly rotated in space

The cloud became more dense, rotated faster, heated up, and flattened to form a disk.

As the cloud contracted, it grew warmer, triggering a nuclear fusion reaction that created the Sun Nuclear Fusion happens in the Sun. Nuclear Fusion is a process that occurs when atoms combine to form a new element and release energy.

The leftover matter became the planets and asteroids First four inner planets – small and rocky with iron cores. last four outer planets – large and lightweight …

Planet orbits are elliptical and the Sun is not directly in the center of the orbits.

Section II The Inner Planets also known as the terrestrial planets. What is a major reason the inner planets have smaller levels of Helium and Hydrogen? Answer: These are lighter gases so the Sun’s energy burns off the lighter gases.

Mercury Closest to the Sun, smallest planet Difficult to observe with the naked eye because it is so close to the sun Mercury, Venus, And Jupiter have Virtually no axial tilt

Weak magnetic field suggests an iron core Has many craters and high cliffs no true atmosphere, so surface temperatures range from very hot to very cold Fastest Planet No Moons

Venus Sometimes called Earth’s twin second from the Sun and similar to Earth in size and mass

extremely dense atmosphere of clouds Carbon dioxide traps solar energy Venus has a very dense atmosphere of C02 Hottest planet No Moon

The dense atmosphere of CO2 causes an intense greenhouse effect Results in surface temperatures between 450°C and 475°C Venus and Uranus rotate clockwise (backwards or retrograde). Most planets spin counter-clockwise (direct rotation)

Earth average distance between Earth and the Sun is 150 million km/ 93 million miles or 1 Astronomical Unit (AU) Water exists on surface as solid, liquid, and gas which supports life Earth also has high amount of oxygen (21%) in its atmosphere so animal life is possible Earth has 1 moon

More than 70% of surface covered with water Atmosphere protects surface from most meteors and Sun’s radiation. This is why the Earth does not experience as many meteor strikes as the Moon.

Mars Called red planet because iron oxide in rocks makes them reddish-yellow Polar ice caps made mostly of frozen carbon dioxide and frozen water Atmosphere is very thin 2 moons

Has largest volcano in the solar system

Soil shows NO evidence of life……….. perhaps……………

Has gullies and deposits of soil and rocks, which may indicate the presence of liquid groundwater

Thin atmosphere of mostly carbon dioxide Strong winds caused by differences in temperature between day and night

Mars is tilted on its axis, which causes seasons

MarsTwo small moons, Phobos and Deimos

Volcanoes Only the inner planets have volcanoes Venus and Earth are the only ones that have active volcanoes. Mercury and Mars have extinct volcanoes. Olympus Mons is found on Mars The outer planets are gas giants and do not have land masses on which to have a volcano

Where is the asteroid belt located? Answer-between Mars and Jupiter What is the asteroid belt? Answer-rocky objects measuring mm To Km in diameter

Section III The Outer Planets also called Gas Giants Have high concentrations of hydrogen

Jupiter fifth planet from the Sun, largest planet in the solar system

Below atmosphere, liquid hydrogen and helium are suspected Solid rocky core may exist below liquid level

The Great Red Spot is the most spectacular of Jupiter’s many constant high-pressure gas storms This storm is Several times the size of Earth.

Jupiter Earth

Jupiter Has rings

Has at least 61 moons – four are large and have atmospheres (Io, Europa, Ganymede, and Callisto)

Io is very volcanically active; the closest large moon to Jupiter

Europa composed mostly of rock; may have an ocean of water under a thick layer of ice

Ganymede largest moon in solar system, even larger than planet Mercury

Callisto cratered rock and ice crust may surround a salty ocean and rock core

Saturn Sixth planet from the sun, second largest in the solar system, lowest density

Thick outer atmosphere of hydrogen, helium, ammonia, methane, and water vapor

Might have a small, rocky core

Each large ring composed of thousands of ringlets of ice and rock particles

Saturn Has at least 31 moons

Saturn’s Largest moon, Titan, is larger than the planet Mercury Thick clouds on Titan prevent scientists from seeing surface…….

Uranus Seventh planet from the Sun, large, and gaseous Tilt of Uranus Angle is 90 degrees

Uranus has thin, dark rings Atmosphere of hydrogen, helium, and methane Methane makes the planet bluish-green in color 22 moons

Axis of rotation nearly parallel to plane of orbit

Neptune eighth planet from the sun, large and gaseous

bluish-green colored atmosphere similar to that of Uranus Storms on Neptune reveal an active and rapidly changing atmosphere has at least 11 moons, of which pinkish Triton is largest

Pluto Pluto is a dwarf planet located within the Kuiper Belt. Pluto is small and nonluminous which is why powerful telescopes have problems detecting Pluto.

A. Comet: dust and rock particles combined with frozen water, methane, and ammonia.

1. Halley’s comet: orbits Sun every 76 years.

2. Oort Cloud: large group of comets surrounding solar system beyond Pluto.

4. Comet structure: large dirty snowball of frozen rock and ice.

Comets a. Ice and dust vaporize as comet nears Sun. b. Vaporized material forms bright cloud called coma around comet nucleus. c. Solar wind pushes on gas and dust in the coma, causing the particles to form a tail that always points away from the Sun. d. Eventually, most of the ice in the comet’s nucleus vaporizes, leaving only small particles.

Comets vaporize and break up after passing close to the Sun several times. When the nucleus breaks up, pieces spread out. The dust and rock fragments are called Meteoroids.

B. (1.) Meteoroid: name given to small pieces of comet when they move through space.

B. (2.) Meteor: small meteoroid that burns up in Earth’s atmosphere.

B. (3.) Meteor Showers: occur when Earth’s orbit passes through a group of meteoroids that enter the atmosphere.

B. (4.) Meteorite: meteoroid that strikes Earth.

C. Asteroid: rock similar to that which formed planets.

C. (1.) Most asteroids lie in an asteroid belt located between Mars and Jupiter.

Asteroid Info: Jupiter’s gravity may have kept these asteroids from forming a planet. some planets’ moons may be asteroids pulled from the asteroid belt. asteroid sizes range from very tiny to 940 km in diameter.

What is a shooting star? It is NOT a star!! Answer-Meteor