SOLAR SYSTEM

The Sun Closest star to Earth Yellow star Medium in size compared to the other

stars About 4.6 billion years old More than 1 million Earths could fit

inside it Central body of our solar system Main source of energy for Earth Essential to life on this planet

Energy from the Sun Made mostly of hydrogen and helium

The Sun’s energy comes from nuclear fusion Nuclear fusion – changes hydrogen to helium

Only one-fourth as dense as Earth (Earth is a rocky planet)

Temperature on surface is 5,500 degrees Celsius (9,932 Fahrenheit)

Temperature at the core about 15,000,000 degrees Celsius

The Sun’s Effect on Earth’sEnergy

Sun is the main source of energy on Earth

Solar radiation provides heat to keep Earth warm and livable

Ocean and atmosphere help moderate temperatures

The Sun’s Effect on EarthFood

Photosynthesis – plants use sunlight to produce food (producers)

When a consumer eats a plant the energy is transferred to the animal

The sun is the energy source for nearly all living things

The Sun’s Effect on EarthWinds

Winds form because of the sun

Winds blow from regions of high air pressure to low air pressure

Differences in air pressure form because of the Sun’s uneven heating of Earth’s surface

The Sun’s Effect on EarthWater Cycle

Drives the water cycle

Causes water on Earth’s surface to evaporate

Life Cycle of a Star Nebula - All stars start from

enormous rotating clouds of dust and gasses – mostly hydrogen

Protostar – the nebula collapses into a very dense mass

Main-Sequence Star – When a newly formed star stabilizes, this stage can last billions of years, our Sun is in this stage

Life Cycle of a Star

Red Giant – the outer part expands while the core contracts, becomes very bright but cools

Planetary Nebula – the outer layers are released

White Dwarf – over a long period of time the star shrinks, there is no fuel left in its core

Black Dwarf – remaining heat radiates into space until it fades to a black dwarf

Life Cycle of a Star

Planets – large bodies that orbit the Sun

Galaxy – a huge system of gas, dust and stars Our solar system is a very small

part of a much larger system called the Milky Way galaxy

Moons Moon – a natural satellite orbiting around

another body in space About 140 moons in our solar system Earth’s Moon

Diameter of 3,476 km – four times smaller than Earth

Rotates on an axis and revolves around Earth One month for the Moon to make a complete

rotation Reflects the light from the sun Phases are produced by the alignment of the

Moon and the Sun in the sky.

Phases of the Moon

Asteroids Relatively small, rocky object

that orbits the sun Most orbit in a band called the

asteroid belt between Mars and Jupiter

Comets A small, orbiting body made of dust, ice, and

frozen gases. When a comet approaches the sun, frozen

solids vaporize Gases and dust are released, producing a

glowing region called a coma Charged particles push out of the coma,

producing a glowing tail Some comets can take 30 million years to orbit

the Sun

Meteoroids/Meteors Meteoroids – bits of rock or metal

that orbit the sun Meteor – a meteoroid that enters

Earth’s atmosphere and is heated by friction with the air For a few moments, they burn as they

fall, appearing as streaks of light against the sky

Also called falling/shooting stars

Inner Planets Mercury

Closest to sun, extremely hot (800 degrees) and cold (-343 degrees)

Cratered surface due to collisions with asteroids

Venus Second planet from the sun Covered by thick, poisonous clouds Pressure would crush your bones Almost the same size as Earth Temperatures hot enough to melt lead

Inner Planets Earth

Only planet known to have liquid water

Largest inner planet Mars

Red planet, may have once had liquid water

Inner Planets

Photo from Mars Rover

Mercury

Mars

VenusEarth

Outer Planets Jupiter

Fifth planet from the sun One of the brightest object in the sky Winds can reach up to 400mph Famous for its Great Red Spot – storm

system Has many moons and rings

Saturn Sixth planet from the sun Known for its rings – made mostly of ice

particles Least dense - Saturn would float in water

Jupiter

Saturn

Outer Planets Uranus

Seventh plant from the sun Has at least 27 moons and 11 rings

Neptune Eighth planet Winds can reach 1,500 mph At least 11 moons

Pluto Classified as a dwarf planet in 2006 3 moons

Gravity Gravitation is an attractive force

between objects that have mass It is weak unless the masses involved

are very large (like Earth) Gravity causes objects to speed up

as they fall Acceleration due to gravity at Earth’s

surface is about 9.8 meters per second per second

Air resistance, or drag, will slow a falling object

Planets Orbiting the Sun

Just like we are pulled to Earth because it has a greater mass than us – The sun has a greater mass than the Earth which pulls the planet keeping it in orbit around it

Astronomers

Astronomer – a scientist who studies outer space

Famous Astronomers Copernicus – reasoned that the sun is at the center of the solar system

Galileo – the first person to use a telescope