Unit 2 Lesson 1

LESSON topic: formation of the solar system

- Solar system formation

- Star formation

- Models of the solar system

- Planets in our solar system

Origin of the universe• Big bang theory

• According to this theory, all matter was created in an explosionapproximately 13.7 billion years ago.

• The universe is STILL expanding to this day from the big bang.

• After millions of years, the gas and debris from the big bang began to cool and condense. This became the base for our universe.

Galaxies

• There are millions of galaxies in the universe.

• Inside the galaxies, millions of stars were also forming out of the same material.

Solar system development

Solar Systems

• Within each galaxy, there are millions of solar systems

• The Laplace hypothesis theory helps explain how our own solar system formed.

• 1. large dust cloud is formed ( super nova) and begins to rotate

• 2. dust cloud condenses in center forms a star.

• 3. Dust clouds flattens into rings of debris

• 4. left over dust condensesas debris collides

• 5. Planets are formed

Our solar system is 4.6 billion years old

Astronomy facts• The earth is the closest to the sun during

the winter. And furthest away in the summer.

• The distance from the earth to the sun is called an astronomical unit. 1 AU is equal to 92,955,807.273 miles.

• The next CLOSEST star is 4.2 light years away• NASA voyager space craft is traveling at 37-

thousand mph. At that rate it couldn't reach the nearest star until after 80-thousand years.!!

All planets orbit the sun !

like Earth’s orbit, the other planets orbits are NOTperfectly circular , but in closed shapes called

ellipses

Stars STARS – A large ball of gas held together by gravity.

• Stars come in different colors- the color depend on its

temperature

• Blue stars are Hotter, While red stars are cooler

STARS – A large ball of gas held together by gravity.

• Luminosity = how bright a star is compared to our sun.

Luminosity depends on size. The bigger the star, the more

luminous. (brighter)

*** NOTE- a star may appear brighter to us, because it closer,

when in reality it may be a small, dimmer star. All Luminosity

values are compared to the value of the sun ( which is 1.0 - see

the HR Diagram)

ESRT pg 15

Our star the Sun

Our sun

• Our Sun is an average star (medium mass). It is approximately 5 billion years old. It will live for about another 5 billion years.

• It is composed mainly of hydrogen (which is the most abundant – Or plentiful element in the universe).

•

How a star creates and uses energy that eventually makes its way to Earth

• The life cycle of a star is based on its MASS at birth (low or medium mass compared to a high mass star).

• A star is born when NUCLEAR FUSION takes place (hydrogen converting to helium).

•H + H He

Planets nets

• Our solar system has 8 Planets

•Terrestrial (Inner) Planets:

Mercury, Venus, Earth, Mars

•Rocky, high density, few moons

(3)

SOLAR SYSTEM DATA CHART PAGE 15

Inner Planets - Terrestrial

Asteroid belt • Asteroid belt = clusters of asteroids orbiting the sun separating the terrestrial

and Jovian planets

• Habitable Zone: where you may find life near a star

Gas Giants • Jovian (Outer) Planets: Jupiter, Saturn, Uranus,

Neptune

• Gas, low density, rings, many moons (154)

OuterOuter ( Jovian) planets –Jovian Planets

Other celestial objects,

•Moons

•Asteroids

•Comets

•Meteoroids,

•Meteors

•Meteorites

Comparing and contrasting the planets using the ESRT page 15

Terrestrial ( inner) planets

• Size (DIAMETER)

• Distance

• # of moons

• DENSITY

• MASS

Jovian ( outer) planets

Order of the Universe

•Smallest to Largest:•Planet•Star•Solar System•Galaxy•Universe

•Size Comparison of Celestial Objects:

•http://www.wimp.com/biggeststars/

•Fast Fact! Saturn will float in water—due to its low density