AstronomyStudy of objects in space such as the

Sun, stars, planets, comets, gas, & galaxies.

*Also, the Earth’s place in the universe.

Universe = everything that exists

Disclaimer:Astrology is NOT science !!!

There is currently no evidence that star positions affect human behavior or your future.

Go ahead & read your

horoscope but remember

that it is just entertainment!

Geo-centric

Helio-centric

Earth-centeredview of universe

Sun-centeredview of solar system

C. Ptolemy90-168

N. Copernicus1473-1543modern view of the solar system:

“the Sun” is a star

planets orbit the Sun

Cosmic Size and Distance

Cosmic Size and Distance

Cosmic Size and Distance

Cosmic Size and Distance

Galaxies = groups of billions of stars

Spiral

IrregularElliptical

there are more than 100

billion galaxies

they all have different

shapes

Cosmic Size

The “Big Dipper”

constellation is a

pattern made of 7 stars

Earth’s Seasons = caused by the tilted axis (23.5o)Equinox = equal hours of daylight & darkness

Solstice = longest day & shortest day

(longest

day)

Spring

(shortest

day)

Fall

SUN

Sep. 21

Dec. 21Jun. 21

Mar. 21

Earth’s Motions

Winter – closest to the sunSummer – farthest from the sun

Earth’s Motions

• Rotation▪ spinning of Earth

from west to east on an axis

▪ results in day / night

▪ Earth makes one rotation in 24 hours

•Revolution▪ Earth moves

around the sun every 365¼ days

Equatorial Bulge

▪ The Earth is not completely round

▪ There is a bulge at the equator because of rotation

Video Link

Earth’s Motions

•Precession

▪ The change in direction of the northern axis

▪ North star is different

▪ Nutation

▪ Slight wobble, or change, in Earth’s axis from 23.5°

▪ Very slow movement due to the gravity of the moon

Kepler’s Laws▪ 1st Law: ▫ orbital paths are ellipses (ovals)▫ Sun is at one focal point

Animation of Laws

Kepler’s Laws

▪ 2nd Law:

▫ a planet sweeps out equal areas in equal times

Kepler’s Laws

▪ 3rd Law:

▫ T2 = d3

▫ T= time of orbit

▫ d = distance (avg) from the sun

Nebula A cloud of space dust or gas.

Nebular Hypothesis

A. cloud of mostly hydrogen & helium

B.

Started rotating & collapsing toward center because of gravity forming an accretion disk , also

the Sun forms

C.rocky & metallic materials form as

nebula cools

D.collisions of particles created

asteroid-sized objects (protoplanets or planetesmals)

E.

Sun = most dense object, nuclear fusion

Rock / Terrestrial planets = more dense, heavy material, closer orbit

Gas / Jovian planets = least dense, lighter material, farther orbit

A. nebula

C. cooling

D. protoplanets

E. solar system

B. accretion disk

Barycenter

▪ The point between two objects where they balance each other

▪ The actual center of our solar system

▪ The sun orbits around this point

Barycenter Video

Music :)

Energy

Nuclear Fusion Nuclear Fission

▪ The fusion of two atoms to create energy

▪ Happens within stars

▪ The splitting of an atom to create energy

▪ Produced in nuclear reactors

Apple in the DarkImagine you are sitting at a table with a red apple in front of you.

Your friend turns off all the lights. It is totally dark in the room. There are no windows in the room or crack around the door. No light can enter the room.

Write the statement you believe best describes how you would see the apple in the dark & explain your answer in a short paragraph.

A. You will not see the red apple, regardless of how long you are in the room.

B. You will see the red apple after your eyes have had time to adjust to the darkness.

C. You will see the apple after your eyes have had time to adjust to the darkness, but you will not see the red color.

D. You will only see the shadow of the apple after your eyes have had time to adjust to the darkness.

E. You will see only a faint outline of the apple after your eyes have had time to adjust to the darkness.

spectrum on:

p. 484 & 678

Electromagnetic Energyenergy that travels in waves

spectrum on:

p. 484 & 678

The Electromagnetic Spectrum

1. Gamma Rays 1 cm2. X – Rays 2 cm3. Ultraviolet 3 cm4. Visible Light 4 cm5. Infrared 5 cm6. Microwaves 6 cm7. Radio Waves 7 cm

spectrum on:

p. 484 & 678

How we “see” the universe:

this is a

RADIO

TELESCOPE

we use this information

to study galaxies

Lunar Eclipses

▪ Occurs during full moon phases▪ Do not see the moon because the Earth blocks light▪ Sun, Earth, moon in a line

Solar Eclipses

▪ Occurs when sun is blocked by the moon▪ Sun, moon, Earth▪ If the moon is partially blocking the sun, a

partial solar eclipse will occur

▪ At one time, the universe was a hot, super dense ball smaller than an atom.

▪ About 13.7 billion years ago, a rapid expansion occurred sending material in all directions.

▪ This was the beginning of the universe.

▪ Eventually, matter cooled & condensed into galaxies, stars, & planets.

Support for the Big Bang Theory

▪ Red shifts

▪ Cosmic background radiation (CBR)

▫ Signals coming from every direction in space.

▫ Radio, microwave, infrared, & X-rays.

▫ Believed to be created by the big bang expansion.

Video

The Expanding Universe

▪ 1929 – Edwin Hubble found that the universe is expanding▫ Estimated distances,

relative brightness, Doppler red shifts

Hubble’s Law: galaxies are moving away from us (red-shift) at a speed that is proportional to their distance

the more distant the galaxy, the greater the velocity (moving away at faster speeds)

Doppler Effectwavelength changes if an object is moving toward or away

from you

pitch gets higher

pitch gets lower

BASS !!!

Whitney Houston !!!

Doppler shifts from stars

Doppler Effect Song by Astrocapella

Cosmic Background Radiation (CBR)

▪ The hypothesis that the universe has always been expanding (since the “Big Bang”) predicted (1948) that radiation produced from the first moment of expansion would permeate the universe.

▪ In 1965 this radiation was discovered

▪ In 2003 astronomers studying the CBR determined the universe is 13.7 billion years old

Cosmic Speed Limit

Speed of light = 300,000 km/s

Light-year = the distance light travels in

one year (9,500,000,000,000 km)

The 2nd nearest star is 4.3 light yearsaway (Alpha Centauri = triple-star system)

Incandescence: glowing from heat

Blue = hottestRed=coolest

Learning from Light

Spectrum: light separated into

component wavelengthsspectrum on:

p. 484 & 678

What is a prism?What is white light?

What is ROY G. BIV?Is there light we can’t see?

Types of spectra

•Sunlight, light bulbs

•Sunlight that has traveled through our atmosphere

•Hot gas

Practice Drawing Spectra!

Sodium