Yesterday an earthquake hit Haiti. Initial estimates are that “hundreds of thousands” have died. More are homeless. Consider making a contribution to assist in the recovery. Here are a few agencies that will need help: Oxfam: Red Cross: Doctors Without Borders: doctorswithoutborders.org UNICEF: unicefusa.org/haitiquake unicefusa.org/haitiquake Save the Children:savethechildren.org

If you intend to enroll in this class, but are not yet enrolled (e.g., on waitlist): 1) Send to Dr. Dash indicating your intention to enroll in the class. Include your name and IU 2) Continue to attend class and participate as if you are already enrolled.

Stellar Birth: Adrift 1,500 light-years away in one of the most recognizable constellations, the glowing Orion Nebula and the dark Horsehead Nebula. The former is a great example of a stellar nursery.

Stellar death: In 1987, the brightest supernova in recent history occurred in the Large Magellanic Cloud, a companion galaxy to the Milky Way. At the center of the picture is an object central to the remains of the violent stellar explosion.

Homework #1 will be posted next week. There will be an announcement posted and an broadcast concerning this homework when it is posted.

Class web page: Homework assignments, announcements, reading assignments, etc. Consult this site on a regular basis.

Long, long, ago, On a hillside far, far, away…

Science begins with observation:

And now, an exercise in observation and analytic thinking… “Observed Facts” and Interpretation Science begins with observations…

You will be shown a sequence of images of successive full Moons (20 cycles, repeated) assembled into a video format. Working with people near you, address the following: Describe how the Moon’s appearance changes from one full moon to the next.

What do we see in the sky? (with the unaided “naked” eye)

STARSSTARS Many points of light “fixed” in relation to each other but changing location in the sky with time

SUNSUN Location changes on yearly cycle (typical star)

MOONMOON Moves relative to stars and regularly changes position and appearance over a period of a month (satellite of a planet)

PLANETS: Five points of light that slowly wander with respect to stars

MILKY WAY Cloud-like band through sky (our galaxy)MILKY WAY

NEBULAE Fuzzy cloud-like objects (clouds of gas, dust)NEBULAE

COMETS Extended objects with tails (“dirty snowballs”)COMETS

METEORS “Falling Stars” (rocky or metallic objects)METEORS

Some things are visible only with telescopes

PLANETARY SATELLITESPLANETARY SATELLITES: “Moons”

ASTEROIDSASTEROIDS: Rocky or metallic planetesimals

GALAXIESGALAXIES: Homes of stars, gas, dust, …

“home”

Typical Galaxy: roughly stars Observable Universe: roughly galaxies How much is ?

McDonalds has sold over hamburgers! hamburgers If you counted one number per second, worked an eight hour day, it would take 10,000 years to count to !hour OR…

Local Group – Few dozen “nearby” galaxies Outside of Local Group, essentially all galaxies moving away from Milky Way with velocity proportional to distance! Direct prediction of uniformly expanding universe BIG BANG – Universe approx. 13 x 10 9 years old

Galaxies don’t like to live alone… CLUSTERS of GALAXIESCLUSTERS of GALAXIES: few to thousands of gravitationally bound galaxies SUPERCLUSTERSSUPERCLUSTERS: Clusters of clusters of galaxies

What is the Earth’s place in the Universe?

A video interlude… “The Cosmic Connection”