If you intend to enroll in this class, but are not yet enrolled (e. g If you intend to enroll in this class, but are not yet enrolled (e.g., on waitlist): 1) Send email to Dr. Dash (tomsc@astro.indiana.edu) indicating your intention to enroll in the class. Include your name and IU email address. 2) Continue to attend class and participate as if you are already enrolled. There are several people on the waitlist. I suspect they will all eventually get into the class, but some may not get in before the end of the waitlist period. We need to know who plans on enrolling so we can add them t Oncourse, giving them access to the Oncourse class page.

Science attempts to systemize knowledge through: observing questioning hypothesizing testing Using critical thinking & creative thinking. Thus, scientific thinking has applications to all fields of human endeavors, not just science. We will return to these concepts over and over. Be sure to emphasize observation and “observed facts”.

And now, an exercise in observation and analytic thinking… “Observed Facts” and Interpretation Science begins with observations… The following exercise forces students to observe and report. It also allows us to distinguish between observed facts and hypothesis/models/interpretation.

Working with people near you, address the following: 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. When you ask students for a description of what they see, be prepared for some to report their interpretation (e.g., a shadow on a sphere) that is not an observed fact, but rather a model constructed to account for the observed facts. Try to make the distinction clear with the students. When we start to talk about models of the universe, it will become clear to students that observed facts can be accounted for by more than one model, or subject to multiple interpretations.

You can let this run as long as you want – it won’t stop.

(with the unaided “naked” eye) What do we see in the sky? (with the unaided “naked” eye) Now comes a long sequesnce of slides meant to introduce students to the types of objects found in the universe (at least, the larger objects). It will be followed by viewing the Cosmic Journey.

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

SUN Moves across the sky daily Location in the sky changes on yearly cycle (typical star)

MOON 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 The slide states “five points of light” because here I am talking about the objects that can be seen with the unaided eye and thus were know to the “ancients”.

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

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

COMETS Extended objects with tails (“dirty snowballs”)

METEORS “Falling Stars” (rocky or metallic objects)

Some things are visible only with telescopes

PLANETARY SATELLITES: “Moons”

ASTEROIDS: Rocky or metallic planetesimals

GALAXIES: Homes of stars, gas, dust, …

What’s Out There? The Hubble Ultra Deep Field (2004) The deepest picture of the Universe ever taken Hubble Space Telescope imaged a “blank” piece of sky for ~1 million seconds (11.5 days) 10,000 objects 19

Typical Galaxy: roughly 1011 stars Observable Universe: roughly 1011 galaxies How much is 1011?

McDonalds has sold over 1011 hamburgers! If you counted one number per second, worked an eight hour day, it would take 10,000 years to count to 1011! OR… McDonalds has sold over 1011 hamburgers!

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. 13.7 x 109 years old

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

“The Cosmic Connection” A video interlude… “The Cosmic Connection”