Title: Week 4: The Stars
Course: ASTRON103: The Evolving Universe: Stars, Galaxies, and Cosmology (001) DHH SU18 > Section: Week 4

Overview

Welcome to Week 4! The theme for this week is The Stars — the infinitesimal points of light in the night sky, that are actually vast nuclear powerhouses similar to our own Sun.  We're going to learn how we go about measuring properties of stars such as that mass, and how we can make sense of these properties using a plot called the Hertzsprung-Russell diagram. We'll then figure out how to measure the distances to the stars, using a variety of techniques. To finish up, we'll examine the gas and dust between the stars — the so-called interstellar medium — and learn how this material is intimately related to the stars embedded in it.

To get started, watch the video below where Rich and DK provide an overview of the week ahead. Then, dive into the Content (book and videos) and start planning how you'll undertake the weekly Activities (writing assignment, discussion forum, At Play in the Cosmos, weekly quiz, and longer-term project). To help you organize these tasks, we provide a Schedule and Checklist at the bottom of the page.

Content

Readings

The following readings from the Astronomy book cover the topics that we'll be focusing on this week:

- Chapter 18: The Stars: A Celestial Census (all sections)
- Chapter 19: Celestial Distances (all sections)
- Chapter 20: Between the Stars: Gas and Dust in Space (all sections)

Two-Minute Universe

In these mini-lectures, Rich and DK cover a single topic from the book in a couple of minutes, by building up a page of notes and visuals summarizing the key facts and concepts you need to know. The summary page is available for download separately from the video, as a Portable Document Format (PDF) file).

- A Stellar Census (1m35s; video, summary)
- Measuring the Mass of Stars (2m47s; video, summary)
- The Diameters of Stars (5m6s; video, summary)
- The Hertzsprung-Russell Diagram (3m25s; video, summary)
- Distances in the Solar System (2m19s; video, summary)
- Parallax and Distances to Stars (2m14s; video, summary)
- Variable Stars to find Distances (1m33s; video, summary)
- The HR Diagram and Cosmic Distances (4m1s; video, summary)
- The Interstellar Medium (1m25s; video, summary)
- Types of Interstellar Gas (2m7s; video, summary)
- Dust in Space (2m13s; video, summary)
- The Cycle of Matter in Space (1m57s; video, summary)

Whiteboard

In these more in-depth lectures, DK explores a variety of topics with the aid of white-board sketches.

- Pocket Solar System (9m15s; video)

To make your own pocket universe, you can try glueing together pieces of paper to make a long strip, or find a roll of paper that gets fed into receipt printing machines. An Amazon link to one is here — though mostly they are sold in bulk so it may not be a practical purchase. Other options include being really nice the next time you go shopping anywhere and just asking if you can have a roll (or a strip of it). If you are in Madison, you can also message me to pick some up directly from the Astronomy Department Office.

At Play in the Cosmos Flythroughs

In these flythroughs of the At Play in the Cosmos game, Rich provides commentary on the concepts being presented, highlights some pitfalls to be aware of, and tries to avoid being blown up by the bad guys.

- Mission 16: More Power (11m59s; hi-res video, lo-res video)
- Mission 17: A Galaxy Far, Far Away (9m1s; hi-res video, lo-res video)
- Mission 18: Galactic Collisions (9m47s; hi-res video, lo-res video)
- Mission 19: Through a Fog (14m22s; hi-res video, lo-res video)
- Mission 20: Special Delivery (6m31s; hi-res video, lo-res video)

Special Topics

In these videos, Rich and DK focus on special topics that aren't part of the core course content, but really enrich your engagement with Astronomy-related topics and resources.

- The SIMBAD Astronomical Database (8m56s; video)
- The GAIA-Sky Galaxy Visualization Software (16m27s; video)

Activities

Writing Assignment

This week's writing assignment focuses on a single star of your choice, reflecting on what was happening in history when the star's light was originally being emitted. Review the writing assignment and begin reflecting on relevant themes early during the week; summer courses move quickly, so it's to your advantage to think ahead.  The assignment is due by 11:59pm on Wednesday, July 11^th.

At Play in the Cosmos Missions

This week's game missions bring the story arc to a close in a dramatic fashion. We suggest you try these missions by yourself at first, and then dip into Rich's flythroughs (see above) for guidance and commentary. The deadline for completing the missions is 11:59 PM on Friday, July 13^th.

Discussion

This week's discussion asks you to reflect on the investment of resources (e.g., tax dollars) in studying the Cosmos — is this reasonable?  You need to make an initial post in order to see other students' responses, and you must make a total of three posts by the deadline of 11:59 PM on Saturday, July 14^th.

Quiz

This week's quiz tests your understanding of the topics covered throughout the week, and is drawn from Chapters 18, 19 and 20 of the Astronomy book. It consists of ten questions with written answers. You can take it anytime up until 11:59pm on Sunday, July 15^th.

Multi-Week Project

This week you'll be finishing the second multi-week project, design a star-finding pamphlet to share with your friends and family. The project is due by 11:59 PM on Sunday, July 15^th.

Weekly Schedule & Checklist

Use the schedule below to pace yourself during this week, and the check-boxes to mark off your progress.  Each horizontal line represents an important task and the corresponding days on which you should focus on that task. It is important that you keep pace to perform well on the weekly quiz, and to participate fully in the discussion forum.

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