Welcome

Credit: XKCD  (https://xkcd.com/428/).

Welcome to AS151: Stars, Stellar Systems, and Cosmology.  I have taught this course at Colby College since 2012.  In 2015, I had students write blog posts about topics of interest to them.  I enjoyed reading the many creative entries, while students enjoyed the freedom to showcase their own unique skills in demonstrating their knowledge of the course material.  This year we will continue in that tradition.

The goals of this course are for students to gain an understanding of the physical laws of nature so that they can appreciate and think critically about the results of scientific research that will almost certainly impact their lives, regardless of their ultimate career path.  At times during the semester, students will be asked to demonstrate their knowledge of course concepts through interpretation of diagrams, or mathematical calculations.  As a scientist, however, the ability to communicate results to others, who may lack detailed knowledge of the subject matter, is a skill that is of utmost importance.  Likewise, I find that spending time explaining a concept to others strengthens one's own understanding and retention of that knowledge.  It is for these reasons that I will ask students to explain some of the core course concepts throughout the semester on this blog site. I hope that not only will my students find this useful, but that others crawling the web may find this blog to provide simple explanations of some really cool phenomena.

To give you a taste of what to expect from now through December, here's some topics we'll be covering:

• Other Earths? Astronomers recently discovered an Earth-like planet in the so-called "habitable zone" around or nearest neighbor, Proxima Centauri.  How did they do it and what are the implications?

Artist's impression of the surface of the recently discovered Earth-like planet, Proxima b. Image credit: ESO/M. Kornmesser https://www.eso.org/public/images/eso1629j/

• Cosmic Time Machine!  By looking at galaxies more and more distant from us, we learn about what the Universe was like in the past.

Image credit: NASA, ESA - http://sci.esa.int/hubble/52786-hubble-explores-the-origins-of-modern-galaxies-heic1315/

• Why does the sun shine?  We know the Sun provides light and heat for our home here on planet Earth, but what makes it all possible?  (Spoiler alert: it's nuclear fusion - you don't want to mess with that stuff!)

Image credit: NASA/SDO/AIA/Goddard Space Flight Center - http://www.nasa.gov/mission_pages/rbsp/news/third-belt.html

• How long does a star live? (Hint: a loooooooong time!)  And how does it die?  (It's spectacular!)

Image credit: NASA, ESA, J. Hester and A. Loll (Arizona State University) - Hubble site

• How do galaxies form and evolve over time?

Image credit: NASA, HST, ACS Science and Engineering Team - Hubble site

• What is Dark Matter and Dark Energy?  This mysterious stuff makes up over 95% of the entire Universe!

Image credit: ESA/ Planck - http://www.esa.int/Our_Activities/Space_Science/Planck/Planck_reveals_an_almost_perfect_Universe

It should be a fun semester!  I know I'm looking forward to some creative entries from my students.