How to “enroll” in this course

1. How to “enroll” in this course • Go to “bb” if from the campus network berkeley.edu, otherwise “blackboard.berkeley.edu” • Click “Create Account”. You will have to choose a username. • Fill out all red-starred information slots, then “submit” at the bottom • Click “Courses” tab in upper left; “Letters & Science”; “Astronomy” • Click “Astro 10 (astron10-fa02)” • Choose “Enroll in this Course” and follow directions • You should end up in the Astro 10 Announcement screen • You will have to use the username & password you chose above to log in; this will be your username for the course

2. The CourseInfo website by Blackboard

3. The Website Discussion Forum

4. The Course Syllabusand Plan You can get directly here by using the URL: http://astro.berkeley.edu/~ basri/astro10/

5. Grading and Exams

6. Further Comments • There will be NO sections this week • You are not in the course unless a GSI has enrolled you on the course website into a section (Telebears aside) • For that to happen, you MUST get an account in Blackboard • Sections next week are all in the basement of Campbell Hall • This is not a mathematical course, but there is simple algebra in it (like L=R2 T4 ) a bit. Critical thinking IS required. • The main source of material is the book, but lectures tell you what is important (and fill out detail – the book is brief) • Falling behind in reading or homework is fatal – this material CANNOT be crammed at the end • If you aren’t used to critical thinking, or don’t need the grade, we strongly encourage you to take the course P/NP

7. Science vs Non-science (nonsense?) • What is “science”? • Empirical : must always be based on observations • Predictive : should be able to predict new observations • Reductionist(?) : tries to discover underlying “laws” • Why don’t astronomers believe in astrology? • Precession has moved the “Sun signs” • The constellations are not real entities • Local forces are much greater than forces due to stars or planets • Astrology is not really predictive (rigorous statistical analyses shows this) [of course, just because it is not science doesn’t mean it should be banned, just that it shouldn’t pretend to be science]

8. Exponentials

9. Powers of Ten We jump by a factor of 100 in each frame. This also shows the context of the Earth in the Universe.

10. The Solar System

11. Our place in the Universe

12. Timeline graphic

13. The Universe in a Day Let’s look at the entire history of the Universe as though it took place in a single day. The present is at the stroke of midnight at the end of that day. Since it is about 12 billion years old, each hour will be worth 0.5 billion years. A million years takes only a little over 7 seconds. The Big Bang (as an opaque fireball) and the formation of H and He all take place in the first nanosecond. The Universe becomes transparent in about 2 seconds. The first stars and galaxies appear after about 2am, and our Galaxy forms at perhaps 4am. Generations of stars are born and die.

14. The Universe in a Day The Solar System does not form until 3pm. The first life (bacterial) appears on the Earth by 4pm. Our atmosphere begins to have free oxygen at 7 or 8 pm, and this promotes the development of creatures which can move more aggressively and eat each other. Life does not begin to take on complex forms (multicellular) until 10:45pm. It moves onto land at 11:10. The dinosaurs appear at about 11:40, and become extinct at 11:52. Pre-human primates appear at around 14 seconds before midnight, and all of recorded history occurs in the last 70 milliseconds. Looking to the future, we can expect the Universe of stars to go on for another at least a millennium (using the same time compression factor). After that, there are other ages of the Universe (not dominated by stars), which grow colder and more bizarre, and take place on astronomical timescales (even after this compression of timescale).