Astronomy 1001 Stars and Galaxies (Introductory Astronomy Part 2) An introduction to astronomy beyond the solar system for non-science students. Topics include: the Sun as a star, stars and star clusters, stellar evolution, nebulae, the Milky Way, galaxies and galaxy clusters, active galaxies, cosmology. Homework consists of bi-weekly assignments and labs, some of which require the use of the Burke-Gaffney Observatory.

Lecture 1. Key Points 1. Layout of the course. 2. Astronomy as a science. 3. Examples of astronomy in everyday life. 4. The scale of the universe. Distance = Time. 5. Science versus pseudoscience. Is the concept testable? 6. Getting started. Learn your way around the night sky.

1. Layout Course textbook: 21 st Century Astronomy Hester, Smith, Blumenthal, Kay, Voss Read… read… read… read… read… Assignments/Lab Exercises (biweekly)25% Mid-term Test (February) 25% Final Examination (April) 50% Observing Projects* 20% Total Grade 100% * Can replace portion of grade from any other component of final grade.

2. Astronomy as a Science Science versus pseudoscience: is the concept testable: falsifiable? E.g. astrology, Van Daniken, Velikovsky… Star Trek Star Wars Much of what is depicted in the Star Trek and Star Wars shows is actually unrealistic and contradicts basic laws of physics, but so is a lot of what is displayed in most action movies.

3. Examples of Astronomy in Everyday Life Starry Night Over Rhone Van Gogh’s Starry Night Over Rhone 1888

The beginnings… Perfect Numbers ? The beginnings… Perfect Numbers ?

A perfect number is the sum of its proper positive divisors, e.g. 6 = = 1  2  3 28 = = 1  2  14 = 1  4  7 Very few perfect numbers exist. 6, 28, 496, 8128, 33,550,336, 8,589,869,056 

28 is close to the length in days of the Moon’s phases (29½ days). 6 is the basis for many different numbers we use every day: 24 hour day, 6- sided die, 360° circle, etc.

Ordering the Planets Outwards ObjectMotion relative to the Stars Starsinfinite Saturn29.30 years Jupiter11.86 years Mars1.88 years Sun365¼ days Venus225 days Mercury88 days Moon27½ days

Saturn governs the 1 st hour of the 1 st day, Jupiter the 2 nd hour, Mars the 3 rd hour, etc., and Mars the 24 th hour. The Sun then governs the 1 st hour of the 2 nd day, the Moon the 1 st hour of the 3 rd day, Mars the 1 st hour of the 4 th day, Mercury the 1 st hour of the 5 th day, Jupiter the 1 st hour of the 6 th day, and Venus the 1 st hour of the 7 th day. The days of the week are therefore: Saturn-day Sun-day Moon-day Mars-day Mercury-day Jupiter-day Venus-day

What examples can you think of?

4. The Scale of the Universe The speed of light in a vacuum is a constant speed of ~300,000 km/s. The speed of light is the maximum speed that anything can travel. The distance that light travels in one year is referred to as a light year, and it is a measure of distance not time. Earth – Moon = 1¼ light second Earth – Sun = 8½ light minutes Earth – Neptune = 8¼ light hours Earth – Proxima Centauri = 4 light years Earth – Milky Way Centre = 26½ thousand l.y. Earth – Andromeda Galaxy = 2½ million l.y. Earth – UGC 3378 (SN 2010LT) = 250 million l.y.

10 billion years ago, there were no planets. There are roughly 300 billion stars in the Milky Way Galaxy. 1 light year = 12 trillion km Stars are made up of 75% hydrogen, 24% helium and 1% metals (everything not H or He). The sun produces helium. Human beings are composed of elements that are created in stars. Astronomy as a science is limited by observations of celestial objects, and many observations can only be done once, or, in some cases, not at all.

5. Science versus pseudoscience. The key: Is the concept testable? If it is, it is considered a scientific concept. If not, pseudoscientific. Examples from the present and past: astrological forecasts Van Daniken and visits from UFOs Velikovsky and bouncing planets diseases from space? How many such concepts can you think of?

6. Getting started. Learn your way around the night sky. An image from January 5 (morning) by Mike Boschat.

The Summer Triangle Groups that look like their namesakes.

Hercules Normally pictured holding the world.

Sagittarius An archer? Better pictured as a teapot.

The Perseus Group A story in the stars.

Ursa Major Does this group truly look like a bear??!

A better way? − from Rambling Through the Skies, George Lovi, Sky & Telescope, December 1990.

The stars of Orion as pointers.

The field of Orion

The Heavenly G. Captain, all d’uh riggin’ seems perfectly polished.