1. Introduction

Page last updated January 14, 2005 10:03 AM

Meet your instructor, Dr Gareth Wynn-Williams and TA, Ben Granett,

There are 5 sections of 110 this semester.  They are taught differently. This is section 3.  You must attend the lectures and exams of the section you are enrolled in. 

See policies handout for information about

• office hours, phone and email contact numbers
• textbook
• internet access

Discussion point: What questions would you like to ask about astronomy?

03.01
04.01
05.1

a) What's in the course?

Pdf version of Ben Granett's lecture on 1/12/05  (1.6 Mbytes)

For most of you the goal is to satisfy the science requirement

My goal is that you understand what science is. Astronomy is a means to this end.

• The Universe is comprehensible
• Science is not dogma; good theories are continually being replaced by better theories

Not everything in science has the same reliability. Learning which ideas to accept and which ones to question is one of the skills that makes a good scientist. There is a gradation of certainty within any science, and these levels of certainly change as new observations are made and new theories are formed. 

• Don't think twice about it: Sun will rise tomorrow
• All astronomers would bet their careers: Earth moves round Sun. Chemical elements are the same everywhere in the Universe. The Earth is billions of years old.
• Astronomers very confident, but could cope with a change: Black holes are made when large stars explode. Comets are mostly made of ice. 
• Room for discussion among astronomers:  What is the future of the Universe? 
• Lots of doubt:  Is there life elsewhere in the Universe?

One of the exciting things about an astronomy course is that I can bring you to the frontiers of science, which is impossible in a 100-level physics or chemistry class.

What will we be learning about in this course?

i) What’s out there, and where is it?

We will learn about the main different kinds of object in the Universe such as

• Stars, of which the Sun is one
• Planets, just as Earth and Jupiter, which are small objects that orbit stars
• Galaxies, which are vast collections of stars; our own galaxy is the Milky Way
• Cosmology

ii) How things work, and why things happen

• Why the Sun shines
• How the Moon stays in orbit around the Earth
• Why Jupiter is much bigger than the Earth
• How the elements in our bodies were made.

iii) How do we know?

• How do we measure the distance to the stars?
• How do we know that the Sun is made mainly of hydrogen?
• How do we measure the age of the Moon and the age of the Universe?
• How can we tell how the Universe was created and how it will end?

iv) Topics we treat only lightly

• Star names, constellations
• Navigation
• History
• Astrology

05.2

b) Astronomy and Math

There is a definite need for quantitative measurements in astronomy. We can't just say that some things are "big" and other things are "bigger". I will expect you to know the sizes of a few objects.

I expect you to be familiar with the length units of the Metric system, which is used throughout astronomy and in almost every country in the world. The most important units are those for length:

• 1 km is about 5/8 mile
• 1 meter is just over a yard
• 1 cm is about 0.4 inches
• 1 mm is 1/10 cm

03f.1

00.1

You must be familiar with the powers of ten notation (also called Scientific Notation), which is necessary in astronomy to avoid spending all one's time writing and counting zeros.

For example, the distance to the Sun is about 150,000,000,000 meters, which is written as 1.5 x 10¹¹ meters.

See pages 4-5 in your book or in almost any math or science book

02.1

Section 2: Understanding the Sky

Course Outline

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