Introduction to Astronomy

This web site uses frames to provide a permanent index in the window with the black background at the left side of your web browser. All the notes will appear in the main window with a white background. At the top of each main page there is a link which when selected will let you view a full window version of the notes. To get back to the framed version with an index you must click on the BACK button on your browser or select the link at the bottom of each set of notes that takes you back to the beginning of the Astronomy Notes. All links are highlighted in blue, when visited they will turn purple.

If at any time you wish to return to Jodrell Bank's Distance Learning web site then just click on the image at the top of the index window on the left of your browser.

Contents

1. Astronomy as a Science and a Sense of Scale. I introduce astronomy's place in science, and give a sense of the size and time scales involved.
2. Method for Finding Scientific Truth. Borrowing from Pine's book ``Science and the Human Prospect'' I discuss the scientific method, correlations, problem of induction, positivism, levels of testimony, empiricism, models correspondence with reality.
3. Astronomy Without a Telescope. I discuss the celestial sphere, motions of the Sun (solar and sidereal days, time zones, equation of time, and seasons), motions of the Moon (phases and eclipses), and planetary motions.
4. History of Astronomy. I focus on the rise of modern science in Europe, from the ancient Greeks to Kepler.
5. Newton's Law of Gravity. Newton's laws of motion and his law of gravity are discussed. Applications of those laws (esp. gravity) are covered (e.g., measuring the masses of planets and stars, orbital motion, interplanetary trips, tides, etc.).
6. Electromagnetic Radiation (Light). General properties of light, definition of frequency, spectrum, temperature. Light production: Continuous (thermal) spectra, emission lines, absorption lines and the Bohr model for the atom. Doppler Effect and why spectral lines must be used to measure the doppler shifts.
7. Telescopes. Covers refractors, reflectors, radio telescopes, light-gathering power, resolving power, interferometers, magnification, and atmospheric distortion such as seeing, reddening, and extinction.
8. Planetary Science. This chapter is an introduction to planetary science. I discuss the techniques astronomers use to find out about the planets, their atmospheres (what determines if an atmosphere sticks around, the transport of energy, and appearance), their magnetic fields (the magnetic dynamo theory), and their interiors. In a separate section I focus on a comparison between the atmospheres of Earth, Venus, and Mars and why they are now so radically different from each other (greenhouse effect, carbon cycle, runaway refrigerator, etc.) There are links to three graphical descriptions of the concepts covered: the Earth-Venus-Mars comparison (a flowchart), the greenhouse effect and the UV dissociation of water, and a flowchart of the calculations involved in determining if an atmosphere sticks around for billions of years. I end the chapter with a discussion of the major moons in the solar system and ring systems.
9. Solar System Fluff. The basics of meteorites, asteroids, and comets are introduced and how they can tell us the ``when'' and the ``how'' of the formation of the solar system. At the end is an exploration of the other planetary systems.
10. Determining Star Properties. Notes for the properties of stars and how we determine them. Things like distances to stars, their masses, radii, composition and speeds. Also HR diagram, spectral types, and spectroscopic parallax. The dangers of selection effects and biased samples are also discussed with the application of finding what a typical star is like.
11. The Sun and Stellar Structure. This chapter covers: The Sun, interiors of stars, and nuclear fusion, neutrinos, the solar neutrino problem, and helioseismology. The concept of hydrostatic equilibrium is used to explain the mass-luminosity relation and the reason for the mass cut-off at the high and low ends.
12. Lives and Deaths of Stars. This chapter covers: stellar evolution (all nine stages) and stellar remnants (white dwarfs, neutron stars, black holes).
13. The Interstellar Medium and the Milky Way. This chapter covers: the dust and gas between the stars and how we use the 21-cm line radiation to map the Galaxy. Also, the structure of the Milky Way Galaxy, our place in it, and how we determine these things. The rotation curve and the existence of the dark matter halo, stellar populations, and the galactic center are also discussed.
14. Other Galaxies and Active Galaxies. This chapter covers: the characteristics of other normal galaxies, active galaxies, and finding distances to other galaxies (this includes the distance-scale ladder). Also, large-scale structure is covered (galaxy clusters and collisions and superclusters).
15. Cosmology. This chapter covers cosmology. The distance-scale topic is dealt with in the Steps to the Hubble Constant document. I discuss Olbers' Paradox, the cosmic microwave background radiation, the fate of the universe (open or closed), dark matter, inflation, and the cosmological constant.
16. Life Beyond the Earth. This chapter covers: lifezones, types of stars to focus on in the search for suitable planets, basic definitions of life, the kind of planet where we think life would likely arise, and finally the frequencies we use in the Search for Extra-terrestrial Intelligence (S.E.T.I.).

Appendices

1. Angular Momentum in Astronomy. I define angular momentum and give several examples of angular momentum in astronomy: Kepler's second law of orbital motion, Earth-Moon system, rapidly spinning neutron stars, accretion disk in a binary system, and a collapsing galactic cloud.
2. Quick Mathematics Review. Here's a quick run through some basic mathematics: working with fractions and percentages, exponents, roots, powers of ten, working with really BIG or really small numbers---scientific notation and the metric system. I assume that the reader has had this stuff before, so the quick run through will be sufficient to jog the dormant memory.
3. Tables. Astronomy constants, physical constants, planets (orbital properties, physical characteristics, atmospheres), 100 nearest stars, and 100 brightest stars as seen from the Earth.
4. Glossary. Definitions of astronomy terms used in this web site.
5. Study Skills: Homework and Exams. Some tips to improve your study skills so that you study more efficiently and take exams with better results.

Back to top page of Astronomy Notes by Nick Strobel