Useful Links for Astr 212 H -- Fall 2010
Black Screen
26) Solar Nebula Hypothesis revisited
25) Planets orbiting other stars
24) Meteoroids, Meteors, and Meteorites -- Earth Imapcts
- Meteor showers (Geminid meteor shower, Dec 13&14) occasionally produce fireballs (Bone, Indonesia, Oct 09)
- Larger meteoroids that hit the ground are called meteorites
- Iron, stony, and stony-iron meteorites
- Very rare, very large impactors leave craters: over 100 are known on Earth, including:
- Barringer (Arizona), 1 km across
- Manicouagan (Canada), 70 km across
- Mjolnir (Barents Sea), 40 km across
- Chicxulub(Mexico), 200 km across (the dino-killer?)
- Peru -- a recent big fall (September 16, 2007)
- Near Earth Object detection and monitoring program.
- Movie showing orbits of NEOs discovered to date (movie showing close calls from 2002; [Animations Page]).
23) Comets
22) Pluto -- is it a planet?
21) Jovian moons & rings
20) Uranus & Neptune (ice giants)
19) Jupiter & Saturn (gas giants)
18) Asteroids
17) Global Climate Change on Earth
16) Mars:
15) Venus:
- Thick atmosphere, mostly carbon dioxide gas (so greenhouse effect operates very efficiently), with a perpetual blanket of clouds (sulfuric acid, etc).
- Slow planetary rotation is "backwards," possibly caused by a cataclysmic impact on proto-Venus. Slow rotation may explain lack of magnetic field.
- Soviet landers: Venera 9, Venera 13, and Venera 14 (pictures and on-site measurements)
- NASA radar mappers: Magellan (1990-1994) high resolution global map:
- volcanos with lava flows akin to ones on Earth
- local tectonics produced cracks and ridges in crust
- coronae and arachnoids may indicate upwelling plumes of hot mantle that fail to penetrate the thick crust.
- impact craters (few suggesting young surface, 500 Myr old, only large ones b/c small meteors burn up in atm)
- hints of surface wind blowing material (some wind erosion or deposition?)
- Other spacecraft missions: Past, present, and future. ESA's Venus Express is there now.
- More images and text at nineplanets.org.
14) Mercury:
13) Earth's Moon:
- Web activity developing a simple model of tides in Earth's oceans, NOAA tides online.
- More info and pictures of the moon's surface from NinePlanets.org
- Images of the moon: highland terrain, maria, far side; Apollo 11 and Apollo 12 landing sites.
- Mare Humorum, Taurus-Littrow Valley, more highland terrain.
- Maps of moon showing whole moon, maria, mountains/craterwalls, etc: its fun to turn the moon!
- Crater features: crater rim, central peak, rays, smooth dark crater floor; sizes range from 1000 km (rare) to tiny pits (everywhere).
- Breccia and lunar dust due to impacts, inferred rate of cratering over lunar history, impacts still happening.
- Earth's impact craters.
- Apollo moon missions: highlights in video and still photos (NASA image archive and more photos & videos).
- Un-crewed missions to the moon, past, present and future.
- Visit a moon rock at the Neil Armstrong Museum in Wapakoneta, OH, or the museum at NASA/Glenn in Cleveland.
- A discussion of lunar landing conspiracy theories by BGSU undergrad Gloria Doller (2003).
- Federal funding (Office of Management and Budget)
- Lunar formation: computer simulation (mathematical model) & artist's conception
- Websites for Apollo reading and Moon, Mars & Beyond (also, opposition article, NASA MMB site).
12)
The Earth:
11) Solar System Structure and Origins:
10) Solar Activity: images and movies to help you visualize magnetic phenomena on the Sun.
- remember, granulation in the sun is due to convection, not magnetic fields, so it is not technically "solar activity"
- "magnetic trilobite" video -- erupting magnetic field
- X-ray jets may help to heat the corona, in addition to vibrating magnetic field lines directly moving atoms in the corona
- spaceweather.com = today's solar activity and forecasts (plus other news and pictures)
- solar cycle = number of sunspots (prominences, flares, etc) varies with ~11 year cycle.
9) Atoms and Light and Temperature
- Periodic Table of the Elements (click to get visuals of different elements) ... some elements we will meet often in class:
- hydrogen (1H) has 1 proton, 0 neutrons, and 1 electron (when neutral, i.e., not ionized)
- helium (4He) has 2 protons, 2 neutrons, 2 electrons when neutral
- carbon (12C) has 6 protons, 6 neutrons , and 6 electrons when neutral
- iron (56Fe) has 26 protons, 30 neutrons, and 26 electrons when neutral
- Examples of different electromagnetic radiation (light) in daily life:
- Gamma Rays have the highest energies and shortest wavelengths, and are only found (on Earth) in very energetic environments like nuclear reactors and bombs.
- X-rays are a bit less energetic (slightly longer wavelengths), and are used in medical X-rays.
- Ultraviolet (UV, "beyond violet") light has lower energy still, and is used in tanning, "black lights", and water purification.
- The entire visible spectrum of light is a narrow range of wavelengths/energies in the full EM spectrum. Your eyes/vision use visible light.
- Infrared (IR) light has longer wavelengths and lower energies than visible red light ("less red"), and is used in heat lamps to keep fast food warm, and by military/firefighters to "see" in dark/smoky environments ("cool" website).
- Microwaves (longer wavelength, lower energies than IR), as in a microwave oven.
- Radio waves have the longest wavelengths (often meters or more between crests!) and lowest energies of the EM spectrum. They are used to transmit radio and television signals
8) Solar Atmosphere
- Photosphere -- visible "surface" of sun, has sunspots first viewed by Galileo.
- Chromosphere -- layer above that glows with reddish glow, has prominences seen during total solar eclipse.
- Corona -- outermost layer of the sun, faint white streamers visible during total solar eclipse.
- Solar wind -- stream of charged particles moving away from sun, learn today's forecast at spaceweather.com
7) Renaissance Astronomy -- Orbits and Gravity
6) Ancient Astronomy
5) Solar Eclipses
4) Lunar Phases and Eclipses:
3) The Relationship between Angular Size and Distance:
2) Time -- Daily and Yearly Motion and the Seasons:
1) Introduction:
- Significant Figures: rules for counting them, doing caluclations (+- and */), and why they are important.
- Powers of Ten from the Eames Office: A sequence of images drawn from the famous (to scientists) movie of the same name, in which we step back a factor of 10 times in every frame. Click on the "0" in the black box on the right to start your journey, and click on successive numbers (1, 2, 3, ... 25) to "step out," or multiply, by that number of powers of 10. For example, 5 will get you out five powers of 10, or (10 x 10 x 10 x 10 x 10) = 100,000 = 10^5 (ten to the fifth) times the original view. If you click the negative numbers, you will go "inward", or divide your distance by powers of 10, so -5 = 1/10/10/10/10/10 = 0.00001 = 10^-5 (ten to the minus five) times the original view.
Andy Layden, Fall 2010
