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Astronomy Hypertext

• Cosmic Mystery Tour: Multimedia Guide to the Cosmos
Michael Norman, of the Center for Super Comuting Applications at U. Ill. has developed a eye capturing and easily navagitable multimedia of the comos; from the beginning to the present. You will swim in the Quark Soup, you will see matter freeze out of the soup, you will watch galaxies being born.
• Cosmology and the Origin of Life
Enjoy the pleasure of learning without the pain of finding parking at the university. This course is designed to be an exploration of the process by which the Universe grows to a state of self-awareness, as defined by the emergence of intelligence which asks questions and seeks information about that very Universe. More specifically, it is a study in the evolution of ideas, based on observations, and the development of a non-unique evolutionary model that describes the origin of the Universe and the development of life. Since the model proceeds on the basis of human perception of external events, it is highly imperfect and flawed because of the intrinsic uncertainty associated with observation. Thus, we will consider the question of "How do we know, what we know?" as well as emphasizing that which we do not know. In the end we hope to arrive at a consistent evolutionary model for understanding the existence of intelligence and then explore the implications of that model in terms of the existence of extra-terrestrial intelligence. In this way this course is designed to ascertain if our species qualifies as an intelligent one. This will be a different course, unlike what you think its going to be. The final exam will be quite different (see below) and will hopefully force you to reflect on how you think everything in the universe fits together. All lectures in this course will be delivered electronically
• Solar System Geology
This is Prof. Greg Bothun' Astronomy 121 course in a can (computer). The study of the Solar System is primarily an exercise in planetary geology. The input data, in most cases, consists only of images of planetary surfaces from which we attempt to reconstruct its particular geological history. Each planetary surface in our Solar System has a unique geological history and a wealth of network accessible information now exists. Well over 10,000 individual images of planetary surfaces are now available via the World Wide Web/Internet system. The main goals of this class are to: To gain an understanding of some of the detailed properties of the various objects that make up our solar system. To achieve a coherent understanding of how the solar system was able to form in the Galaxy and the probability that similar formation processes occurred elsewhere.
• Properties of Galaxies
A 1.2 Meg Mpeg Movie of the properties and structure of M31. You must have an Mped video app in order to view. Netscape will take care of the downloading of the App for you.
• Planetary Motion
This is an assorbing presentation of Kepler's Laws of Motion and the Ptolemeic attempt of epicycles as an explaination of retrograde motion.
• Inverse Square Law
This is a somewhat trite video that illitrates the inverse square law by a dropped bomb into a cow pasture. It's called the cow bomb. Narration is available. Don't plan on seeing the sequal.
• Interstellar Medium
Here is an opportunity to thank Bob Wing (graduate of Berkley) professor at The Ohio State University, for his contributions to astronomy in the areas of multiband photometry (Wing filters) and the first penetration of the interstellar medium to the galatic center. This page is under construction but offer some neat stuff already. So, one the count of three, scatter.... 'cause that's what the interstellar meduim does best.
• Stellar Evolution
This is another contribution from the University of Oregon's Electronics Universe, project. U. of O. seems to be a developing force in the area of multimedia astronomy education. Here is a synopsis of their multi media presentation:
Stellar Evolution is driven entirely by the never ending battle between Pressure and Gravity . As imbalances are reached, the star is driven to find a new Energy source. Each new stage in stellar evolution is hence marked by a different energy generation mechansism. These stages are discussed below: Structure of a Main Sequence Star Here see that a main sequence star has a simple structure. Pressure and gravitational forces are equal, the star is stable and its core is sufficiently hot to fuse Hydrogen into Helium . Eventually the core of the main sequence star will become pure Helium and that will mark a new evolutionary phase for the star. --> More about main sequence stars Structure of a Post Main Sequence Star Now the star has two chemically distinct zones, a core of Helium surrounded by an envelope of Hydrogen. Since Helium has 2 protons in its nucleus then the fusion of Helium requires a higher temperature, to overcome this electrostatic barrier, than the fusion of Hydrogen.Structure of a Red Giant Star Now the core of the star has heated to a temperature of 100 Million Degrees which is the threshold temperature for the fusion of Helium into Carbon . The star is again stable as pressure and gravity are equal. The lifetime of a star as a Red Giant is about 10% of its main sequence lifetime. The luminosity generated by the core fusion of Helium into Carbon is far greater than the shell luminosity associated with the fusion of Hydrogen into Helium.
Quit impressive!
• Nucleosysthesis
All stars derive their energy through the thermonuclear fusion of light elements in to heavy elements. High temperatures are required so that the mutual electrostatic repulsion of the protons in each fusing atomic nucleus is overcome. This requires a high velocity collsion which can only be achieved under conditions of high temperature. The minimum temperature require for the fusion of Hydgrogen is 5 million degrees. Elements with more protons in their nuclei require higher temperatures. For instance, to fuse Carbon requires a temperature of about 1 billion degrees. This sequence is now shown in the animation below. Refer to the legend below for all the animations: Take a look!
• Evolution of Star Clusters
CM diagram Young Cluster In this case we see the Main Sequence fully represented. The blue dots represent massive stars with short main sequence lifetimes. This stars would have masses greater than 2 solar masses. The yellow dots represent stars with masses between 1 and 2 solar masses and the red dots represent stars with masses less than 1 solar mass. Since the cluster is very young, no Red Giants have appeared. CM diagram 10 Million Years Old Now we are seeing the disappearance of the most massive main sequence stars as their main sequence lifetimes is less than 10 million years. These stars have evolved to become the first generation of Red Giants . CM diagram 1 Billion years Old Now we see that all the blue stars have evolved off the main sequence and that some of the Red Giants have evolved to become White Dwarfs . As the main sequence lifeftime of a 2 solar mass star is about one billion years, then there are no stars still on the main sequence with masses higher than this. Thus, identifying the most massive star which is still on the main sequence is an effective means of determining the age of a stellar cluster. CM digram 10 Billion years Old All of the yellow stars have no disappeared. The Giant Branch is now well populated, Overall, the cluster colors would be very red since all the stars are either red giants or low mass mainsequence stars. The number of white dwarfs has increased quite bit. In the next few billion years the cluster will continue to evolve and slowly fade as all its former members end up as white dwarfs, neutron stars or black holes.
• Astronomy Course for Middle and High School
ASTRONOMY. Even the word conjures up wondrous images in your mind. Images of distant galaxies, maybe, or exploding stars, or comets, meteors, stars, constellations, telescopes, or maybe even your own memories of a night under a truly dark sky where the universe seemed to glow with "billions" of stars. Whatever image the word astronomy creates in your mind, the subject of astronomy has captured the interest and attention of virtually every human on the planet since humans were able to look up. What follows is a course on astronomy using the Internet. It is adaptable to most age and interest levels. Each of the units in the course are listed below in the Table of Contents, and each unit has its own separate "page." I hope you will enjoy using the course and will come back again and again as I make changes and additions to it.
• Introductory Astronomy Textbook for Undergraduates
Topics in Astronomy: Cosmology and the Origin of Life complete course, Solar System Geology, Properties of Galaxies, Planetary Motion, Inverse Square Law, The Interstellar Medium, Stellar Evolution, Nucleosynthesis in Stars, The Evolution of Star Clusters.
• A Complete Primer on Earth's Magnetosphere
• Illustrated Tour of the Aurora
Most of us think of Earth's environment as ending somewhere above the clouds but below the space shuttle. We think of the Sun as a blazing yellow disk that moves from horizon to horizon, spreading sunbeams and sunburns. But what about the space in between Earth and Sun? With the advent of radios, RAM, and rockets, scientists found that Earth's environment extends nearly a million miles into space, and the Sun brings us far more than warming daylight. From observatories in the air and on the ground, physicists now study an invisible realm as changeable as the weather, windier than a mountain peak, and as electric as a city night...They call it geospace.
• EARTH AND UNIVERSE
A multemedia guide to the universe, with images, movies, sounds, etc. From Armagh Planetarium and Bradford Technology LTD. UK
•  CERES
Through funding from NASA, faculty at Montana State University and classroom teachers from across the nation have developed an extensive library of on-line and interactive K-12 science education materials for teaching astronomy. Closely aligned with the NRC National Science Education Standards, these web based lessons make maximum use of exciting on-line NASA resources, data, and images. In addition to classroom-ready materials using contemporary teaching strategies, CERES has developed several on-line NASA data search engines and two graduate level distance learning courses, available over the internet to K-12 teachers.

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