Final Exam Schedule for Astronomy 1000:

Exams will be primarily multiple-choice questions with a few true/false questionsn. Remember to bring a pencil and a ParSCORE (red) SCANTRON. This SCANTRON has room for 50-answers on the front and 50-answers on the back.

Pop-quizes will consist of 10 True/False questions based on the previous lecture and will also use the ParSCORE (red) SCANTRONS.

You should purchase about 10 ParSCORE scantrons and bring them with you to class.

Lecture-1: This lecture serves as an introduction to the class. I will provide an overview of the topics covered in this class, go over the grading system (e.g., exams, pop-quizes, final, and extra-credit essays), and show the student where to find copies of the syllabus. At the end I briefly discuss what Science is (and isn't).

This lecture covers material from Chapter 1.1-1.2 in the text.

notes for Lecture 1 (Introduction)>Lecture-1 Notes

Here is the computer simulation showing two Milky Way-like galaxies merging over roughly 1-billion years due to gravity. The yellow dots represent stars and the blue dots represent clouds of gas, mainly hydrogen, all following bound orbits due to the gravitational tug of all the other stars and gas clouds. In other words, we have two model galaxies that are subject to all the laws of physics as we currently understand them, and we can study their evolution (and merger!). Computer models like this help us understand how galaxies are structured, as well as how they are born and (in this case) change dramatically. Computational astronomy is a very important branch of modern astronomy. If you like computers you might consider a career in computational physics or astronomy. >Spiral_Merger

Lecture-2: In this lecture we discuss the objects visible to the unaided eye in the night-sky, and explain why they appear to move from night to night and month to month. We also see how seasons result from the tilted rotational axis of the Earth.

This lecture covers material from Chapter 1.2-1.6 and 2.2, 2.3 in your text.

notes for Lecture 2 (The Night Sky)>Lecture-2 Notes

Here is an animation that illustrates how lunar phases come about. Try to keep in mind that the one half of the moon is always illuminated by the Sun, and it always points towards the Sun.>Lunar-Phases

Here is an animation that tries to show a solar eclipse from the point of view of someone floating in space looking down towards the Earth. Note that there are in fact *two* shaddows cast by the moon - a large shaddow, and at the very center, a small darker shaddow. Where would you have to be to see a *total* eclipse? A *partial* eclipse?>Solar-Eclipse

An animation of a total solar eclipse. Notice how long it takes for the moon to pass completely from one side of the Sun to another. When the Sun's disk is completely covered by the moonn, note that the Sun's "corona" becomes suddenly visible.>Solar-Eclipse2

Lecture-3: In this lecture we begin our exploration of the Universe with our home planet, Earth, including its internal structure and atmosphere. But before we start there is a brief overview of the entire Solar System to set the stage for the next few weeks.

This lecture covers Chapter 6.1-6.4 and 7.1-7.5.

notes for Lecture 3 (Earth)>Lecture-3 Notes

Here is a computer simulation showing how geologists think Earth's continents have moved over the past 300-million years (i.e., continental drift). Notice that 300-million years ago all the continents were joined into a "Super Continent" called Pangea>Continental Drift

Here's an interesting video showing underwater thermal vents where crustal plates move apart>Underwater Smokers

Lecture-4:We finally jump off the Earth to visit the planets Mercury and Venus. Both planets are very different from the Earth. Mercury turns out to be much like Earth's moon. Venus at first glance is Earth's twin. But it is in fact more like Earth's evil twin "Skippy". Can we understand physically why both are so different from the Earth, especially Venus?

Notes for Lecture 4 (Mercury & Venus)>Lecture-4 Notes

Here is a nice GIF showing the surface features on Venus' surface as revealed by Magellan's radar. The black areas are the regions note surveyed by Magellan (Terra Incognita)>Venus Radar

Here are a couple of JPEG files showing additional evidence for volcanic activity on Venus:

radar images of lava flows taken by Magellan in 1995>Lava-Flows

radar image of a lava dome, a giant volcanic "sink hole". Note the diameter of these structures as indicated by the scale-bar>Lava-Dome

If you consider that Venus has nearly the same mass, radius, and density as the Earth, it should have very similar chemical composition. That means the Venus should have a molten metallic core like the Earth's. And that means Venus should have a magnetic field. But check this: >Does Venus have a Magnetic Field?

Lecture-5: This lecture concerns the planet Mars. We will examine the basic properties of this planet - surface features, atmosphere, and likely interior structure, and attempt to understand how it may have transitioned from a fairly warm planet with oceans and thick atmosphere to the extremely dry and cold planet it is today. We will also briefly examine the prospects for life on Mars, if only in the distant past.

This lecture covers material from Chapter 10.

Notes for Lecture 5 (Mars)>Lecture-5 Notes

Here is a computer simulation showing how a team at Caltech (M. Marinova) explain the large difference between the Northern & Southern hemispheres of the planet. In a nutshell, 3-billion years ago a solar system body ~1/2 to 2/3 the mass of our Moon hit Mars with a glancing blow, ripping off the planet's crust over the northern half, and leaving behind a relatively smooth "crust" made of the mantle (the collider itself was destroyed in their computer simulations).>Mars Collision

Here is a link to You-Boob where some amazing movies of Martian ``Dust Devils'' driven by strong winds. Some of these mini-tornadoes are large enough to be seen from orbit. You can see perhaps while climatologists like to have another planet to play with!>Dust Devils on Mars

Here's a movie taken from the surface of Mars showing clouds drifting across the skies of the Red planet. It's my understanding that these clouds are largely frozen CO2, not water as the case on Earth (but I'll check). >Martian Clouds

Lecuture-6: This material actually covers two lectures, with one of them coming after Exam #1. Both are on Jupiter, the "king" of the planets. We will see that Jupiter is unlike any of the planets we have studied so far. Jupiter it turns out represents a kind of solar system in minature, which is one of the reasons it attracts so much attention from astronomers.

For those of you following along in the textbook, this is contained in Chapter 11,

notes for Lecture 6 (Jupiter)>Lecture-6 Notes

Here is a time-lapse movie of Jupiter showing some of the complex motions in its upper-atmosphere. Note the zones (light colored) and belts (darker color), the direction reversals, the rotation of the Great Red Spot and the smaller storms (white spots). Quite a lot of stuff going on here.>Jupiter-Movie1

Here's another time-lapse movie showing Jupiter's rapid rotation (can you estimate this movie's duration?) as well as the orbital motions of two of Jupiter's large "Galilean Moons". Note that they cast shaddows on Jupiter's upper cloud-tops (solar eclipses!).>Jupiter-Movie2

Here is a photo from Jupiter's night-side taken by the Galileo mission showing the inner-most bit of its faint ring system scattering sunlight.>Jupiter Ring

Here is another beautiful image from the Galileo mission showing the volcanic moon Io "occulting" Jupiter. Note the shaddow cast by the moon on the cloud-tops (a solar eclipse!).>Jupiter & Io

And another beautiful image. Here the Galileo mission has captured Io (the volcanic moon) and Europa (deep water ocean under ice crust?) in the same frame. Volcanic activity is evident on Io. Why is it that you can see surface features on Io's night-side?>Europa & Io

What a photogenic planet Jupiter is! Here's an image showing details in the Great Red Spot and its environment, including a new kid on the block - "Red Spot Jr.", which was formed by the merger of 3-4 smaller "white spots" (two of which are visible) that abruptly turned red over a 1-month period.>Red & Red Jr.

Here is a movie of Jupiter's inner-ring made by Voyager in the late-1970's showing the presence of two small moons within. This ring is hard to see (unlike Saturn's ring) because (a) it is made of very small dust-mote sized bits of rock that is (b) not coated with ice (i.e., not very reflective). There's also less material in this ring than Saturn's.>Jupiter Ring movie

Lecture-7: Jupiter (part 2). In this lecture we mainly consider the Moons of Jupiter, which are as fascinating as the big guy himself. We'll see that the four largest moons - known as the Galilean Moons after their discoverer (or maybe not!) Galileo - two may have vast oceans of liquid water under thin ice crusts (and maybe life?) while another is host to active volcanoes. This and more in Lecture-7.

notes for Lecture 7 (Jupiter continued)>Lecture-7 Notes

Lecture-8: The planet Saturn. We will compare it with Jupiter, and describe what we know about its interior structure and composition before examining its remarkable ring system. This will allow us to introduce the concept of the "Roche Limit", setting up a seque back to Jupiter to see how massive planets have saved life on Earth!

For textbook fans, Saturn is covered in Chapter 12.

notes for Lecture 8 (Saturn)>Lecture-8 Notes

Here is a movie of Saturn's rings made by Voyager in the 1980's showing the mysterious "Spokes". Their origin is still not fully understood: they appear to be seasonal (i.e., depending on Saturn's position in its orbit around the sun) and there are suggestions they may be related to lightning discharges on Saturn itself. They appear to be composed of dust particles with minimal ice coating.>Spoke-movie

Here is wide field image taken by the Cassini Orbiter in 2004 from the night-side of Saturn showing another view of Saturn's rings. Note that the ring system is considerably more extensive. Compare with the rings of Jupiter taken from a similar position by the Galileo mission.>Saturn's Rings (wide angle)

Another beautiful image of Saturn captured by the Cassini orbiter. This angle shows the A, B, & C-rings both casting shaddows on Saturn and vice versa.>Saturn's Rings and Shaddows

A black-and-white image from Cassini that is no less spectacular, showing a much-inclined A, B, & C-rings plus four of Saturn's moons (can you tell which ones?).>Rings plus 4-moons.

Lecture-9: Uranus, Neptune and Pluto. We will meet the remaining two Jupiter-like planets and a new class of objects: Dwarf Planets, led by the prototype: Pluto.

This material corresponds to Chap. 13 & 14.3

notes for Lecture 9 (Uranus, Neptune & Pluto)>Lecture-9 Notes

Lecture-10: Asteroids and Comets turn out to be left-overs from the era of planet formation. Their study should uncover clues about how our Solar System (and others) formed. We'll also see that one asteroid or comet can ruin your day completely. Just ask a dinosaur (as in Jurasic Park, not me...).

notes for Lecture 10 (Space Junk)>Lecture-10 Notes

Lecture-11: The Formation of the Solar System. We have learned a lot of facts about the bodies making up the Solar System. However science is not simply a bunch of facts. Science tries to find patterns in facts that can explain for those facts and all the others, i.e., we try to create theories to organize knowledge and explain what we see. So that's what we're going to talk about in this lecture.

notes for Lecture 11 (The Formation of the Solar System)>Lecture-11 Notes

Lecture-12: Since space is so vast, and even the nearest stars are too far away to travel to in any realistic way, astronomers have become clever in squeezing information out of the Electromagnetic Radiation -i.e., *light* - that is emitted, absorbed, or reflected by asteroids, planets, stars, galaxies, clusters - basically, everything in space. In this lecture we will learn some basic facts about EM radiation and the EM spectrum.

notes for Lecture 12 (EM Radiation)>Lecture-12 Notes

Lecture-13: Telescopes allow astronomers to collect faint EM-radiation from extremely distant objects for interrogation. This allows us to determine luminosities, distances, ages, chemical compositions, and histories. In this lecture we consider modern telescopes and detectors.

notes for Lecture 13 (Optical Telescopes)>Lecture-13 Notes

Twinkle-twinkle little star. That's the problem. Visible light from objects in space (like this star) is greatly affected by the turbulent atmosphere it passes through during the last ~5 km of its journey. This file shows the resulting distortions of the star's image dramtically in a rapid series of short exposures. This is a 2.5-m telescope so the star should have an apparent diameter of 1/20'th of an arcsec. Notice that the blurred star image is 1-2 arcseconds in diameter and moves all over the place.>Star Twinkle

Another example of how looking at distant objects (here the surface of the Moon) is affected by the Earth's turbulent atmosphere. The image is from a video camera attached to the focus of a 1.5-m telescope.>Shake_Moon

Here's one way to solve the problem: Adaptive optics. By using a flexible mirror that can be rapidly re-shaped by a computer you can start to take out the "wavefront curvature" imposed by the turbulent atmosphere. This demonstration is from our friends at the Max Planck Institute. The images are: (bottom-left)-The uncorrected blurred star. (top-left)-The curved wavefronts of the star's light-waves after they have passed through the atmosphere. If not for the atmosphere these would be flat surfaces. (middle)-This represents the shape of the flexible mirror (note how rapidly it has to move!) required to remove the curved wavefronts. (top-right)-This shows the shape of the wavefronts after correction by the flexible mirror (they're much flatter..yay!). (bottom-right)-The resulting image of the star is much smaller and actually reaches the theoretical angular resolution of this 2.5-m telescope. >Working Adaptive Optics System

Lecture-14: Basic properties of stars are discussed in this lecture. Turns out, stars show a wide range in sizes, masses, temperature, and lifetimes. Some die dramatically while others just fade away. Surprisingly, they are nearly identical in terms of composition. Is there one single factor that determines all of the others? The answer is: yes.

notes for Lecture 14 (Introduction to Stars)>Lecture-14 Notes

Here's an animation showing how astronomers use Trigonometric Parallax (i.e., triangulation) to measure distances to stars. Two relatively nearby stars are shown as red dots. The white "dots" represent much more distant stars. The upper panel illustrates how the nearby star (red dot) moves back and forth in the sky as the Earth goes around the Sun. A more distant star (another red dot) moves back and forth as well, but by a smaller angle. This angular shift - the Parallax - is inversely proportional to the star's distance. >Trigonometric Parallax Animationm

Lecture-15: Star Formation. Where do those points of light come from? We will try to answer this question starting witn an investigation of the "stuff" that exists between the stars - the ``Inter-Sellar Medium", as this represents the raw material out of which stars are ultimately formed. What forces govern star formation? How long does it take to make a star like the sun? Can we actually see stars in the process of formation?

notes for Lecture 15 (Star Formation and the ISM)>Lecture-15 Notes

Stars form in giant clouds of cold and low density molecular gas. Following this process from start (i.e., with a cloud that may be 10-100 light years in diameter) to finish (i.e., individual stars) with a computer is a daunting task due to the huge range in densities and sizes that have to be described simultaneously. Here is a recent computer model showing the collapse of an initially spherical molecular cloud and subsequent star formation carried out by the "numerical astrophysics" group at Exeter University in England. Compare the final frames with the initial ones: how has the overall shape of the "parent" cloud changed? Does star formation take place everywhere in the cloud? How does the cloud density vary? How are the newly formed stars distributed within the "parent" cloud? Cloud-Collapse1.mp4"

Here is another simulation from the same group that follows one region in a larger cloud as it collapses and forms stars.Cloud-Collapse2.mp4"

If you're interested in this branch of research, which uses the most powerful computers in the world, you might want to look at this page where Prof. Matthew Bate describes this work in more detail. If you're good with computers (or want to be) you might consider this line of research.Exeter Group"

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Lecture-16:The Internal Structure of Stars and their evolution. Why powers the energy output of a star? How is it possible to power a star for billions of years? How is it that we can we say *anything* with confidence about the *center* of a star (temperature and density) from a few basic observations? This lecture deals with one of the most important and persistent questions asked by humans.

notes for Lecture 16 (Stellar Structure)>Lecture-16 Notes

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Lecture-17: Massive Stars. Their Birth, Life, and Dramatic Deaths. By "massive stars" here we mean stars more than 6-times as massive as the Sun. Remember how we saw that the lifetime of a star could be predicted by its mass? More massive stars have much shorter lives than low mass stars, and they end their days in spectacular explosions called Supernovas. We will explore why this happens, as well as the remarkable fact that massive stars are cosmic forges: Massive stars create heavy elements and dispers them through the cosmos. All the Iron and Calcium in your bodies, gold in your rings, etc. was created in a massive star billions of years ago.

notes for Lecture 17 (Massive Stars)>Lecture-17 Notes

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Lecture-18: Non-Optical Telescopes. By this I mean simply telescopes that do not function at optical wavelengths, but in the X-ray, radio, UV, and X-ray regions of the spectrum. We will see how they work and see a few examples of what they can teach us. When we start discussing galaxies (starting with the Milky Way) after the exam, we will rely heavily on non-optical telescopes.

notes for Lecture 18 (Non-Optical Telescopes)>Lecture-18 Notes

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Lecture-19 will be replaced by a Review Section on Tuesday (November 3rd). This means that the material in this lecture (The Milky Way Galaxy) will not be covered in thursday's Exam #3. I will instead answer any questions you have about the other 6-lectures. I repeat: Exam #3 now covers lecture-13 (Optical Telescopes) up to and including lecture-18 (non-Optical Telescopes) Today's class is optional but recommended.

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Lecture-19: The Milky Way Galaxy. We live in a giant collection of stars, gas and dust clouds called a galaxy, just one of literally billions of galaxies. As a prelude to exploring the universe of galaxies we will take a close look at our own, paying special attention to how we figured out its basic properties. As it turns out it, that job was pretty difficult. We'll also see that at the core of the Milky Way lurks a "monster".

notes for Lecture 19 (The Milky Way Galaxy)>Lecture-19 Notes

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Lecture-20: Normal Galaxies. There are billions upon billions of galaxies in the observable universe. Surprisingly these can be classified into a small number of forms. We will look at these basic classes of galaxies and uncover their basic properties, leaving until a later lecture how they formed. We will also outline the history of our unraveling the mystery of their true nature.

notes for Lecture 20 (Normal Galaxies)>Lecture-20 Notes

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Lecture-21: Peculiar and Active Galaxies. Not all galaxies fit into the Hubble Tuning-Fork Diagram. They were at first ignored but eventually recognized for what they are: the result of close passages (or outright collisions) between galaxies. It turns out that galaxies are nothing like isolated "Island Universes". We'll see how galaxy collisions dramatically transform the morphology and star formation rates of galaxies, and even feed a central monster!

notes for Lecture 21 (Peculiar/Active Galaxies)>Lecture-21 Notes

A numerical simulation showing how two spiral galaxies interacting gravitationally can produce something that looks just like "The Mice", a famous peculiar galaxy from the Arp Atlas. The model spiral galaxies are made of stars (white), gas clouds (blue), and "Dark Matter" halos (red). Compare the result of this simulation with the HST image of "The Mice" in your lecture notes.>Mice Movie

Here we rotate the final frame in the "Mice Movie" to show the system from different perspectives, so you can get a better idea of the 3-dimensional structure of the system.>Mice rotated

One of the more profound conclusions of the Toomre brother's work was that interacting galaxies would often merge together (1+1=1). Here is a more up-to-date simulation (including gas and dark-matter) of the merger of two equally massive spiral galaxies. Gas is shown as blue and stars are represented with yellow particles. Note the formation of the wide tidal tails. Also note that while some material in the tails flows back to the merger remnant (that now resembles an elliptical galaxy) some stuff doesn't. In other words, the merger of two spirals can spawn a bunch of objects that resemble dwarf galaxies.>Two-Spirals Merge

How to form a ring galaxy like the "Cartwheel". In this numerical simulation a small elliptical galaxy (the "intruder") is allowed through the center of a bigger spiral galaxy (the "target"). Gas (blue) and stars (white & yellow) are shown, but the "Dark Matter" halo is not shown. The passage of the "intruder" sets up an outwardly moving ring that sweeps up stars and gas. Star formation is enhanced in this moving ring which is why the outer rings in these systems are generally blue in color. Note that the time it takes the ring to form and propagate outwards is roughly 300-million years, roughtly the time it takes a star at the edge of the galaxy to make one orbit. Compare this with the "Cartwheel" galaxy. Is it a good match or not?>Cartwheel Simulation

Minor Merger (top-view). Here we see a dwarf galaxy (about 5% of the spiral's mass) being cannibalized by a bigger galaxy. As in all these numerical simulations, you "build" a galaxy in the memory of a computer using the known laws of physics, in this case, just gravity. The stars are shown as yellow particles and gas clouds are shown as blue particles. The dwarf galaxy is only made of stars in this simulation. Note that the dwarf galaxy works its way to the center of the spiral as it is eaten.>Minor Merger (top)

Minor Merger (side-view). Here is the above cannibalization of a dwarf by a big spiral shown from the side. Again, gas is shown as blue particles while stars are represented as yellow particles. The Dark Matter halo is not shown for clarity, though it is included in the simulation. Watch the dwarf galaxy bob up and down through the spiral's plane as it does its "dance of death"!>Minor Merger (side)

The Toomre brothers realized that interactions between galaxies could lead to their merger, and the result of spirals merging together would be a galaxy that looks like an elliptical galaxy. This simulation takes this idea further. Here we have six spiral galaxies in a group, and we watch them all merge together in a process that takes perhaps 3-4 billion years. What does the final result look like? Again, gas is shown as blue particles and stars are shown as yellow/white particles. Dark Matter is included in the calculations but is not shown. >Group Merger

We too shall merge. It appears that we are on a collison course with the Andromeda galaxy (M31), the nearest big spiral (As if you didn't have enough things to worry about, oy!). Don't lose too much sleep, because this is about 3-billion years in the future. This is how it might look. The red dot shows the sun (and its planets!). Watch us skip around the two merging galaxies as they do their own "dance o' death". >Bye-Bye Milky Way. Hello Elliptical

The formation of a spiral galaxy via many "minor-mergers". In this movie we start ~10-billion years ago and watch the growth of a large spiral galaxy over time through the cannibalization of many many small "dwarf-like" galaxies. At no time is there a "major-merger", i.e., the growing spiral only eats smaller galaxies. This allows the disk to form and grow. Two views of the same object are shown - a top view (left) and a side view (right).>Make a Spiral Galaxy

The formation of an Elliptical galaxy via many "minor-mergers" but at least one late "major-merger". Again, this simulation covers ~10-billion years of time and ends at the current epoch. Note that the galaxy starts out as a spiral but only one "major-merger" was enough to completely obliterate the disk and turn it into a big ball of stars, an elliptical. >Make An Elliptical Galaxy

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Lecture-22: Large Scale Structure. How are galaxies distributed in space? What are the largest structures in the universe that we've observed so far? We will examine these questions and see how distances to hundreds-of-thousands (perhaps millions) of galaxies can be measured in one human lifetime. We will also see the return of Dark Matter into our discussion, and discuss recent results that (paradoxically) show how to locate just where Dark Matter is in galaxy clusters and how much, even though we still don't know what it is.

notes for Lecture 22 (Large Scale Structure)>Lecture-22 Notes

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Study Guides will be posted here before each exam:

Here is the study guide for Exam #1: >StudyGuide1

Here is the study guide for Exam #2: >StudyGuide2

Here is the study guide for Exam #3: >StudyGuide3


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Practice Exams will be posted here before each exam:

Here is a short Practice Exam #1: >(Practice Exam #1 - PDF format; all sections)

Here is a short Practice Exam #2: >(Practice Exam #2 - PDF format; all sections)



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Goodluck and I hope you enjoy this class

Prof. James Higdon