The Search for Exoplanets: What Astronomers Know [TTC Video]
31 March 2016, 18:44
Course No 1802 | MP4, AVC, 643 kbps, 856x480 | AAC, 128 kbps, 2 Ch | 24x30 mins | + PDF Guidebook | 4.13GB
Half a century ago, television viewers thrilled to the exploits of the original Star Trek series with its mission “to explore strange new worlds.” Today, astronomers are doing exactly that, analyzing the data from advanced telescopes and discovering strange worlds orbiting other stars in our galaxy.
Most of the countless stars they are monitoring are invisible to the unaided eye, and the thousands of confirmed and candidate planets they’ve detected can’t be imaged directly, except in a few rare cases. Yet researchers are able to use subtle clues obtained in ingenious ways in order to assemble an astonishing picture of planetary systems far different from our own:
- Systems containing “hot Jupiters,” giant planets orbiting so close to their host stars that it takes days—not Jupiter’s 12 years—to make one orbit.
- Earth-sized planets orbiting even closer—in one case careening around its sun every 8 hours, completing three of its “years” in one of our days.
- Planets circling two different suns, recalling the famous scene in Star Wars, where Luke Skywalker watches a double sunset from his home planet.
These results are much more than science fiction brought to life. They are an astronomical revolution, comparable to the Copernican revolution that established our current view of the solar system. As recently as 1990, it seemed possible that the solar system was an unusual or even unique phenomenon in our galaxy. Now we know that planets are everywhere, and we are living during a new golden age of discovery, with the prospect of finding many planets like our own.
The Search for Exoplanets: What Astronomers Know immerses you in this incomparable adventure in 24 beautifully illustrated half-hour lectures conducted by veteran planet hunter Joshua N. Winn, Associate Professor of Physics at the Massachusetts Institute of Technology.
An award-winning teacher, Professor Winn is also a pioneer in the field of exoplanetary science—the study of planets beyond the solar system. He served on the science team of NASA’s Kepler mission, the most productive planet-finding effort to date, and he is taking part in a new space telescope project that will focus on finding rocky planets in the habitable zones of their parent stars, laying the groundwork for the ultimate objective: detecting earthlike planets with the chemical signatures of life. This goal may still be many years away, but meanwhile Dr. Winn and his colleagues are helping to rewrite the book on planet formation and the evolution of planetary systems.
A Scientific Detective Story
Designed for everyone from armchair explorers to serious skywatchers, The Search for Exoplanets follows the numerous twists and turns in the hunt for exoplanets—the false starts, the sudden breakthroughs, and the extraordinary discoveries. Dr. Winn covers all the necessary background, reviewing the simple mathematics of planetary orbits and the scientific principles behind the techniques that eventually found planets at mind-boggling distances from our home base.
Considering that a star is millions to billions of times brighter than even its largest planet, this is a scientific detective story like no other, involving methods such as these:
- Astrometry: A star and its planet both orbit their common center of mass, typically a point slightly off-center from the center of the star. In principle, this effect can be observed as a tiny wobble in the star’s position in the sky.
- Doppler shift: The slight wobble of a star due to orbiting planets can also be detected as a fluctuating color shift (known as the Doppler shift) in the star’s spectrum, as the star alternately moves toward the observer and then away.
- Transit: When a planet crosses in front of a star (known as a transit), it blocks a small percentage of the starlight. Sensitive instruments can measure this minor drop in light level. The greater the dimming, the larger the planet.
- Gravitational lensing: A foreground star acts like a lens when it passes in front of a more distant star, bending the light of the background star. If the star in front has a planet in the right position, the light temporarily bends a bit more.
- Direct imaging: Most difficult of all is recording an actual image of an exoplanet, which has been compared to spotting a firefly buzzing around a searchlight, with a telescope thousands of miles away. Even so, it has been done!
These techniques not only signal the presence of planetary systems, but also allow astronomers to analyze the data to determine how many planets there are, how large, how far from their parent star, their likely compositions, and the characteristics of their atmospheres. Viewers of The Search for Exoplanets will feel like Dr. Watson in the presence of Sherlock Holmes, as Professor Winn extracts a wealth of information from a spectrum, a light graph, a diffraction pattern, and other subtle clues.Explore Unknown Worlds
To help you grasp the vastness of the universe, Professor Winn demonstrates a virtual scale-model solar system, centered on Times Square in New York City, that serves as a yardstick for comparisons throughout the course. For example, if the Sun is reduced to the size of an adult human, then at the same scale Earth is the size of a grape, two and a half blocks away, and the closest star with a known planet is 32,000 miles away—a distance 30% greater than the circumference of the entire Earth. Imagine trying to detect a grape at that distance!
The lectures are lavishly illustrated with astronomical photographs, graphics, computer animations, and special effects that help you appreciate the extraordinary variety of planetary systems. And Professor Winn’s personal anecdotes add a human dimension, showing the challenge and excitement of science. Since exoplanetary science is unusually interdisciplinary, you are introduced to a wide range of fundamental ideas, including these:
- Astronomy: Among the topics you cover are planetary science, stellar evolution, telescopes, cosmology, and asteroseismology (the science of star “quakes”).
- Physics: You investigate orbits, tides, the electromagnetic spectrum, spectroscopy, optics, quantum mechanics, and special and general relativity.
- Life sciences: You learn about the quest for life, which combines the search for signals from extraterrestrial intelligence with the hunt for biosignatures of microbial life.
After completing this fascinating course, you will be well equipped to understand one of the most momentous developments of our time. Exoplanets will be making big news for years to come, and at the end of the course Professor Winn describes ambitious projects that are on the drawing board as well as discoveries that he predicts for the near future. Perhaps the only reason exoplanets haven’t attracted more attention is that science fiction long ago prepared us for these wonders. But unlike the adventures on Star Trek, these projects are real. We invite you to join a scientist who is on a mission that can only be compared to the exploits of Columbus, Magellan, and Lewis and Clark.
The Life and Operas of Verdi [TTC Video]
08 March 2016, 20:46
Course No 790 | AVI, XviD, 432x288 | MP3, 128 kbps, 2 Ch | 32x30 mins | + PDF Guidebook | 6.32GB
The Italians have a word for the sense of dazzling beauty produced by effortless mastery: "sprezzatura." Perhaps no cultural form associated with Italy is as steeped in the love of sprezzatura as opera, a genre the Italians invented. And no artist working in opera has embodied the ideal of sprezzatura as magnificently as that gruff, self-described "farmer" from the Po Valley and composer of 28 operas, Giuseppe Verdi (1813–1901).
Opera's Best-Loved Composer
Verdi is still the most popular composer in the 400-year-old history of opera. His operas are produced more than any other composer's, and one (admittedly unverifiable) source claims that his La traviata (1853) has been staged live somewhere around the world every evening for the past 100 years.
What are the treasures of creativity that account for this popularity? With Professor Robert Greenberg, you unpack them in depth and detail in this 32-lecture series.
You explore both famous and not-so-famous Verdi operas, as well as his Requiem Mass of 1874, his one great concert work; his early songs; and his very last composition, the Stabat Mater.
You trace his development from a more or less conventional composer of operas in the traditional Italian bel canto ("beautifully sung") style to a creator of truly innovative musical dramas in which the power of music to intensify and explore human emotion is exploited to the fullest degree.
"Verdi was a great dramatist and a great melodist at the same time, whose artistic evolution never ceased across the 50-year span of his career," says Professor Greenberg.
Enjoy a Mix of Biography and Musical Excerpts
The course structure is chronological, allowing you to follow easily the developing patterns in Verdi's work. Combining biography with a variety of musical excerpts, Professor Greenberg presents a memorable mixture of "sights to see and things to think about along the way."
To give a few examples:
- Entertaining anecdotes, including how Verdi first realized Nabucco was a hit, or his response to a dissatisfied operagoer who asked him for a ticket refund—he saw Aida twice and did not like it either time
- Enlightening musical analyses, such as Professor Greenberg's line-by-line examination of the breathtaking "quartet" sequence in Act III of Rigoletto—a musical achievement on a par with Mozart at the top of his operatic game, and an exploration of the massive, 38-minute "Dies irae" movement of the Requiem
- The story behind how Verdi became a larger-than-life, iconic hero of Italian nationalism
- An explanation of how Verdi worked out his complex creations in dealings with everyone from amazingly gifted librettists (such as Arrigo Boito) to maddening censors
- Descriptions of key personal associations with lovers and spouses to business partners and politicians.
- A Brief Biography
- You trace Verdi's long life beginning at his birth in 1813 in the small village of Le Roncole in French-dominated northern Italy (then the Duchy of Parma), where his parents kept a tavern frequented by itinerant musicians.
Verdi's parents sent him to the nearby town of Busseto to study music with Ferdinando Provesi, a cofounder of the Busseto Philharmonic Society. Verdi learned the art of composition by writing hundreds of pieces, which were then performed by the Busseto Orchestra.
The other cofounder, Antonio Barezzi, took the young Verdi under his wing and later financed his compositional studies under Vincenzo Lavigna in Milan, after the Milan Conservatory had rejected his application on the grounds that he was too old and showed little musical promise.
In 1836, Verdi became master of music of the city of Busseto. His first opera, Oberto, was performed at the famous La Scala Opera House in Milan in 1839.
His next opera, Un giorno di regno (King for a Day), was a total flop, and Verdi never forgot the humiliation. From then on, he never had any regard for public opinion, good or bad.
Verdi's first masterpiece was Macbeth, premiered in 1847. This opera marked a watershed in Verdi's compositional development. In it, we begin to see Verdi depart from the traditional Italian bel canto opera, which focused on melodic and vocal beauty, often at the expense of dramatic integrity.
In the 1860s, Verdi began to slow down his prodigious output of operas. Between 1839 and 1859, he had composed 23 operas; between 1862 and 1893, he composed five operas and the Requiem.
When Verdi died in January 1901, 200,000 mourners came to see off to eternity the man who had, by the time of his death, become united Italy's most famous citizen.
The Primacy of Opera
A premise of the course—laid out by Professor Greenberg in his first lecture—is that opera cannot be understood as just one more musical genre among others in Western history.
On the contrary, states Dr. Greenberg, opera, Verdi's medium par excellence, is primary and central; the most important musical invention of the last half-millennium.
Opera was born out of the Italian Renaissance desire to recover and reproduce the dramatic art of the "ancients" by setting entire stage plays to music. What the Renaissance called "works in music" or opera in musica, we have shortened to simply "opera." As a genre, opera made the voice and feelings of the individual central to art as never before.
The implication of opera's primal and central character, argues Professor Greenberg, could not be clearer: If you want to understand classical (or more properly concert) music, you must understand opera.
Each lecture contains one or more musical excerpts, personally chosen by Professor Greenberg to provide you with vivid, concise illustrations of Verdi's artistry. The musical interludes average about 12 minutes per 45-minute lecture. The dates below indicate the year of the premiere.
Works you'll hear in the lectures are excerpted from:
- Sei romanze (Six Romances), nos. 1 and 3, 1838
- Oberto, 1839
- Un giorno di regno, 1840
- Nabucco, 1842
- I Lombardi, 1843
- Ernani, 1844
- I due foscari, 1844
- Macbeth, 1847
- I masnadieri, 1847
- Luisa Miller, 1849
- Rigoletto, 1851
- Il trovatore, 1853
- La traviata, 1853
- Les Vêpres siciliennes, 1855
- Un ballo in maschera, 1859
- La forza del destino, 1862
- Don Carlo, 1867
- Aida, 1871
- Requiem Mass, 1874
- Otello, 1887
- Falstaff, 1893
Optimizing Brain Fitness [TTC Video]
07 March 2016, 17:50
Course No 1651 | WMV, WMV3, 640x480 | WMA, 128 kbps, 2 Ch | 12x30 mins | 4.12GB
With its up to 500 trillion synaptic connections, your brain is easily the most powerful machine in the world. These connections are what create your thoughts, what drive your emotions, and what control your behaviors. Even more incredibly: This amazing machine is constantly changing through a process known as brain plasticity. And you can take advantage of this process to improve and enhance your brain's jaw-dropping powers—at any age.
Brain plasticity, the secret to optimizing your brain's fitness, is one of the most revolutionary discoveries in modern neuroscience. While it was traditionally thought that our brains were fully formed by adulthood, the truth is that our life experiences continually shape and mold our brains in fascinating ways. In fact, optimal brain fitness is the gateway to improvement in a range of areas, including
- attention and focus;
- learning and creativity; and
- sensory acuity and fine motor skills.
Now, discover the secrets to increasing and expanding your brain's power to meet everyday challenges and enhance the quality of your life with Optimizing Brain Fitness, an engaging 12-lecture course that shows you how to take advantage of the basic principles of brain operation and build the brain you want to live with for the rest of your life. Delivered by Dr. Richard Restak, an award-winning teacher, practicing neurologist, and professor at The George Washington University School of Medicine and Health Sciences, these lectures are packed with vital information and research-based exercises you can perform every day to tap into your hidden mental potential.
Explore Your Brain's Most Important Functions
Optimizing Brain Fitness centers on the idea that your brain is a continual work in progress, one whose development depends on the best possible use of your brain's most important everyday functions. You explore many functions in these lectures, with a strong focus on three.
- Attention: Optimal attention skills open the door to top-notch performance in math, reading, and auditory and visual memory. They provide you with the basis for learning what to focus on and what to ignore, and they also coordinate the brain networks that involve sensation, movement, emotions, and thought.
- General memory: General memory facilitates the formation, activation, and retention of neurological circuits that contribute to your brain's optimal functioning. Memory is the veritable bedrock of superior brain health and serves as the basis of your personal identity.
- Working memory: Working memory is linked with your IQ and is the first brain function to decline as you age. It is central to your ability to manipulate stored information and can easily be improved by practicing a series of simple exercises.
You'll also spend time delving into the neurology of motor skills, visual-spatial thinking, creativity, and more.
Engage in a Wealth of Delightful Exercises
Professor Restak proves that exercising your brain doesn't have to be a burden or a chore. Rather, it can be an exciting and eye-opening way to explore how the brain works and to discover your own brain's potential.
Dr. Restak has designed Optimizing Brain Fitness with a wealth of exercises, challenges, practice problems, and tests that will enhance and improve your brain's essential functions. Here is just a small sample of the enjoyable ways that you can improve your brain.
- In one minute, name as many animals as you can without repeating them. You'll have to use your working memory to mentally eliminate animals you've already named. A desirable score is between 17 and 20 animals.
- Close your eyes and envision the room around you, and then open them and check for accuracy. Repeat this memory-recall exercise and pay closer attention to smaller details, such as the number of magazines on a table.
- Take a number of spices at random and set them on a table; then close your eyes and try to identify each of them by smell alone. Take this same approach by identifying spices in a meal that you're eating. Both exercises are great ways to sharpen your senses of smell and taste.
Winner of Georgetown University Medical School's Linacre Medal for Humanity and Medicine, Professor Restak is an accomplished neurologist, prolific author, frequent public lecturer for prestigious institutions, and—above all—a champion of brain fitness. Rooted in the startling new findings emerging from groundbreaking experiments and detailed research studies, his course is the perfect way to maintain or improve the health of the most important organ in your body.
Insightful, instructive, and undeniably fun, Optimizing Brain Fitness is an invaluable part of your personal tool kit for lasting health and wellness.