Radio Astronomy: Observing the Invisible Universe [TTC Video]
07 February 2018, 06:25
Course No 1878 | .MP4, AVC, 1280x720 | AAC, 192 kbps, 2 Ch | 24x30 mins | + PDF Guidebook | 11.31GB
It’s easy to imagine the first modern humans staring up at the heavens in wonder, their eyes and minds dazzled by a beautiful band of light splashed across the night sky, the ever-changing moon so large and bright, and pinpoints of light in every direction. For a few hundred thousand years, our eyes were our primary astronomical tool, and we used them well. We catalogued and analyzed what we saw, filled in the gaps with powerful stories, applied what we knew of mathematics, and then invented complex tools of stone, metal, and glass to expand our knowledge. Everything we knew about the universe was based on light, that small part of the electromagnetic spectrum detectable by human eyes.
Then one day in the 1930s, a young engineer named Karl Jansky was assigned a task at Bell Labs: What were the sources of radio static that could interrupt transatlantic radio communications? After several years of work, he identified one source as radio waves coming from thunderstorms near and far… and another, from something at the center of the Milky Way. For the very first time, we had detected radiation below the visible part of the spectrum emanating from an astronomical object. For years, astronomers had been frustrated by interstellar dust that blocked their view and limited their
Radio Astronomy: Observing the Invisible Universe takes you on a thrilling journey through the universe with stunning visuals and animations to explain the science of radio astronomy and its astounding discoveries. Your guide is Felix J. Lockman, Ph.D., of the Green Bank Observatory, an active radio astronomer whose great passion for his work is absolutely contagious. As Dr. Lockman explains, radio astronomy is not simply a conglomeration of theories with no practical application to our lives today. While radio astronomy has the potential to one day answer the question of extraterrestrial intelligence, it also allows us to more accurately tell time right here on Earth, study terrestrial plate tectonics, and even get smartphone directions to that great new restaurant.
All about That Hydrogen
Some of radio astronomy’s myriad discoveries can be traced to the structure of the hydrogen atom. In hydrogen, one electron is essentially in orbit around one proton and both have a property called “spin,” either up or down. The parallel spin “wants” to decay into antiparallel spin—much like two magnets “wanting” to be aligned north to south, or antiparallel. In jumping position from parallel to antiparallel, a photon of radiation is emitted.
This process is certainly not unique to hydrogen. What is unique is that at the dawn of radio astronomy, a scientist predicted hydrogen would emit this radiation at detectable radio wavelengths, and this prediction offered astronomers a new tool for studying the universe. Three teams of scientists from around the world worked to discover the signal, and there it was, exactly as predicted: with a frequency of 1420 MHz, a wavelength of 21 cm.
For more than a decade, hydrogen at 21 cm wavelength remained the only spectral line which radio astronomers could use for their research. Later, signals from other elements and even molecules were identified. Over time, as both theory and technology improved, radio astronomers made discoveries that completely changed our understanding of the universe. Just a very few of these discoveries include:
- Jupiter’s radiation belts;
- Galactic non-thermal radiation, now called synchrotron emission;
- The birth rate of stars in the Milky Way and the galaxy’s rotational speed;
- Sagittarius A, the black hole at the center of the Milky Way;
- Dark matter;
- Neutron stars, pulsars, and binary pulsar systems;
- Gravitational radiation, as predicted by Einstein;
- Cosmic background radiation, confirming the big bang theory;
- Radio galaxies, quasars, and active galactic nuclei;
- Giant molecular clouds, the birthplaces of stars and planets; and
- Complex organic molecules in interstellar space.
Radio Telescopes, “Seeing” the Invisible
While you might have an optical telescope in your backyard, you will likely never have a radio telescope. Radio telescopes are large—over 100 meters in diameter and beyond—because radio waves contain such a small amount of energy. For example, the signal from your cell phone measured one kilometer away is five million billion times stronger than the radio signals received from a bright quasar! Although each radio telescope is designed for a specific use and often looks very different from others, they are all based on the same physical principles. Each collects, focuses, amplifies, and analyzes radio waves. In Radio Astronomy: Observing the Invisible Universe, Dr. Lockman takes you on an exciting virtual tour of radio telescopes. From the first handmade telescope built by radio astronomy pioneer Grote Reber to those on the drawing board for tomorrow, you’re right there with the scientists:
- The Green Bank Telescope, West Virginia, where Dr. Lockman does his research. At 17 million pounds and with more than 2,000 surface panels that can be repositioned in real time, this telescope is one of the largest moveable, land-based objects ever built.
- The Very Large Array (VLA), New Mexico. With its 27 radio antennas in a Y-shaped configuration, the data can be multiplied to form interference patterns, giving scientists a deeper and clearer look at galaxies than ever before.
- The Atacama Large Millimeter/submillimeter Array (ALMA), Chile. With an array of 66 radio antennas located high above much of the earth’s atmosphere, ALMA has revealed new stars and planetary systems in the making.
- The Very-Long-Baseline Array (VLBA), with multiple locations. The VLBA includes telescopes located thousands of miles apart, all functioning together as one single radio telescope the size of the Earth, allowing scientists to peer deep into the centers of galaxies.
The Biggest Questions
Perhaps the most astounding of all radio astronomy discoveries is this: The dominant molecular structures in interstellar space are based on carbon. That is not what scientists had expected.
We have always labeled these molecules “organic” because life on Earth is carbon based. Now we know that the chemistry of the entire Milky Way is organic, not just our home planet, and it is likely that any extraterrestrial galactic life would be related to us, at least on the molecular level. Will we find other organic lifeforms out there? Radio astronomers don’t know. But they’re working on it, along with the study of many other objects and processes not yet understood. Dr. Lockman’s current research addresses hydrogen clouds in the Andromeda galaxy, the nearest major galaxy to the Milky Way. Other radio astronomers are working to answer myriad questions about dark matter, fast radio bursts, and much more.
If the history of radio astronomy is any predictor, discoveries in these new research areas will lead to new questions, new technologies, more discoveries, and more questions. As Radio Astronomy: Observing the Invisible Universe shows, the field is on the cutting edge of knowledge itself. “Astronomy, by looking outward, leads us to questions that reflect upon ourselves in very deep ways,” Dr. Lockman says. “Astronomical discoveries have changed the way we think.”
Theory of Evolution: A History of Controversy [TTC Video]
07 February 2018, 06:04
Course No 174 | AVI, XviD, 480x352 | MP3, 128 kbps, 2 Ch | 12x30 mins | 2.1GB
Charles Darwin's theory of organic evolution—the idea that life on earth is the product of purely natural causes, not the hand of God—set off shock waves that continue to reverberate through Western society, and especially the United States. What makes evolution such a profoundly provocative concept, so convincing to most scientists, yet so socially and politically divisive? The Theory of Evolution: A History of Controversy is an examination of the varied elements that so often make this science the object of strong sentiments and heated debate.
Professor Edward J. Larson leads you through the "evolution" of evolution, with an eye toward enhancing your understanding of the development of the theory itself and the roots of the controversies that surround it. In these lectures you will:
- Explore pre-Darwinian theories of the origins of life, from Genesis and the ancient Greeks to such 18th- and 19th-century scientists as Georges Cuvier and Chevalier de Lamarck
- Follow the life and work of Charles Darwin, and the impact of his 1859 masterpiece, On the Origin of Species. Darwin's theory of evolution by natural selection was immediately recognized as a threat to traditional religion, but was quickly accepted (the first printing of Origin of Species sold out on the first day)
- Examine the history of evolutionary science after Darwin—a fascinating story that includes the "rediscovery," after 35 years, of Gregor Mendel's work on genetic variation; the unearthing of prehominid, or early human, fossils by Raymond Dart in 1925 and the Leakey family in the 1950s; and the confusion created by the sensational, but later discredited, discovery of Piltdown Man—a fake evolutionary "missing link"—in 1912
- Trace the history of religious objections to evolution, from those of Darwin's own time to contemporary efforts to teach creation science in American schools. This includes a detailed discussion of the famous Scopes "monkey trial," which in fact was a staged media event, designed to create publicity for the town of Dayton, Tennessee.
Are Our Genes more Important than We Are?
This course makes it clear that the history of controversy surrounding evolution is not limited to a dispute between science and religion. Even within the scientific community, the fine details of the theory of evolution have long been a matter of passionate dispute.
In fact, in the last third of the 19th century, the principal objections were scientific, not religious. Although the fossil record was a key piece of evidence for evolution, it had gaps that could be used to argue against the theory. And both proponents and critics wondered how altruistic human qualities such as love and generosity could possibly have evolved through the competitive, often harsh, processes that Darwin described.
From Professor Larson's presentation, you will learn that new ideas in evolution science have often created new controversies. For example, is it truly possible, as some scientists now maintain, that humans exist merely to ensure the survival of their genes? Such research has created disagreement among scientists about the degree to which evolution drives human behavior, and has further alienated many segments of the public.
Evolution's "Dark Side": Social Darwinism
In these lectures, you will review perhaps the most sinister controversy associated with the theory of evolution: social Darwinism. From the beginning, the Darwinian theory of evolution has been linked to economic and political views. Thomas Malthus's theories of population growth and competition for limited resources even inspired Darwin's thinking on natural selection.
Unfortunately, later supporters of evolution carried this line of thinking too far. Beginning with Herbert Spencer, who coined the term "survival of the fittest," Darwin's ideas were used as evidence for a wide range of social beliefs, from laissez-faire capitalism to racism, colonialism, and, in perhaps the worst application, Nazism. In the United States, social Darwinism has served as a basis for the creation of IQ tests and for eugenics programs that resulted in the forced sterilization of thousands of mentally ill or retarded Americans.
Unsettling Implications: The Growing Gulf Between Science and Religion
During the late 19th century, largely through the efforts of scientists who sought to integrate evolutionary science with spiritual belief, evolution was widely accepted by the religious community in the United States. Today, this is hardly the case.
In his last four lectures, Professor Larson examines the trends that have, since 1920, widened the gulf between science and religion. These include an increase in fundamentalist Protestantism, the weakening of liberal Protestantism as a counteracting force, and the growing power of a firmly conservative South.
In the 1960s, federally funded neo-Darwinian textbooks provoked a conservative backlash. Beginning with the publication of Henry M. Morris's The Genesis Flood, efforts to gain equal time for the teaching of creation science, based on biblical teachings, gathered strength. Rebuffed by the courts, creationism continues to thrive through the increasing numbers of private Christian schools and through home schooling.
The growing gulf between science and religion has unsettling implications for our society. Large segments of the American population reject the naturalism of current evolutionary thinking. Nine of 10 Americans believe in spiritual causes for life, with only 10 percent accepting the purely naturalistic explanations espoused by evolution. Strikingly, these statistics are almost exactly the opposite among the scientific community.
A Pulitzer Prize-Winning Teacher
As both a historian of science and a professor of law, Professor Edward J. Larson brings exceptional qualifications to this subject. His book, Summer for the Gods: The Scopes Trial and America's Continuing Debate Over Science and Religion, won the 1998 Pulitzer Prize in History. His analysis provides an invaluable perspective on the volatile history of what is arguably the single most significant idea of modern times.
Martial Arts for Your Mind and Body [TTC Video]
04 February 2018, 09:53
Course No 9468 | MP4, AVC, 1280x720 | AAC, 192 kbps, 2 Ch | 25x30 mins | + PDF Guidebook | 11.75 GB
Martial arts. This phrase conjures up images of peak physical and mental fitness—speed, flexibility, and strength married to meditation, focus, and self-discipline, an image amplified by everything from elegantly choreographed Hollywood movies to mixed martial arts (MMA) cage matches. But the reality is that “martial arts” serves as an umbrella for an amazing range of beneficial and highly specialized practices, from kung fu to tai chi to jeet kune do.
One of the most intimidating aspects of pursuing martial arts is learning enough to understand what works best for you. What is the difference between practicing the quick jabs and furious kicks of karate and tae kwon do, the grapples and rolls of judo, the flowing forms of tai chi, or the street-fighting grit of Krav Maga? These forms of fighting have certain things in common, yet each practice has its own unique philosophy as well as a physical and mental approach. And yet, too often, students and prospective students never get to explore first-hand, and benefit from, the range of opportunities in the martial arts.
Martial Arts for Your Mind and Body offers an immersive introduction to nine leading examples of martial arts. Hosted and brought together by tai chi Grandmaster David-Dorian Ross, these 25 interactive lessons (one more than a typical course) give you a solid grounding in the different philosophies, styles, and techniques of the major martial arts families. For this course, Master Ross has hand-selected seven guest instructors who are award-winning experts in their fields. Whether sensei, sifu, or champion competitor, your teachers are drawn from the best of the best.
You don’t have to be a cross-training warrior or MMA fighter to benefit from exposure to a variety of martial arts. In fact, with suitable guidance, practicing martial arts offers invaluable physical and mental benefits to people of all ages, at all levels of physical fitness. From self-defense to the physical benefits of a disciplined exercise regimen, to the balance and harmony that studying martial arts can bring to all aspects of your life, Martial Arts for Your Mind and Body is an ideal place to begin, resume, or deepen your practice.
Survey Nine Families of Martial Arts
David-Dorian Ross has designed a survey of the martial arts, offering a unique foundation for improved physical and mental training, all of which can help you identify specific practices and traditions that may be especially benefical for you. The course lets you experience, albeit far more efficiently, the same sorts of explorations Master Ross undertook as a young practitioner, when he set out to find the right style of martial arts for himself. With seven guest instructors to accompany him, Master Ross takes you on a tour of:
- Karate: The way of the “empty hand” is perhaps the most well-known Japanese martial art in the West. From kicking to kata, learn the physical and mental techniques that make it such a formidable practice.
- Tae Kwon Do: Like karate, tae kwon do is known for lightning-fast high kicks and the breaking of boards. Find out how this form became so popular quickly after its development in post-World War II Korea, and what makes it unique among martial arts.
- Kung Fu: Beginning in China as far back as the 5th century, this practice has influenced most other forms of Chinese martial arts, and been codified into dozens of variations, many named after animals. Gain insight into the history and basic techniques of kung fu, as you explore the white crane style for close- to medium-range interaction, and then sample a long-range style for maximizing your reach known as praying mantis.
- Tai Chi: Martial arts are not only about speed or vigorous combat. Tai chi has that option but has famously developed practices to cultivate slow, graceful movements, with innumerable benefits for well-being. Tai chi (taiji quan) traces its origins to China in the 17th century.
- Judo: Known for its grappling, flipping, and throwing techniques, judo is an art of surprising grace from Japan. Practice the drills and techniques of “the way of gentleness.” Judo was the first martial art to use the belt system to classify fighters by skill level.
- Jujitsu: Akin to judo, Japanese Jujutsu and Brazilian Jiu-Jitsu are “the pliable fighting art,” and make use of groundwork and wrestling holds to take control of the opponent. Get ready to stretch into new forms!
- Muay Thai: Originating in Thailand but often known simply as kickboxing in the West, Muay Thai is unique among martial arts for the way it incorporates shins, elbows, and the clinch into its fighting style. See why Muay Thai is a favorite among MMA practitioners.
- Jeet Kune Do: Developed by Bruce Lee as a hybrid of traditional Asian martial arts and more modern, global styles, jeet kune do is fascinating for the way it can be adapted and transformed by every individual practitioner.
- Krav Maga: Blending elements from jujitsu, boxing, wrestling, and more, Krav Maga forms a type of street fighting about what to do in situations with no rules. First developed as a way for Polish Jews to defend themselves from fascists, Krav Maga is the signature fighting style of the Israeli Defense Forces.
In addition to these major families, you will also learn about qigong, a system for understanding and working with energy, or Qi, that is frequently practiced alongside other martial arts like tai chi. You’ll also learn meditation techniques and other aspects of the mental and even spiritual side of the martial arts.
Learn Stances, Blocks, Kicks, and Chops
While Master Ross and his colleagues discuss and personally embody the theory and ideals of their respective practices, this is very much a participatory course. Set in a unique dojo-style studio, each of these lessons gives you the chance to work out alongside the instructors, giving you a true immersion in the martial arts. Workouts include warmups, drills, shadowboxing, combos, and partnered exercises. For instance, you will:
- Try an extended “horse stance” exercise to improve your mental toughness.
- Learn kata with Sensei Akira Fukuda, the Team USA Olympic coach, and master of all five styles of karate.
- Improve your physical and mental well-being with Master Ross’s TaijiFit flow workout.
- Participate in a series of one-step sparring exercises with Grandmaster Dave Wheaton.
- Perform a pattern of closed fist and open palm kung fu punches, followed by a combination drill.
- Explore the “why” of Muay Thai kickboxing combinations with five-time world kickboxing champion Kathy Long.
- Find out how to defend against chokes, shirt grabs, and attacks from behind in the Krav Maga style of street fighting.
- And much more.
Physical Mastery, Mental Practice
Master Ross’s approach in this course is to pause and give pointers for each technique. Special camera angles and 3D modeling show you all aspects of each move, and Master Ross's deep understanding of how to help anyone reap benefits from martial arts ensures that you are able to join in and participate safely from lesson one. With this unique approach, you will be ready to punch, kick, block, and grapple your way into improved physical fitness.
But of course, practicing the martial arts is about more than physical fitness or self-defense. Training regularly, with exposure to more than one martial art, benefits all aspects of your life, giving you greater focus, confidence, and self-discipline. The unparalleled experience of nine styles in this course will give you fresh insight into what martial arts are all about, and greater clarity about your own life and goals. Martial Arts for Your Mind and Body is here to show you a way to your best self.