12
Lectures
30
minutes/lecture
1.
A General Introduction to Black Holes
Widely featured in novels, movies, and other media, black holes are not just entertaining plot devices, they're real. Learn how the idea of black holes was proposed more than two centuries ago, and how more recently Einstein's general theory of relativity gave a firm theoretical basis for them.
1.
A General Introduction to Black Holes
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7.
Gravitational Waves—Ripples in Space-Time
Gravity waves are an unexplored new window for studies of black holes. Learn how these hard-to-detect vibrations are the predicted ripples in the fabric of space-time that should result from violent phenomena such as the merging of two black holes.
7.
Gravitational Waves—Ripples in Space-Time
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2.
The Violent Deaths of Massive Stars
Discover how black holes can form from stars that are much more massive than the sun. After exhausting their nuclear fuel, these behemoths end in a colossal explosion called a supernova, leaving behind a superdense neutron star, or in some cases something even denser: a black hole.
2.
The Violent Deaths of Massive Stars
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8.
The Wildest Ride in the Universe
What happens if you fall into a black hole? Take a wild ride into the supermassive black hole at the center of the Milky Way Galaxy with a vivid computer simulation showing the strange effects you would experience before being crushed to incredible density.
8.
The Wildest Ride in the Universe
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3.
Gamma-Ray Bursts—The Birth of Black Holes
Trace the story of gamma-ray bursts. Long a mystery, these intense eruptions of high-energy radiation from random spots in the sky are now thought to be associated with the formation of black holes in distant galaxies. Their visibility from so far away means they are truly titanic explosions.
3.
Gamma-Ray Bursts—The Birth of Black Holes
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9.
Shortcuts through the Universe and Beyond?
Mathematically, black holes seem to connect our universe with others through a gateway called an Einstein-Rosen bridge—nicknamed a wormhole by physicist John Wheeler, who also coined the term black hole. See a computer simulation of what passage through a wormhole would be like.
9.
Shortcuts through the Universe and Beyond?
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4.
Searching for Stellar-Mass Black Holes
If black holes emit no light, how are they detected? Investigate the different clues that establish strong evidence for black holes. For example, a star orbiting an unseen object that exceeds the 3-solar-mass limit for neutron stars is probably circling a black hole.
4.
Searching for Stellar-Mass Black Holes
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10.
Stephen Hawking and Black Hole Evaporation
Learn why black holes may not be completely black. In 1975, physicist Stephen Hawking showed that they can evaporate via a quantum tunneling process, giving off a slow trickle of quantum particles before eventually ending in an explosion of gamma rays.
10.
Stephen Hawking and Black Hole Evaporation
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5.
Monster of the Milky Way and Other Galaxies
This lecture presents the most compelling evidence to date for black holes—found in the core of most galaxies. There, stars and gas clouds typically orbit at high speeds, signaling the presence of a central, supermassive black hole, millions to billions of times the mass of the sun.
5.
Monster of the Milky Way and Other Galaxies
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11.
Black Holes and the Holographic Universe
The "no-hair" theorem says that black holes are utterly simple and preserve almost no information about what went into them. Discover why some physicists believe that the supposedly lost information is contained just outside the black hole in a form that resembles a hologram—and that the universe as a whole may display the same property.
11.
Black Holes and the Holographic Universe
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6.
Quasars—Feasting Supermassive Black Holes
Quasars are another astronomical mystery explained by black holes. Explore the history of these star-like objects that long baffled astronomers, until observers realized they were seeing matter falling into supermassive black holes during the early era of galaxy formation.
6.
Quasars—Feasting Supermassive Black Holes
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12.
Black Holes and the Large Hadron Collider
Professor Filippenko closes by looking at the possibility that a new particle accelerator called the Large Hadron Collider will produce microscopic black holes. Discover why there is no danger that they will devour the Earth, and why there is no risk from any known black holes in space.
12.
Black Holes and the Large Hadron Collider
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12
Lectures
30
minutes/lecture
1.
The Constellations and Their Stars
Begin your study of the night sky by investigating the origin of the constellations—the traditional groupings of stars that mostly date to antiquity. The well-known constellation Orion illustrates the fascinating mix of beauty, mythology, and scientific knowledge to be found wherever you look in the heavens.
1.
The Constellations and Their Stars
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7.
The Northern Sky and the North Celestial Pole
Embarking on the second half of the course in which you systematically tour the entire sky, study two constellations that are continuously in view from the Northern Hemisphere: Ursa Major and Cassiopeia. Also explore the slowly shifting position of true north in the sky.
7.
The Northern Sky and the North Celestial Pole
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2.
Seeing and Navigating the Sky
The naked eye is a powerful instrument—if you know how to use it. Learn the best times and conditions for observing, how to identify the positions and magnitudes of stars and planets, how the sky changes over the course of a night, how to use astronomical maps such as a planisphere, and more.
2.
Seeing and Navigating the Sky
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8.
The Fall Sky
Navigate your way around the autumn sky from the Northern Hemisphere, discovering how the classical myth of Andromeda ties together the stories of the nearby constellations of Cassiopeia, Perseus, Cepheus, Pegasus, and Cetus. The sights include the Andromeda galaxy, the nearest large galaxy to our own.
8.
The Fall Sky
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3.
Using Binoculars and Backyard Telescopes
There are many choices when selecting binoculars or a telescope. Learn what to look for in light-gathering power, optical design, magnification, mounts, and other features. Professor Murphy also suggests several tips for getting the best observing experience out of your equipment.
3.
Using Binoculars and Backyard Telescopes
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9.
The Winter Sky
Continuing your focus on the constellations of the Northern Hemisphere, survey the magnificent winter sky, dominated by Orion. "Star hop" around the region, which includes a wealth of interesting stars, globular clusters, nebulae, and other features, especially the Orion Nebula—the finest nebula in the northern sky—and the Pleiades and Hyades star clusters in Taurus.
9.
The Winter Sky
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4.
Observing the Moon and the Sun
Charting the motions and changes of the sun and moon may be humankind's oldest astronomical activity. Discover how both objects offer rich opportunities for study. Also learn the precautions to take when observing the sun, which is the only star that can be seen up close and in detail.
4.
Observing the Moon and the Sun
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10.
The Spring Sky
The spring sky opens the view into intergalactic space perpendicular to the plane of the Milky Way. Among the objects visible are the immensely rich galaxy clusters in Virgo and Coma Berenices, which are many millions of light-years distant and can be seen with small and moderate telescopes.
10.
The Spring Sky
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5.
Observing the Planets with a Telescope
The rings of Saturn, the bands of Jupiter, the phases of Venus, the polar caps of Mars—these and other planetary features are visible through a small telescope. Learn when viewing opportunities arise for each of the planets and what sights await the dedicated observer.
5.
Observing the Planets with a Telescope
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11.
The Summer Sky
Arching high overhead in the summer sky is the Milky Way, which is the plane of our galaxy seen from the inside. Tour this densely packed region of stars of all types, from dusty regions of star birth to the exquisite shells of dying stars. Here, a useful orienting feature is the Summer Triangle.
11.
The Summer Sky
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6.
Meteor Showers, Comets, Eclipses, and More
Explore a variety of special phenomena that are among the wonders of the sky. Some, like bright meteors, aurora, and many comets, are largely unpredictable. Others, like eclipses and annual meteor showers, occur at well-known times—although it may require a special trip to see them.
6.
Meteor Showers, Comets, Eclipses, and More
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12.
The Southern Sky and the Milky Way
In this final lecture, travel to the Southern Hemisphere for sky views inaccessible from northern latitudes. Discover the famous Southern Cross, the Large and Small Magellanic Clouds, and a spectacular panorama of the Milky Way—along with new myths and stories that add a human dimension to our marvelous night sky.
12.
The Southern Sky and the Milky Way
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