12
Lectures
30
minutes/lecture
1.
The Rationale for a Space Telescope
Begin your exploration of the scientific stories behind 10 of the most fascinating images made by the Hubble Space Telescope. In this lecture, learn about Hubble's design and how its operations were almost cut short by a flaw in its mirror, a problem corrected during a space shuttle servicing mission.
1.
The Rationale for a Space Telescope
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7.
The Sombrero Galaxy—An Island Universe
In the 1920s, astronomer Edwin Hubble discovered the true nature of galaxies as "island universes." Some 80 years later, the telescope named in his honor has made thousands of breathtaking pictures of galaxies. Focus on one in particular—an edge-on view of the striking Sombrero galaxy.
7.
The Sombrero Galaxy—An Island Universe
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2.
Comet Shoemaker-Levy 9 and Jupiter
Shortly after its optics were repaired, Hubble had the opportunity to observe the solar system event of the century: the collision of a string of comets with Jupiter in 1994. Examine Hubble's stunning image of the aftermath of this crash.
2.
Comet Shoemaker-Levy 9 and Jupiter
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8.
Hubble's View of Galaxies Near and Far
Hubble's image of the nearby galaxy NGC 3370 includes many faint galaxies in the background, exemplifying the telescope's mission to establish an accurate distance scale to galaxies near and far—along with the related expansion rate of the universe. Discover how Hubble's success has led to the concept of dark energy.
8.
Hubble's View of Galaxies Near and Far
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3.
The Sagittarius Star Cloud
Hubble's view of a tiny region of the Sagittarius Star Cloud has an astonishing 12,000 stars. Study this dazzling image and learn how its unprecedented resolution is helping to chart the stellar history and evolution of the Milky Way galaxy.
3.
The Sagittarius Star Cloud
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9.
The Antennae Galaxies—A Cosmic Collision
A pair of interacting galaxies called the Antennae represent Hubble's most dramatic snapshot of a galactic collision. Learn how such events unfold over the course of millions of years and how the nearby Andromeda galaxy will have a similar encounter with our own Milky Way in the far distant future.
9.
The Antennae Galaxies—A Cosmic Collision
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4.
The Star Factory inside the Eagle Nebula
Explore the most iconic Hubble photo of all: the glowing pillars of gas and dust at the core of the Eagle Nebula. Resembling a fantasy landscape, this view shows young stars emerging from their cocoons of gas and dust in an interstellar molecular cloud.
4.
The Star Factory inside the Eagle Nebula
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10.
Abell 2218—A Massive Gravitational Lens
One of the consequences of Einstein's general theory of relativity is evident in Hubble's picture of the galaxy cluster Abell 2218. Investigate the physics of this phenomenon, called gravitational lensing, and discover how Hubble has used it to study extremely distant galaxies as well as dark matter.
10.
Abell 2218—A Massive Gravitational Lens
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5.
The Cat's Eye Nebula—A Stellar Demise
Turning from star birth to star death, get a preview of the sun's distant future by examining the Cat's Eye Nebulae. Such planetary nebulae (which have nothing to do with planets) are the exposed debris of dying stars and are among the most beautiful objects in the Hubble gallery.
5.
The Cat's Eye Nebula—A Stellar Demise
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11.
The Hubble Ultra Deep Field
Completing your tour of 10 remarkable Hubble images, plunge into the Hubble Ultra Deep Field, the deepest optical image of the cosmos made to date. This extraordinary view shows 10,000 galaxies extending far beyond the Milky Way and back to the epoch of galaxy formation.
11.
The Hubble Ultra Deep Field
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6.
The Crab Nebula—A Supernova's Aftermath
Stars more than eight times as massive as the sun take a radically different path at the end of their lives, disintegrating in a colossal explosion known as a supernova. Hubble's image of the famous Crab Nebula shows the expanding cloud of material from a supernova that was witnessed on Earth in the year 1054.
6.
The Crab Nebula—A Supernova's Aftermath
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12.
Hubble's Legacy and Beyond
Finish the course by looking at the future of Hubble and the next generation of space telescopes. Focus in particular on the search for extrasolar planets, how they are found, and the role Hubble and other telescopes play in extending our knowledge of possibly earthlike worlds.
12.
Hubble's Legacy and Beyond
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24
Lectures
30
minutes/lecture
1.
Is There Life Elsewhere in Our Universe?
Is there life in our universe? As you get an overview of the course—including the five major questions it will endeavor to answer—consider the possibility that life exists in some form in the cosmos. Learn how exponential growth in technological developments is enabling breakthroughs that were recently impossible.
1.
Is There Life Elsewhere in Our Universe?
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13.
Liquid Assets—The Moons of Jupiter
Gas giant Jupiter is unlikely to inhabit life—but what about its moons? Look quickly at the importance that Galileo's discovery of Jupiter's moons had for the powerful Medici family before moving on to examine the connection between the moons' mean motion resonance and the possibility of subsurface life existing in the ice-covered oceans of Europa, Ganymede, and possibly, Callisto.
13.
Liquid Assets—The Moons of Jupiter
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2.
Bang! A Universe Built for Life
How did we go from a dead universe to a universe full of life? Begin to answer this question by evaluating the scientific evidence supporting the big bang theory of the universe's creation, and learning the role stars play in creating carbon and the key elements needed for life.
2.
Bang! A Universe Built for Life
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14.
Liquid on Titan and Enceladus
Continue traveling to the cold gas giant Saturn and its large moon, Titan. Watch a video featuring actual data taken by the Huygens Probe as it pierces the thick atmosphere and lands on the surface of this frozen world, and witness the surprising Earth-like structures this probe and its mother ship found on their journey to Saturn's moons.
14.
Liquid on Titan and Enceladus
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3.
A Star Is Born—Forming the Solar System
How do you make a planet? Look at what is currently known about the process by which our solar system's planets formed from billions of small planetesimals, as well as how this process left the universe teaming with asteroids and comets that play an important role in life on Earth.
3.
A Star Is Born—Forming the Solar System
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15.
Discovery of Extrasolar Planets
Is our solar system common or rare? As you investigate planets orbiting around other stars, learn how the use of adaptive optics allows extrasolar planetary scientists to discover new alien solar systems with ground telescopes, and explore the three main ways astronomers detect planets: small "radio velocity wobbles," "transits," and direct imaging.
15.
Discovery of Extrasolar Planets
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4.
The Early Earth and Its Moon
Follow a series of mishaps and cataclysmic events that set the stage for early Earth to finally flourish with life after 650 million years. Learn how a hot core, a large moon, and other properties on Earth helped lead to an active biosphere.
4.
The Early Earth and Its Moon
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16.
The Kepler Spacecraft's Planets
The Kepler mission is changing everything we know about extrasolar planets. Learn how this supersensitive-imaging instrument works to monitor 157,000 stars continuously for years and what it has uncovered since launching in 2009. But first, review the transit effect created when a parent star crosses its orbiting planet.
16.
The Kepler Spacecraft's Planets
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5.
Impacts—Bringers of Death … or Life?
Delve into the Late Heavy Bombardment period that kept Earth stuck in a lifeless state for 650 million years, then watch an animation demonstrating the K-T impact event that wiped out the dinosaurs. Consider whether it's possible to protect ourselves from asteroids hurtling toward Earth—and why Hollywood gets it all wrong.
5.
Impacts—Bringers of Death … or Life?
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17.
A Tour of Exotic Alien Solar Systems
Based on data from Kepler, there are thought to be four main classes of transiting planets: hot Jupiters, hot Neptunes, super-Earths, and Earth-like planets. In this lecture, you will look at detailed highlights of the most fascinating examples of each of these new classes of alien worlds, from most to least massive.
17.
A Tour of Exotic Alien Solar Systems
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6.
Evidence of the First Life on Earth
How has the Earth managed to stay within a moderate range of temperatures for billions of years, despite the atmosphere's wild fluctuations in oxygen? Study how convection, greenhouse gases, and the carbon rock cycle contribute to a powerful system of checks and balances that keep Earth's climate consistent with supporting life. Also, meet some of Earth's earliest life.
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Evidence of the First Life on Earth
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18.
Extraterrestrial Intelligent Life
How common is simple life is in our universe? What about intelligent life? Start to answer these questions by estimating the prevalence of prokaryotic single-celled microbes and reviewing the process of evolution. Evaluate arguments in the book Rare Earth by Ward and Brownlee claiming that while microbial life is common, only Earth has intelligent life. Finally, touch on how aliens might appear.
18.
Extraterrestrial Intelligent Life
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7.
Common Themes for All Life on Earth
Now that you have covered the key elements necessary for life to exist, take a closer look at the things all life on Earth shares. Learn why the Biosphere 2 experiment in the 1990s failed, examine the behavior of microbes—the most important constituents of our biosphere—and trace life back to your universal ancestor.
7.
Common Themes for All Life on Earth
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19.
SETI—The Search for Intelligent Life
In a lecture that "skims right on the edge of science fact and science fiction," delve into the search for extraterrestrial life, or SETI, as the method used to gauge the likelihood of intelligent communicating civilizations is known. Look closely at the Drake Equation—the mathematical rubric commonly used in the field of SETI—and consider the challenge of communicating across our enormous galaxy.
19.
SETI—The Search for Intelligent Life
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8.
Origin of Terrestrial Life
For something to be "living," it generally must use energy to drive chemical reactions, be capable of reproduction, and undergo some degree of evolution. Sort through science's best educated guesses for how and why life sprang from nonliving matter, including lessons from the groundbreaking Miller-Urey experiment. Watch an animation of protocells growing and splitting to replicate genetic information.
8.
Origin of Terrestrial Life
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20.
The Fermi Paradox—Where Is Everyone?
After 50 years of SETI, we have zero hard evidence of alien civilizations, "cosmic wanderlust" resulting in Earth visitations, or UFOs being extraterrestrial in nature, despite—or perhaps because of—the expansiveness of the galaxy. Speculate on reasons for, and solutions to, this so-called Fermi Paradox.
20.
The Fermi Paradox—Where Is Everyone?
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9.
Astrobiology—Life beyond Earth
Why is liquid water so important? Why do icebergs float? After quickly reviewing what you have learned about the requirements for terrestrial life, take a closer look at the "liquid water carbon chemistry juggernaut," which allows organic life to thrive on Earth. Consider whether other liquids could operate as solvents for life.
9.
Astrobiology—Life beyond Earth
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21.
Space Travel—A Reality Check
Space is so vast that inventing a method of faster-than-light travel is the only way humans could conceivably travel the cosmos conveniently. How hard is space travel, really? In this mind-bending lecture, review the obstacles to space travel and consider their theoretical solutions—from combining matter and antimatter into energy, to taking "short cuts" via warp drive and wormholes.
21.
Space Travel—A Reality Check
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10.
Has Mars Always Been Dead?
Mars ranks as NASA's number one priority in the search for exolife. Here, you delve into why Mars is so intriguing to astrobiologists and what the search has found to date. Start with a comparison of Mars and the Earth, then watch the first-ever observation of water ice on Mars sublimating into vapor.
10.
Has Mars Always Been Dead?
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22.
Terraforming a Planet
Terraforming is a new scientific concept whereby an uninhabitable planetary environment is engineered to become more Earth-like to support human life. Explore how this complex process would play out on the two planets considered potential candidates, Mars and Venus, to fully understand the individual steps involved and the technologies necessary to achieve those steps.
22.
Terraforming a Planet
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11.
Evidence for Fossilized Life from Mars
In 1996, NASA claimed to have found evidence of past life on Mars inside an unassuming meteor. Evaluate the three points scientists gave in support of the microbes being Martian in origin to determine their validity. Then, learn about the theory of panspermia and meet the water bear, a tiny animal capable of surviving the extreme conditions of outer space.
11.
Evidence for Fossilized Life from Mars
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23.
The Future of Terrestrial Life
Professor Close highlights why we shouldn't be complacent about the long-term viability of Earth and presents the timescale in which humans will need to leave Earth or become vulnerable to extinction. Inspect historical evidence indicating that Earth is warming, and learn what will happen to the atmosphere in the future.
23.
The Future of Terrestrial Life
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12.
Could Life Ever Have Existed on Venus?
Venus is the closest planet to the Earth and the next planet moving toward the sun, so it is a logical place to look for life. However, Venus is extremely hot and dry. Could life ever have existed? Explore the nightmarish conditions on Venus and learn why all the water vanished.
12.
Could Life Ever Have Existed on Venus?
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24.
The Search for Another Earth
Now that you've seen why humanity will eventually have to leave Earth, consider astronomers' next steps, challenges, and planned missions. Examine why specialized optical systems called coronagraphs are necessary to detect habitable Earths, and how the use of direct imaging spectra is crucial to identifying whether the biomarkers of life are present on other worlds.
24.
The Search for Another Earth
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