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00:00In the quest to explore the universe, our greatest ally is the Hubble Space Telescope.
00:10No scientific instrument in history has revealed so much or taken us so far.
00:20Perched above the distorting veil of Earth's atmosphere, Hubble sees what we cannot.
00:26Using vivid color to represent scientific data, Hubble paints pictures of unprecedented
00:31clarity, pictures that bridge the domains of art and science, and form a direct link
00:37the most powerful forces in nature and the human spirit.
01:07For as long as there have been people to look up, the night sky has been an endless source
01:31of wonder and mystery.
01:39It's easy to understand why.
01:43Like so much of the natural world, the stars, planets and other objects that fill the heavens
01:48exist in plain sight.
01:52But unlike just about anything else, they also exist beyond human reach.
02:04For our ancestors, this made the night sky a supernatural place, a place they eventually
02:12filled with mythical beasts and the gods.
02:18In time, this mythical view gave way to a more mathematical understanding of the sky.
02:25But the stars remained as mysterious and distant as ever.
02:34Unable to touch the heavens, humans eventually came up with an ingenious device to bring
02:40the heavens closer.
02:43It's called the telescope.
02:53Although telescopes today vary in size and complexity, the underlying principle is always
02:58the same.
03:00At its heart, a telescope is a device that magnifies our sight.
03:05Using mirrors or lenses, and often both, it makes distant objects appear closer.
03:11In this way, the telescope can reveal details about our universe that are inaccessible to
03:16the naked eye.
03:18Equally important, a telescope is like a funnel for light.
03:23It's wider at one end, and it grows progressively narrower as it gathers and concentrates far
03:29more light than would otherwise pass through the narrow pupil of the human eye.
03:35And this is why, through a telescope, objects that are dim appear brighter, while objects
03:40that are too faint to be seen at all emerge from the shadows.
03:49Because it extends the power of the human eye, the telescope was the tool that finally
03:54allowed astronomers to see what kind of universe we live in.
03:59As it turns out, it's a far larger and deeper universe than our ancestors ever imagined.
04:09It was only after the telescope was invented that people began to grasp that our entire
04:14world is just one planet among many, and that our sun, in turn, is just one star in a galaxy
04:26we call the Milky Way, a galaxy that holds a hundred million times the number of stars
04:34that can be seen with the naked eye.
04:40Thanks to the telescope, the Milky Way was, itself, revealed to be just one among billions
04:46of other galaxies, great islands of matter and light adrift in a cosmic ocean that is
04:53as vast as it is dark.
05:05But for all the power the telescope brings to the study of our universe, for nearly four
05:10hundred years it was limited by a factor beyond human control.
05:20For Earth-bound stargazers, the atmosphere is a fickle window on the cosmos.
05:29Its constantly shifting patterns mean that our exploration of the night sky is conducted
05:35at the whim of the weather.
05:40Even on the clearest night, the air above Earth is always in motion, like a turbulent
05:46cauldron of invisible soup.
05:52This ever-changing turbulence bends and distorts the incoming light of stars and galaxies.
06:01Even for the biggest and best telescopes in the world, the fine details of our universe
06:06are blurred away.
06:12If the effects of Earth's atmosphere could somehow be eliminated, we would improve our
06:18view of the universe a hundredfold.
06:24It would be the biggest single leap forward since the invention of the telescope.
06:4820.
06:50T-minus 20 seconds.
06:5215.
06:5412.
06:5611.
06:5810.
07:009.
07:028.
07:047.
07:064.
07:08We have a go for maintenance.
07:103.
07:122.
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07:16In 1990, humanity took that leap.
07:22The Hubble Space Telescope was lofted into orbit aboard the space shuttle Discovery.
07:34Lots of mirrors.
07:36Come and starboard nicely.
07:38A little bit more.
07:42Years in the making, the telescope was named in honour of Edwin Hubble, the celebrated
07:48American astronomer who first proved that galaxies exist and demonstrated that our universe
07:54is expanding.
07:56OK, we have a go for release.
07:58OK, Charlie.
08:00With its unique status as the first large telescope to operate outside the limits imposed
08:04by the atmosphere, astronomers hoped that Hubble's namesake would lead them to equally
08:10important discoveries.
08:12Houston, Discovery.
08:14Go ahead, Charlie.
08:16OK, Story.
08:18We've been taking marks.
08:20Residuals and ratios look good.
08:22And we'd like to go ahead and go to filter state.
08:26Expectations were running high.
08:28But what astronomers saw was not what they expected.
08:34Within days of Hubble's launch, it became obvious that the telescope could not see
08:39properly.
08:43Images that should have been crisp and detailed were blurry.
08:49The problem was soon identified.
08:53A slight but fatal flaw in Hubble's main mirror meant that it was unable to focus incoming
08:59light.
09:01The flaw had been introduced years before due to an error in the way the mirror was
09:07manufactured.
09:19It had gone unnoticed until the Hubble was already in orbit.
09:27Fortunately, the Hubble's disastrous debut came with a silver lining.
09:31Because the flaw in its mirror was so well understood, it was possible to craft a precise
09:37set of corrective optics.
09:39It was the astronomical equivalent of contact lenses.
09:43The result was spectacular.
10:01After its dramatic repair in December of 1993, the out-of-focus images that Hubble had been
10:19beaming down to Earth were replaced with views of breathtaking clarity.
10:25The pictures were not only better, they were the best astronomical images in history.
10:37For the first time since the invention of the telescope, astronomers had a new way
10:43of seeing the sky.
10:47One that would change our view of the universe forever.
10:51One that would change our view of the universe forever
10:55and fill our eyes with images of breathtaking beauty.
11:09The age of Hubble was underway.
11:21Hubblecast is produced by ESA, the European Southern Observatory.
11:29The Hubble mission is a project of international cooperation
11:33between NASA and the European Space Agency.
11:37Hubblecast is produced by ESA, the European Southern Observatory.
11:43The Hubble mission is a project of international cooperation
11:47between NASA and the European Space Agency.
11:53Sometimes the power of great art is the way it reveals the extraordinary within the ordinary.
11:59In the universe, there's nothing more ordinary than the death of an average star.
12:05An exceptional event becomes a scene of stirring beauty and rebirth.
12:36When a typical star runs out of energy, it cools and expands.
12:48Like a dying gasp, its outer layers are puffed outward into space,
12:54forming an expanding bubble of glowing gas.
12:58As the bubble grows more diffuse, the star's core is soon laid bare.
13:04It is now a tiny but intensely hot white dwarf star.
13:12The intense radiation it gives off energizes the expanding gas,
13:18which takes on the appearance of a luminous flower blossoming in space.
13:24It's called a planetary nebula because over a century ago,
13:30astronomers thought that the rounded shapes of objects like this looked like distant planets.
13:36For the Hubble, a planetary nebula offers more than an opportunity to study the universe.
13:42It is a place where the universe is absorbed by the stars.
13:46The Hubble mission is a project of international cooperation
13:50between NASA and the European Southern Observatory.
13:54The Hubble mission is a project of international cooperation
13:58between NASA and the European Southern Observatory.
14:02A planetary nebula offers more than an opportunity
14:06to study the final stages of a star's life.
14:12Each one of these colorful blossoms is unique,
14:16like a flower in a painter's still life.
14:26Among all the objects in the universe,
14:30these are the most beautiful and breathtaking images to Hubble's collection.
14:38And they are as diverse as they are beautiful.
14:44While some are symmetrical and round,
14:48others have turbulent and complex structures.
15:00Here, Hubble zooms in on one of the best examples.
15:06This planetary nebula resembles a bow tie.
15:16Its complexity tells us that the nebula likely formed
15:20in a series of ejections rather than one great outburst.
15:24This is also true of the Cat's Eye Nebula.
15:30Astronomers are still trying to decipher the events
15:34that formed this unusual object.
15:42The nebula is also the largest nebula in the universe.
15:46Near the center lies a series of intersecting shells
15:50that were ejected from the dying star over the past 1,000 years.
16:00Two jets of material have pierced these shells on opposite sides.
16:08Meanwhile, the nebula is the largest nebula in the universe.
16:12Meanwhile, these structures sit within
16:16a larger succession of concentric shells,
16:20which were released over thousands of years in regular bursts
16:24and which now make up the outer portions of the Cat's Eye.
16:32One theory that may help explain the unusual shape of the Cat's Eye
16:36holds that the nebula's central star
16:40is not a single white dwarf star,
16:44but two stars in a close orbit around each other.
16:52The idea that the presence of a second star
16:56can greatly complicate the shape of a planetary nebula
17:00is already known from another striking example.
17:04Astronomers call this object
17:08the Red Rectangle.
17:12Here it's believed that two stars are in orbit around each other,
17:16with a ring of dust surrounding both stars.
17:24When one star aged
17:28and began ejecting its outer layers into space,
17:32the ring became a waistband,
17:36forcing the material to move outward in two narrow cones,
17:40rather than in a spherical shell.
17:54The Hubble can also show us many other examples
17:59with an hourglass shape.
18:13The cause of this shape may not be the same in all cases.
18:19Different theories suggest that the gravity of a companion star,
18:23large planets or simply the interaction of gas with a star's magnetic field
18:27can explain their remarkable forms.
18:45Now, with Hubble's penetrating eye,
18:49astronomers are zeroing in on some of the largest and brightest examples,
18:53searching for clues to their formation and structure.
18:59They have good reason to be curious.
19:11A planetary nebula may be lovely to look at,
19:15but its true significance to us
19:19is the material it releases into space.
19:31The vivid color in this Hubble image
19:35corresponds to different atoms emitted by the dying star.
19:41In this case, the green light represents oxygen atoms,
19:45while the red color is due to nitrogen.
20:05The shells of stellar debris expelled by dying stars
20:09are not simply made of atoms, the basic building blocks of matter.
20:13They produce molecules, combinations of two or more atoms,
20:17including molecules that are instrumental to the origin and development of life.
20:25In the past, it was believed that such molecules would be destroyed
20:29by the intense radiation from the white dwarf at the center of each planetary nebula.
20:33With Hubble's help, astronomers have learned this is not the case.
20:43Among the best locations to study this exciting new development
20:47is the Helix Nebula.
20:51It is one of the nearest examples of a planetary nebula to Earth,
20:55which makes it an ideal target for the Hubble.
21:13The catch is
21:17that the Helix Nebula is large,
21:21much larger than the Hubble's field of view.
21:29To capture the entire nebula,
21:33Hubble took many separate images,
21:37which were combined to make a grand mosaic.
21:41Normally, there would not be enough room in Hubble's schedule
21:45to dedicate so much time to a single object.
21:49But a few years ago, a passing cloud of meteoroids
21:53forced the telescope to be placed in a protective mode.
21:57In order to shield its vulnerable primary mirror,
22:01Hubble kept its back to the incoming meteoroids
22:05and, as a result, had to stare at the same part of the sky for many hours.
22:09Fortunately, that part of the sky included the Helix Nebula.
22:21So what has Hubble found in this incredibly detailed view?
22:25Like other examples,
22:29we find the Helix Nebula is composed of nested structures,
22:33one inside the other,
22:37each blown off in different episodes during the central star's transition to a white dwarf.
22:41But because the Helix is so much nearer than other examples,
22:45astronomers can see much more detail within those structures
22:49and they have a better chance to explain how they formed.
22:57The Helix Nebula is the largest nebula in the solar system
23:01and the largest nebula in the solar system.
23:05One result of this investigation
23:09is that it's now clear the Helix contains a pair of gaseous discs
23:13that are tilted with respect to each other.
23:19This reconstruction shows what the Helix actually looks like
23:23when it's tilted.
23:27At this angle, the two discs are more obvious.
23:31But exactly why they are oriented in this way
23:35is not so easy to understand.
23:39Perhaps, as in so many cases,
23:43it's because the two discs are so close to each other
23:47that they can't see each other.
23:51Perhaps, as in so many cases,
23:55it's because the star at the center of the Helix
23:59is really two stars in one,
24:03which has complicated the structure of the expanding nebula.
24:09Even more intriguing than the Helix's overall shape
24:13are the many tiny clumps of material
24:18on the inner edge of the nebula's glowing rings.
24:22Astronomers have dubbed these objects
24:26cometary knots because they look so much like comets
24:30with their long streaming tails.
24:34These knots cannot be comets, however,
24:38because they are too large.
24:42Instead, it's believed they are denser clumps of material
24:46on the expanding shell of the Helix nebula.
24:50As the fast-moving stellar wind from the central star
24:54pushes outward on the nebula,
24:58the clumps are gradually exposed.
25:02But while the bright gas in much of the nebula
25:06is seared by the incredible heat of the central star,
25:10the molecules within the cometary knots remain protected.
25:14Here, carbon-bearing molecules can form and survive
25:18until they are eventually dispersed
25:22into interstellar space.
25:26This is why places like the Helix nebula are cosmic flowers
25:30in more ways than one. After they blossom,
25:34they not only dazzle us with their fleeting beauty,
25:38as Hubble has shown, they are also scattering the seeds of future life.
25:44Music
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26:32Next on OASIS-HD, Hubble's Canvas.
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