Nat Geo_Hubble Trouble
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00:00One incredible device has made us look again at everything in the night sky.
00:07It shows the heavens in stunning clarity.
00:11It captures the birth of planets and the death of stars.
00:16It transports us back to the dawn of time to witness the creation of the cosmos.
00:25The Hubble Space Telescope has revolutionized the way we look and think about the universe
00:31and our place in it.
00:35The Hubblecast highlights the latest discoveries of the world´s most recognized and prized space observatory.
00:51This is the Cat´s Eye Nebula.
00:54It´s over 17,000 trillion miles from Earth.
00:59But we see its astonishing beauty thanks to one extraordinary telescope.
01:05Hubble.
01:08A giant gas cloud appears in breathtaking detail.
01:14We track the weather on Mars and study the atmosphere of a planet 150 light-years from Earth.
01:22Hubble shows us the universe in a new light.
01:26It´s a flagship of our fleet, plain and simple.
01:30We humans have always been fascinated by the stars above.
01:35And the world´s greatest telescope delivers them in revolutionary clarity
01:40because it´s in orbit 300 miles above us, free from all the distortion of Earth.
01:48The Hubblecast highlights the latest discoveries of the world´s most recognized and prized space observatory.
01:53When a distant star emits a beam of light, it launches it on a journey across unimaginable distances.
02:00The light travels at 186,000 miles a second across the cold, clean clarity of space.
02:09For 12 billion years, it can hurdle towards a final target, our eyes.
02:14But in the last 500th of a second, the light slams straight into Earth´s atmosphere.
02:23Above our heads, the air disrupts the passage of starlight.
02:28We see the distortion every time we look up at the night sky.
02:33The stars themselves don´t twinkle. It´s the air.
02:38Mountain air is thinner, drier, cleaner, so telescopes on lofty peaks can get a crisper image.
02:45But they´re still not high enough.
02:48To truly see the stars in crystal clarity, to try to divine the size and age of the universe,
02:55scientists need a whole new type of telescope.
02:59One far above the smog, the dust and the air itself.
03:05It was clear to the entire astronomical community that to make progress in that field, it was necessary to go to space.
03:14A giant telescope in orbit will capture the light fresh from the stars themselves.
03:19It will also test the limits of Earth-bound engineering.
03:24Dominic Tenorelli is there from the start.
03:27There were several of us who took it as a personal responsibility
03:31to make sure that we were going to provide the finest telescope that had ever been built.
03:37Hubble is one of the 20th century´s greatest feats of engineering.
03:42The final design combines 400,000 components and 26,000 miles of wiring in a telescope the size of a school bus.
03:53It was going to be one of the largest telescopes that we had on the planet, but only now flying above the clouds.
04:02Lockheed´s Jim Crocker remembers the key challenges Hubble´s engineers had to tackle.
04:07How good the optics are, how big the optics are and how stable you can hold them.
04:13Those three things really set the limit to what Hubble could accomplish.
04:18The first major design hurdle is the mirrors at the telescope´s core.
04:23Hubble is a reflecting telescope.
04:26It collects photons of light from distant stars using a giant concave mirror.
04:34The light gathered by the first mirror then bounces on to a second smaller convex one.
04:40This in turn reflects it back through a hole to form a focused bright image.
04:48Constructing these light collecting optics is a Herculean task.
04:54It takes engineers four million man hours to design and build the mirrors.
05:00The optics were the heart of the telescope.
05:03Everything depended on the quality of the optics and the preciseness of its prescription.
05:12The mirror´s weight must be kept to a minimum.
05:15So they set the glass in a sandwiched honeycomb structure.
05:20This drops the weight from 8,000 pounds to 1,800, but keeps it strong enough to withstand blast-off.
05:29For extra precision, they shape the 94-inch wide main mirror using a pioneering computer-controlled rig.
05:38The rig carefully polishes the block of glass into the smoothest large surface ever made.
05:46If the mirror was the size of North America, the tallest bumps on its surface would be just inches high.
05:53The telescope will sit above Earth´s murky atmosphere,
05:57allowing the precise mirror to make a quantum leap in observing power.
06:01Once Hubble is launched, it will reveal 100 times more detail than giant ground-based telescopes.
06:08But that precision will be wasted if the space telescope itself isn´t held rock steady.
06:14Stability is key.
06:17If you think about it, when you hold your camera,
06:20the camera has to be very still when you take a picture so it doesn´t blur.
06:25And if you have a big telephoto lens,
06:29and if you have a big telephoto lens on the front of the camera,
06:32you have to be even more stable in holding it.
06:38The design team turns to a high-grade substance to achieve maximum stability.
06:44Graphite epoxy.
06:46They use it for the struts and supports that hold Hubble´s mirrors in place.
06:52When Hubble was designed, graphite epoxy was cutting edge in space engineering.
06:57Today you´ll find it in many tennis rackets and golf clubs.
07:02The rigidity and lightness that make it ideal for sports are also key to Hubble.
07:08But graphite epoxy´s real value lies in how it reacts to temperature changes.
07:14In orbit, Hubble travels in and out of the Earth´s shadow 16 times a day.
07:20As it does so, the temperature changes by more than 100 degrees Fahrenheit.
07:26Most materials expand or contract when heated or cooled.
07:31But the graphite epoxy structure will deform by only a thirteenth of the amount that a steel version would.
07:40It will hardly warp or flex, and so will keep the mirrors perfectly aligned.
07:46For added protection, the entire telescope is wrapped in reflective thermal blankets
07:52and dotted with 800 built-in heaters.
07:56They will keep Hubble´s core within one degree of room temperature.
08:02As you go from day to night, these heaters turn on and off to control the temperature very, very accurately.
08:12The final challenge is to make sure that Hubble actually works.
08:17Finding the right star in the night sky using a powerful telescope in orbit
08:22makes finding a needle in a haystack look like child´s play.
08:27It´s like looking for one particular window with a high-powered zoom lens.
08:32If you can´t see the wider picture, you have no way of knowing if you´re even looking in the right area.
08:38So the designers equip Hubble´s guidance computer with a map of 15 million guide stars.
08:47Razor-sharp ridges inside the telescope tube will block any stray light from the Sun, Earth or Moon.
08:54And this means that only light from the celestial targets will reach the cameras and other instruments behind the main mirror.
09:03Each element of Hubble´s design needs to work flawlessly for it to succeed.
09:10The telescope´s prime goal is to build on the work of the man it´s named after,
09:14Edwin Hubble.
09:16He launched a revolution in astronomy and continues to inspire modern scientists,
09:22such as the Carnegie Institute´s Wendy Friedman.
09:25Edwin Hubble was no doubt the greatest astronomer of the 20th century.
09:31One of the most remarkable astronomers of all time.
09:34In the 1920s, Hubble carefully measured the huge distances of space using giant telescopes in California.
09:41And his results shocked the world.
09:45There were other galaxies outside the Milky Way, and almost all of them were flying away from us.
09:53Hubble discovered that the Universe was bigger than anyone had thought and was getting ever larger.
10:02Hubble´s breakthrough was enormously revolutionary.
10:05It completely changed the perception of the Universe that we live in.
10:08But even using the largest telescope on Earth, Hubble couldn´t measure the exact size and age of the Universe.
10:16Now, decades later, his mechanical namesake will pick up where he left off.
10:25CDR, Houston. Good morning, Lauren. You´re loud and clear.
10:28April 24th, 1990.
10:31The Space Shuttle Discovery stands on the launch pad.
10:34Aboard is the Hubble Space Telescope.
10:37Not including the launch itself, the Hubble has cost $2 billion to design and build.
10:43All that money, almost two decades of hard work, and countless reputations, depend on the Space Telescope being a success.
10:525, 4, 3, 2, 1, and liftoff!
10:58Discovery blasts off and carries Hubble 380 miles up.
11:03The shuttle bay doors open.
11:06The communication dishes deploy.
11:09The solar panels unfurl.
11:12The shuttle gently lets go and powers away.
11:19Hubble is in orbit.
11:28Finally, after weeks of testing, the telescope takes its first image.
11:33That was a joy. That was a joy to see first light. We had a telescope up there.
11:40The shot isn´t beautiful. Just two lonely stars.
11:45It looks promising.
11:48But the elation doesn´t last long.
11:51Now, within 24 hours, we knew we had a problem.
11:55Instead of pinpricks of light, the stars are fuzzy.
12:00Detailed analysis shows that even above the atmosphere, there´s still something blurring the images.
12:06I think we were so stunned, we really didn´t realize at first the extent of the problem.
12:15The images are out of focus, and the cause is devastatingly simple.
12:21Hubble is nearsighted.
12:24The conclusion we´ve come to from that is that there´s a significant spherical aberration that appears to be present in the optics.
12:32The vast primary concave mirror is too flat.
12:38Its outer edge is two microns lower than it should be.
12:42The mirror was crowned a little too much away on the edges, about the thickness of one twentieth of a human hair.
12:50Now, that doesn´t sound like much, but in optical terms, it was enormous.
12:56How could this have happened?
12:59Engineers discovered that a piece of mirror-testing equipment had been wrongly assembled.
13:04One humble washer in the wrong place has wrecked Hubble´s accuracy.
13:09Hubble is not just nearsighted, it´s also shaky.
13:13The solar panels are unstable.
13:16Every time Hubble passes from day into night, the temperature change causes them to flex, jolting the entire satellite.
13:24Hubble is in crisis.
13:27The optics and the stability are both seriously flawed.
13:32It was just devastating to have worked so long on something, and it´s not going anywhere.
13:37You work so long on something and then see your hope shattered.
13:43Some science is still possible.
13:46Computers clean up some of the images.
13:49But the detailed astronomy that the space telescope has been built for will not be possible.
13:55Hubble´s primary mission, the Grand Survey of the Size and Age of the Universe, cannot even be attempted.
14:03For our own project, which was called the Hubble Key Project, to measure the distance scale, it was almost a complete disaster.
14:11People can make mistakes.
14:14But when you found out the history of the problem, that´s when you got angry.
14:20Overnight, Hubble goes from being science´s next big thing to astronomy´s techno-turkey.
14:27Coming on the heels, if you will, of the Challenger accident, it looked like NASA had lost the right stuff.
14:35NASA must fix Hubble.
14:39A team of astronauts will have to travel up to the telescope and attempt a repair in orbit.
14:45They need to fit a series of lenses or mirrors that will cancel out the flaw in the main mirror.
14:51They should work like a pair of glasses for Hubble.
14:54It sounds simple, putting glasses on something, but these glasses were very, very difficult to build.
15:01The lenses were the size of nickels, dimes and quarters.
15:05And they had a very unusual shape. It´s called an anamorphic asphere on a toroidal blank.
15:11What that means is they look like potato chips.
15:14Four contractors race to produce the lenses.
15:18Only one succeeds.
15:21But there is still the problem of how to fit them.
15:24The razor-sharp ridges inside Hubble mean that astronauts cannot enter the telescope tube.
15:31Then Crocker has a eureka moment while visiting colleagues in Germany.
15:36I was taking a shower and in Germany they have these showers that are on a rod.
15:42And so I slid it up and basically put it in position and then I realized what the fix could be.
15:49Like the shower head, a system of rods could slide the lenses into position.
15:55A robotic arm would then angle them into the correct alignment.
16:01With the correction device in construction, NASA assembles an elite team of astronauts to install it in Hubble.
16:09It includes spacewalk specialist Jeff Hoffman.
16:13The pressure is intense.
16:15We were told face-to-face by the NASA administrator at the time who said,
16:20you know, that´s the only thing that I want to tell you guys before you go up for your mission. Fix Hubble.
16:25The astronauts embark on 12 months of grueling training.
16:30Working alongside them is Hubble engineer Mike Weiss.
16:34It was extremely challenging, probably the most challenging shuttle mission ever attempted.
16:39The agency had never attempted five back-to-back spacewalks. Never.
16:44While the astronauts train, Weiss has to ensure that all the new hardware will survive the shock of a shuttle launch and the rigors of life in orbit.
16:55The men and machinery take on a barrage of tests.
16:59We are standing in the middle of the envy of every teenager in the world, a giant acoustic test facility.
17:07We take every piece of hardware that we fly, attach it to the floor, and with the speakers you see in this facility,
17:14hit it with two minutes of acoustic energy, about 150 decibels.
17:18The two minutes is what it sees in flight.
17:22There were many different types of training.
17:25For the spacewalks, certainly the most important is the underwater training tank.
17:31We were doing some very, very fine work.
17:33I mean fine in the sense of Swiss clockmakers type of fine, which is not easy in a space suit.
17:44We are looking at a very, very large thermal vacuum facility.
17:48The thermal vacuum facility is where we put our hardware, pull a vacuum on it, cool it down, heat it up,
17:55make sure it can survive those harsh environments that it sees in space.
17:59We got incredible cooperation from everybody, much more so than in a typical mission.
18:05Everybody was working together on it. Everybody was rooting for us.
18:09This is our centrifuge test facility.
18:12Basically what we do is we hang the payload off the other end, spin it up,
18:16develop the acceleration loads that we'd see in flight,
18:19and just prove that we can survive that type of environment.
18:22If we needed to, we could develop 30Gs.
18:24For a full year, the team and the equipment are put through their paces.
18:29There will be no second chances on this mission.
18:34This was a very intense training period.
18:39And it's what you sign up for.
18:42It really made us a very tight-knit group.
18:46December 2, 1919.
18:49The crew boards the shuttle Endeavour.
18:52The world watches as they blast off toward the stricken Hubble.
18:58OK, it's daylight outside, so you might want to put your visors down.
19:03Each of five spacewalks tackles a set task.
19:07To carry out maintenance work, to replace the faulty solar panels,
19:12and to install new equipment.
19:14Working in spacesuits and zero-gravity isn't easy.
19:18But there are some upsides.
19:21We were moving around pieces of equipment the size and the shape of a grand piano.
19:26No way could I have moved that around on the Earth.
19:29You know, you feel like Superman up there.
19:33They fit the new correction device successfully.
19:37And they're ready to go.
19:39But not everything goes smoothly.
19:42One of the faulty solar panels is too warped to roll back into its original holder.
19:47The astronauts jettison it into space.
19:53It started to somersault, and we were just mesmerized.
19:57It was flapping, you know, it was like the wings of some giant prehistoric bird.
20:02But the most difficult part was to get it to land.
20:05It was like the wings of some giant prehistoric bird.
20:08But the most challenging surprise comes as Hoffman tries to close one of Hubble's equipment bay doors.
20:15It's not closing. The doors aren't closing right.
20:18Like, if I'm just doing it at the top, I can get them to come together.
20:23This was something we had done dozens of times underwater.
20:27But when I went to close them, oh, it didn't close right.
20:31The effects of zero gravity have deformed the door.
20:36If it isn't shut, the telescope won't be optically sealed.
20:40All future observations will be ruined.
20:44It was a potentially fatal problem. You'll basically lose the telescope.
20:49Another astronaut joins Hoffman at the door.
20:53Between them, they can hold it closed.
20:56But then neither has a free hand to lock it shut.
20:58We came up with an idea of adapting one of our tools in a completely non-standard manner,
21:07but basically to work as an extra hand.
21:10Their plan is to hold the door shut with a strapping device, leaving them free to close the locks.
21:17They suggest the idea to ground control.
21:20I think they had visions of us wrapping this tool all the way around Hubble and cinching it down,
21:25and Hubble was going to collapse like an aluminum beer can.
21:29Finally, the flight director, I think, made a good call.
21:33He said, look, team, we sent these people up, they can see better than we can.
21:38Let's let them go ahead and do what they think needs to be done.
21:42The plan works.
21:45Mental ingenuity and some old-fashioned elbow grease get the door sealed.
21:51Hoffman's team returns to the shuttle.
21:54At 7 hours and 54 minutes, it clocks in as the second longest spacewalk in history.
22:01That's just a spectacular vantage point.
22:04You're floating in the middle of nowhere, 50 feet above the shuttle, 400 miles above the Earth,
22:11sort of hanging between heaven and earth, so to speak.
22:14That's something I'll never forget.
22:17After 12 months of preparation and 11 dramatic days in space,
22:22Hoffman and his team accomplish their mission.
22:27The focus now shifts to the lenses of the correction device itself.
22:37As Endeavour touches down in Florida,
22:40the engineers at Hubble Headquarters prepare to take the make-or-break test image.
22:46December 13th, 1993.
22:50The astronauts who have installed a correction device on the flawed Hubble telescope return to Earth.
22:57Their work is done.
23:00Now, everyone waits for Hubble to beam down a test image.
23:05We had been told by everyone in the press that what we were doing was impossible.
23:10But when we did find out that it was possible,
23:13but when we did finally get the optics aligned and took a look at the first image, we were all stunned.
23:30They were better than we expected. They were better than we hoped.
23:34They were perfect.
23:36The mood was elation.
23:39Hubble had been fixed.
23:41The trouble with Hubble is over.
23:45The improvement is startling.
23:48All distortion is gone.
23:50The focus is perfect.
23:52Hubble begins unveiling celestial objects in breathtaking detail.
23:58The images that came down were spectacular.
24:01Distant galaxies, star formation regions.
24:04Nothing like that had ever been seen.
24:06It was incredibly exciting.
24:08The stability problem is also gone.
24:11Hubble is so steady that if the telescope were in Manhattan,
24:16it could keep a laser beam locked on a dime nearly 200 miles away in Boston.
24:22Well, now we knew we had a telescope up there that would perform how we originally wanted it to perform.
24:29The optics are performing perfectly, and Hubble's instruments start capturing flawless data.
24:34Hubble carries two cameras and two spectrographs.
24:38Each is designed for a specific type of observation.
24:41Since launch, Hubble has beamed down enough science data from these instruments to fill over 40,000 compact disks.
24:50Scientists around the world have used this information to transform the science of astronomy.
24:56Objects that have been studied for hundreds, if not thousands of years, are now seen in a new light.
25:03One of Hubble's greatest hits comes just months after the successful repair mission.
25:11Astronomers know a comet is about to crash into Jupiter.
25:15They point Hubble at the planet, prime it to capture the collision, and wait for the crash.
25:21Astrophysicist Mario Livio watches the historic event live.
25:30This is the first time anyone will witness a collision in space.
25:36Hubble really gave us a ringside view of that event.
25:41For us to have Hubble at the right time to watch that was extraordinarily exciting.
25:46And we could actually see the plumes as they were coming up in the atmosphere.
25:55The comet strikes with 600 times the force of the world's entire nuclear arsenal.
26:05And this event was taking place in Hubble's backyard.
26:09Jupiter is nearly half a billion miles away.
26:12The light it emits takes around 45 minutes to reach us.
26:17But when Hubble looks at another star on the other side of our galaxy,
26:21the light has taken thousands of years.
26:25When it looks at another galaxy on the other side of the universe,
26:29the light has traveled for billions of years to reach us.
26:33That's probably just as well.
26:36Because there are objects in the sky,
26:38that if they were closer, would destroy us in an instant.
26:43Black holes.
26:45These were massive stars that collapsed in on themselves as a result of their own gravity.
26:51They devour everything in their path, even light itself.
26:55So how can Hubble see something that is totally black?
27:00Hubble really does not see anything black.
27:03Hubble really does not see a black hole.
27:06You see the effects of the black hole on its surroundings.
27:10For example, we would see the disk of matter that is around that black hole.
27:16Or sometimes the presence of the black hole there would modify the orbits of the stars around it.
27:25If a giant black hole was bearing down on Earth,
27:28If a giant black hole was bearing down on Earth,
27:32there would be nothing we could do to stop it.
27:35The void would swallow the Sun and all its planets whole, us included.
27:41Thankfully, even in the vast reaches of space, such things are still rare.
27:47It takes the sheer power of Hubble to spot them within the cosmos.
27:52And it can also study less destructive objects that might make us rethink our place in the universe.
27:59Planets orbiting distant stars that might hold the ingredients needed for life.
28:06David Charbonneau explores one of them, known by the catchy little name of HD 209458b.
28:15In 1999, Charbonneau is still only a student at Harvard.
28:19When he starts studying the gassy planet, using a tiny telescope set up in a parking lot.
28:29There's only four inches in diameter.
28:32You could have bundled the entire observatory up and put it in the trunk of your car.
28:36The small telescope reveals that this planet's orbit carries it between its star and Earth.
28:43This means that starlight passes through its atmosphere.
28:46Opening it up for further tests.
28:49But Charbonneau's ground telescope wasn't up to this sort of work.
28:53In fact, the only device that could do the tests was the mighty Hubble.
28:59There was a huge shift to go from the little four inch telescope in a woodshed to the Hubble Space Telescope.
29:05Which is possibly the most powerful observatory that astronomers have ever built.
29:09Charbonneau uses a Hubble instrument called the STIS spectrograph.
29:13To detect what chemicals are in the planet's atmosphere.
29:17Like a prism, the spectrograph breaks down the light that has passed through the atmosphere into its constituent parts.
29:25Different substances emit different types of light.
29:29Each ray of light carries an imprint of the chemicals it has come from and passed through.
29:35And you may not realize it, but you see the way substances affect light as they pass through it.
29:41The way substances affect light every 4th of July.
29:49If you've ever been to a fireworks display, you might wait for a rocket to go up.
29:53And then you'll see this very distinct color of light.
29:57And that particular color of light, whether it's that particular green or red or white or blue,
30:03points to a particular chemical that's been used in the contents of that rocket.
30:07And so when you see that color of light, then you can figure out what chemical you're dealing with.
30:12Chemicals also absorb light, the same color they emit.
30:18The atmosphere around Charbonneau's planet absorbs a particular shade of the color yellow,
30:24which means there is sodium present.
30:27Follow-up Hubble studies show that the atmosphere also contains carbon, oxygen and perhaps even water.
30:34The vital ingredients for life as we know it.
30:38But the planet is heated to a scorching 1500 degrees.
30:43It seems an unlikely candidate for an alien homeworld.
30:47The Hubble is really in a class all its own in terms of being able to focus in and study the atmospheres of these very exotic extrasolar planets.
30:57In an area of space called the Orion Nebula, Hubble can see how planets are formed.
31:05The nebula is a giant gas cloud 30 light-years across.
31:10And inside it, hundreds of stars are being born.
31:16Discs of gas swirl around some of the stars.
31:20Inside the discs float tiny dust grains, grains that one day may clump together into a fledgling planet.
31:28Henry Throop of the Southwest Research Institute needs Hubble to test this theory.
31:34I was particularly interested in whether you could see the first stages of planet formation in the outer edges of these discs.
31:40We're looking at formation of planets. We're looking at answering the question of how unique we are.
31:45Conventional ground-based telescopes can hardly make the discs out.
31:50But the extremely high-resolution ACS camera on Hubble can see them clearly.
31:56And by tracking how the discs affect starlight, Throop can study the dust grains inside them.
32:02We can tell the difference in the grain size by how the light passes through them.
32:07The effect the dust grains have on starlight is the same as foam blocks on water waves.
32:16Now you can see these waves coming out in the water over here.
32:20They're radiating outward in much the same way that the light from the Orion Nebula is coming out.
32:26These blocks represent the dust grains in Orion.
32:30And we're going to send the light waves through, just like the light in Orion gets sent through the dust.
32:37Now what you can see here is the light, the waves, are traveling through the dust grains, the blocks here, and going outward.
32:47So we can see the waves as if they weren't blocked by anything.
32:50Throop believes larger particles will have a different effect.
32:56Now what you see here is these dust grains are blocking the light much more than the small grains were.
33:02It's just not transmitted through nearly as strongly.
33:05And that's exactly the same thing that we're seeing up in Orion.
33:08Up in space, Hubble sees the changing effect on the light as changes in color.
33:14Normally, the starlight coming through the dust appears red.
33:18That's because the dust grains block the red light less than the other colors.
33:23Its long wavelength means it can wriggle through.
33:27But the disks in Orion appear gray to Hubble.
33:31This means that the dust grains are getting bigger and blocking all of the colors of light.
33:36One day the grains in the disks may snowball into new planets, perhaps even one like Earth.
33:43Now, that's really the big question here. Are we unique? Is the Earth unique? Is the solar system unique? And where do we fit in?
33:49Ultimately, Hubble reminds us that Earth is just one tiny planet floating in the enormous reaches of space.
33:57But the pioneering telescope can also transport us back in time, back to the dawn of the universe itself.
34:06The Hubble Telescope works like a time machine.
34:10The starlight it sees has taken millions, sometimes billions of years to reach us.
34:16The events themselves happened before magic happened.
34:21The Hubble Telescope is the world's largest telescope.
34:25The starlight it sees has taken millions, sometimes billions of years to reach us.
34:32The events themselves happened before man had even evolved.
34:37The deeper into space Hubble searches, the further back in time it travels, and the fainter the stars and galaxies appear.
34:46And this poses a big question. Just how far back can Hubble see?
34:52Dr. Henry Ferguson's team decided to find out.
34:57These galaxies that we're seeing at the far distant reaches of the universe are very, very faint.
35:03And some of the faintest ones that we're seeing, we're seeing about one photon per week striking the human eye.
35:10So there's very, very few photons of light reaching us. And it just takes a lot of effort to collect that much light.
35:18There's no chance of seeing these galaxies in the night sky.
35:23Even Hubble struggles to pick out their dim light.
35:27To overcome the challenge, the team develops an innovative use for the space telescope.
35:33It's called a deep field, and it works just like photographing stars in the city.
35:40Taking the Hubble deep field is very much like trying to take a time exposure with a normal camera.
35:45You could just click the shutter and you wouldn't see anything, because you haven't let light get in for very long.
35:52If you want more light, you probably need more time.
35:56When you leave the camera's shutter open for a whole minute, it can collect and build the faint starlight into an image.
36:04Now if you do that in a city, with lots of bright lights around you, in the final image you might see a few dozen stars.
36:10If you get out to a cold mountain top, you'll see a lot of stars.
36:15And if you do it with a big telescope, you'll start to see distant galaxies.
36:20The deep field plan is inventive, but risky.
36:24Over a week of Hubble's highly sought after time will be spent taking images of one blank, boring spot in the sky.
36:33The team picks a dark area with no bright nearby stars.
36:37They have to avoid anything that would mask the dim light coming from distant galaxies.
36:43But no one really knows what they're going to find out there.
36:48There wasn't very much a sense of fishing with the Hubble deep field.
36:52It's just not obvious what you're going to find.
36:57Over ten days, Hubble takes more than 300 images of a single spot in the sky.
37:03Each only captures minute traces of light.
37:07But layer one on top of another, and empty space soon fills up.
37:14On one snowy morning when the people were able to finally gather around a computer screen and put up the images,
37:22that was extremely exciting.
37:24One of the memorable moments, certainly in my career.
37:27It might not be one of Hubble's prettiest pictures, but it's one of the most exciting.
37:33Its contents make it one of the most mind-blowing.
37:36The slice of sky that you're seeing in the Hubble deep field is about the size of a grain of sand held at arm's length.
37:43It's this tiny, tiny spot on the sky.
37:46And yet when you blow that up with a telescope like Hubble, there are 3,000 galaxies in that tiny grain of sand.
37:53Each galaxy has anywhere from a billion to a hundred billion stars in it.
37:59Every sliver of the sky contains this vast profusion of early galaxies.
38:07They're nothing like our own galaxy.
38:10Yet cosmologists believe that they eventually combined to produce galaxies like our Milky Way.
38:18Subsequent deep field surveys probe even further back.
38:21The deepest so far is the Ultra Deep Field.
38:25It combines 800 individual shots into one image, twice as many as the original deep field.
38:34Its final image reveals the universe's oldest stars, 13 billion light years from Earth,
38:42about 2 billion further than the first deep field.
38:45Ancient stars like these forged the matter that makes up Earth and us humans.
38:50But Hubble's most startling data finally allows us to close in on the event that created all the matter in the universe.
38:58The Big Bang.
39:01Ever since that titanic explosion, all the structures and galaxies of the universe have been flying apart.
39:08Measure how fast, and you can track back to the moment the universe began.
39:16This was scientist Edwin Hubble's dream back in the 1930s.
39:21Now, Wendy Friedman can get precise results using the telescope named in his honor.
39:29She measures the distance from the Earth to the Big Bang.
39:32She can get precise results using the telescope named in his honor.
39:37She measures the distances by studying one particular type of star called Cepheids.
39:44All Cepheid stars have standard brightnesses, like street lamps.
39:49And like a string of street lamps, those which are close to us look bright, and those further away look dim.
39:57By measuring the brightness of a Cepheid star, you can calculate how far away it is.
40:05Friedman's team measures the brightness of 800 separate stars.
40:11She then calculates their relative speed and position.
40:17The results confirm that the universe is expanding.
40:21The galaxies are flying apart from one another.
40:25But if Friedman then plays this motion in reverse, she can calculate when all of the galaxies started out in one concentrated spot.
40:34An event we call the Big Bang.
40:40Before the Hubble Space Telescope, we didn't know whether the universe was 10 billion years old or whether it was 20 billion years old.
40:48There was a factor of two discrepancy, and when you think of that, that's huge.
40:52The Hubble's accuracy has allowed Friedman to calculate the date of the Big Bang.
40:58Time, the universe, and everything in it, exploded into existence 13.7 billion years ago.
41:07In terms of our understanding these questions of the expansion of the universe and its composition,
41:13the Hubble Space Telescope has been probably the most powerful tool we have ever had access to.
41:21In dating the Big Bang, Hubble has achieved its greatest goal.
41:27And now, it's tackling new challenges.
41:32One is a mysterious substance that is holding everything in the universe together.
41:38It's invisible, but Hubble is still able to find it.
41:43In the years since its launch, the Hubble Telescope has achieved its main goal.
41:49It has let us calculate the age of the universe.
41:53But in the process, it has found substances that the scientists haven't even seen before.
42:00One new challenge is called dark matter.
42:03It's an unknown material that seems to be binding everything together.
42:07We can't see it and don't know what it's made of.
42:11But Richard Massey of Caltech is using Hubble to study it.
42:15Dark matter is kind of embarrassing, really.
42:18The fact that it makes up the vast majority of the universe,
42:22but we still know absolutely nothing about it is really rather embarrassing.
42:27But despite this, the cosmologists are certain that dark matter must exist.
42:33The cosmologists are certain that dark matter must exist.
42:37If it didn't, galaxies like our own Milky Way would rip themselves apart.
42:43So you can think of a galaxy rather like a pizza base.
42:46Both are spinning around, but they have something holding them together, keep all their parts in one place.
42:52In the case of the pizza, it's the stickiness of the dough that keeps it together.
42:57For the galaxy, it's the gravity of all of its different bits that hold it together.
43:00The problem is that when you look at your average galaxy,
43:03there doesn't seem to be enough matter in it to hold it together.
43:06Not enough matter and not enough gravity.
43:08So you'd expect it, when it starts spinning, to fall apart, just like a pizza base with holes in it.
43:14So a galaxy doesn't fall apart because there's an extra secret ingredient in there.
43:18And that's the dark matter. It's this additional mass that holds it all together.
43:22Dark matter emits no light. It's invisible, even to Hubble.
43:27But its gravity does bend the light from stars.
43:31Hubble can detect this bending. It's an effect called gravitational lensing.
43:36And it works like a magnifying glass.
43:39Words seen through a magnifying glass appear slightly bigger, but also distorted at the edges.
43:44The lines which were straight curl up.
43:47If you couldn't see the magnifying glass, you would still know it was there because it bends the letters.
43:53In the same way, Massey can detect the dark matter because it bends the starlight.
43:58He can see its distorting effect within some of the super-high-res Hubble images.
44:04A map of the dark matter actually looks very much like a map of a country,
44:09seen at night from a satellite in orbit.
44:11You can just see the strings of lights lighting up along roads and highways.
44:16And in between that, there's these vast, empty voids in the universe.
44:19The dark matter plays a vital role in building the world we live in.
44:24The dark matter forms, if you like, a scaffolding of structures.
44:29And it's crucial to the formation of stars and planets because the ordinary material that we're made of,
44:34all that can only form inside this dark matter scaffolding.
44:37Hubble reveals where dark matter exists.
44:41And it will continue to discover more about this mysterious substance.
44:45It will do so with upgraded instruments.
44:50The team at Goddard Space Flight Center is testing a new set of hardware,
44:55due to be installed on Hubble in 2008.
44:59We keep sending astronauts back to Hubble because when we put a new instrument on this telescope,
45:05it's like a brand new telescope.
45:07It can be ten times or a hundred times more powerful than it was before.
45:12The 2008 servicing mission will be Hubble's last.
45:17It's expected to keep working until about 2013.
45:21But eventually, its systems will fail.
45:25It will slip out of orbit and plummet back down to Earth.
45:29By then, however, its successor, the James Webb Space Telescope,
45:35will have joined it in orbit.
45:37Its 21-foot main mirror will be almost six times the size of Hubble's,
45:42allowing it to detect even fainter objects.
45:46But even when the Hubble Telescope is long gone,
45:50its legacy will live on.
45:54When you're on a project like this, and you're so passionate about it,
45:59you give your heart and your soul and your life to it.
46:03You give your heart and your soul and your life to the project.
46:09One of the greatest thrills that I'll ever have was to touch Hubble with these hands, you know, in space.
46:16It doesn't get much better than that.
46:18Hubble is one of the most important scientific instruments that has ever existed.
46:24And for some problems, it's the most important scientific instrument that has ever existed.
46:29Hubble's supreme achievement has been to change the way we look at the night sky.
46:36Its images give us an inkling of the scale and majesty of the heavens above.
46:41It has shown us distant planets and galaxies,
46:46found unknown matter and structures,
46:50and measured the age of the cosmos.
46:52It has changed our understanding of the universe and our place in it.