Journey Through The Solar System, Episode 01 - Our Star, The Sun - video Dailymotion

TV Hub

Watch Journey Through The Solar System, Episode 01 - Our Star, The Sun - TV Hub on Dailymotion

Transcript

00:00There are billions of stars in this galaxy called the Milky Way.

00:21Our star, the Sun, provides Earth organisms the energy to live and thrive.

00:27The Milky Way and our Sun circle the many planets of our solar system.

00:31And many as they are, the planets of our solar system are only a fraction of the mass of our Sun.

00:39And our Sun is a relatively small star in the universal scale.

00:57Music

01:26I'm Larry Ross, Director of Space Programs at the NASA Lewis Research Center in Cleveland, Ohio.

01:31And I'm your host for a series of 13 programs about the solar system.

01:36During the series, Journey Through the Solar System,

01:39we'll closely examine our corner of the universe, beginning at the Sun

01:44and moving outward to Mercury, Venus, Earth, the Moon, Jupiter, Saturn, and beyond.

01:52Let's begin with the Sun.

01:54Inside, its temperature could be as high as 25 million degrees.

01:59Pressures are estimated at a trillion pounds per square inch.

02:04Not many years ago, man knew little about the Sun.

02:08Now, from a motion picture called Partnership in Space Mission Helios,

02:13we have a clip about the past.

02:16Man has been fascinated by the Sun since the beginning.

02:24In ancient Britain, the Druids built a mysterious monument to it.

02:29In Egypt, the Sun was worshipped as a deity, and its passage from day to night was sanctified.

02:36The Mayans offered sacrifices to the Sun.

02:40For the Aztecs, it measured time.

02:43Some artists reproduced it in colorful stones and gold.

02:48Others captured its mysterious quality on canvas.

02:53Children see it as a smiling face.

02:58It is the source of bounty,

03:04and, as in parts of Africa, an element of devastation.

03:15Early man brought the Sun down from the sky to within his reach.

03:19Modern man journeys upward to understand it.

03:22Still, it remains a mystery.

03:25To many of the ancient peoples of Earth, the Sun was not the center of the solar system.

03:30Often, Earth was considered the center of the universe.

03:34An excerpt from the film called A View of the Sky explains these views.

03:39First, we had to come out of the darkness and shed a world of mysteries and superstitious beliefs.

03:53First, we had to fight our way upwards to clarity and light,

03:57to take the position we thought belonged to us, the very center of creation.

04:20It was Claudius Ptolemaeus who devised the first complete system of the universe.

04:26Ptolemy, who lived in Alexandria around 200 A.D., said this,

04:31The Earth is the center of the universe.

04:34The Sun and the planets turn around it in circles.

04:38Beyond the planets lie the celestial sphere of stars, which also turns around the Earth.

04:46It is not surprising that Ptolemy should have placed the Earth and with it himself at the center of the universe.

04:53This was dictated to him by the Greek image of man, Greek love and respect for the human body and mind.

05:05The Greek knew that man was beautiful and that he was a hero, knew it beyond all doubt.

05:12That is why he created gods after his own image.

05:16And that is why he could conceive of only one place for himself in the universe, at the very hub.

05:24Nor is it surprising that Ptolemy's heavenly bodies should have moved in circles.

05:30Greek love for harmony is reflected by a love for geometric forms and above all for roundness.

05:38Nor were the Greeks content with just loving roundness.

05:42In typical Greek fashion, they systematized their instinct and promoted roundness to a principle of nature.

05:49Aristotle, the father of Greek physics, proclaimed the circle the perfect form.

05:55Circular movement, the perfect movement.

06:02Since the planets were bodies of divine nature, they could move only in circles.

06:07This to the Greeks was so obvious that it became the supreme law of their astronomy.

06:14Ptolemy's contribution of course is far more than having applied Greek philosophy to the sky.

06:20His great achievement is having brought the essence of Greek thought and Greek culture into agreement with observation.

06:28Today we know that the family of planets, asteroids and comets circle the Sun.

06:33We also know that our star is like a grain of sand on an infinite beach.

06:43There are so many stars that we cannot truly count them all.

06:53What is the model of the structure of our Sun, this average-sized star?

06:58For that and how we study the Sun, let's go to the motion picture universe narrated by William Shatner.

07:07Some small stars do not travel in the company of other stars.

07:11Our own Sun is one of these.

07:17To the astronomer, the Sun is a vast laboratory for the detailed study of a star's structure and energy.

07:25The vertical tower of the solar observatory supports a heliostat mirror which tracks the Sun,

07:32gathers its rays and reflects them down a light shaft that extends 300 feet below ground.

07:44At the end of the shaft, the rays are cast back to an observing room

07:48where minute-by-minute changes across the face of the Sun are observed.

07:55Another mirror projects a light beam to a spectroscope,

08:00an instrument which splits the light into its component colors, a visible spectrum.

08:06The dark lines that cut across the spectrum band

08:09are produced by the radiation from the Sun's interior shining through its atmosphere.

08:15Each line is the signature of a chemical element such as sodium, iron, calcium.

08:21It is this array of lines that forms the code which describes the properties and motion of a star.

08:30By narrowing the view of the Sun to a single line of the spectrum,

08:33each level of the solar atmosphere can be photographed,

08:38and each reveals a remarkably different aspect.

08:44And with the addition of computer mapping and color processing

08:48that distinguishes levels of brightness,

08:51a detailed and multidimensional picture is obtained of a Sun

08:55undergoing dramatic and turbulent change.

09:02The Sun is a sphere of hot, seething gases and surges of radiation.

09:09Most of the light we get from the Sun comes from the thin, bright layer

09:12which defines its visible edge, the photosphere.

09:19Above it, the chromosphere, a region of flaming outbursts of gas,

09:25extends through a transition zone to the thin outer atmosphere of the corona.

09:33Once thought to be a quiet layer of the solar atmosphere,

09:37the corona is now revealed to be a region of dramatic large-scale changes and unexpected turbulence,

09:44with temperatures reaching millions of degrees.

09:49Deep beneath the Sun's atmospheric shell is the core, a violent nuclear furnace.

09:58Here, hydrogen is fused into helium,

10:01and in the process, some of the matter is converted into an enormous amount of energy.

10:08Radiating outward as a gas, it convects like a boiling liquid beneath the surface.

10:15The turbulent, bubbling motion is visible in the granular cells of the photosphere.

10:24Sunspots, regions of intense magnetic fields, appear on the surface,

10:31disappear in a few hours,

10:34or grow and persist for months in a mysterious 11-year cycle.

10:45The Sun rotates once in 27 days.

10:49Because its equatorial regions rotate faster than the polar caps,

10:53the shearing action in the gas contorts the magnetic field into tangled structures

10:59which give rise to the Sun's eruptive action.

11:05Shaped by these magnetic fields are the spectacular prominences,

11:10titanic streamers of gas reaching heights of more than half a million miles above the surface.

11:20The greatest explosions in the solar system are flares,

11:26intense bursts of light erupting with the force of billions of hydrogen bombs.

11:33They move at hundreds of miles a second,

11:36then, after minutes or hours, they fade away.

11:43The dark areas across the solar disk are coronal holes

11:48which may provide new clues to the Sun's interior

11:52and may be a source of the solar wind that blows outward to the farthest planets.

11:58On Earth, effects of these solar events are visible

12:03when auroras light up the dark Arctic sky and radio communication is disrupted.

12:17The Sun is an average, middle-aged star

12:21yet it will generate heat and light for billions of years to come

12:25as it has for five billion years past.

12:28It dominates the motions of all bodies in the solar system.

12:33Parts of that film are based on facts gathered during the three Skylab flights.

12:38The three Skylab missions of the 1970s gave us more knowledge of our Sun

12:43than in all the previous history of the solar system.

12:46Several telescopes were mounted aboard Skylab.

12:49The last crew of three men spent almost three months in space,

12:53much of that time observing the Sun and making thousands of pictures.

12:58Here's another clip from the Helios film.

13:01NASA recently took solar research a long stride forward with its Skylab program.

13:07It is the first of its kind in the world.

13:11NASA recently took solar research a long stride forward with its Skylab program.

13:17From its spectacular Touch and Go mission in June 1973,

13:22Skylab returned 25,000 unique portraits of the Sun.

13:27Scientists estimate that the Sun will burn for another five billion years.

13:33Its energy is created through nuclear fusion,

13:36but little else is known about the Sun's surface.

13:38Solar research is vital to our control over physical conditions on this planet.

13:44A better understanding of the Sun can help us cope with its menacing and dangerous aspects.

13:51During solar eruptions, compass needles on airplanes may swing erratically.

13:56Ship communications could black out.

13:58An ability to predict such eruptions would help prevent many tragedies.

14:02Storms, tornadoes, and hurricanes could be anticipated

14:05if we understood what is happening on the Sun's surface.

14:09The Helios mission is an important advance in the exploration of the Sun's activity.

14:15The results of Skylab came to us because telescopes and other instruments

14:20were carried above the Earth's interfering atmosphere.

14:23Many of the observations of the Sun made from Skylab

14:27are impossible to make from the ground because observation in parts of the spectrum is not possible.

14:32Dr. Richard Towsey explains an instrument called a spectroscope,

14:36which was used by Skylab's astronauts to dissect the Sun's ultraviolet light for study.

14:42Here's a small sample section of three of the spectra.

14:46On this scale, the whole spectrum would be about 100 feet long.

14:51This instrument is so powerful that it can separate nearly 100,000 different ultraviolet colors.

14:58Just what do all these black line images mean?

15:02Each atom produces its very own combination of spectral lines,

15:07just as each one of us has his own very special set of lines on his fingertips.

15:13So, if we have a complete list of atomic fingerprints,

15:18and we do have a tremendous data file on atomic spectra,

15:22we can tell exactly what atoms are present.

15:26More yet, by studying the intensities of the lines and their widths,

15:32we can say what the conditions were at the place on the Sun that the instrument was observing.

15:38We can calculate the temperature and the density.

15:42We can make a chemical analysis,

15:45and we can even derive the velocities of the atoms.

15:49This is what the Sun looks like in the extreme ultraviolet,

15:52and it is what the astronaut will see produced on his scope

15:57by the closed-loop extreme ultraviolet TV monitor that forms a part of the B instrument.

16:03The spectrograph slit is very tiny,

16:07something like this little red sliver, if you can see it.

16:12There are all sorts of different features and phenomena on the Sun's disk,

16:18and above its limb in the corona.

16:23These regions are the active areas,

16:28which are the spawning ground for solar flares.

16:32We can place the slit here,

16:35move it around,

16:37explore the structure of the region,

16:41and we can hope to be lucky enough to catch a flare.

16:47Or we can slew the ATM

16:51to point at this curious bright ring

16:55that surrounds most of the Sun

16:58and study the conditions at the limb.

17:01By moving the slit out,

17:03we can investigate the changes in the Sun's atmosphere

17:07at height intervals of about 500 miles,

17:10much as the meteorologist studies the Earth's atmosphere

17:14with sounding balloons.

17:17Why do we want to do all this?

17:20Because we still do not understand very well

17:24how the tremendous energy of the Sun escapes.

17:28The outer Sun's atmosphere, or corona,

17:31has a temperature of a million degrees,

17:34but inside the corona,

17:36the edge of the Sun is at only 4,000 degrees.

17:40We all know that heat flows from hot to cold,

17:44but never from cold to hot.

17:47Even more mysterious and closer to our lives

17:51is the solar cycle.

17:53Happily, the Sun is almost absolutely constant.

17:58But in the extreme ultraviolet and X-rays,

18:02the part studied by Skylab,

18:05it is anything but constant.

18:07In X-rays, every 11 years,

18:10it goes from almost nothing

18:11to very great intensities,

18:14and back to nothing.

18:16It is certain that the solar cycle

18:19has controlled the Earth's climatic changes

18:22from prehistoric times.

18:24Many of us think it has a lot to do

18:27with our monthly weather.

18:29In any case, the Sun is the object

18:32that is most important to life,

18:35and we must learn all we can about it.

18:39Dr. Towsey also described

18:41some of the early results of Skylab,

18:43just a few of the thousands of facts gathered.

18:46In the corona, the Sun's disk is dark,

18:50with most of the emission above the limb.

18:54The active regions on the disk itself

18:57show all kinds of fantastic forms,

19:00but loops are still present,

19:03and it is clear that magnetic fields

19:06extend way up into the corona.

19:09The large amount of information

19:12gathered during the Skylab mission

19:14is still being analyzed

19:16by scientists and astronomers.

19:18Hundreds of articles have been published

19:20in the scientific journals.

19:22Pictures tell us the story

19:24in a simpler way.

19:26In its quiet times,

19:28the Sun is far from calm.

19:30It is a churning ball of hot gases.

19:33Its surface has bubbling granules.

19:34Sunspots come and go.

19:42During its quiet periods,

19:44observations from Skylab and the ground

19:47led to a better understanding

19:49of the solar atmosphere,

19:51temperature, density,

19:53chemical composition,

19:55magnetic fields, and physics.

19:57From analysis of thousands of pictures

19:59of the Sun taken in the ultraviolet spectrum,

20:02we have gained new insights

20:04on how wave energy

20:06is transmitted upward

20:08to heat the outer layer of the Sun.

20:10Ultraviolet pictures were processed

20:12at color code differences.

20:17Green shows part of the Sun

20:19called the chromosphere

20:21with temperatures of about

20:2335,000 degrees Fahrenheit.

20:27Red reveals the hotter part

20:29of the chromosphere,

20:31which is almost 270,000 degrees Fahrenheit.

20:35Blue shows us the corona

20:38with temperatures around

20:402.5 million degrees Fahrenheit.

20:47The poles of the Sun

20:49were found to be different

20:51from the rest of the star.

20:53At the poles,

20:55the solar atmosphere is stretched upward

20:57and there are long-lived holes

20:59in the corona.

21:01At these holes,

21:02heat and solar particles

21:04of the solar wind

21:06can flow easily into space.

21:17That the coronal holes

21:19are clearly the source

21:21of solar wind disturbances

21:23was an important finding.

21:25The solar wind affects

21:27the Earth's upper atmosphere.

21:29Changes in the upper atmosphere

21:30affect radio communications

21:32as well as weather on Earth.

21:44Like scattered jewels,

21:46bright points of light

21:48dot the solar disk

21:50in this X-ray picture.

21:56Scientists checked

21:58magnetic maps of the Sun

22:00and found that bright points

22:02overlie compact magnetic regions

22:04that have both positive

22:06and negative polarity.

22:08About 100 of these bright points

22:10can be seen at one time

22:12on the Sun's hemisphere

22:14and they come and go

22:16at about 8-hour intervals,

22:18though some last longer

22:20and others are gone in a few minutes.

22:24X-rays are emitted

22:26by the Sun's high-temperature gases,

22:28so only the hot corona is seen.

22:30Almost 60,000 X-ray pictures

22:32of the corona were taken.

22:34Scientists learned

22:36that the corona is built

22:38entirely of magnetic loops

22:40and arches.

22:54Cloud-like extensions

22:56of the chromosphere

22:58are called solar prominences.

23:00They are associated

23:02with magnetic fields

23:04on the Sun's surface.

23:06These long ribbons

23:08persist for weeks

23:10or months before fading.

23:14The Sun's outer atmosphere,

23:16or corona,

23:18reaches out millions of miles.

23:20One of Skylab's telescopes

23:22masked the Sun's disk

23:24creating artificial eclipses.

23:26Eight months of eclipse observation

23:28were done by Skylab

23:30as compared to less than 80 hours

23:32observed from all the natural eclipses

23:34since the use of photography

23:36began in 1839.

23:42The outer corona was found

23:44to be constantly changing.

23:49The Sun is a seething inferno.

23:52There are huge eruptions

23:54and explosions.

23:58All this Skylab showed us

24:00in detail we had not seen before.

24:08Immense clouds of coronal material

24:10called transients

24:12are propelled outward

24:14by flares and prominence eruptions.

24:16The Sun can have violent periods.

24:24We learned a lot from Skylab

24:26but we still have much to learn

24:28about the star that keeps

24:30changing.

24:33In 1986,

24:35NASA plans to launch

24:37the International Solar Polar Mission.

24:39The shuttle will carry

24:41the Lewis Centaur rocket

24:43into low Earth orbit.

24:45The Centaur will ignite

24:47sending the probe to the Sun.

24:54The objective is to learn more

24:56about the Sun's polar regions

24:58and the space around them.

25:00As we saw,

25:02the polar regions are the source

25:04of the solar wind

25:06which affects radio communications

25:08and the weather.

25:20Man shall continue to study the Sun

25:22because his curiosity is insatiable

25:27and because we are of the Sun.

25:31Without it,

25:33we would not exist

25:35and we must understand

25:37how it affects our weather,

25:39our communications

25:41and our destiny.

25:57That brings us

25:58to the end of our first episode,

26:00Our Star of the Sun.

26:08Next time,

26:10during this 13-program journey

26:12through the solar system,

26:14we will preview the planets

26:16and examine in detail Mercury,

26:18the planet nearest the Sun.

26:29This is Larry Ross

26:31saying goodbye

26:33from NASA's Lewis Research Center

26:35in Cleveland, Ohio.

26:58NASA Jet Propulsion Laboratory

27:00California Institute of Technology

27:29NASA Jet Propulsion Laboratory

27:31California Institute of Technology

27:58California Institute of Technology

Recommended

Journey Through The Solar System, Episode 01 - Our Star, The Sun

Category

Transcript

Recommended