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Dust & soul I: The wide, the whole, the One We used to think of outer space as a black blank void sparsely
decorated with burning suns, but new space telescopes have given us space
blooming in vast brilliant gardens of billowing dust. These clouds are how
cosmos creates itself: dust clouds pulled tight burn as stars and then explode
and make more dust. But what is cosmic dust? In this first session
of Dust & soul we will take up the ravishing languages of cosmological
process (deep field images, bow shocks, dust lanes, dark nebulae, stellar
winds, superbubbles, jets and turbulent flows) and cosmological fantasy
(the Tulip Nebula, the Dark Tower, the Coalsack, the Mountains of Creation,
the Cygnus Wall, the Thousand Ruby Galaxy) - and look carefully at a collection
of space telescope images that let us actually see the wide brilliant dances
of cosmic self-creation.
1. Introduction This workshop began with images and is based on those images. Here's one that arrived as a memory, in writing: When I was once asked to give a talk about land and community the image that came to me first was an image from probably midsummer of the year that I was maybe eight or nine. It's an image from sitting in church on a Sunday evening. The church I had to go to was a small Mennonite church three miles out from our nearest village. It was on the main road, which was a gravel road. It was right next to the road and it had two big windows that looked west onto it. In northern Alberta in summer the evenings are very long. What I remember is sitting there in the pew and a pickup truck went past. It went as fast as it could, and what it left behind was this cloud of gravel dust. The dust was backlit, so there was rising into the bottom of the window frame this wonderful cloud of luminous dust with all the curls and swerves in it. You know the way dust gets kicked up and it slowly rises and expands and it lingers and hangs there in the air. It was completely lit up. So the memory I have of it was of sitting in this cooped-up congregation looking at what I wouldn't have know to call but what I certainly felt to be the real thing. Because, in church, there we were, the men in the back on the left side, the boys in the front of the left side, the women in the back of the right side, the girls in the front of the right side, and there was this guy always in front of us. The feeling that I certainly had was that this guy was unentitled. He was unentitled to be preaching at me because he couldn't see me, and he had never been interested in seeing me. And, moreover, he was telling lies, because he was saying that what creates and sustains us is a father in the sky. This did not make sense because obviously what sustains us is where we are - the world itself. The vegetables are coming from the garden not from god. And my mother made me. So I was at odds with the creation myth of my community, let's put it that way. Correctly so, because that was not a creation myth that had any place for me. Or for what I loved and believed in. There was the congregation singing about staying near the cross, or the blood of the lamb - what seemed to be peculiar displacements of the facts. There were people who suffered; we didn't have to look as far as the sky to find them. Our parents suffered, and we were suffering. We suffered at school, and sometimes at home too. And it was our mother who bled. Where was the mention of real pain, and where was the love and praise for what was really wonderful and beautiful around us? I remembered the hymns as having more in them about the world than there was; I remembered things about green hills and golden waves of grain and holy nights and starry skies. But when I went back to the hymn book recently and combed through it, those few mentions were just about it. The gods I believed in were creek, poplar, willow, road, hill, moon, snow. The gods I feared were the Hereford bull and my father. And the lifting dust - although I couldn't exactly know this, I could feel it - the lawful motion of the lifting dust, the universality of that motion: that was true, visible cosmology. I lived in cities for many years, and the sky above these cities was usually a pinkish-grey murk in which only a few of the more famous stars showed up. I'd go camping in the desert and lie on the ground in my sleeping bag staring up feeling I'd like someday to know more about what was there, and then go back to the city and somehow never get to it. Meantime I did have the NASA daily star site bookmarked on my browser and would be getting ravishing images of nebulae, images I loved and would sometimes repost on Facebook, but didn't understand. Then a bit more than a year ago I moved to the country where the sky is black and clear. In winter there's Orion riding steadily west all through the night, every night. My bed is parallel to a big window and from my pillow I can see his feet - just at the top of the window frame - moving through the branches of a big Engelmann oak. So I began with Orion. I called up all the Orion nebula images from the last ten years of the NASA site. I studied the Orion pages in my field guide to the stars. Then I realized I didn't know what the images are actually showing, what a nebula really is, what it's made of, what it's doing. So I got into all of that a bit more, and quite avidly, because these astronomical images show us the universe creating itself, and that's the whole foundation of our existence and that of everything else. Our ultimate origin, our ultimate context, our ultimate place. That foundationalness and ultimateness also has something to do the sorts of gratitude and peril and awe and devotion and lyricism we associate with notions of soul. The French philosopher Gaston Bachelard (1884-1962), who was both a philosopher of science and a philosopher of poetry, talked about keeping our two consciences clear (I think in The poetics of reverie), and in the two sessions of this workshop I want to try to do that. In the first session, this one, I'll go into the observable science of cosmic dust, and in the second we can try to talk about some of ways cosmic images and cosmic presences evoke and portray soul and soulfulness. 2. Recommended resources: Ian Ridpath and Wil Tirion Stars and planets: the most complete guide to the stars, planets, galaxies and the solar system Princeton Field Guides NASA Astronomy picture of the day Starship Asterisk: Orion collection of images Wikipedia is excellent for explanations of astronomical terms. Origins: fourteen billion years of cosmic evolution, part 4 Back to the beginning, PBS Nova program first aired in 2004.
Guy Murchie 1967 Music of the spheres: the material universe from atom to quasar, Vol I The macrocosm: planets, stars, galaxies, cosmology and Vol II The microcosm Dover
3. Space telescopes - how the images are made astron nomos: star-order. Because of off-world orbiting telescopes, the last ten years are the first time humans are seeing the universe the way we are seeing it now. Being above the atmosphere eliminates airglow, allowing space telescopes to make observations of ultrafaint objects. Hubble has been in low Earth orbit since 1990, is expected to function until at least 2013. It has four main instruments that observe in near ultraviolet, visible, and near infrared wavelengths. What 'observe' means here is long exposure photos. The photos I'll show this afternoon are mostly composites as well as being long exposures. They may combine many different long-exposure photos taken with filters sensitive to different wavelengths. Composites may also include images from many different telescopes, some of which are ground-based. Some images or some aspects of images can be true color, which means colors as our eyes would see them if we could see them with our naked eyes, or false color, which means assigned various colors to mean various things. An example of true color is where we see heated hydrogen gas glowing red. An example of false color is when radio, x-ray or infrared waves - which aren't visible and so don't have a color - are given assigned colors. Deep field images: Space telescopes have collected many images from our own galaxy, the Milky Way, but they recently they have also been pointed out beyond our own galaxy into slices of the wider universe. Hubble Extreme Deep Field image This is the most recent most sensitive astronomical image ever made at visible wavelengths, was released in 2012. This image is the combined total of over 2000 separate images, and the total exposure is two million seconds, or 23 days! It shows over 5500 galaxies - nearly everything you see in the picture is a galaxy, an island universe of billions of stars. Only a handful of individual stars in the foreground of our own galaxy can be seen. The purpose of this and the other deep field images is to look as far away and as far back in time as we can to see what the universe was like when it began. Because light takes billions of years to reach Earth from very distant galaxies, we see them as they were billions of years ago; thus, extending the scope of such research to increasingly distant galaxies allows a better understanding of how they evolve. The image shows mature galaxies in the foreground plane, nearly mature galaxies from 5 to 9 billion years ago, and protogalaxies beyond 9 billion years. The most distant objects here are over 13 billion light years away, and we see them when they were only 500 million years old. 4. What's out there - definitions and examples OUTER SPACE is what exists between celestial objects. It is not completely empty, but contains an extremely low density (less than one hydrogen atom per cubic meter) of hydrogen and helium so hot it is ionized, as well as electromagnetic radiation, magnetic fields, and neutrinos. (Observations have recently shown that it also contains dark matter and dark energy - ie effects so-far unexplainable by visible phenomena.) INTERGALACTIC AND INTERSTELLAR MEDIUM Space-time and hot and cold gas and molecular dust grains dispersing and cohering. The INTERGALACTIC MEDIUM is a sparse gas that extends between the galaxies of the universe. It shows as filaments with thin wisps and walls separating vast void areas. Most of the universe is quite cold but the wisps of hydrogen gas between the galaxies are hotter because gas heats up and ionizes as it falls into the intergalactic medium from the huge voids surrounding it. The INTERSTELLAR MEDIUM is whatever exists in the space within the star systems in a galaxy. It includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the INTERSTELLAR RADIATION FIELD. 99% is gas in any form, and 1% is dust. In cool, dense regions it is primarily in molecular form, and in hot, diffuse regions it is primarily ionized gas. Of the gas, 89% of atoms are hydrogen and 9% are helium, with 2% of atoms being elements heavier than hydrogen or helium, which are called 'metals'. The hydrogen and helium are a result of PRIMORDIAL NUCLEOSYNTHESIS, while the heavier elements are formed in stars. Stars form within MOLECULAR CLOUDS, the densest regions of the interstellar medium, and replenish it through stellar winds and supernova explosions. Stars eject both dust and gas. The interplay between stars and the interstellar medium helps determine the rate at which a galaxy depletes its gases and therefore its lifespan of active star formation. PATTERNED SPACE: What's an atom, what's a molecule, what's an element? Think of space dimpled with very tiny knots of pattern, tension, motion - standing and moving waves. These tiny knots forming, unforming, eddying in place, moving within larger patterns, being blasted around at unthinkable speeds. ATOMS are the tiny bits of patterned space that glom onto each other chemically to make the molecules that combine to make everything else. Hydrogen is the simplest little standing wave pattern. Helium is the second-simplest. Most hydrogen and helium are believed to have been created in the Big Bang. The elements we're made of - the carbon, oxygen, nitrogen, calcium, etc - are formed in the cores of stars from primordial hydrogen and helium. Stars larger than our sun fuse not just hydrogen into helium, but helium into carbon, nitrogen, and oxygen. The iron in our blood and iodine in our thyroids could only have been formed when a massive star explodes. GAS AND PLASMA A GAS is a vastly separated, therefore loose and mobile, pattern of little patterns, either all of one kind or of different kinds. A gas may be made up of individual atoms, or elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). PLASMAS - ionized atoms and molecules - are so hot/active they lose part of their usual structure and so interact differently with other atoms and molecules. For instance, unlike a gas, a plasma may form structures such as filaments under the influence of a magnetic field. COSMIC DUST - intergalactic and interstellar dust Cosmic dust is made of dust grains and aggregates of dust grains. Dust grains for the most part are very small, from a few molecules to 0.1 micron in size, one millionth of a meter. Aggregate particles are irregularly-shaped and may be fluffy or compact. 120 different kinds of molecules have been discovered in cosmic dust so far, created by different kinds of process. The materials in an aggregate particle may show that the grains formed in different locations and at different times. Some materials could only have been formed at high temperatures, while other grain materials could only have been formed at much lower temperatures. Grains in dense clouds on average are larger than dust particles in the diffuse interstellar medium. May for instance include fine needle-shaped grains of carbon. The bulk of cosmic dust accretes cold onto preexisting dust in dark molecular clouds of the galaxy. Those molecular clouds are very cold so that ices of many kinds may accrete onto grains, perhaps to be destroyed later. A small fraction of all dust in space consists of crystalline minerals with high melting points - eg magnesium, silicon, nickel, zinc and iron - that condense within exploding very high temperature (red giant) stars. It is called 'STARDUST.' Stardust is less than 0.1% of the mass of total interstellar solids. Silicon is manufactured in explosions of massive stars that have lifetimes of millions of years. Iron is produced primarily in explosions of lighter, longer-lived sunlike stars that reach the end of their lives after a billion years or more. The most massive objects in our galaxy are giant clouds of molecules and dust. In these clouds stars and planets are formed. An INTERSTELLAR CLOUD is a denser-than-average region of the interstellar medium. Generic name given to an accumulation of plasma, gas and dust in galaxies. Depending on the density, size and temperature of a given cloud, the hydrogen in it can be neutral, a plasma, or molecular. Neutral and plasma clouds are sometimes also called diffuse clouds, while molecular clouds are sometimes also referred to as dense clouds. EXAMPLES of dust clouds: New evidence indicates that successive generations of stars formed in this region in an expanding pattern of triggered star formation. The older, earlier generations of stars seem to cluster near the middle of the enormous cavities, with younger stars seen near the rims. Winds and radiation from the older, central stars likely carve out and compress surrounding interstellar material, triggering the collapse that gave rise to younger, later generations of stars farther out. Heated dust still within the cavities appears red, while the youngest stars are forming in the whitish areas. This area is part of a complex region popularly dubbed the Heart and Soul Nebulae. Here interstellar clouds of cold gas and dust are sculpted by winds and radiation from a hot, massive star outside the picture (just above and to the right). New stars are forming also triggered by the massive star. Massive stars, abrasive winds, mountains of dust, and energetic light sculpt one of the largest and most picturesque regions of star formation in the Local Group of Galaxies. The region is visible on the upper right of many images of its home galaxy, the Milky Way neighbor known as the Large Magellanic Clouds. It actually houses three successive generations of star formation. Compact globules of dark dust housing emerging young stars are also visible around the image. What is a MOLECULAR CLOUD? A molecular cloud is a type of interstellar cloud whose density and size permits the formation of molecules, most commonly molecular hydrogen (H2). In cool, dense regions matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3. Stars form within the densest regions. Interstellar molecules are formed by chemical reactions within very sparse interstellar or circumstellar clouds of dust and gas. High energy radiation, such as ultraviolet light, can break the molecular bonds which hold atoms in molecules. In general, then, molecules are found in cool astrophysical environments. The general hypothesis is that the creation of new stars occurs exclusively within molecular clouds. This is a natural consequence of their low temperatures and high densities, since gravity acts to collapse the cloud. Molecules that have been detected in the interstellar medium and circumstellar envelopes include sodium chloride, carbon dioxide, water, sulphur dioxide, formaldehyde, hydrogen peroxide, ammonia, methane, formic acid, acetic acid, acetone, benzene, and more - 120 so far. INTERSTELLAR MOLECULES are formed by chemical reactions within very sparse interstellar or circumstellar clouds of dust and gas. Usually this occurs when a molecule becomes ionized, often as the result of an interaction with a cosmic ray. This positively-charged molecule then draws in a nearby reactant by electrostatic attraction of the neutral molecule's electrons. Molecules can also be generated by reactions between neutral atoms and molecules, although this process is generally slower. ORGANIC DUSTS In October 2011, scientists reported that cosmic dust contains complex organic matter that could be created naturally, and rapidly, by stars. Until recently the rates of chemical reactions in interstellar clouds were expected to be very slow, with minimal products being produced due to the low temperature and density of the clouds. However, ORGANIC MOLECULES that scientists would not have expected to find under these conditions have been found. The reactions needed to create such substances are familiar to scientists only at the much higher temperatures and pressures of earth and earth-based laboratories. The fact that they were found indicates that these chemical reactions in interstellar clouds take place in reactions unfamiliar to organic chemistry as observed on earth. In September 2012, NASA scientists reported that polycyclic aromatic hydrocarbons, subjected to interstellar medium conditions, are transformed, through hydrogenation, oxygenation and hydroxylation, to more complex organics - "a step along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively". They are also found in the interstellar medium, in comets, and in meteorites and are a candidate molecule to act as a basis for the earliest forms of life. There is a hypothesis that as nebulae of a certain type approach the ends of their lives, convection currents cause carbon and hydrogen in the nebulae's core to get caught in stellar winds, and radiate outward. As they cool, the atoms supposedly bond to each other in various ways and eventually form particles of a million or more atoms. 5. What's it doing - dynamics STELLAR WIND A stellar wind is a flow of gases ejected from the upper atmosphere of a star. Here's a star moving fast, probably because a more massive companion star exploded and flung it toward the left. Its strong stellar wind, pushed out ahead of it, is compressing and heating the dust and gas in its way, so that it shows a BOW WAVE or curved SHOCK FRONT.
DARK NEBULAE - Are dust clouds so dense they block the light from stars and bright nebulae. The apparent rifts that can be seen in the band of the Milky Way are caused by absorption of background starlight by molecular clouds within a few thousand light years of Earth. Here's a dark nebula of dust and molecular gas shaped by intense radiation from hot stars to the sides, that are also lighting up its borders. New stars may be forming within the darkness.
REFLECTION NEBULAE Are clouds of interstellar dust that reflect the light of a nearby star or stars with a frequency spectrum like that of those illuminating stars. The blue light from new stars is reflected by carbon grains in the dust clouds surrounding them. (The diffraction spikes are lens artifacts.)
EMISSION NEBULAE Are clouds of ionized gas giving off light of various colors, most commonly lit up by hot young stars in their midst. Many give off the red glow of ionized hydrogen. Shows emission from hydrogen, oxygen and sulfur.
Heart and Soul Nebulae in Cassiopeia Here's a giant star forming region over 200 light-years across and about 6,500 light-years away in the constellation Cassiopeia.
The smoke-looking clouds are mostly hydrogen, but also dust, including carbon grains. Rippling dust and gas lanes give the Flaming Star Nebula its name.
Flaming star huge neighbourhood This view looks along the plane of our Milky Way galaxy, near the direction of the GALACTIC ANTICENTER.
STARS A star is a massive, luminous sphere of plasma held together by gravity - a gravity-crushed ball of gas made incandescent by nuclear reactions deep in its interior generating heat and light for billions usually of years. They transform hydrogen to helium by crushing 4 hydrogen atoms together to make one helium atom. They form when more densely associated knots in massive clouds of gas and dust begin to pull toward each other. As that happens the process moves faster ('heats' 'energy transferred from one body to another' 'rapidly vibrating molecules') until the repatterning ('nuclear reaction') begins. A NUCLEAR REACTION is when internal parts of a knot-pattern overlie ('collide') so that the overall knot pattern is altered. It can be made to happen by arriving wave motion and will cause wave motion to be propagated away ('energy released'). Stars are therefore regions of loose but relatively packed pattern whose constant, active repatterning propagates wave motion in all directions. STAR FORMING REGIONS Here are new stars lighting up and pushing into the gas and dust clouds they were born within with shock waves. You can see places where starlight is reflected off interstellar dust and places where it is heating it up, causing it to glow red. (Notice distant galaxies in the background.)
STELLAR ASSOCIATIONS arise in particularly large clouds in the spiral arms of a galaxy - vast scatterings of young stars hundreds of light years across. Most of the bright stars in Orion are similar distances from us. OPEN CLUSTERS An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. Young open clusters may still be contained within the molecular cloud from which they formed, illuminating it. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist. They are loosely bound to each other by mutual gravitational attraction and travel together; they eventually become disrupted by close encounters with other clusters and clouds of gas as they orbit the galactic center, drift apart over time, disperse completely. Our sun was probably a member of such a cluster when it began 4600 million years ago. Example: the Pleiades cluster is estimated to contain about 100 stars, youngest no more than 2 million years ago.. BLUE GIANTS, RED GIANTS Red stars are cooler, with surface temperatures of around 3,000 kelvins (K), while blue stars are hotter and can have temperatures over 30,000 K. Our own lovely yellow sun's temperature is a comforting 6,000 K. SUPERNOVA A supernova is a stellar explosion that is extremely luminous and causes a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months. During this short interval a supernova can radiate as much energy as the Sun is expected to emit over its entire life span. The explosion expels much or all of a star's material at a velocity of up to 10% of the speed of light, driving a shock wave into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a SUPERNOVA REMNANT. There was a supernova off Orion's shoulder in AD 1054 as bright as the full moon for almost a month, and visible in the middle of the day. At night it bathed the earth in a ghostly ruby-colored light. Over the next six years this light slowly faded. Simeis filaments in Taurus and Auriga (Spaghetti Nebula) A star exploded 40,000 years ago and there are still traces of that explosion visible here as shocked glowing hydrogen in the far reach of that explosion. It is about 150 light-years across.
BUBBLES AND SUPERBUBBLES A superbubble is a cavity hundreds of light years across, filled with hot gas blown into the interstellar medium by multiple supernovae and stellar winds. The most massive stars have strong stellar winds, and all of these stars explode as supernovae at the ends of their lives. These winds can form stellar wind bubbles dozens of light years across. Where giant stars are close enough that their wind bubbles merge, they form a giant bubble called a superbubble. When stars die, supernova explosions similarly drive blast waves that can reach even larger sizes. 6. The Orion Molecular Cloud Homer mentions Orion in the Odyssey and the Iliad. It is also shown in Native American drawings and stone circles. Orion is an ASTERISM, that is, a visual configuration of stars that are not necessarily near each other. Of the seven chief stars in Orion it happens that the most distant from earth (Mintaka, its left-most belt star at 2000 light years) is eight times more distant from Bellatrix (left shoulder - at 243 light years) than Bellatrix is from us. Stars at different distances from galactic center are rotating at different speeds so that, as a result, their spatial visual relation to each other changes. The change is imperceptible enough over the several thousand years of recorded time so that Homer's Orion three millennia ago is our Orion, near enough. But in one hundred millennia its impeccable geometry will have been changed. Orion is in our arm of the Milky Way Galaxy, or we could say we are in the Orion Arm. In Ursula Le Guin's Hainish novels, the ancient civilization of Hain seeds humans on planets throughout the ORION ARM OF THE MILKY WAY. Orion's right shoulder is next to the dense band of stars we call the Milky Way. When we are looking toward Orion we are looking out along the galactic plane toward its rim; we have our backs to galactic center. Orion's cone of space passes so near the angle where our local galaxy is thickest, that it includes a lot of what astronomers call OBJECTS. In the newly detailed views of space telescopes it shows as a spectacular garden of form and color. The ORION MOLECULAR CLOUD COMPLEX Orion's stars are at different distances from us but the Orion Molecular Cloud Complex is a specific area of space about 1500 light years away and hundreds of light years across - a patch of gaseous wisps, mainly a 10:1 mix of hydrogen and helium, that will slowly disperse over the next 100,000 years. This patch of space has embedded within it examples of everything we've mentioned: dark nebulae, emission nebulae, reflection nebulae, regions of star formation, and also the small disks of gas and dust forming planetary systems. It is one of the most active regions of stellar formation that can be seen in the night sky. ORION'S MAIN STARS Alnitak, Alnilam, Mintaka are the bright bluish stars, from east to west, of Orion's belt - three blue supergiant stars hotter and much more massive than the Sun. About 1,500 light-years away. Rigel, Orion's left foot, also a blue supergiant, is the brightest star in Orion. Orion's cool red supergiant Betelgeuse stands out from the other, hotter, bluish stars composing the body of the constellation. SUPERBUBBLE Barnard's Loop is an immense red C centred approximately on the Orion Nebula and circling Orion's east side. It is a 300 light-year wide arc shaped by long gone supernova explosions and the winds from massive stars. It lies about 1,500 light-years away. The stars within the Orion Nebula are believed to be responsible for ionizing the loop. May have originated in a supernova explosion about 2 million years ago. DARK NEBULAE Just to the right of Alnitak, the most eastern belt star, lies the Horsehead Nebula, a dark formation of dense dust that has perhaps the most recognized nebular shapes on the sky.
REFLECTION NEBULAE Are clouds of interstellar dust that reflect the light of a nearby star or stars with a frequency spectrum like that of those illuminating stars. Rigel and the Witch Head Nebula The Witch Head Nebula glows primarily by light reflected from the bright star Rigel, to its right. Fine dust in the nebula reflects the light. The blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. EMISSION NEBULAE Are clouds of ionized gas giving off light of various colors, most commonly lit up by hot young stars in their midst. Many give off the red glow of ionized hydrogen. Orion Nebula (also called M42)
The infrared image detects heat, so it shows the nebula's many nascent stars. This is a false-color view because infrared isn't a wavelength visible to humans. The view spans about 40 light-years. Compared to its visual wavelength appearance, the brightest portion of the nebula is likewise centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But the infrared image also detects the nebula's many protostars, still in the process of formation, seen here in red hues. Just below Alnitak, the lowest of the three belt stars, is the Flame Nebula, glowing with excited hydrogen gas and immersed in filaments of dark brown dust.
This view spans about 13 degrees across the center of the well-known constellation with the Great Orion Nebula, the closest large star forming region, just right of center. Glowing hydrogen cradles new stars at the edge of the giant molecular cloud some 1,500 light-years away. The deep mosaic image also includes the Horsehead Nebula, the Flame Nebula, and Orion's belt stars. Image data acquired with a hydrogen alpha filter adds other remarkable features to this wide angle cosmic vista - pervasive tendrils of energized atomic hydrogen gas and portions of the surrounding Barnard's Loop. Orion's head, the next largest nebula after Barnard's Loop surrounding a star called Meissa at 1060 light years - not in the Orion Molecular Cloud. And now three views of a structure that is not in the Orion Molecular Cloud Complex but it is visually close by: Rosette Nebula - just the flower At the edge of a large molecular cloud some 5,000 light years away, the petals of this rose are actually a stellar nursery whose lovely, symmetric shape is sculpted by the winds and radiation from its central cluster of hot young stars, whose winds and energetic light are evacuating the nebula's center. The stars in the energetic cluster are only a few million years old. The central cavity in the Rosette Nebula is about 50 light-years in diameter. The nebula can be seen firsthand with a small telescope toward the constellation of the Unicorn (Monoceros). Its faint loop is twice the apparent diameter of the full moon, roughly 130 light years in diameter. The column of dust and gas that appears like a rose's stem extends hundreds of light years. Across this image, the bright blue star just left and below the center is part of the open cluster of stars known as the Snowflake cluster. To the right of S Mon is a dark pointy featured called the Cone nebula, a nebula likely shaped by winds flowing out a massive star obscured by dust. To the left of S Mon is the Fox Fur nebula, a tumultuous region created by the rapidly evolving Snowflake cluster. The Rosette region, at about 5,000 light years distant, is about twice as far away as the region surrounding S Mon. The entire field can be seen with a small telescope toward the constellation of the Unicorn (Monoceros). STELLAR NURSERY The Orion Nebula offers one of the best opportunities to study how stars are born partly because it is the nearest large star-forming region, but also because the nebula's energetic stars have blown away obscuring gas and dust clouds that would otherwise block our view - providing an intimate look at a range of ongoing stages of starbirth and evolution. Orion Nebula Cluster, a grouping of about 2,000 stars within a diameter of 20 light-years. Orion's young stars are only about 1 million years old, compared to the Sun's age of 4.6 billion years. The region's hottest stars are found in the Trapezium Cluster. The Trapezium Cluster is the Orion Nebula's hot central star cluster, a tight open cluster of stars, a relatively young cluster that has formed directly out of the parent nebula. The five brightest stars are on the order of 15-30 solar masses in size. They are within a diameter of 1.5 light-years of each other and are responsible for much of the illumination of the surrounding nebula. About half the stars within the cluster have been found to contain evaporating circumstellar disks, a likely precursor to planetary formation. 7. Spiral galaxies To end the workshop, a small collection of lacy spirals: Andromeda is the nearest major galaxy to our own Milky Way Galaxy. Our Galaxy is thought to look much like Andromeda. Together these two galaxies dominate the Local Group of galaxies. The diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it. The several distinct stars that surround Andromeda's image are actually stars in our Galaxy that are well in front of the background object. Andromeda is frequently referred to as M31 since it is the 31st object on Messier's list of diffuse sky objects. M31 is so distant it takes about two million years for light to reach us from there.
Thousand-ruby Galaxy (M83) A face-on barred spiral galaxy in Hydra. Our own galaxy might look like this if we could see it from outside. M83 has been the site of more known supernovae than any other Messier object, six in all. It is one of the brightest and closest galaxies outside the Local Group, about 15 million l.y. away. Some distance below Spica in Virgo. Big, bright, and beautiful, spiral galaxy M83 lies a mere twelve million light-years away, near the southeastern tip of the very long constellation Hydra. This cosmic close-up, a mosaic based on data from the Hubble Legacy Archive, traces dark dust and young, blue star clusters along prominent spiral arms that lend M83 its nickname, The Southern Pinwheel. Typically found near the edges of the thick dust lanes, a wealth of reddish star forming regions also suggest another popular moniker for M83, The Thousand-Ruby Galaxy. Dominated by light from older stars, the bright yellowish core of M83 lies at the upper right. The core is also bright at x-ray energies that reveal a high concentration of neutron stars and black holes left from an intense burst of star formation. In fact, M83 is a member of a group of galaxies that includes active galaxy Centaurus A. The close-up field of view spans over 25,000 light-years at the estimated distance of M83. Thousand Ruby Galaxy - close-up Zooming in on M83's nucleus with the latest telescopes shows the center to be an energetic and busy place. Visible in the above image -- from the newly installed Wide Field Camera 3 pointing through the recently refurbished Hubble Space Telescope -- are bright newly formed stars and giant lanes of dark dust. Pinwheel Galaxy (M33) Filmier version of the same galaxy 2.7 ly away. Light spread over a large area, covers a larger area of the sky than the full Moon.
Pinwheel Galaxy (M101) There's another lovely spiral, M101 in Ursa Major, bit above and between the final two stars of the handle. 22 million l.y. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way Galaxy. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away. M101's relatively close distance of about 27 million light years allows it to be studied in some detail. Recent evidence indicates that a close gravitational interaction with a neighboring galaxy created waves of high mass and condensed gas which continue to orbit the galaxy center. These waves compress existing gas and cause star formation. One result is that M101 has several extremely bright star-forming regions spread across its spiral arms. M101 is so large that its immense gravity distorts smaller nearby galaxies. 2011 August 26 a young supernova: a nearby star has exploded and telescopes all over the world are turning to monitor it. it likely occurred in the Pinwheel Galaxy M101, which, being only about 21 million light years away, makes it one of the closest supernovas seen in decades.
Whirlpool Galaxy (M51)
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