Hubble Space Telescope Imagery -2/2

This image shows the edge of a giant gaseous cavity within the star-forming region called NGC 3324. The glowing nebula has been carved out by intense ultraviolet radiation and stellar winds from several hot, young stars. A cluster of extremely massive stars, located well outside this image in the center of the nebula, is responsible for the ionization of the nebula and excavation of the cavity. The image also reveals dramatic dark towers of cool gas and dust that rise above the glowing wall of gas. The dense gas at the top resists the blistering ultraviolet radiation from the central stars, and creates a tower that points in the direction of the energy flow. The high-energy radiation blazing out from the hot, young stars in NGC 3324 is sculpting the wall of the nebula by slowly eroding it away. Located in the Southern Hemisphere, NGC 3324 is at the northwest corner of the Carina Nebula (NGC 3372), home of the Keyhole Nebula and the active, outbursting star Eta Carinae. The entire Carina Nebula complex is located at a distance of roughly 7,200 light-years, and lies in the constellation Carina.

This portrait of Stephan's Quintet, also known as Hickson Compact Group 92, was taken by the new Wide Field Camera 3 (WFC3) aboard NASA's Hubble Space Telescope. Stephan's Quintet, as the name implies, is a group of five galaxies. The name, however, is a bit of a misnomer. Studies have shown that group member NGC 7320, at lower right, is actually a foreground galaxy about seven times closer to Earth than the rest of the group. NGC 7320 is 40 million light-years from Earth. The other members of the quintet reside 290 million light-years away in the constellation Pegasus. WFC3 observed the quintet in July and August 2009.

This very deep image taken with the NASA/ESA Hubble Space Telescope shows the spiral galaxy NGC 4921 along with a spectacular backdrop of more distant galaxies. It was created from a total of 80 separate pictures through yellow and near-infrared filters.

Huge waves are sculpted in NGC 6537, the Red Spider Nebula, a two-lobed nebula some 3000 light-years away in the constellation of Sagittarius. This warm planetary nebula harbours one of the hottest stars known and its powerful stellar winds generate waves 100 billion kilometres high. The waves are caused by supersonic shocks, formed when the local gas is compressed and heated in front of the rapidly expanding lobes. The atoms caught in the shock emit the spectacular radiation seen in this image.

A small region inside the massive globular cluster Omega Centauri which boasts nearly 10 million stars. The stars in Omega Centauri are about about 16,000 light-years from Earth, and are between 10 billion and 12 billion years old. The majority of the stars in the image are yellow-white, like our Sun. These are adult stars that are shining by hydrogen fusion. Toward the end of their normal lives, the stars become cooler and larger. These late-life stars are the orange dots in the image. Even later in their life cycles, the stars continue to cool down and expand in size, becoming red giants. These bright red stars swell to many times larger than our Sun's size and begin to shed their gaseous envelopes. After ejecting most of their mass and exhausting much of their hydrogen fuel, the stars appear brilliant blue. Only a thin layer of material covers their super-hot cores. These stars are desperately trying to extend their lives by fusing helium in their cores. At this stage, they emit much of their light at ultraviolet wavelengths. When the helium runs out, the stars reach the end of their lives. Only their burned-out cores remain, and they are called white dwarfs (the faint blue dots in the image). White dwarfs are no longer generating energy through nuclear fusion and have gravitationally contracted to the size of Earth. They will continue to cool and grow dimmer for many billions of years until they become dark cinders. All of the stars in the image are cozy neighbors. The average distance between any two stars in the cluster's crowded core is only about a third of a light-year, roughly 13 times closer than our Sun's nearest stellar neighbor, Alpha Centauri. Although the stars are close together, WFC3's sharpness can resolve each of them as individual stars. If anyone lived in this globular cluster, they would behold a star-saturated sky that is roughly 100 times brighter than Earth's sky. Hubble observed Omega Centauri on July 15, 2009, in ultraviolet and visible light.

This image from NASA's Hubble Space Telescope shows the diverse collection of galaxies in the cluster Abell S0740 that is over 450 million light-years away in the direction of the constellation Centaurus. The giant elliptical ESO 325-G004 looms large at the cluster's center. The galaxy is as massive as 100 billion of our suns. Hubble resolves thousands of globular star clusters orbiting ESO 325-G004. At the galaxy's distance they appear as pinpoints of light contained within the diffuse halo. Other fuzzy elliptical galaxies dot the image. Some have evidence of a disk or ring structure that gives them a bow-tie shape. Several spiral galaxies are also present. The starlight in these galaxies is mainly contained in a disk and follows along spiral arms. This image was created by combining Hubble science observations taken in January 2005 with Hubble Heritage observations taken a year later to form a 3-color composite. The filters that isolate blue, red and infrared light were used with the Advanced Camera for Surveys aboard Hubble.

This portrait is the most detailed view of the largest stellar nursery in our local galactic neighborhood. The massive, young stellar grouping, called R136, is only a few million years old and resides in the 30 Doradus Nebula, a turbulent star-birth region in the Large Magellanic Cloud, a satellite galaxy of our Milky Way located some 170,000 light-years away. Many of the diamond-like icy blue stars are among the most massive stars known. Several of them are over 100 times more massive than our Sun. The image, taken by Hubble on October 20-27, 2009, spans about 100 light-years across.

Hubble's Advance Camera for Surveys (ACS) recently took this image of galaxy NGC 4522 in the Virgo Cluster. Backdropped by many other more distant galaxies, the impression given by NGC 4522 is that it is flying apart. A phenomenon called ram pressure stripping is mangling the galaxy as it hurtles through a region of hot x-ray emitting gas at 10 million kilometers per hour- stripping away its own gas content. NGC 4522 is some 60 million light years away.

The star cluster Pismis 24 lies in the core of the large emission nebula NGC 6357 that extends one degree on the sky in the direction of the Scorpius constellation. Part of the nebula is ionised by the youngest (bluest) heavy stars in Pismis 24. The intense ultraviolet radiation from the blazing stars heats the gas surrounding the cluster and creates a bubble in NGC 6357. The presence of these surrounding gas clouds makes probing into the region even harder. One of the top candidates for the title of "Milky Way stellar heavyweight champion" was, until now, Pismis 24-1, a bright young star that lies in the core of the small open star cluster Pismis 24 (the bright stars in the Hubble image) about 8,000 light-years away from Earth. Pismis 24-1 was thought to have an incredibly large mass of 200 to 300 solar masses. New NASA/ESA Hubble measurements of the star, have, however, resolved Pismis 24-1 into two separate stars, and, in doing so, have "halved" its mass to around 100 solar masses.

The photographer itself - a crew member aboard the Space Shuttle Atlantis captured this still image of the Hubble Space Telescope above the Earth, as the two spacecraft continued their relative separation on May 19, 2009 after having been linked together for the better part of a week during the STS-125 mission. During the week five spacewalks were performed to complete the final servicing mission for the orbital observatory.

In 2004, Hubble created the deepest visible-light image of the Universe and now, with its brand-new camera, it is seeing even farther in the same region. This image, taken by the HUDF09 team with the new WFC3/infrared camera on Hubble in late August 2009, during a total of four days of pointing for 173,000 seconds of total exposure time, is the deepest image of the universe ever taken in near-infrared light. Nearly every smudge and bit of light in this image is a separate galaxy made up of billions of stars. The faintest and reddest objects in the image are galaxies that formed 600 million years after the Big Bang. No galaxies have been seen before at such early times. The image was taken in the same region as the Hubble Ultra Deep Field (2004), and is roughly 2.4 arcminutes wide. Again, I invite you to step outside some dark night in the future and gaze up at the sky, knowing that every bit of apparent darkness above is really filled with the faint light of these billions of faraway galaxies.

In January 2002, a dull star in an obscure constellation suddenly became 600,000 times more luminous than our Sun, temporarily making it the brightest star in our galaxy. The star, called V838 Monocerotis, has long since faded back to obscurity, but observations of a phenomenon called a "light echo" around the star have uncovered remarkable new features over the following years (this animation covers two years' time). The light echo is light from the earlier explosion echoing off dust surrounding the star. Light from the outburst traveled to the dust and then was reflected to Earth. Because of this indirect path, the light arrived at Earth months after light from the star that traveled directly from the star.

In early January of 2000, Hubble took this image of Galaxy Cluster Abell 2218, and its massive amount of "gravitational lensing". Abell 2218 lies some 2 billion light-years away in the Draco constellation and is so massive that its enormous gravitational field deflects light rays passing through it, much as an optical lens bends light to form an image. These magnifying powers provides a powerful "zoom lens" for viewing distant galaxies that could not normally be observed with the largest telescopes. The visible "arcs" are the distorted images of very distant galaxies, which lie 5 to 10 times farther away than the lensing cluster itself.

About 55 million years ago, a star near the dusty lenticular galaxy NGC 4526 exploded into a supernova, seen as a bright spot at lower left. In 1994, the Hubble Space telescope caught the weeks-long explosion as the light from it finally reached the Earth, and we called it Supernova 1994D, a fairly typical stellar explosion. The host galaxy also known as the Lost Galaxy lies in the background and is part of the Virgo Cluster.

Also around 55 million light-years distant, we see here the colliding Antennae Galaxies (NGC 4038/NGC 4039) - a pair of interacting galaxies that lie in the constellation Corvus. The two spiral galaxies started to fuse together a few hundred million years ago making the Antenna galaxies the nearest and youngest example of a pair of colliding galaxies. Nearly half of the faint objects in the Antennae are young clusters containing tens of thousands of stars.

This image, taken by the Advanced Camera for Surveys (ACS), represents a small section of a larger mosaic - the sharpest view ever taken of the Orion Nebula - a picture book of star formation with massive young stars that are shaping the nebula and pillars of dense gas that may be the homes of budding stars. The bright glow at left is from M43, a small region being shaped by ultraviolet light from a massive young star. Astronomers call the region a miniature Orion Nebula because only one star is sculpting the landscape. The Orion Nebula has four such stars. The Orion Nebula is 1,500 light-years away, the nearest star-forming region to Earth.

A nearly perfect ring of hot, blue stars pinwheels about the yellow nucleus of an unusual galaxy known as Hoag's Object. This image captures a face-on view of the galaxy's ring of stars, revealing more detail than any existing photo of this object. The entire galaxy is about 120,000 light-years wide, which is slightly larger than our Milky Way Galaxy. The blue ring, which is dominated by clusters of young, massive stars, contrasts sharply with the yellow nucleus of mostly older stars. What appears to be a gap separating the two stellar populations may actually contain some star clusters that are almost too faint to see. Curiously, an object that bears an uncanny resemblance to Hoag's Object can be seen in the gap at the one o'clock position. The object is probably a background ring galaxy.

Called I Zwicky 18, this galaxy - some 59 million light-years distant - has a youthful appearance that resembles galaxies typically found only in the early universe. Hubble has now found faint, older stars within this galaxy, suggesting that the galaxy may have formed at the same time as most other galaxies. I Zwicky 18 is classified as a dwarf irregular galaxy and is much smaller than our Milky Way Galaxy. The concentrated bluish-white knots embedded in the heart of the galaxy are two major starburst regions where stars are forming at a furious rate. The wispy blue filaments surrounding the central starburst regions are bubbles of gas that have been blown away by stellar winds and supernovae explosions from a previous generation of hot, young stars. A companion galaxy lies just above and to the left and may be interacting with I Zwicky 18.

Just weeks after NASA astronauts repaired the Hubble Space Telescope in December 1999, the Hubble Heritage Project snapped this picture of NGC 1999, a nebula some 1,500 light-years away from Earth, in the constellation Orion. The Hubble Heritage astronomers, in collaboration with scientists in Texas and Ireland, used Hubble's Wide Field Planetary Camera 2 (WFPC2) to obtain this colour image.

This image of the ancient open star cluster NGC 6791 was taken in early 2008. Studying the dimmest stars in the cluster, astronomers uncovered three different age groups of stars. Two of the populations are burned-out stars called white dwarfs. One group of these low-wattage stellar remnants appears to be 6 billion years old, another appears to be 4 billion years old. The ages are problematically out of sync with those of the cluster's normal stars, which are 8 billion years old. Located 13,300 light-years away in the constellation Lyra, NGC 6791 is one of the oldest and largest open clusters known, containing roughly 10,000 stars. Also interesting to note are the numerous distant galaxies far beyond our Milky Way Galaxy that are visible between the crowded mass of stars.

This object is a billowing tower of cold gas and dust rising from a stellar nursery called the Eagle Nebula. 7,000 light-years distant from us, the soaring tower is 9.5 light-years or about 90 trillion kilometers tall. Stars in the Eagle Nebula are born in clouds of cold hydrogen gas that reside in chaotic neighbourhoods, where energy from young stars sculpts fantasy-like landscapes in the gas. The tower may be a giant incubator for those newborn stars. A torrent of ultraviolet light from a band of massive, hot, young stars [off the top of the image] is eroding the pillar. The column is silhouetted against the background glow of more distant gas. The bumps and fingers of material in the center of the tower are examples of stellar birthing areas. These regions may look small but they are roughly the size of our solar system. The blue colour at the top is from glowing oxygen, the red color in the lower region is from glowing hydrogen. This image was taken in November 2004 with the Advanced Camera for Surveys.

This is the sharpest image ever made of the large "grand design" spiral galaxy M81, or Bode's Galaxy made with Hubble data acquired over a two-year period. A spiral-shaped system of stars, dust, and gas clouds, the galaxy's arms wind all the way down into the nucleus. Though the galaxy is located 11.6 million light-years away, the Hubble Space Telescope's view is so sharp that it can resolve individual stars, along with open star clusters, globular star clusters, and even glowing regions of fluorescent gas. Bode's galaxy is about 70,000 light-years across - slightly smaller than our own Milky Way, estimated to be 100,000 light-years in diameter.

The "Retina Nebula" is in fact, a dying star named IC 4406. The left and right halves of the Hubble image are nearly mirror images of the other. If we could fly around IC 4406 in a starship, we would see that the gas and dust form a vast donut of material streaming outward from the dying star. From Earth, we are viewing the donut from the side. This side view allows us to see the intricate tendrils of dust that have been compared to the eye's retina. Gas on the inside of the donut is ionized by light from the central star and glows brightly. Light from oxygen atoms is rendered blue in this image; hydrogen is shown as green, and nitrogen as red. One of the most interesting features here is the irregular lattice of dark lanes that criss-cross the center of the nebula. These lanes are about 24 billion kilometers wide, and are like an open mesh veil that has been wrapped around the bright donut.

This image shows a handful of Bok globules (dark clouds of dense dust and gas) within a larger mosaic image of the Carina Nebula assembled in April of 2007. The clumps of dark clouds are nodules of dust and gas that have resisted being completely photoionized by the strong ultraviolet radiation of nearby young, bright stars. The globule at right is nicknamed "the caterpillar" - its glowing edge indicating that it is in the process of photoionization by the hottest stars in the cluster. the Carina nebula lies some 7,500 light-years away from Earth.

Resembling a rippling pool illuminated by underwater lights, the Egg Nebula offers astronomers a special look at the normally invisible dust shells swaddling an aging star. These dust layers, extending over one-tenth of a light-year from the star, have an onionskin structure that forms concentric rings around the star. A thicker dust belt, running almost vertically through the image, blocks off light from the central star. Twin beams of light radiate from the hidden star and illuminate the pitch-black dust, like a shining flashlight in a smoky room. The Egg Nebula is located 3,000 light-years away in the constellation Cygnus. This image was taken with Hubble's Advanced Camera for Surveys in September and October 2002.

The gas giant Saturn, seen at full-tilt in November of 1999. Saturn's orbit lies some 1.2 billion kilometers (about 67 light-minutes) away from earth. The planet itself is roughly 9.5 times wider than Earth and its rings - composed of 93 percent water ice - extend out to 120,000 km above its equator, averaging approximately 20 meters in thickness.

The tattered remains of a supernova explosion known as Cassiopeia A (Cas A), the youngest known remnant from a supernova explosion in the Milky Way. This composite image shows the Cas A remnant as a broken ring of bright filamentary and clumpy stellar ejecta. These huge swirls of debris glow with the heat generated by the passage of a shockwave from the supernova blast. The various colours of the gaseous shards indicate differences in chemical composition. Bright green filaments are rich in oxygen, red and purple are sulphur, and blue are composed mostly of hydrogen and nitrogen. Cas A is located ten thousand light-years away from Earth in the constellation of Cassiopeia.

"The Grasshopper", or UGC 4881, is a stunning system consisting of two colliding galaxies. It has a bright curly tail containing a remarkable number of star clusters. The galaxies are thought to be halfway through a merger - the cores of the parent galaxies are still clearly separated, but their discs are overlapping. A supernova exploded in this system in 1999 and astronomers believe that a vigorous burst of star formation may have just started. This notable object is located in the constellation of Lynx, some 500 million light-years away from Earth. UGC 4881 is the 55th galaxy in Arp's Atlas of Peculiar Galaxies. This image is part of a large collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on the occasion of its 18th anniversary on April 24th, 2008.

Part of the famous "Pillars of Creation" formation in the Eagle Nebula, this eerie, dark structure, resembling an imaginary sea serpent's head, is a column of cool molecular hydrogen gas (two atoms of hydrogen in each molecule) and dust that is an incubator for new stars. The stars are embedded inside finger-like protrusions extending from the top of the nebula. Each 'fingertip' is somewhat larger than our own solar system. The Eagle Nebula is 7,000 light-years distant from Earth.

Tightly wound, almost concentric, arms of dark dust encircle the bright nucleus of the otherwise nondescript galaxy, NGC 2787, in this image created by the Hubble Heritage team. Astronomer Marcella Carollo (Swiss Federal Institute of Technology, Zurich) and collaborators used Hubble's Wide Field Planetary Camera 2 to collect the data in January 1999.

This object, nicknamed Gomez's Hamburger, is a sun-like star about 6,500 light-years away that is nearing the end of its life. The "hamburger buns" are light reflecting off dust and the "patty" is actually the shadow of a thick disk around the central star, which is seen edge-on from Earth. The star itself, with a surface temperature of approximately 18,000 degrees Fahrenheit (10,000 degrees Celsius), is hidden within this disk. However, light from the star does emerge in the directions perpendicular to the disk and illuminates dust above and below it.

Looking across 26,000 light-years of space toward the center of our Galaxy, Hubble captured this dense view of over 150,000 stars in February of 2004 while monitoring for any dips in brightness, or transits of orbiting planets. 16 candidate stars were found for closer scrutiny.

Seen here is a very thin section of a supernova remnant caused by a stellar explosion that occurred more than 1,000 years ago. On or around May 1, 1006 A.D., observers around the world witnessed and recorded the arrival of light from what is now called SN 1006, a tremendous supernova explosion caused by the final death throes of a white dwarf star nearly 7,000 light-years away. The supernova was probably the brightest star ever seen by humans, and surpassed Venus as the brightest object in the night time sky, only to be surpassed by the moon. It was visible even during the day for weeks, and remained visible to the naked eye for at least two and a half years before fading away. Today we know that the shockwave of SN 1006 has a diameter of nearly 60 light-years, and it is still expanding at roughly 6 million miles per hour.

The Cat's Eye Nebula (NGC 6543), about 3,300 light-years distant, shows a bull's eye pattern of eleven or even more concentric rings, or shells, around the its center. Each "ring" is actually the edge of a spherical bubble seen projected onto the sky - that's why it appears bright along its outer edge. Observations suggest the star ejected its mass in a series of pulses at 1,500-year intervals. These convulsions created dust shells, each of which contain as much mass as all of the planets in our solar system combined (still only one percent of the Sun's mass). The view from Hubble is like seeing an onion cut in half, where each skin layer is discernible.

ESO 593-8 is an impressive pair of interacting galaxies with a feather-like galaxy crossing a companion galaxy. The two components will probably merge to form a single galaxy in the future. The pair is adorned with a number of bright blue star clusters. ESO 593-8 is located in the constellation of Sagittarius, the Archer, some 650 million light-years away from Earth.

This image is called the Hubble Ultra Deep Field, and it is by far my favorite Hubble image. Starting in late 2003, astronomers pointed Hubble at a tiny, relatively empty part of our sky (only a few stars from the Milky Way visible), and created an exposure nearly 12 days long over a four-month period. The result is this amazing image, looking back through time at thousands of galaxies that range from 1 to 13 billion light-years away from Earth. Some 10,000 galaxies were observed in this tiny patch of sky (a tenth the size of the full moon) - each galaxy a home to billions of stars. Go outside tonight, take a ball-point pen with you, and hold it up in front of the night sky at arm's length. The tip of your pen is about 1 millimeter wide, and at arm's length, it would cover the 10,000 galaxies seen in the Ultra Deep Field image. That's how unbelievably massive the visible universe is. By way of comparison, to really put us Earthlings in our place in the Grand Scheme, please have a look at another famous image, thePale Bule Dot - a photograph taken of the Earth (the tiny pale speck, top center) by Voyager 1 in 1990 from 4 billion miles away (about 6 light-hours). I will finish with the words of astronomer Carl Sagan about this Pale Blue Dot: "That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar", every "supreme leader", every saint and sinner in the history of our species lived there - on a mote of dust suspended in a sunbeam."