Image of NGC 3324

Hubble image shows the edge of the 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 image is a composite of data taken with two of Hubble's science instruments. Data taken with the Advanced Camera for Surveys (ACS) in 2006 isolated light emitted by hydrogen. More recent data, taken in 2008 with the Wide Field Planetary Camera 2 (WFPC2), isolated light emitted by sulfur and oxygen gas. To create a color composite, the data from the sulfur filter are represented by red, from the oxygen filter by blue, and from the hydrogen filter by green.

NGC 6960: The Witch's Broom Nebula

Credit & Copyright: Adam Block, Mount Lemmon SkyCenter, Univ. Arizona

Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light must suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was an exploding star and record the colorful expanding cloud as the Veil Nebula. Pictured above is the west end of the Veil Nebula known technically as NGC 6960 but less formally as the Witch's Broom Nebula. The expanding debris cloud gains its colors by sweeping up and exciting existing nearby gas. The supernova remnant lies about 1400 light-years away towards the constellation of Cygnus. This Witch's Broom actually spans over three times the angular size of the full Moon. The bright star 52 Cygni is visible with the unaided eye from a dark location but unrelated to the ancient supernova.

31 Million Miles from Planet Earth

Univ. Maryland, EPOCh/DIXI Science Teams

Explanation: On July 4th, 2005, the Deep Impact spacecraft directed a probe to impact the nucleus of Comet Tempel 1. Still cruising through the solar system, earlier this year the robotic spacecraft looked back to record a series of images of its home world 31 million miles (50 million kilometers) away. In a sequence from top left to bottom right, these four frames from the video show a rotating Earth. They combine visible and near-infrared image data with enough resolution and contrast to see clouds, oceans, and continents. They also follow a remarkable transit of Earth by its large, natural satellite, the Moon. The Moon's orbital motion carries it across the field of view from left to right. Imaging the Earth from this distant perspective allows astronomers to connect overall variations in brightness at different wavelengths with planetary features. The observations will aid in the search for earthlike planets in other planetary systems.

Mirach's Ghost

Credit & Copyright: Anthony Ayiomamitis (TWAN)

Explanation: As far as ghosts go, Mirach's Ghost isn't really that scary. In fact, Mirach's Ghost is just a faint, fuzzy galaxy, well known to astronomers, that happens to be seen nearly along the line-of-sight to Mirach, a bright star. Centered in this star field, Mirach is also called Beta Andromedae. About 200 light-years distant, Mirach is a red giant star, cooler than the Sun but much larger and so intrinsically much brighter than our parent star. In most telescopic views, glare and diffraction spikes tend to hide things that lie near Mirach and make the faint, fuzzy galaxy look like a ghostly internal reflection of the almost overwhelming starlight. Still, appearing in this sharp image just above and to the right, Mirach's Ghost is cataloged as galaxy NGC 404 and is estimated to be some 10 million light-years away.

Thackeray's Globules

Credit: Hubble Heritage Team (STScI/AURA), NASA

Explanation: Rich star fields and glowing hydrogen gas silhouette dense, opaque clouds of interstellar gas and dust in this Hubble Space Telescope close-up of IC 2944, a bright star forming region in Centaurus, 5,900 light-years away. The largest of these dark globules, first spotted by South African astronomer A. D. Thackeray in 1950, is likely two separate but overlapping clouds, each more than one light-year wide. Combined the clouds contain material equivalent to about 15 times the mass of the Sun, but will they actually collapse to form massive stars? Along with other data, the sharp Hubble images indicate that Thackeray's globules are fractured and churning as a result of intense ultraviolet radiation from young, hot stars already energizing and heating the bright emission nebula. These and similar dark globules known to be associated with other star forming regions may ultimately be dissipated by their hostile environment -- like cosmic lumps of butter in a hot frying pan.

NGC 1569: Starburst in a Dwarf Irregular Galaxy

Credit: NASA, ESA, Hubble Heritage (STScI/AURA)

Explanation: Grand spiral galaxies often seem to get all the glory, flaunting their young, bright, blue star clusters in beautiful, symmetric spiral arms. But small, irregular galaxies form stars too. In fact, as pictured here, dwarf galaxy NGC 1569 is apparently undergoing a burst of star forming activity, thought to have begun over 25 million years ago. The resulting turbulent environment is fed by supernova explosions as the cosmic detonations spew out material and trigger further star formation. Two massive star clusters - youthful counterparts to globular star clusters in our own spiral Milky Way galaxy - are seen left of center in the gorgeous Hubble Space Telescope image. The above picture spans about 8,000 light-years across NGC 1569. A mere 11 million light-years distant, this relatively close starburst galaxy offers astronomers an excellent opportunity to study stellar populations in rapidly evolving galaxies. NGC 1569 lies in the long-necked constellation Camelopardalis.

The Small Cloud of Magellan

Credit & Copyright: Josch Hambsch, Robert Gendler

Explanation: Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial wonders easily visible for southern hemisphere skygazers are known as the Clouds of Magellan. These cosmic clouds are now understood to be dwarf irregular galaxies, satellites of our larger spiral Milky Way Galaxy. The Small Magellanic Cloud pictured above actually spans 15,000 light-years or so and contains several hundred million stars. About 210,000 light-years distant in the constellation Tucana, it is the fourth closest of the Milky Way's known satellite galaxies, after the Canis Major and Sagittarius Dwarf galaxies and the Large Magellanic Cloud. This gorgeous view also includes two foreground globular star clusters NGC 362 (top left) and 47 Tucanae. Spectacular 47 Tucanae is a mere 13,000 light-years away and seen here to the right of the Small Magellanic Cloud.

NGC 7023: The Iris Nebula

Image Credit & Copyright: Jim Misti (acquisition), Robert Gendler (processing)

Explanation: Like delicate cosmic petals, these clouds of interstellar dust and gas have blossomed 1,300 light-years away in the fertile star fields of the constellation Cepheus. Sometimes called the Iris Nebula and dutifully cataloged as NGC 7023, this is not the only nebula in the sky to evoke the imagery of flowers. Still, the beautiful digital image shows off the Iris Nebula's range of colors and symmetries in impressive detail. Within the Iris, dusty nebular material surrounds a massive, hot, young star in its formative years. Central filaments of cosmic dust glow with a reddish photoluminesence as some dust grains effectively convert the star's invisible ultraviolet radiation to visible red light. Yet the dominant color of the nebula is blue, characteristic of dust grains reflecting starlight. Dark, obscuring clouds of dust and cold molecular gas are also present and can lead the eye to see other convoluted and fantastic shapes. Infrared observations indicate that this nebula may contain complex carbon molecules known as PAHs. As shown here, the Iris Nebula is about 6 light-years across.

Himalayan Horizon From Space

Credit: Expedition 1, ISS, EOL NASA

Explanation: This stunning aerial view shows the rugged snow covered peaks of a Himalayan mountain range in Nepal. The seventh-highest peak on the planet, Dhaulagiri, is the high point on the horizon at the left while in the foreground lies the southern Tibetan Plateau of China. But, contrary to appearances, this picture wasn't taken from an airliner cruising at 30,000 feet. Instead it was taken with a 35mm camera and telephoto lens by the Expedition 1 crew aboard the International Space Station -- orbiting 200 nautical miles above the Earth. The Himalayan mountains were created by crustal plate tectonics on planet Earth some 70 million years ago, as the Indian plate began a collision with the Eurasian plate. Himalayan uplift still continues today at a rate of a few millimeters per year.

G21.5-0.9: A Supernova's Cosmic Shell

Credit: Heather Matheson & Samar Safi-Harb (Univ. Manitoba), CXC, NASA

Explanation: The picture is lovely, but this pretty cosmic shell was produced by almost unbelievable violence - created when a star with nearly 20 times the mass of the sun blasted away its outer layers in a spectacular supernova explosion. As the expanding debris cloud swept through surrounding interstellar material, shock waves heated the gas causing the supernova remnant to glow in x-rays. In fact, it is possible that all supernova explosions create similar shells, some brighter than others. Cataloged as G21.5-0.9, this shell supernova remnant is relatively faint, requiring about 150 hours of x-ray data from the orbiting Chandra Observatory to create this false-color image. G21.5-0.9 is about 20,000 light-years distant in the constellation Scutum and measures about 30 light-years across. Based on the remnant's size, astronomers estimate that light from the original stellar explosion first reached Earth several thousand years ago.

The Hercules Cluster of Galaxies

Credit & Copyright: Jim Misti (Misti Mountain Observatory)

Explanation: These are galaxies of the Hercules Cluster, an archipelago of "island universes" a mere 650 million light-years distant. This cluster is loaded with gas and dust rich, star forming, spiral galaxies but has relatively few elliptical galaxies, which lack gas and dust and the associated newborn stars. Colors in the composite image show the star forming galaxies with a blue tint and ellipticals with a slightly yellowish cast. In this cosmic vista many galaxies seem to be colliding or merging while others seem distorted - clear evidence that cluster galaxies commonly interact. Over time, the galaxy interactions are likely to affect the the content of the cluster itself. Researchers believe that the Hercules Cluster is significantly similar to young galaxy clusters in the distant, early Universe and that exploring galaxy types and their interactions in nearby Hercules will help unravel the threads of galaxy andcluster evolution.

M51: Cosmic Whirlpool

Credit: S. Beckwith (STScI) Hubble Heritage Team, (STScI/AURA), ESA, NASA

Explanation: Follow the handle of the Big Dipper away from the dipper's bowl, until you get to the handle's last bright star. Then, just slide your telescope a little south and west and you might find this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195. The pair are about 31 million light-years distant and officially lie within the boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy in small, earthbound telescopes, this sharpest ever picture of M51 was made in January 2005 with the Advanced Camera for Surveys on board the Hubble Space Telescope.

La Superba

Credit & Copyright: Processing - Noel Carboni, Imaging - Greg Parker, New Forest Observatory

Explanation: Y Canum Venaticorum (Y CVn) is a very rare star in planet Earth's night sky. It's also very red, exhibiting such a remarkable spectrum of light, 19th century astronomer Angelo Secchi dubbed it La Superba. Located 710 light-years away in northern constellation Canes Venatici (the Hunting Dogs), the star varies in brightness over a period of about half a year. Near maximum, it becomes just bright enough to see with the unaided eye, but the star's beautiful red hue is easy to see in binoculars or a small telescope. In fact, La Superba is among the brightest of the carbon stars - cool, highly evolved red giant stars with exceptional abundances of carbon. The carbon is created by helium fusion near the stellar core and dredged up into the stars' outer layers. The resulting overabundance of simple carbon molecules (like CO, CN, C2) in the atmospheres of carbon stars strongly absorbs bands of bluer light and gives these stars a deep red color. La Superba is losing its carbon-rich atmosphere into the surrounding interstellar material through a strong stellar wind, and could be near the beginning of a transition to a planetary nebula phase.

Milky Way Illustrated

Illustration Credit & Copyright: Mark Garlick (Space-art)

Explanation: What does our Milky Way Galaxy look like from afar? Since we are stuck inside, and since opaque dust truncates our view in visible light, nobody knows for sure. Drawn above, however, is a good guess based on many different types of observations. In the Milky Way's center is a very bright core region centered on a large black hole. The Milky Way's bright central bulge is now thought to be an asymmetrical bar of relatively old and red stars. The outer regions are where the spiral arms are found, dominated in appearance by open clusters of young, bright, blue stars, by red emission nebula, and by dark dust. The spiral arms reside in a disk dominated in mass by relatively dim stars and loose gas composed mostly of hydrogen. What is not depicted is a huge spherical halo of invisible dark matter that dominates the mass of the Milky Way as well as the motions of stars away from the center.

The Pleiades Star Cluster

Credit and Copyright: Matthew T. Russell

Explanation: Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters. The Pleiades contains over 3000 stars, is about 400 light years away, and only 13 light years across. Quite evident in the above photograph are the blue reflection nebulae that surround the brighter cluster stars. Low mass, faint, brown dwarfs have also been found in the Pleiades. (Editors' note: The prominent diffraction spikes are caused by the telescope itself and may be either distracting or provide aesthetic enhancement, depending on your point of view.)

Welcome to Planet Earth

Credit: Apollo 17 Crew, NASA

Explanation:

Welcome to Planet Earth, the third planet from a star named the Sun. The Earth is shaped like a sphere and composed mostly of rock. Over 70 percent of the Earth's surface is water. The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen. Earth has a single large Moon that is about 1/4 of its diameter and, from the planet's surface, is seen to have almost exactly the same angular size as the Sun. With its abundance of liquid water, Earth supports a large variety of life forms, including potentially intelligent species such as dolphins and humans. Please enjoy your stay on Planet Earth.

Manicouagan Impact Crater

Credit: STS-9 Crew, NASA

Explanation: Manicouagan Crater in northern Canada is one of the oldest impact craters known. Formed about 200 million years ago, the present day terrain supports a 70-kilometer diameter hydroelectric reservoir in the telltale form of an annular lake. The crater itself has been worn away by the passing of glaciers and other erosional processes. Still, the hard rock at the impact site has preserved much of the complex impact structure and so allows scientists a leading case to help understand large impact features on Earth and other Solar System bodies. Also visible above is the vertical fin of the Space Shuttle Columbia from which the picture was taken in 1983.

Abell 2218: A Galaxy Cluster Lens

Picture Credit: NASA, HST, WFPC2, W. Couch (UNSW)

Explanation: Sometimes one of the largest concentrations of mass known can act like a lens. Almost all of the bright objects in this image are galaxies in the cluster known as Abell 2218. The cluster is so massive and so compact that it bends light from galaxies that lie behind it, causing many of them to appear as stretched out arcs. Many dim, elongated arcs are visible on this photograph. This picture was taken with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope.

July 10, 1995

A Meteoric View of Apollo 13

Picture Credit: Unknown

Explanation: Meteors, also called shooting stars, normally begin as bits of dust from the tails of comets or even small pieces chipped off asteroids. Falling toward Earth, these particles enter the atmosphere at extremely high speeds. Friction with the air heats them up and makes them glow brightly. Their rapid motion across the sky causes them to show up as bright streaks in photographs. In this picture, however, the bright streaks which appear to be meteor trails are believed to be two large pieces of the Apollo 13 spacecraft, the service and lunar modules, reentering the atmosphere.

Damage to Apollo 13

Picture Credit: NASA, Crew of Apollo 13

Explanation: In April of 1970, after an oxygen tank exploded and damaged their service module, the Apollo 13 astronauts were forced to abandon their plans to make the third manned lunar landing. The extent of the damage is revealed in this photo, taken as the crippled module was drifting away - jettisoned prior to their reentry and eventual safe splashdown. An entire panel on the right side of the module is seen to have been blown away and damage to internal structures is apparent.