1. Hoag's Object: A Strange Ring Galaxy In 1950, astronomer Art Hoag chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older.
2. NGC 1365: Majestic Island Universe This barred spiral galaxy has intense star forming regions at the ends of the bar and along the spiral arms, and details of dust lanes cutting across the galaxy's bright core. At the core lies a super-massive black hole.
3. M27: Not a Comet While hunting for comets in the skies above 18th century France, Charles Messier kept a list of objects he encountered. Number 27 on his famous list is a gaseous emission nebula created as a star runs out of fuel.
4. Hole in the Sun This dark shape sprawling across the Sun is a coronal hole. Coronal holes are known to be the source of high-speed solar wind that flows outward along magnetic fields and trigger auroral displays on Earth.
5. FUN FACT: Shooting stars are usually just tiny dust particles falling through our atmosphere. Comets sometimes pass through Earth’s orbit, leaving trails of dust behind. Then as Earth plows through the dust in its path, the particles heat up, creating the streaks in the night sky.
6. Large Space Station Over Earth The International Space Station is the largest object ever constructed by humans in space. The perimeter extends over the area of a football field, although only a small fraction of modules are habitable by humans.
7. The Bubble Nebula This nebula offers evidence of a violent processes. At the center is a hot O-type star creating fierce stellar winds and the intense radiation from the star has blasted out against denser material in a surrounding molecular cloud.
8. Young Suns of NGC 7129 Young suns lie within dusty NGC 7129. The lovely bluish dust clouds reflect the youthful starlight. The smaller deep red crescent shapes are glowing hydrogen gas shocked by jets streaming away from newborn stars.
9. The Small Cloud of Magellan Navigator Ferdinand Magellan studied the southern sky during the first circumnavigation of Earth. As a result, two celestial wonders visible in the southern hemisphere are known as the Clouds of Magellan.
10. FUN FACT: Scientists believe that we can only see about 5% of the matter in the Universe. The rest is made up of invisible matter (called Dark Matter) and a mysterious form of energy known as Dark Energy.
11. Martian Moon Phobos from Mars Express Phobos is the largest of two Martian moons. Its unusual orbit and color indicate that it may be a captured asteroid. This picture of Phobos was taken by the robot spacecraft Mars Express currently orbiting Mars.
12. The Rippled Red Ribbons of SNR 0509 The ripples of this supernova remnant were imaged in unprecedented detail by the Hubble Space Telescope. The red glowing ring is the expansion of light related to an explosion that occurred about 400 years earlier.
13. Polar Ring Galaxy NGC 660 NGC 660 can be found in the constellation Pisces. A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk.
14. Night Launch of the Space Shuttle Endeavour The space shuttle Endeavour lifted off from Kennedy Space Center bound for the International Space Station. It is framed by an exhaust plume.
15. FUN FACT: The Sun produces so much energy, that every second the core releases the equivalent of 100 billion nuclear bombs.
16. Alnitak, Alnilam, Mintaka Alnitak, Alnilam, and Mintaka, are the bright bluish stars from left to right along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion, these stars are hotter and more massive than the Sun.
17. Globular Star Cluster 47 Tucanae This globular star cluster roams the halo of our Milky Way Galaxy. It lies about 13,000 light-years away and can be naked-eye spotted near the Small Magellanic Cloud in the constellation of the Toucan.
18. The Seagull Nebula This broad expanse of glowing gas and dust presents a bird-like visage to astronomers. Dominated by the reddish glow of atomic hydrogen, the gas and dust clouds with bright young stars spans over 100 light-years.
19. The Cosmic Web of the Tarantula Nebula It is the largest and most complex star forming region located in the Large Magellanic Cloud. The spindly arms of this nebula surround NGC 2070, a star cluster that contains some of the brightest, most massive stars known.
20. FUN FACT: Galileo Galilei is often incorrectly credited with the invention of the telescope. Instead, historians now believe the Dutch eyeglass maker Johannes Lippershey as its creator.
21. A Sun Halo Beyond Stockholm As water freezes in the upper atmosphere, small, flat, six-sided, ice crystals form. As these crystals flutter to the ground, an observer may pass through the same plane as many of the falling ice crystals. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our view.
22. NGC 2170 Reflecting the light of nearby hot stars, NGC 2170 is joined by other bluish reflection nebulae, a compact red emission region, and streamers of obscuring dust against a backdrop of stars.
23. Decorating the Sky Bright stars, dust and glowing nebulae decorate this cosmic scene: a bluish reflection nebula (left); a red emission nebulae of hydrogen gas (center); and a dark dust cloud forming a prominent silhouette (right).
24. Looking Back at an Eclipsed Earth Here is what the Earth looks like during a solar eclipse. The shadow of the Moon can be seen darkening part of Earth. The two bright spots that appear on the upper left are thought to be Jupiter and Saturn.
25. FUN FACT: Black Holes are so dense, and produce such intense gravity, that even light can not escape.
26. M82: Galaxy with a Supergalactic Wind The Cigar Galaxy, as this irregular galaxy is also known, contains outward expanding gas being driven out by the combined emerging particle winds of many stars creating a galactic superwind.
27. A Green Flash from the Sun As the Sun disappears completely from view, a last glimmer appears startlingly green. The effect is typically visible from locations with a low distant horizon, and is caused by the Earth's atmosphere acting like a prism.
28. Flame Nebula This nebula's reddish color is due to the glow of hydrogen atoms at the edge of the giant Orion molecular cloud complex. The central dark lane of absorbing interstellar dust hides a cluster of hot, young stars.
29. M81 and Arp's Loop Spiral galaxy M81 is one of the brightest galaxies in planet Earth's sky and similar in size to the Milky Way. The arching feature, known as Arp's loop, seems to rise from the galaxy's disk at the right.
30. FUN FACT: Light from distant stars and galaxies takes so long to reach us, that we are actually seeing objects as they appeared hundreds, thousands or even millions of years ago. So, as we look up at the sky, we are really looking back in time.
31. Comet Hartley Passes a Double Star Cluster This double cluster is bright enough to be seen from a dark location with the naked-eye. The bright comet Hartley (visible on the right) passed well in front but only a few degrees away from the famous double cluster.
32. NGC 7023: The Iris Nebula These clouds of interstellar dust and gas have blossomed 1,300 light-years away in the constellation Cepheus. Within the Iris, dusty nebular material surrounds a hot, young star.
33. The International Space Station Over the Horizon When the Space Shuttle Atlantis undocked from the International Space Station (ISS) and returned to Earth the crew took the below image. Visible on the ISS are numerous modules, trusses, and solar panels.
34. A Massive Star in NGC 6357 For reasons unknown, NGC 6357 is forming some of the most massive stars ever discovered. One such massive star is framed below carving out its own interstellar castle with light, surrounding gas and dust.
35. FUN FACT: The Crab Nebula was produced by a supernova explosion in 1054 A.D. The Chinese and Arab astronomers at the time noted that the explosion was so bright, that it was visible during the day, and lit up the night sky for months.
36. Virgo Cluster Galaxy NGC 4731 Barred spiral galaxy NGC 4731 lies some 65 million light-years away and resides in the large Virgo cluster of galaxies. Its broad arms are distorted by gravitational interaction with a fellow Virgo cluster member.
37. Ghost of the Cepheus Flare Spooky shapes seem to haunt this starry expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds faintly visible in dimly reflected starlight.
38. A Partial Lunar Eclipse Once again, part of the Moon moved through the Earth's shadow. This happens about once or twice a year on the average, but not each month since the Moon's orbit around the Earth is slightly tilted.
39. Sisters of the Dusty Sky Hurtling through a cosmic dust cloud some 400 light-years away, the lovely Pleiades or Seven Sisters star cluster is well-known for its striking blue reflection nebulae.
40. FUN FACT: Even though Mercury is the closest planet to the Sun, temperatures can reach -280 degrees F. Why? Since Mercury has almost no atmosphere, there is nothing to trap heat near the surface. So, the dark side of Mercury (the side facing away from the Sun) is very cold.
41. Pacman and Hartley Touring the solar system with a 6 year orbital period, small comet Hartley has been a tempting telescopic target, seen here with an alluring green coma as it shares the frame with emission nebula NGC 281.
42. Hubble's Lagoon This photograph of the Lagoon Nebula was recorded by the Hubble Space Telescope. This close-up view reveals shapes sculpted by light and winds from the region's new born stars.
43. Hidden Treasures of M78 This image was selected as the winner of the Hidden Treasures 2010 astrophotography competition. The image depicts M78 (center) embraced in dark dusty clouds, along with a smaller reflection nebula NGC 2071 (top).
44. The Once and Future Stars of the Andromeda Galaxy Two space-based observatories combined to produce this composite radar image. The reddish hues are stars, dust and gas comprising future star formation. The blue hues are star systems in the final stages of evolution.
45. FUN FACT: A supernova is a stellar explosion that 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.
46. Atoms-for-Peace Galaxy Collision NGC 7252 is a jumble of stars created by a huge collision between two large galaxies. The resulting pandemonium has been dubbed the Atoms-for-Peace galaxy because of its similarity to a cartoon of a large atom.
47. Home from Above Peering out of the windows of the International Space Station (ISS), astronaut Tracy Caldwell Dyson takes in the planet. ISS orbits the Earth once every 90 minutes and can be seen overhead just after sunset.
48. Jets on the Sun This photograph is the highest resolution image of solar flux tubes. Time-sequenced images have shown that spicules last about five minutes, starting out as tall tubes of rapidly rising gas that peak then fall back down.
49. NGC 346 in the Small Magellanic Cloud NGC 346 is a star forming region found in the Small Magellanic Cloud. These embryonic stars are strung along the dark intersecting dust lanes. The stellar infants' light is reddened by the intervening dust.
50. FUN FACT: Sunlight takes 8 minutes to reach the Earth and is responsible for the ocean currents and weather patterns on our planet.
51. Vista with NGC 2170 These dusty streamers and new born stars are part of an active star-forming region, embedded in a giant molecular cloud. This view reveals signs of ongoing star formation and massive young stars otherwise hidden by dust.
52. Horsehead and Orion Nebulas The Horsehead Nebula and the Orion Nebula are contrasting cosmic vistas. Adrift 1,500 light-years away in the night sky's most recognizable constellations, they appear in opposite corners of this stunning mosaic.
53. The Crown of the Sun During a solar eclipse, the Sun's extensive outer atmosphere, or corona, is an inspirational sight. This composite of 7 consecutive digital images over a range of exposure times reveals the crown of the Sun in all its glory.
54. Shaping NGC 6188 Dark shapes with bright edges winging their way through dusty NGC 6188. The recent star formation was likely triggered by winds and supernova explosions that swept up and compressed the molecular gas.
55. FUN FACT: The planet Neptune was discovered more than150 years ago in 1846, and since then it still has not yet completed an orbit around the Sun, as one Neptune year equals to 165 Earth years.
56. Moons Beyond the Rings of Saturn The robotic Cassini spacecraft orbiting Saturn took this view across the Solar System's most famous rings. Although it seems to be hovering over the rings, Saturn's moon Janus is actually far behind them, and even farther out from the camera is the heavily cratered Rhea.
57. Meteor in the Desert Sky A bright meteor with a greenish tinge flashes through the sky over the Mojave Desert. Recognizable in the background are bright stars in the northern asterism known as the Big Dipper.
58. An Enigmatic Star Cloud from Hubble Particularly enigmatic is the bright upside-down V that defines the upper edge of this floating mountain of interstellar dust. In general, this ghost-like nebula involves a small star forming region filled with dark dust.
59. The Medusa Nebula This old planetary nebula is 1,500 light-years away in the constellation Gemini and represents a final stage in stellar evolution as the low mass star transforms from a red giant to hot white dwarf and shrugs off its outer layers.
60. FUN FACT: Polaris, the north star, is the only star in the sky that doesn't appear to move from night to night. It lies almost exactly above the Earth’s northern axis, the point around which the whole sky turns. That’s why you can always use Polaris to find the direction north.
61. Dust Pillar of the Carina Nebula Inside this interstellar monster is a star that is slowly destroying it. This is actually a pillar of gas and dust that measures over a light year in length. The star is bursting out of the dust by ejecting particle beams.
62. Astronaut Installs Panoramic Space Window Floating just below the International Space Station (ISS), astronaut Nicholas Patrick put some finishing touches on the newly installed panoramic space windows
63. M78 and Reflecting Dust Clouds in Orion An eerie blue glow and ominous columns of dark dust highlight M78. M78 is about five light-years across and appears only as it was 1600 years ago because that is how long it takes light to go from there to here.
64. Radar Indicates Buried Glaciers on Mars New radar images from the Mars Reconnaissance Orbiter bolster an exciting hypothesis: huge glaciers of buried ice that might make a good drinking reservoir for future astronauts exploring Mars.
65. FUN FACT: The Moon is the only non-Earth object upon which a man has walked. The giant footprint left on the moon by astronaut Neil Armstrong is believed to be the oldest footprint.
66. The Elusive Jellyfish Nebula Normally faint and elusive, the Jellyfish Nebula is caught flanked by two bright stars. In fact, the cosmic jellyfish is seen to be part of the expanding debris cloud from a massive star that exploded.
67. The Magnificent Horsehead Nebula Sculpted by stellar winds and radiation, a magnificent interstellar dust cloud by chance has assumed this recognizable shape some 1,500 light-years distant, embedded in the vast Orion cloud complex.
68. Bright Sun and Crescent Earth from the Space Station This breathtaking view from the International Space Station depicts the Sun, a crescent Earth, and the long arm of a solar panel visible outside a window.
69. Moonquakes Surprisingly Common Analysis of seismometers left on the moon by the Apollo moon landings has revealed a surprising number of moonquakes. Pictured below is Apollo 11 astronaut Buzz Aldrin standing beside a lunar seismometer.
70. FUN FACT: The Sun is 4.5 billion years old and produces 383 billion trillion kilowatts of energy. However, lightning in the sky is nearly 3 times hotter than the Sun.
71. HCG 87: A Small Group of Galaxies These galaxies are gravitationally stretching each other during their 100-million year orbits around a common center. The pulling creates colliding gas that causes bright bursts of star formation.
72. The Veil Nebula This nebula is a large supernova remnant, an expanding cloud born of the death explosion of a massive star. Light from the original supernova explosion likely reached Earth over 5,000 years ago.
73. Galaxies on a String These galaxies are connected by a cosmic trail of gas, dust, and stars about 22,000 light-years long that is caused by mutual gravitational tides. Drawn out over billions of years, the gravitation will likely result in their merger into a single galaxy.
74. Comet Halley's Nucleus: An Orbiting Iceberg In 1986, the European spacecraft Giotto became one of the first spacecraft to encounter and photograph the nucleus of a comet. This image of Halley's nucleus features the dark nucleus and gas and dust flowing into Halley's coma.
75. FUN FACT: Earth is the only planet whose name is not derived from Greek/Roman mythology. Rather the word Earth developed over time as part of the English language to mean land