ESO

The galaxy Centaurus A (NGC 5128) is pictured in this image, taken with by the Wide Field Imager attached to the MPG/ESO 2.2-meter telescope at the European Southern Observatory's La Silla Observatory in Chile. With a total exposure time of more than 50 hours, this could be deepest view of Centaurus A ever created.

Astronomers are taking a long, deep look at one of the best-known galaxies beyond our own Milky Way, to learn more about what happened when it gobbled up another agglomeration of stars that got too close.

The entrails of the gobbled galaxy are prominent in this view of Centaurus A, a galaxy about 12 million light-years away in the constellation Centaurus. The bright haze of stars is the typical signature of an elliptical galaxy, but the dark, swirling band of dust around the center is a tip-off that the "A" in Centaurus A stands for "atypical."

Scientists believe the band represents the dusty leftovers of the galaxy that has been consumed in a gravitationally driven merger. Flashes of fresh hot stars can be seen along the edges of the band. It's thought that an energetic black hole, 100 million times as massive as our sun, is blasting out strong radio emissions from the center of the haze.

Much of this has been seen before, in previous images of Centaurus A. But today's image, captured by the Wide Field Imager on the European Southern Observatory's MPG/ESO 2.2-meter telescope in Chile, reveals extra details. That's because the camera exposure lasted for more than 50 hours, making this one of the deepest views of Centaurus A ever produced.

One reddish filament of material is visible above the left edge of the dark band. A fainter filament can be made out near the upper left corner of the picture. These filaments, hotbeds for infant stars, appear to line up with radio-emitting jets that are being spewed out from the central black hole. Such features can help astronomers reconstruct how Centaurus A gobbled a galaxy in the first place, and how the remains are being digested. Further studies, involving ESO's ALMA Observatory, will shed additional light on the scene.

More about the gobbling galaxy:

• Hubble spies a firestorm of starbirth
• Giant galaxy caught in mid-gobble
• Snapshot reveals a black hole's jets
• Cosmic collision probably spawned huge galaxy
• Scientists find 'normal' black hole in Centaurus A

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Slideshow: The World at Night 2012

Christoph Otawa / The World at Night

Experience the wonders of the night sky in a slideshow that features the winners of the 2012 "Earth & Sky" contest, presented by The World at Night.

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Light pollution never looked so good: The World at Night's annual photography contest highlights the beauties of the night sky, but it also highlights the challenges posed by humanity's efforts to light up the night.

This year's winners reveal how artificial lighting can add another dimension to the natural wonders of the stars and planets — or spoil the view forever. Hundreds of pictures were sent in from about 50 countries, including exotic locales such as the sub-Antarctic island of South Georgia, the national parks of Reunion Island and the savannas of South Africa, said Babak Tafreshi, the founder and leader of The World at Night. "We received a lot of submissions from Asian countries this year, especially China, India, Iran and Indonesia," the Iranian-born astrophotographer said in an email exchange.

He said the message of The World at Night is definitely getting out: "In general, it looks as if TWAN's aim of reclaiming the natural beauty of the night sky and promoting nightscape photography is reaching a growing audience worldwide, while the activities by amateur and professional astronomers and environmentalists to increase awareness on the light pollution issue is truly getting a lot of public attention."

This year's contest is limited to images taken since the beginning of 2011, but that leaves a lot to choose from — including pictures of Comet Lovejoy, the spectacular "Christmas Comet" that wowed skywatchers in the southern hemisphere, as well as the stunning auroral images that have cropped up over the past few months. Both those phenomena are represented in today's top-10 roundup from TWAN.

Tafreshi drew attention to two potential perils facing astrophotographers nowadays: light pollution and photo fakery. He noted that the increasing glare of city lights was "not just an astronomer's problem," but also "a major waste of energy, and like any other form of pollution, it disrupts ecosystems and has adverse health effects."

"Today, most city skies are virtually empty of stars," he said in his email. "About two-thirds of the human population today lives under light-polluted skies, not dark enough to see the Milky Way. Seeing a real dark sky is a must-see experience in the life of each of us, moments that you will not forget in your entire life."

Tafreshi also said there's a fast-rising concern about images that may not be telling the truth about the earth and sky.

"Unfortunately, a majority of photographers who are interested in nightscape photography are less familiar with astronomy, and the natural look and color of the night sky," he said. "So many landscape astrophotos today are intensely saturated, unnaturally contrasted, and sometimes with totally wrong colors of the sky. We had stunning compositions and amazing landscapes at night, some made by famous photographers, which were ruled out of the contest simply because they were 'overcooked' in processing."

You can rely on TWAN's prize-winning pictures to show the true glories of the night sky, along with the glow of the world below. Check out our slideshow, and read more of Tafreshi's observations in the comment space below.

More astronomy slideshows:

• The World at Night 2011
• Cosmic Log archive of auroral imagery
• All-time top 10 astronomy pictures from APOD
• Month in Space Pictures | Year in Space Pictures 2011

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL-Caltech / SSI

Two of Saturn's more than 60 moons join the ringed planet in this scene, captured by the Cassini orbiter on Jan. 19 and released on April 30. Tethys appears as a small white dot above the rings on the far left of the image. Enceladus appears as a smaller bright speck beside the planet. The rings cast wide shadows on the planet's southern latitudes.

Two of Saturn's moons are dwarfed by the giant planet and its rings in this family portrait from the Cassini spacecraft, which will mark its eighth year in Saturnian orbit in July. This image was put out by the Cassini imaging team on Monday, just a little too late to make our Top 20 roundup for the Month in Space Pictures — but it's worth passing along as a bonus prize.

You can see 660-mile-wide Tethys as a white dot toward the left edge of the image, and 313-mile-wide Enceladus as a smaller bright speck beside the planet. Tethys is thought to be composed mostly of water ice with a bit of rock mixed in, while Enceladus is a very special case: Cassini has repeatedly documented geysers of water ice spewing from fissures in that moon's surface — suggesting that liquid water and perhaps even living things may lie beneath. It'll be up to a future probe to plumb the mysteries of Enceladus more deeply.

Saturn's rings are seen nearly edge-on, and in this picture they're casting wide, curved shadows on Saturn's southern hemisphere. Bad Astronomy's Phil Plait says he can't help noticing the thin white ribbon of clouds stretching across the planet's northern hemisphere. Those may be the remnants of a monster storm that wrapped itself around the globe for months, starting in late 2010. "Our gas giants don't screw around," he writes. "When they do something, they do it big."

And when we do the Month in Space Pictures slideshow, we do it big as well. Click on the image below to see some of the best out-of-this-world views from the month of April. You'll find shots from the final flights of the shuttles Discovery and Enterprise, photos of weird phenomena on Mars and Uranus, and even a UFO (Galaxy, that is). If you want to find out more about the stories behind the pictures, leave a comment and I'll try to point you in the right direction.

Slideshow: Month in Space: A blaze of glory

NASA/SDO/AIA

Click through a solar eruption, the final odyssey of the shuttle Discovery and other outer-space highlights from April 2012.

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Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Skywatchers as far south as Colorado and Kansas witnessed a quick flare-up of the northern lights this week, which called to mind the brilliant, beautiful displays that northerners saw earlier this year. The skies have settled down — for now — but developments on the sun suggest we could be in for another wave of auroral glories.

The greenish glow over Lake Superior, recorded from Michigan's Upper Peninsula at 2 o'clock in the morning by Shawn Malone of LakeSuperiorPhoto.com, was impressive enough to make NBC's "Nightly News" on Tuesday night. In an email, Malone told me that the "intensity caught me off guard."

"Check out the passing freighter for scale," Malone said in his comments on the Vimeo version of the video. "What a view those sailors must have had!"

Mark Riutta had a similar view from Copper Harbor Cabins on the Upper Peninsula, as the time-lapse video below illustrates. Riutta told me over the phone that he and his girlfriend were getting the cabins ready for the summer season and were surprised by how bright Tuesday's display turned out to be. "We were just about to go to sleep, when we looked out and wondered, 'Why is it so light out there?' he said.

SpaceWeather.com provides a roundup of auroral images from a dozen U.S. states, mostly in the Midwest but also including the top state for the northern lights, Alaska. And speaking of Alaska, here's an unconventional view of the aurora that was recorded from a height of 90,000 feet during "Project Aether: Aurora," a scientific experiment that took place this month:

Project Aether, led by University of Houston physicist Ben Longmier, sent up almost two dozen weather balloons laden with high-definition cameras and scientific instruments to monitor auroral activity near Fairbanks. Most of the payloads have been recovered, but the student researchers are still on the lookout for a few that haven't yet been located. If you happen to be in the Fairbanks area and find one of them, you could win a prize.

More prizes could be in store for aurora-watchers: The National Oceanic and Atmospheric Administration's Space Weather Prediction Center reports that we're currently in the midst of a minor geomagnetic storm, which could spark another wave of northern lights. What's more, an active region of the sun known as AR1465 has developed the type of magnetic field that's associated with stronger X-class outbursts.

To keep tabs on the solar weather report, check in with SpaceWeather.com as well as the Space Weather Prediction Center's website and Facebook page. And to watch some classic auroral videos, check out the gallery offered by NASA's Gateway to Astronaut Photography of Earth.

More auroral glories:

• Awesome auroras on Uranus ... and Earth
• Farewell to the northern lights
• Northern lights make for must-see TV
• Southern exposure for auroral lights
• Slideshow: The best of the northern lights
• Cosmic Log's auroral archive

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto,"my book about the controversial dwarf planet and the search for other worlds.

Bill Ingalls / NASA

The prototype space shuttle Enterprise is seen mated on top of NASA's modified Boeing 747 Shuttle Carrier Aircraft at Dulles International Airport in Virginia on Friday. Enterprise was the first orbiter built for the space shuttle program, but never went into orbit. It was used primarily for ground and flight tests within the atmosphere. Enterprise had been on display at the Smithsonian National Air and Space Museum's Udvar-Hazy Center in Virginia, but is now being prepared for its new home at the Intrepid Sea Air and Space Museum in New York.

A day after the space shuttle Discovery took its place at the Smithsonian, the prototype shuttle Enterprise is perched on a modified 747 jet for its journey to New York. Now the timing of the trip depends on East Coast weather.

Overnight, Enterprise was towed out to Dulles International Airport and hoisted up into the air with two giant cranes. The jet, known as the Shuttle Carrier Aircraft or SCA, was brought underneath the 75-ton artifact. Then Enterprise was lowered down and "soft-mated" onto the plane at three attach points. The bolts will be tightened down for hard-mating on Saturday, in preparation for the big flight to New York.

This is the same process that Discovery went through in Florida leading up to Tuesday's flight to Dulles for its installation at the Smithsonian National Air and Space Museum's Steven F. Udvar-Hazy Center, next to the airport. On Thursday, Enterprise was moved out of the space it held since the center's opening in 2003, and Discovery was moved in.

NASA had been planning for Enterprise and the SCA to take off from Dulles as early as Monday morning, but this afternoon the space agency said the flight would be delayed due to a forecast of inclement weather in Washington as well as New York. "Managers will continue to review weather forecasts and announce a new flight date as soon as practical," NASA said in its advisory.

When forecasters give the go-ahead, the shuttle-jet combo will head up the East Coast and do a series of New York flyovers. You can expect to see the double-decker behemoth sailing over the Statue of Liberty as well as the Intrepid Sea, Air and Space Museum, the retooled ship where Enterprise will be put on display. After the flyovers, the Enterprise will be set down at New York's John F. Kennedy International Airport.

The shuttle-jet flight is old hat for Enterprise: The craft was the first vehicle built for the space shuttle program, and got its name in part thanks to a write-in campaign by "Star Trek" fans. Unlike the fictional starship, NASA's Enterprise never flew in space. Instead, it was used for ground tests as well as aerodynamic test flights atop the 747 carrier plane. Once the shuttle launches ramped up, Enterprise was deemed no longer needed for testing. It was handed over to the Smithsonian in 1985. The Udvar-Hazy Center's James S. McDonnell Space Hangar was specifically designed to show off the Enterprise.

After the 2003 Columbia tragedy, some sections of the Enterprise's wing panels were removed for impact tests, and those tests made a huge contribution to the accident investigation. That demonstrated that the shuttles can continue to benefit the space program long after their retirement.

It will take a few weeks for Enterprise to settle into its retirement home: The cranes will have to be set up for the shuttle's "demating" at JFK. Then Enterprise will have to be lifted onto a barge and brought up the Hudson River by a tugboat. The schedule calls for Enterprise to be hoisted aboard the Intrepid's flight deck sometime in June. It'll be put on display in a temporary climate-controlled pavilion this summer, and eventually housed in a permanent exhibit facility.

After Enterprise, there's one more shuttle-jet flight on tap: the transfer of Endeavour from NASA's Kennedy Space Center to the California Science Center in Los Angeles. That cross-country trip, due to take place in the latter part of this year, is likely to spark a nationwide frenzy of "Spot the Shuttle" sightings.

The last shuttle that flew in space, Atlantis, is going just down the road to Kennedy Space Center's visitor center, so there'll be no need to bring out the plane for that trip.

For more pictures of the Enterprise-747 mating, check out NASA Headquarters' Flickr gallery. And to get updates on the timing of Enterprise's flight and the flyovers, keep tabs on NASA's website as well as msnbc.com's space news section.

More about the shuttle shuffle:

• Astronauts revisit the shuttle's pros and cons
• How NASA selected the shuttles' future homes
• Seattle gets first pieces of shuttle trainer

Updated 5:20 p.m. ET.

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Slideshow: 2012's top underwater shots

Ximena Olds

Click through the best pictures from the University of Miami's 2012 Annual Underwater Photography Contest, hosted by the Rosenstiel School of Marine and Atmospheric Science.

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Even a humble sea slug can be stylish, if you find the right slug in the right place. That's what photographer Ximena Olds did when she snapped a picture of an orange headshield sea slug amid the green seagrass in the U.S. Virgin Islands. Her contrasting-color picture took the top prize in this year's Underwater Photography Contest, hosted by the University of Miami's Rosenstiel School of Marine and Atmospheric Science.

More than 700 images were submitted for the 2012 contest, showing scenes from 20 countries. Awards were given in several categories, including Macro, Wide Angle, and Fish or Marine Mammal Portrait. Another category was set aside for University of Miami students. Olds' photo was submitted in the Macro category but was singled out for the "Best Overall" prize.

The judges included University of Miami lecturer Myron Wang, underwater photographer Nicole Wang and Michael Schmale, a professor at the Rosenstiel School.

"The quality of photos keeps getting better each year," Myron Wang, who has been judging the contest since its inception in 2005, said in today's announcement of the winners. "Judging becomes more difficult when you have so many wonderful pictures to choose from. For me, there were excellent entries in every category, but this year’s standout was the great picture of the juvenile sperm whale taken by Douglas Kahle in Dominica — it is spectacular!”

This year, for the first time, a "Fan Favorite" category was created for Internet voting. More than 1,200 ballots were cast in the poll, with Todd Aki's shot of a silhouetted jellyfish taking the prize.

The underwater photography contest is held annually, and is open to all amateur photographers who earn no more than 20 percent of their income from their photography. Click through the slideshow above, or check out the Rosenstiel School's website for more about the winners.

More underwater beauties:

• Flip through this year's candidates for fan favorite
• Bellyflop! Amazing photos of underwater dogs
• 2011: Cameras capture underwater wonders
• Photo exhibit displayed on artificial reef

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

DigitalGlobe

This picture from DigitalGlobe's QuickBird satellite shows the launch pad at the Tongchang-ri Launch Facility in North Korea, as seen on April 9. Three dark-colored support vehicles are lined up on the launch apron. The rail-mounted mobile launch platform is toward the bottom of the pad, with an exhaust deflector that's designed to deal with the hot blast of launch.

While North Korean officials were showing off their preparations for a controversial satellite launch, DigitalGlobe's Quickbird satellite was snapping high-resolution pictures of the scene from far above. The images reveal how far the North Koreans have come — and how much can be gleaned about their intentions from orbit.

DigitalGlobe is a commercial satellite imagery provider, and QuickBird can provide pictures at a resolution of a half-meter (20 inches) per pixel. But you can bet that U.S. intelligence agencies are getting significantly better views of the Tongchang-ri Launch Center from their satellites.

North Korea is due to launch its Unha-3 ("Milky Way 3") rocket anytime between now and April 16, ostensibly to send an Earth-observing satellite known as Kwangmyongsong-3 ("Bright Shining Star 3") into a pole-to-pole orbit. The United States and its allies worry that the launch is really more of a test of North Korea's capability to launch intercontinental missiles as weapons.

International journalists, including a team from NBC News, were invited to visit the secretive hard-line communist nation this week for an on-the-ground assessment of the space mission. NBC News space analyst James Oberg said that in its current configuration, the booster is "not a military missile ... but it's darn close."

"This rocket is not a weapon, but it's maybe 98 percent of one," Oberg said. "It can be converted all too easily and all too frighteningly into a weapon, and they don't need it."

AmericaSpace's Craig Covault said the Tongchang-ri facility is clearly built to handle rockets much larger than the Unha-3. He quoted U.S. and South Korean intelligence analysts as saying they believe the complex could be used for tests of North Korea's "Satan" long-range ballistic missile, as well as a North Korean-Iranian booster with up to six engines clustered in the first stage.

"Iran and possibly North Korea plan to use the large new space launch booster to send Iranian and North Korean astronauts into space," Covault wrote. He lays out a Korean-Iranian missile development program that sounds positively scary.

North Korea might have been hoping that this week's visit by journalists would put Washington's fears to rest. But based on the feedback so far, it doesn't sound as if that'll be the case.

Here's tonight's report from NBC News' Richard Engel in Pyongyang:

... Here's a computer-generated animation of the expected launch from Analytical Graphics Inc.:

... And here are more satellite pictures from DigitalGlobe:

An orbital view from DigitalGlobe's QuickBird satellite shows North Korea's Tongchang-ri Launch Facility from an altitude of 420 miles (680 kilometers).

James Oberg / msnbc.com (left) / DigitalGlobe (right)

The map of the Tongchang-ri Launch Facility that was displayed by the North Koreans during a news briefing (left) is compared with the overhead view from DigitalGlobe (right). The orientation of the satellite picture has been rotated to approximate the orientation of the map.

DigitalGlobe

This satellite view shows the horizontal processing building at the Tongchang-ri Launch Facility in North Korea, with a support vehicle parked in the dark-colored parking lot below the building.

DigitalGlobe

This DigitalGlobe satellite image, taken from orbit on April 9, shows the Tongchang-ri Launch Facility in North Korea. The structure in the lower part of the frame is known as the high-bay processing building, and the structures in the upper pat are housing facilities. VIP housing is at leff.

More about North Korea's space plans:

• North Korea says it's fueling rocket for launch
• What you need to know about the launch
• North Koreans desperate for Western approval
• Clues about North Korea's plans come to light
• North Korea shows off its launch pad and satellite
• Q&A: Rocket is 'not a military missile ... but it's darn close'
• World News: NBC gets a rare peek inside North Korea
• PhotoBlog: Pictures from the North Korea rocket tour
• Inside North Korea: Closely watched launch poses risks
• North Korea's launch sparks more worries than Iran's
• A look at North Korea's rocket technology

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Thorbjørn Haagensen

Thorbjørn Haagensen took this picture of the northern lights on April 3 from Hillesøy, close to Tromsø in northern Norway.

A stunning aurora season is finally coming to an end in the far north, thanks to the longer days and the shorter nights. But there were still a few opportunities this week for the northern lights to ripple across the sky in a "last dance," as this picture from Norwegian photographer Thorbjørn Riise Haagensen shows.

"Beginning in the middle of May, the midnight sun brings sunshine all night long," Haagensen told SpaceWeather.com today. "Already some daylight is visible at the horizon at midnight. There is still enough darkness, though, for the last dance of the auroras."

Haagensen's photograph shows the aurora's glow in northern Norway; click on over to his Haagensenfoto.no website for more of his pictures, including an aurora gallery. Speaking of galleries, SpaceWeather.com offers some thrilling pictures from Minnesota and northern Quebec as well as Norway.

Here's a time-lapse movie of the northern lights' last dance that was captured by Jan R. Olsen, a photographer who lives in Olderdalen, Norway. "Not many days left with the aurora," he wrote. "This was shot on the night of April 2nd. Soon it will be too light in the night to see the aurora."

Even though the northern lights may be on the wane, the southern lights should be hitting their prime — and the people in the best position to see the show in the south are the astronauts on the International Space Station. Keep an eye on the Gateway to Astronaut Photography of Earth for shots of the aurora australis from space.

Earlier stories of auroral glories:

• Northern lights make for must-see TV
• Southern exposure for auroral lights
• Sky lights go wild, north and south
• Solar storm lights up northern skies
• Slideshow: The best of the northern lights
• Cosmic Log's auroral archive

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.