Laurent Silvani

The northern lights shine over La Baie in Quebec at 2 a.m. Saturday, in a picture taken by Laurent Silvani. To see more of Silvani's work, check out his Silvani.ca website and his Facebook page.

A slight solar storm ejected from a powerful sunspot sparked northern lights as far south as Colorado on Friday night — and there should be more to come.

The heightened aurora was sparked by a burst of electrically charged particles thrown off from an active spot on the sun known as Region 1748. That region is the one responsible for four powerful X-class flares that blasted out from the sun this week. Region 1748 is just now turning in our direction, and forecasters at the National Oceanic and Atmospheric Administration's Space Weather Prediction Center say it has the potential to throw some hefty storms our way.

Storms from the sun have the potential to disrupt satellite communications and power grids, and in extreme cases, the radiation risk could force airlines to reroute their intercontinental flights to lower latitudes. But Joe Kunches, a spokesman for the prediction center, said experts now have much better capabilities at their command to reduce the risks. And so far, he said, the active sun has been throwing "softballs" at us — at least compared with bigger flare-ups like the Halloween storms of 2003 or the Bastille Day storm of 2000.

The most noticeable effects of recent solar disruptions have come in the form of enhanced auroral displays. SpaceWeather.com reports that faint glows were recorded Friday night in Colorado as well as Vermont, New York, Michigan, Wisconsin, Iowa and Washington state.

Farther north, the fireworks show was significantly brighter. Astrophotographer Laurent Silvani captured some great images from Quebec's Saguenay region, about 100 miles (160 kilometers) north of Quebec City.

"Following a magnetic storm, the aurora borealis was particularly visible in the sky with its waves and colors. A particularly beautiful sight!" he wrote in an email. "Many people from the Saguenay do not know that there are auroras occasionally here. They are surprised to see my pictures every time."

Check out Silvani's website and Facebook page for more.

For additional views of auroral glories — including, yes, some photos of the southern lights as seen from Antarctica —take a spin through SpaceWeather.com's photo gallery. And who knows? You might be able to catch the show yourself over the next couple of nights. Another geomagnetic storm is expected to sweep over Earth's magnetic field on Sunday, according to the Space Weather Prediction Center.

To find out what can be seen from where, keep an eye on the center's Facebook page as well as its Ovation aurora forecast maps. If you're in the aurora zone, the best time to look is after midnight. The best places are far away from city lights, with clear, crisp skies. Got pictures? Share them with us via NBC News' FirstPerson photo upload page.

While you're waiting for those dark skies, feast your eyes on these beautiful time-lapse aurora videos, plus our slideshow: 

Slideshow: Lights in the sky

Click through stunning images of the auroral displays created by geomagnetic storms.

Launch slideshow

More auroral glories:

• Northern lights dance with a comet
• Spend a night with the lights — in a minute
• Cosmic Log's aurora archive

Alan Boyle is NBCNews.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. To keep up with Cosmic Log and the rest of NBCNews.com's science and space coverage, sign up for the Tech & Science newsletter, delivered to your email in-box. 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 2013

Andreas Max Baeckle

The winners of the 2013 "Earth and Sky" photo contest show off the beauties of the night sky and demonstrate the effects of light pollution.

Launch slideshow

Are the images featured in The World at Night's annual "Earth and Sky" photography contest meant to celebrate the wonders of the night sky, or draw attention to the worries about the night sky? They're meant to do both, says astrophotographer Babak Tafreshi.

For example, consider "Stars Over Salzburg," one of this year's top-rated images. Your first impulse is to marvel at the golden glow of the Austrian city, as seen from an Alpine vantage point high above.

"But then you realize the photographer has moved away from the city to the mountaintops in order to separate himself from the light pollution," Tafreshi, founder of The World at Night, told NBC News in an email. "Inside the yellow light cast by the city, people are no longer able to see this beauty."

That's the tragedy of the modern world, right? Studies suggest that as much as 80 percent of the world's population can no longer see the Milky Way, due to the lights that illuminate our cities and roadways. But it doesn't have to be that way, and the picture of Salzburg proves it. Tafreshi pointed out that the direct, unshielded glow of city lights can be seen even from a mountaintop.

"That shows that the lights are shining upward," he said. "Light pollution is not the lights we need for our modern world. It's the unnecessary, wrong-directed and excessive light that scatters to the sky instead of illuminating the ground. It isn't just an astronomer's problem. It's a major waste of energy, it disrupts ecosystems and has adverse health effects."

The International Dark-Sky Association estimates that $1 billion is spent in the United States every year to generate artificial light that goes to waste. And as other countries become more urbanized, the stars disappear from wider swaths of the world.

"Our images try to show how the night sky is an essential part of our environment, and not just an astronomer's laboratory," Tafreshi said. "They display how the night sky is becoming a forgotten part of nature for many people in urban, light-polluted areas. A major goal for us in TWAN imaging is to reclaim the beauties of the night sky and make people aware of this."

The World at Night isn't just about the dark side of the disappearing sky. The winning photos include views that reveal cosmic glories in all their purity. "A good example in this year's contest is 'Crossed Destiny' by Luc Perrot, from Reunion Island near Madagascar," Tafreshi said. "The stunning view of the Milky Way above the Indian Ocean has no touch of our modern world. The galactic band is merged with the horizon of our planet."

Click through our slideshow of images from this year's "Earth and Sky" contest, and check out The World at Night's website for still more cosmic glories and cautionary tales.

More beauties of the world at night:

• The World at Night 2012: Darkness and light
• Slideshow: The World at Night 2011
• All-time top 10 astronomy pictures
• The Month in Space Pictures: April 2013

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Slideshow: Art of Science 2013

Mingzhai Sun and Joshua Shaevitz / Princeton

Click through the top images from Princeton University's Art of Science Competition, which features images of artistic merit created during the course of scientific research.

Launch slideshow

Worms are a source of wonder in this year's crop of aesthetically pleasing scientific images, served up by Princeton University's Art of Science Competition.

"C. instagram," one of the contest's top photos, features a wriggling network of C. elegans worms on an agar plate covered with E. coli bacteria. Ewwww, right? But when Princeton molecular biology student Meredith Wright looked at the scene through a microscope, she had a different reaction: Cooool!

"I found the pattern on this plate particularly lovely, and was able to capture it with my cell phone by holding the lens of my phone's camera up to the microscope eyepiece," she wrote. "I've since shared the photo on social networking sites and have had friends who've never been interested in biology ask me more about my work because of this photo."

Researchers don't do what they do to create beautiful pictures, but beauty often arises amid the search for scientific truth. That's what the Art of Science program is going for: Images produced in the course of scientific research that have aesthetic merit as well.

This year's theme was "Connections." Andrew Zwicker, director of science education at the Princeton Plasma Physics Laboratory, said that some of history's most exciting scientific discoveries have come from making connections between different disciplines.

"For example, with physics and biology, everyday there is a new finding showing that the two are connected in the most fascinating and profound way," he said in this year's contest announcement. "In a similar vein, connecting the aesthetics of laboratory images to their scientific importance has transformed how we look at our data and results. With the 2013 Art of Science competition, we are celebrating all manner of connections."

Meredith Wright / Princeton Art of Science Competition

"C. instagram" shows masses of C. elegans worms on an agar plate. The picture was taken with a smartphone camera through a microscope, and shared via Instagram.

The connections between beauty and truth are reflected in this year's three top-rated images. First prize goes to Martin Jucker's visualization of Earth's wind patterns in shades of red and blue. Michael Kosk's photomicrograph of crushed birch wood took second place. And third prize went to a many-branching visualization of online connections for the websites set up by the plasma physics lab and by the Lewis Center for the arts.

"These two embroidery-like figures visually give us an idea of the similarities and differences of a website devoted to science and one devoted to the arts," said the prize-winning webmasters, Paul Csogi and Chris Cane.

The three prize-winners will share $500, divided into shares of $250, $154.51 and $95.49 in accordance with the aesthetically pleasing golden ratio. Another 40 images are included in Princeton's Art of Science 2013 exhibit, which opened on Friday in the atrium of Princeton's Friend Center. The works were chosen from 170 images submitted from 24 different departments across campus.

Click through our slideshow featuring some of the pictures in the exhibit, and then be sure to visit the Art of Science website and the Art of Science Facebook page for much, much more. And don't forget to share. That's precisely what Meredith Wright hopes you'll do with "C. instagram."

"This image represents the simple pleasure of finding something beautiful when you don't expect to," she wrote, "and it shows how easy it is to connect science with new audiences by simply clicking 'share.'"

More artistic science to share:

• Solid science turns into crowd-pleasing art
• Creepy critters and cool close-ups
• How beauty was found in a slimeball

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Canada's new printed-polymer $5 bill has received the country's highest sendoff, altitude-wise, from International Space Station commander Chris Hadfield. Tuesday's currency-unveiling ceremony in space was just the latest in a series of achievements that have drawn attention to Canada's best-known spaceflier.

Hadfield already has made his mark as a photographer, a musician and composer, and an explainer of outer-space phenomena ranging from crying to vomiting in zero-G. There's a reason why the Bank of Canada turned to him to introduce one of the last currency notes to be converted to counterfeit-resistant polymer: One side of the $5 bill celebrates Canada's contributions to space exploration, including the space station's Canadarm2 and DEXTRE robot.

"I just want to tell you how proud I am to be able to see Canada's achievements in space highlighted on our money," Hadfield told Canadian officials via a space-to-Earth video link. Hadfield said the pictures played to Canada's strength in space robotics.

As Hadfield spoke, he plucked a bill from the wall of the station's Destiny laboratory and set it spinning in zero gravity in front of the camera. The other side of the bill has a less spacey theme: It features a portrait of Sir Wilfrid Laurier, who was Canada's prime minister from 1896 to 1911.

Bank of Canada spokeswoman Julie Girard said the outer-space ceremony was "quite a few months in the making." The polymer note was flown up to the space station with Hadfield back in December, and held in reserve for Tuesday's ceremony. "We wanted to be the first to unveil a bank note in space," she told NBC News.

Bank of Canada

This rendition of the Canadian $5 bill shows Canadarm2 and DEXTRE in more detail. The bank note is to be issued in November.

Canada's new $10 note, which commemorates the country's rail system, was unveiled at the same time in Ottawa. The $5 and $10 bills will complete Canada's conversion to polymer-based currency, tricked up with transparent areas and hologram markings to make them harder to counterfeit. The Bank of Canada says these notes should last two to three times longer than the country's cotton-based paper bank notes — and when they wear out, they can be traded in and recycled.

The new notes won't be rolled out to the Canadian public until November. That'll provide enough lead time for training clerks and law enforcement officials to get familiar with the bills. Hadfield will be back on Earth long before November: He's due to get on board the next Soyuz capsule leaving the station on May 14, alongside NASA's Tom Marshburn and Russia's Roman Romanenko.

So what happens to Hadfield's $5 bill? Girard said the astronaut will bring the note down with him, and it will eventually be put on exhibit at the Bank of Canada's currency museum.

Several of Hadfield's priceless photographs of Earth from space are already on exhibit in our latest Month in Space Pictures slideshow. Check out the pictures, plus this bonus 3-D picture of Mars from NASA's Curiosity rover. The 3-D photo was featured in our "Where in the Cosmos" contest on Facebook. Cosmic Log fan Ryan Meader was the first to report that the mountain featured in the picture is referred to as Mount Sharp (by Curiosity's science team) and Aeolis Mons (by the International Astronomical Union).

Meader says he's a long-time reader: "I think it's fair to say that I'm on the hard-core passionate end of the spectrum — so it was to my great delight that I got the jump on this little contest," he wrote.

We're delighted to send Meader a free pair of red-blue 3-D glasses, compliments of Microsoft Research's WorldWide Telescope project — and we'll have a few more spectacles to give away in the weeks to come. So click on the "like" button for the Cosmic Log Facebook page and get ready for the next "Where in the Cosmos" contest.

Slideshow: Month in Space: April 2013

Chris Hadfield / CSA

Feast your eyes on an alligator-like mountain range and other curiosities seen from outer space in April 2013.

Launch slideshow

NASA / JPL-Caltech

A stereo image from NASA's Mars Curiosity rover shows the terrain between the robot and Mount Sharp (a.k.a. Aeolis Mons) inside Gale Crater. Wear red-blue glasses to get the 3-D effect, and don't dwell too much on the hardware in the foreground. Trying to focus in on that part of the picture can make you go cross-eyed.

More about Canada's best-known spaceflier:

• Chris Hadfield's tribute to Boston bomb victims
• What happens to a washcloth in space?
• NBC News archive on Chris Hadfield

Alan Boyle is NBCNews.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. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. 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

The spinning vortex of Saturn's north polar storm resembles a deep red rose in this false-color image from NASA's Cassini spacecraft. Measurements have sized the eye at a staggering 1,250 miles (2,000 kilometers) across with cloud speeds as fast as 330 miles per hour (150 meters per second). This image was taken from a distance of 261,000 miles (419,000 kilometers) on Nov. 27, 2012, with filters sensitive to near-infrared light.

The eye of a super-hurricane at Saturn's north pole looks like a peaceful red rose in a fresh bouquet of pictures from NASA's Cassini orbiter. But don't be fooled: That rosy appearance is merely due to the false colors ascribed to infrared wavelengths.

This storm's eye measures 1,250 miles (2,000 kilometers) in diameter, about 20 times wider than the average hurricane's eye on Earth. The outer clouds at the hurricane's edge are traveling at 330 mph (530 kilometers per hour), which would be off the scale on our planet. The vortex whirls inside Saturn's mysterious hexagonal cloud pattern, and it's not going anywhere.

"We did a double take when we saw this vortex, because it looks so much like a hurricane on Earth," Caltech's Andrew Ingersoll, a member of the Cassini imaging team, said in a NASA news release on Monday. "But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapor in Saturn's hydrogen atmosphere."

On Earth, hurricanes are fed by warm ocean water. But there are no oceans on Saturn — so what source drives this super-hurricane? Cassini's scientists want to find out, and whatever they find might add to our understanding of storm dynamics on Earth as well.

The Cassini team suspects that this storm has been active for years, but Cassini has only recently been able to watch it in visible light. When the bus-sized spacecraft arrived in 2004 to begin its $3.5 billion mission to study Saturn and its moons, the north pole was shrouded in winter darkness. Now spring is coming to the north, and Cassini has shifted to an orbit that makes it easier to see the increasingly sunlit storm.

In an email, Cassini imaging team leader Carolyn Porco of the Colorado-based Space Science Institute said the hexagon-ringed vortex is "one of the most gorgeous sights we have been privileged to see at Saturn." But such sights won't last forever: Cassini's extended mission to Saturn is due to end in 2017 with a controlled plunge into Saturn's clouds.

To keep up with the mission in its final years, check in on NASA's Cassini website as well as the online home of the Cassini imaging team, and follow @CassiniSaturn on Twitter.  

NASA / JPL-Caltech / SSI

A false-color image from Cassini highlights the storms at Saturn's north pole. The angry eye of a hurricane-like storm appears dark red, while the fast-moving hexagonal jet stream framing it is a yellowish green. Low-lying clouds circling inside the hexagonal feature appear in a muted orange color. A second, smaller vortex pops out in teal at the lower right of the image. The rings of Saturn appear in vivid blue at the top right. The colors are coded to show different near-infrared wavelengths, which are associated with different altitudes.

Slideshow: Best of Cassini

The Cassini spacecraft is sending back unprecedented imagery of Saturn, its rings and its moons. Click "Launch" to see some of the greatest hits from the Cassini mission.

Launch slideshow

Update for 8:25 p.m. ET April 30: NBC Nightly News anchor Brian Williams found these pictures as awe-inspiring as I did. Here's the video clip:

More beauties from Saturn:

• Venus sparkles in Cassini snapshot
• Seasons change, and so does Saturn
• Cosmic Log archive on the Cassini mission

Alan Boyle is NBCNews.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. To keep up NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Slideshow: Month in Space: April 2013

Chris Hadfield / Canadian Space Agency

Feast your eyes on an alligator-like mountain range and other curiosities seen from outer space in April 2013.

Launch slideshow

Slideshow: Our fragile Earth

AFP - Getty Images

Images from outer space highlight the fragility — and the resilience — of our beautiful blue planet.

Launch slideshow

Technological advances aren't always kind to Mother Earth — witness the impact of nuclear waste, industrial emissions and plastic bottles — but high-tech environmental monitoring systems are also helping us get a handle on the state of our planet. It's good to remember that as Earth Week draws to a close.

Just in the past couple of years, NASA has added to the nation's fleet of Earth-observing satellites. In 2011, the $1.5 billion Suomi NPP satellite went into orbit, blazing a trail for a new generation of planet-watchers that can provide data about extreme weather as well as environmental indicators. Suomi's five sensor systems are tracking atmospheric and sea surface temperatures, biological productivity, ozone levels and much, much more.

This February, the $855 million Landsat Data Continuity Mission finally got off the ground, opening a new chapter for the 41-year-old Landsat Earth-monitoring program. LDCM will monitor surface temperatures around the planet and generate 400 images a day in visible and infrared wavelengths. Multi-wavelength observation is a key technology for monitoring the planet's health, because thermal infrared readings can tell you how vegetation is faring, how much heat the world's cities are putting out, and how the world is coping with climate change.

"If you want to deal with climate, you need observations, instead of just talking about belief or simulations," Compton Tucker, senior biospheric scientist at NASA's Goddard Space Flight Center, told NBC News.

Even Earth's gravity field can provide insights into how the planet is changing: Readings from the Gravity Recovery and Climate Experiment, or GRACE, have traced the loss of ice from the world's glaciers and ice caps by measuring subtle changes in our planet's distribution of mass. "It's really a phenomenal source of information to study water on the surface," Tucker said. 

For decades, observations from outer space — including data from NASA satellites such as Terra and Aqua, as well as the National Oceanic and Atmospheric Administration's weather satellites and the Landsat constellation — have been helping scientists understand what's happening to our environment.

Suomi NPP and LDCM are continuing that legacy, but there are still concerns about the future: Last year, the National Research Council voiced grave concerns about America's aging Earth-observing system, saying that the projected loss of satellite capability "will have profound consequences on science and society, from weather forecasting to responding to natural hazards."

The federal government's money troubles could trigger more immediate cutbacks in the nation's Earth-watching capability. It may well turn out that the biggest obstacles to understanding what ails our planet aren't natural phenomena, but problems of our own making.

More about high-tech environmental monitoring:

• How's Earth's health? New network to keep tabs
• Landsat celebrates 40 years of watching our planet
• How satellites are saving the world

Alan Boyle is NBCNews.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. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / JPL / Cornell

When some people look at this nine-year-old picture from NASA's Spirit rover, they see a graphic depiction of manhood. Actually, it's standard operating procedure for making a turn on Mars.

Some Mars maniacs just won't grow up: A picture of the track patterns left behind by the Mars rovers' standard turning maneuver has drawn giggles and gasps — merely because it looks like a penis scrawled on the Red Planet.

"The rude drawing has emerged in a series of images taken by one of its rover machines. ... The latest pictures beamed back from one of the rovers show signs that the project's controllers have started to get a bit bored," The Sun, a British tabloid, reported on Wednesday.

Even Sarcastic Rover, one of Twitter's top parody personas, got into the act: "Since everyone's asking, let me just say that some other robot did this ... definitely not me," it tweeted.

The jibes from Sarcastic Rover and The Sun, and tons more like them, were sparked by a Reddit forum's discovery of the picture the day before. But this picture isn't the product of a bored (or filthy-minded) rover driver, and it wasn't beamed down recently. It's part of a classic nine-year-old panorama from NASA's Spirit rover, looking back toward its landing platform. (You can actually see the platform in the high-resolution version of the panorama.)

This type of rover wheel-track pattern, which could euphemistically be called "a bat and two balls," has been left on Mars many times, not only by Spirit (which gave up the ghost in 2010 or so), but also by Opportunity (which is still going strong more than nine years after landing on Mars) and Curiosity (which landed last year).

All those rovers have six wheels, three on each side, and they leave behind two parallel tracks when they're traveling in a straight line. When the rover has to make a turn, the wheels rotate in place to put the robot in the desired direction for the next leg of its trek. If the turn is significant enough, you get a nice set of circles at the end of a pair of parallel tracks.

Got it? Now we can move on — for instance, to lewd pictures from the Hubble Space Telescope.

NASA / ESA / STScI / AURA / La Plata Obs.

A sub-cloud of dust in the Carina Nebula displays what some have called "the cosmic finger of friendship."

More tracks from the Red Planet:

• That's one small step ... on Mars?
• Curiosity leaves tracks in Morse code
• 3-D adds depth to tracks on Mars

Tip o' the Log to Jia-Rui Cook at NASA's Jet Propulsion Laboratory for finding the original Spirit panorama from Mars.

Alan Boyle is NBCNews.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. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

J.-Y. Li (PSI) / NASA / ESA

Comet C/2012 S1 (ISON) takes on a fuzzy glow in an April 10 image from the Hubble Space Telescope. The blue tint has been added to the black-and-white imagery.

Comet ISON, the long-traveling iceball that skywatchers hope will turn into the "Comet of the Century," takes on a fuzzy glow in an image captured two weeks ago by the Hubble Space Telescope and unveiled on Tuesday.

The picture was taken on April 10, using Hubble's Wide Field Camera 3, when the comet was 386 million miles (621 million kilometers) from the sun and 394 million miles (634 million kilometers) from Earth. That's just inside the orbit of Jupiter. Right now, the comet's brightness is roughly magnitude-16, which means it can only be seen with telescopes. But comet-watchers are hoping that ISON will get dramatically brighter as it swings around the sun in late November. Some have said the comet could match the brightness of Venus or even the full moon.

The reason for those hopes — and the reason for all the "coulds" and "mights" — is that ISON appears to be a long-period comet, coming in from the far reaches of the solar system for the first time in living memory. Such comets are unpredictable: Will they shed lots of dust and glowing gas, or will they turn out to be duds? ISON's orbit is due to bring it within 700,000 miles (1.2 million kilometers) of the sun's surface. That could cause ISON to crumble like Comet Elenin did in 2011, or it could spark a flare-up of Comet Lovejoy proportions.

Unlike Comet Lovejoy, which lit up the Southern Hemisphere's skies during 2011's holiday season, Comet ISON should be visible from the Northern Hemisphere — which means Americans might get an eyeful during this year's winter holidays. (There's that pesky "might"!)

The picture from Hubble helps astronomers get a better fix on the current state of Comet ISON: The nucleus appears to be no larger than three or four miles (five to seven kilometers) across. In Tuesday's image release, the Hubble team says that's "remarkably small, considering the high level of activity observed in the comet so far." The comet's fuzzy head, known as the coma, measures about 3,100 miles (5,000 kilometers) across, or a little less than the distance from New York to Dublin. ISON's tail extends more than 57,000 miles, far beyond Hubble's field of view.

Detailed readings from Hubble could unlock the secrets of ISON's origins, University of Maryland astronomer Michael A'Hearn said in a news release. "We want to look for the ratio of the three dominant ices, water, frozen carbon monoxide, and frozen carbon dioxide, or dry ice," A'Hearn said. "That can tell us the temperature at which the comet formed, and with that temperature, we can then say where in the solar system it formed."  

Comet ISON was discovered last September and is formally known as C/2012 S1 (ISON). It takes its name from the International Scientific Optical Network, a group of observatories in 10 countries managed by Russia's Keldysh Institute of Applied Mathematics.

J.-Y. Li (PSI) / NASA / ESA

This contrast-enhanced image was produced from Hubble's view of Comet ISON to reveal the subtle structure in the inner coma of the comet. Such enhancements help astronomers determine the comet's shape and evolution, plus the spin of its solid nucleus.

More about comets:

• Moon and Comet PanSTARRS pair up
• Flash interactive: Inside a comet
• Cosmic Log archive on comets

The image was created from Hubble data from proposal 13198: J.-Y. Li (Planetary Science Institute), P. Lamy (Laboratoire d'Astrophysique de Marseille), H. Weaver (JHU/APL), M. A'Hearn and M. Kelley (University of Maryland), M. Knight (Lowell Observatory), T. Farnham (University of Maryland), and I. Toth (Hungarian Academy of Sciences).

Alan Boyle is NBCNews.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. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / ESA / AURA / STScI

The Horsehead Nebula shines in a Hubble Space Telescope image that marks this month's 23rd anniversary of the orbiting observatory's launch.

Astronomers have come out with a Horsehead Nebula of a different color to celebrate the Hubble Space Telescope's 23rd birthday.

The iconic nebula in the constellation Orion, about 1,500 light-years away, can be seen even through small telescopes. In visible light, it's a dark dust cloud in the shape of a horse's head, silhouetted against a backdrop of glowing hydrogen gas. But the Horsehead takes on a completely different look in the new view released Friday.

"This image was taken in the infrared," Joe Liske, an astronomer from the European Southern Observatory, explains in a video introducing the picture. "In infrared light, we can pierce right through some of the bulky plumes of dusty material which usually mask and obscure the inner regions of the Horsehead. The result is this rather fragile-looking structure, made of delicate, wispy folds of gas — very different to the nebula's appearance in the visible."

The infrared glow, captured by Hubble's Wide Field Camera 3, lights up the nebula's clouds from within. Liske says it's "a fitting celebration of an incredible 23 years of the NASA/ESA Hubble Space Telescope."

The Hubble team traditionally releases an eye-popping shot to celebrate the anniversary of the space telescope's launch on April 24, 1990. As part of this year's celebration, the Hubble Heritage Project asked astronomers around the world to send in their own Horsehead Nebula photos, and you can see the collection via Flickr and Tumblr.

Like a veteran racehorse, Hubble is hitting its stride — but that hasn't always been the case. The first couple of years of operation were hampered by a flaw in the telescope's main mirror. Equipment to compensate for the problem was installed during a crucial series of spacewalks 20 years ago, in 1993. The shuttle Atlantis paid a final servicing visit to Hubble in 2009, and the telescope has been working just fine since then.

Hubble operations have been extended through 2016 — and if the telescope remains in good working order, it's likely to continue being funded at least until 2018, when the $8.8 billion James Webb Space Telescope is scheduled for launch. Eventually, Hubble will have to be sent down to a fiery doom. But who knows? Maybe the old telescope will hang around to experience life after 30.

Slideshow: Classic Hubble Hits

NASA / ESA / STSI via Reuters

See the Hubble Space Telescope's best-known images.

Launch slideshow

More Hubble birthday gifts:

• 22 years: Panorama of the Tarantula Nebula
• 21 years: Raise your glass for Hubble's birthday
• Cosmic Log archive on Hubble Space Telescope

Alan Boyle is NBCNews.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. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Chris Hadfield / CSA via Twitter

Canadian astronaut Chris Hadfield passed along this picture of Boston at night, as seen from the International Space Station, in recognition of the city's tragedy.

Monday's Boston Marathon bombing prompted expressions of sympathy from humanity's farthest-flung outpost: the International Space Station.

"Our crew just heard about the horrible events at the Boston Marathon," the space station's commander, Canadian astronaut Chris Hadfield, wrote in a Twitter update. "We all pass along our condolences and thoughts to everyone affected."

Later, Hadfield tweeted a picture of the city at night in recognition of "a somber spring night in Boston."

Even though the space station wheels around our planet at a height of 230 miles (370 kilometers) or so, the crew stays in touch with earthly news through official NASA communications as well as Internet links that make use of the space agency's TDRS satellite network. For example, the space station has been receiving a digital version of NBC Nightly News for years.

All that altitude gives the station's crew a unique perspective on Earth's tragedies. On Sept. 11, 2001, NASA astronaut Frank Culbertson looked down on the smoke streaming from the wreckage of New York's World Trade Center. "It was like seeing a wound in the side of your country, of your family, your friends," he said years later. Last October, astronauts watched as Superstorm Sandy blasted its way toward the East Coast.

The horrible events in Boston may not have been visible from space — but Hadfield's tweets demonstrate how we connect during times of tragedy, even when we're off the planet.

More perspectives from space:

• A space memorial for Newtown
• Last shuttle descent seen from orbit
• Awesome space views of typhoon

NASA / JPL-Caltech / Marco Di Lorenzo / Ken Kremer

The Curiosity rover's instrument-laden robotic arm is front and center in this mosaic view captured by the Mars rover's NavCam system and assembled by Marco Di Lorenzo and Ken Kremer. The colorized black-and-white imagery was captured on March 23. Click on the image to see the full panorama.

After a week of down time due to a computer glitch, NASA's Mars Curiosity rover is once again sending back pictures of its rocky Red Planet locale at Yellowknife Bay. In this fresh panorama, the rover looks as if it's sticking its drill-equipped robotic arm right in your face.

"That drill is hungry, looking for something tasty to eat, and 'you' (loaded with water and organics) are it," jokes scientist-writer Ken Kremer, who collaborated with Italian colleague Marco Di Lorenzo to assemble the panorama.

Curiosity's percussive drill played a key role in the science team's most recently reported breakthrough: the finding that powder drilled out of a Martian rock contained the chemical traces of a life-friendly environment that existed on Mars billions of years ago. The team's chemical analysis of the powder indicated that the minerals were probably formed in the presence of drinkable water.

That kind of water no longer exists in liquid form on the Martian surface. The place where Curiosity is currently working may have once been in the vicinity of a riverbed, but it's now a cold and dry wasteland of sand and rock. In the weeks to come, Curiosity's scientists plan to drill into the rock again, looking for confirmatory clues about the potentially habitable environment in the Red Planet's past.

The plan has been held up due to a series of minor setbacks — including a memory failure that may have been due to a cosmic-ray strike, a precautionary stand-down to weather a solar storm, and most recently a computer file glitch that put the rover into safe mode. The Curiosity team has been carefully bringing the rover back to full operation, and this picture is presumably part of the checkout process.

It won't be long before the rover will once more have to reduce its contact with its handlers back on Earth, due to an Earth-Mars-sun conjunction that will interfere with radio signaling. Curiosity's communication gap is expected to last from April 4 to May 1, as detailed in a mission update from NASA's Jet Propulsion Laboratory. During the break, Curiosity is expected to carry on with its experiments, but the transmission of science data and images will have to wait until May. So let's enjoy these fresh images while we can.

For more of Curiosity's raw imagery, check out the galleries on JPL's Mars Science Laboratory website. You'll also find great pictures on UnmannedSpaceflight.com, where Kremer, Di Lorenzo and other image-processing gurus post their work. If you have 3-D glasses, whip 'em out and take a look at Ed Truthan's red-blue view of Curiosity's first drilling site.

Slideshow: Curiosity's space odyssey to Mars

Trace the Curiosity rover's journey to Mars and see the pictures that the six-wheeled robot has sent back from the Red Planet.

Launch slideshow

More about Mars:

• How a Martian mountain would look on Earth
• What's next for the Curiosity rover
• NBC News archive on Mars

Alan Boyle is NBCNews.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. To keep up with Cosmic Log and the rest of NBCNews.com's science and space coverage, sign up for the Tech & Science newsletter, delivered to your email in-box. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.