Wanna name a crater on Mercury? Find out how

Artist’s view of the MESSENGER spacecraft flying over Mercury’s surface displayed in enhanced color. The crater ringed by bright orange is 42-mile-diameter Calvino crater. Click to enter the contest. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

NASA’s orbiting MESSENGER spacecraft has snapped more than 250,000 photos since plunking into orbit around Mercury in 2011. The solar system’s innermost planet’s ancient surface is Swiss-cheesy with craters of all sizes, all named – according to convention – after deceased artists, musicians, painters, and authors who have made outstanding contributions to their field.

Mercury is a small, crater-rich planet that resembles the Moon. At center is the 129-mile-diameter Copland crater, named after American composer Aaron Copland. Credit: NASA

Hellacious holes bear the names of Beethoven, John Lennon, Anton Chekhov and even the ancient Greek poet Homer. Wouldn’t you like to put your mark on one? The MESSENGER Education and Public Outreach Team is holding a competition to name five impact craters on Mercury. As per International Astronomical Union (IAU) rules, they must be named after named after an artist, composer, or writer who was famous for more than 50 years and has been dead for more than three years. Nor should the name have any political, religious or military significance.

Crater A lies near the center of an area called the “Northern Rise”, a volcanic region that was uplifted long ago. No crater on the Rise has yet to be named. Naming this one would help communicate new findings about the area. Credit: NASA

You have until 5:59 p.m. (23:59 UT) January 15th to complete the entry form and submit it online. You can send in as many entries as you like, but before you go crazy, don’t forget to check your choice against the current, approved list of solar system features. It’s the only way to know whether your proposed name is unique or has already been assigned. Just type it in the search box in the upper right corner.

Not to scare you, but there are presently over 18,000 named craters on Mercury. A tiny number really, compared to all the artists that have stirred our emotions across the history of civilization, so have at it!

Wikipedia’s OK for looking up potential choices but won’t be accepted as a source. For that you’ll need something more definitive like a biography, magazine article, book or encyclopedia. The IAU provides this list of references you’ll find most helpful.

A type of cliff called a scarp cuts through unnamed Crater C. Scarps formed on Mercury as the planet cooled and its crust shrunk and wrinkled like a grape that dries to become a raisin. Yellow-orange volcanic deposits are also seen. By studying this crater scientists can learn about how Mercury formed and the origin of its volcanic landscapes. Credit: NASA

All entries will be reviewed by MESSENGER team representatives and expert panels.15 finalist names will be submitted to the IAU for selection of the five winners. Winning submissions will be announced by the IAU to coincide with MESSENGER’s End of Mission Operations in late March/April 2015.

Naming things is important. As scientists study the tsunami of data returned by MESSENGER, it becomes important to give names to surface features that are of special scientific interest. Having names for landforms like mountains, craters, and cliffs makes it easier for scientists and others to communicate.The MESSENGER science team has selected five craters of particular geological interest, two of which are shown here.

Good luck in your submissions! If you participate, we’d love to know what names you selected. Please share them via the Comments link below.

Ever seen a lunar eclipse from Mercury? Me neither … till now

Wednesday’s lunar eclipse photographed by NASA’s MESSENGER spacecraft at Mercury

As millions of us awoke at dawn and trundled outside to watch the total lunar eclipse this week another set of eyes was keeping tabs from afar. 66 million miles away, NASA’s MESSENGER spacecraft turned its camera toward Earth to capture several images of the moon disappearing into our planet’s shadow. Laced together, they make for a brief but fascinating glimpse of planetary bodies in motion.

Two of the still images showing Earth and moon before and during Wednesday morning’s total eclipse. Credit: NASA

The animation was constructed from 31 images taken two minutes apart from 5:18 to 6:18 a.m. EDT. The images start just before the Moon entered the umbra, the darkest part of the Earth’s shadow.

“From Mercury, the Earth and Moon normally appear as if they were two very bright stars,” noted Hari Nair, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory, in Laurel, Md. “During a lunar eclipse, the Moon seems to disappear during its passage through the Earth’s shadow, as shown in the movie.”

MESSENGER photographed Earth and moon on May 6, 2010 from 114 million miles (183 million km) away. Credit: NASA

Because the moon is so much darker than Earth its brightness has been increased 25 times to show its disappearance more clearly. I’ve included another picture of the Earth and moon against the starry backdrop of deep space also photographed by MESSENGER. Sure puts things in perspective. While not as breathtaking as photos of Earth taken by the Apollo astronauts, seeing our tiny home floating in the void effectively communicates how improbable our existence is. Thank goodness life got a grip and kept it. After 3.5 billion years of evolution the double helix has proven itself a force with which to be reckoned.

The 133-mile-wide double ringed crater Vivaldi captured at sunrise. The low sun highlights valleys and chains of secondary impact craters radiating away from it. Credit: NASA

MESSENGER has been in orbit around Mercury since March 2011 studying the chemical composition of the surface, measuring planet’s magnetic field, mapping polar ices and of course taking pictures. Enjoy a few recent ones.

Hollows on the floor of an unnamed crater on Mercury. Hollows may be areas “eaten away” by the ceaseless bombardment of particles in the solar wind. Or they may form when heat from volcanic activity melts away softer rocks. No one knows for sure. Credit: NASA

Come fly with me to Mercury

MESSENGER flies over Mercury. The spacecraft blasted off from Cape Canaveral on August 3, 2004.

To commemorate this week’s 10th anniversary of the launch of NASA’s MESSENGER spacecraft to Mercury, NASA released this amazing video of a flight over the planet’s north polar region. The movie was assembled from 214 images taken once per second by the probe’s narrow-angle camera on June 8, 2014. Enjoy the cratery desolation.

As the photos were snapped, MESSENGER orbited at altitudes ranging from 71 to 102 miles (115 to 165 km), traveling at a speed of 2.3 miles per second relative to the surface.

One of the highest resolution pictures ever taken of Mercury’s surface shows a field of craters only 1.8 miles (3 km) wide photographed on June 11, 2014. MESSENGER will drop down much closer to the planet – only 31 miles – starting August 19. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

“This view is what a traveler on the MESSENGER spacecraft might see during low-altitude operations in the coming year,” said MESSENGER co-investigator Scott Murchie. “During the final phase of its mission, MESSENGER’s science instruments will use low-altitude operations like this to explore the surface and subsurface of Mercury at unprecedented resolution.”

Mercury is presently too close to the sun to see safely, but on August 2 it lined up in conjunction with Jupiter as seen through the coronagraph (sun-blocking device) on the Solar and Heliospheric Observatory. Credit: NASA/ESA

Mercury orbits closest to the sun of the eight planets, completing one revolution every 88 days. It has virtually no atmosphere and measures only about a thousand miles larger than Earth’s moon.

Daytime surface temperatures there can reach 801°F (427°C). Despite the extreme heat, MESSENGER’s instruments detected water ice in permanently shadowed craters in the planet’s polar regions.

Launched in August 2004, MESSENGER traveled 4.9 billion miles (7.9 billion km) to finally settle into orbit around the speedy planet on March 18, 2011. Its convoluted journey included 15 trips around the Sun and flybys of Earth once, Venus twice, and Mercury three times. All of this was done to slow the craft down so it could enter orbit about the planet. It’s returned more than 240,000 pictures so far, many of which you can browse HERE.

Mercury leaps into dusk – don’t miss it!

The sky facing west about 40 minutes after sunset in mid-May when Mercury will be just shy of one outstretched fist above the northwestern horizon.  It shines brightly at magnitude -0.3 this week. Use higher, brighter Jupiter to make a sight line to the planet. Mercury’s making its best evening appearance of the year for northern hemisphere sky watchers. Stellarium

Now through the end of May is the prime time to look for Mercury in the evening sky. Like the rock star Prince, this small, speedy planet is elusive, making only a few brief appearances a year.  Consider this a personal invite to the show.

To find Mercury, pick out a place with a wide open view to the west-northwest in the direction of sunset. Start looking a half hour after sundown about a fist to the left of the brightest glow left on the horizon by the setting sun. Mercury will be some 8-10 degrees (about one outstretched fist) above the horizon. It looks like a solitary diamond in twilight’s pink glow.

Mercury shows phases as it revolves around the sun as seen from Earth’s perspective outside looking in. Mercury, like Venus, appears largest when nearly lined up between Earth and sun at inferior conjunction. Planets not to scale and phases shown are approximate. Illustration: Bob King

Mercury gets easier to see as the sky darkens … to a point. Once it’s within a few degrees of the horizon, the thicker, dustier air in that direction quenches its light and the planet fades.

The one-day old evening crescent moon with Mercury (upper left) on Jan. 31 this year. Credit: Bob King

It’s amazing that Mercury’s rates as a planet considering how small it is – just 3,021 miles (4,880 km) in diameter. At 2,160 miles across, our own moon is 71% as large. Jupiter’s moon Ganymede is even bigger at 3,275 miles (5,270 km). If it were orbiting the sun instead of Jupiter, Ganymede would easily be considered a planet. Pluto, demoted to dwarf planet status in 2006, spans just 1,430 miles (2,302 km).

Despite Mercury’s diminutive dimensions, its self-gravity easily crushed it into a sphere long ago. That plus the fact that it revolves around the sun and has cleared its orbit of competition from other smaller bodies places it firmly within the realm of the planets.

And there’s no planet quite like it. Mercury hovers near the sun too close to see and a few weeks later leaps into the morning sky. Drifts back down toward the sun in a few weeks and then leaps into the evening sky. So it goes, back and forth like that a half dozen times a year. Northern hemisphere observers see it best at dusk during late winter and spring ‘elongations’ and at dawn in the fall.

It’s easy to guess the reason for its swift maneuvering – a tight orbit around the sun lasting only 88 days keeps Mercury on the move.

Mercury looks like a tiny gibbous moon this week through a small telescope. Use at least 75x to make out its shape.  Illustration: Bob King

Like Venus and the moon, Mercury shows phases. Right now, if you’re lucky enough to train a telescope on it before it atmospheric turbulence near the horizon mushes up the view, the planet would look like a very tiny gibbous moon 66% illuminated.

Its phase changes quickly too. Within a few weeks, as it moves closer to Earth and grows in apparent size, the planet will morph from gibbous to half to a dim crescent. Yes, dim! Mercury is brightest when at ‘full moon’ phase, being nearly as brilliant as Sirius, but fades to 3rd magnitude when a thin crescent. This week we’ll see it brightest; next week the planet will start to fade noticeably.

Orbiting between 28 and 43 million miles (46 and 70 million km) from the sun and possessing no atmosphere, Mercury’s temperature ranges from an extremely hot 800 F (430 C) on the dayside to marrow-chilling -280 F (-170 C) on the nightside.

To the eye, Mercury would appear as shades of dark brown. NASA enhanced the subtle colors to in this photo of the planet, a mosaic of images taken by MESSENGER. Younger craters with their bright rays appear blue. Plains formed form ancient lava eruptions are tan or orange. Credit: NASA

Because the planet’s axis is tilted only .01 degree – it essentially rotates straight up and down perpendicular to the sun – sunlight never reaches into craters in its polar regions. Locked in permanent shadow, NASA’s MESSENGER spacecraft has found strong evidence for abundant water ice and other volatile materials stored there for millions of years.

We could go on and on about this strange little planet, but I’d be holding you back from getting outside to see it for yourself. For more information, check out NASA’s quick-facts summary and a wonderful gallery of photos from MESSENGER.

Imagine a crater named John Lennon – it’s easy if you try

The 59-mile-wide John Lennon crater on Mercury photographed by the orbiting MESSENGER spacecraft. Click to enlarge. Credit: NASA/JHUAPL/Carnegie Institution of Washington

The International Astronomical Union, the final authority on the names of planets and satellites in the solar system since 1919, recently approved 10 new names for craters on the planet Mercury. All the crater names are in keeping with the established theme of naming features after ”deceased artists, musicians, painters, and authors who have made outstanding or fundamental contributions to their field and have been recognized as art
historically significant figures for more than 50 years.”

The Mercury MESSENGER spacecraft science team proposed the latest bunch, one of which will go to John Lennon (1940-1980), who helped found the Beatles, the most commercially successful and critically acclaimed band in the history of popular music.

Other craters named in the recent update include Capote after Truman Capote (1924-1984), author of “In Cold Blood” and other books, and Caruso, for the Italian tenor Enrico Caruso (1873-1921), whose incredible voice resounded in opera houses across Europe and the Americas.

John Lennon – Imagine video 

Lennon Crater is 59 miles (95 km) in diameter and located in Mercury’s southern hemisphere. The crater is filled with melted rock from the impact and displays a central peak and lovely terraced walls. You can imagine being there by reading by clicking this whimsical version of Lennon’s “Imagine” lyrics that appears on the MESSENGER website:

Imagine some ejecta
It isn’t hard to do
Terraced walls and impact melt
Secondary craters too
Imagine central peaks
Rising above the floor…

You may say I’m a complex crater
But I’m not the only one
Someday more will join us
On the planet closest to the sun.

Comet ISON outburst continues / Comet Encke flies by Mercury this weekend

It’s hard to believe this is the same Comet ISON as two mornings ago. This photo was taken with a 4-inch (105mm) wide-field refractor this morning Nov. 15. Click to enlarge. Credit: Damian Peach

What a horrible morning. A sky perfectly clear at 4 a.m. turned nearly overcast just in time to check out this week’s impressive outburst of Comet ISON. I did say “nearly”. Driving north to find a clearing failed, so I turned the car around and sped southeast toward Lake Superior. There along the beach, a few cracks in the clouds glided across Virgo, buoying hopes that sooner or later ISON would pop through the clouds if only for a minute.

And it did. While I could have measured the amount of time spent viewing the comet on a stop watch – maybe 3 minutes total – I enjoyed every juicy second. The head of the comet, a wimpy thing on Wednesday morning, had doubled in size and burned pale blue with a bright, intense, fuzzy center.

My pitiful attempt to record the comet this morning through clouds with a basic camera and 35mm lens. A small bluish coma or comet head is visible at the bottom of the tail. Credit: Bob King

Even through thin clouds ISON and the first half degree of its tail were easy grabs in 10×50 binoculars. Its brightness, measured on the magnitude scale, was 5.0 this morning or 2.5 magnitudes brighter than earlier in the week. That translates to a tenfold increase in brightness in just two days.

Comet ISON glows brightly in X-rays as seen by NASA’s Chandra X-ray Observatory. X-ray are given off when the comet’s neutral molecules and atoms interact with the ionized atoms of the solar wind. The picture is color-coded — yellow and red indicate greater intensity, blue less. Credit: Casey Lisse/Chandra

Around 5:15 a.m., the sky completely cleared around the comet for a single precious, complete minute. I dashed to the telescope for one last look at the bulbous blue head and tail that stretched at least a degree (twice the diameter of the full moon) up to the northwest. OK, it wasn’t such a horrible morning.

Pictures taken of both Comets Encke and ISON last week by the MESSENGER spacecraft in orbit around Mercury. Green circles are shown around cataloged background stars. Click to enlarge. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Southwest Research Institute

Today was the last for dark skies without interference from the moon. Beginning tomorrow and continuing for at least the next 10 days, the moon will light up the sky well into morning twilight and beyond. While it will make the comet difficult to see with the naked eye – assuming it doesn’t leap again in brightness – it should still be visible in binoculars. ISON is rapidly approaching the sun and will soon be difficult to see. Go out to look at it the next clear morning if you can.

You can use the map from yesterday’s blog to help you find ISON. Although low, it’s near the bright star Spica in Virgo. I’m also including a new map for amateurs willing to tackle Comet Encke, located even lower in the sky and near the planet Mercury. Encke is only a few days away from perihelion or closest to the sun. These next few days will be the last time to see the comet this apparition for northern hemisphere viewers.

You can use Arcturus and Spica in the eastern sky at dawn this coming Sunday and Monday mornings to help you find Mercury and Comet Encke. The map shows the sky facing southeast about 1 hour before sunrise. The comet is now around magnitude 6.5-7. Stellarium

Space probe paparazzis to point cameras at Earth tomorrow

How Earth will appear to the Cassini spacecraft at Saturn tomorrow afternoon when its snaps a series of pictures of the planet from nearly 900 million miles away. Credit: NASA

Get ready planet Earth – there’s no escaping celebrity. Not only will NASA’s Cassini spacecraft be taking your picture tomorrow but so will the Mercury MESSENGER probe at the other end of the solar system.

Last month I described NASA’s plan to snap a picture of Earth from Saturn using the Cassini spacecraft, which has orbited the ringed planet since 2004. That happens tomorrow July 19 over a 15-minute span beginning at 4:27 p.m. (Central Daylight Time) and ending at 4:42 p.m.

Inspired in part by the Cassini team’s plans, scientists reexamined planned observations of NASA’s MESSENGER spacecraft in orbit around Mercury and realized that Earth would coincidentally be in some of the images during a planned search for possible Mercury moons on July 19-20.

Also coincidentally, MESSENGER will see the side of Earth that Cassini does not and more. Taken together, the two spacecraft will picture most of humanity compressed down to a pixel or two. This is an important point — literally. Earth is too far from both probes to appear as anything more than a tiny dot.

NASA folks encourage you to wave at Saturn tomorrow July 19 when Cassini takes the planet’s portrait. Click for more information. Credit: NASA

If you live in North America, Central America and the northern part of South America, Saturn will appear in the daylight sky. NASA encourages you to look to the southeast at the time and wave at the planet. You might even consider going that extra mile and shouting out “cheese!”

While it will be daylight in much of the western hemisphere at the time of the photo shoot, European and African observers will see Saturn glowing in the southwestern sky when the shutter winks open and close. Meanwhile, MESSENGER will snap its portraits of Earth at 6:49 a.m., 7:38 a.m. and 8:41 a.m. CDT on both days. Mercury will be about one fist held at arm’s length to the right (west) of the sun at the time and invisible in its glare.

Mercury around 8 a.m. July 19 when MESSENGER will face the Earth and begin snapping photos. Created with Stellarium

“Nearly half of the Earth, including all the Americas, Africa, and Europe and Central Asia will be illuminated and facing MESSENGER, says Hari Nair, the Johns Hopkins University Applied Physics Laboratory planetary scientist who designed and is implementing the campaign,” according to a press release on the MESSENGER website.

The images on the second day will also include pictures of the Moon as will the Cassini photos. Details about the Saturn campaign including maps for various cities to help you find the planet can be found HERE. More information on the event’s Facebook page.

While the photos won’t reveal any details on the planet, seeing Earth as a point of light will refresh our day with a cosmic perspective on life.

Mercury MESSENGER mission scores 100%

Global maps of Mercury. Half the globe is shown in black & white, the other in color. Each map is composed of thousands of images. Click this and any of the other photos for hi-res versions. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Nice job MESSENGER! After two years in orbit, the entire planet of Mercury has been mapped. Can a cellphone map app be far behind? Prior to MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging), human eyes had seen less than half of the planet up close. No spacecraft had dropped by the solar system’s innermost planet since Mariner 10 sent us the first detailed images of Mercury during three brief flyby loops executed in 1974-75.

Craters (from left) Tolkien, Tryggvadottir and Chesterton are located close to the planet’s north pole and have permanently shadowed floors. MESSENGER found evidence for ice in all three. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Over the past two years the probe has taken more than 168,000 pictures of Mercury’s numerous craters, ridges and enigmatic “hollows”, mapped its topography and determined the makeup of minerals on its surface through examination of the light they reflect from the sun.The probe also revealed water ice coated with organic materials within permanently shadowed craters at the planet’s north pole.

The 20.5-mile-diameter crater Kertesz, named for photographer Andre Kertesz. Mercury craters are named for artists. Kertesz’s floor is pocked by enigmatic “hollows” which could be material boiled off by the sun’s heat and radiation. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

With the probe’s original mission extended from one to two years, it’s now coming to an end. Unless a further extension is approval, March 17 would be the last for data gathering. Principal investigator, Sean Solomon of Columbia University’s Lamont-Doherty Earth Observatory, has submitted a proposal that would keep MESSENGER and mission control in business for another two years, about the time it runs out of fuel and crash lands on Mercury.

Waters crater was recently named in honor of blues legend “Muddy Waters” (a.k.a. McKinley Morganfield). The “mud” pouring out below it is melted rock from the impact. A color image at upper right shows it’s appropriately blue-toned. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Keeping the mission running would let scientists continue targeted studies of various features and shoot photos at incredibly high resolution as MESSENGER’s decaying orbit carries it closer and closer to the surface. Not only that, but the spacecraft is ideally placed to study and photograph Comet ISON when it makes it grazes the sun later this fall.

An oblique view of a 174-mile-long escarpment cutting through a crater. The slope is a geologic fault resembling an “overbite” that formed when the planet shrunk due to cooling of its interior. The left side is 1.2 miles higher than the right. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

To celebrate MESSENGER’s milestone, I thought you’d enjoy a selection of images from recent photo shoots.We’ll know in April whether the mission will continue once a science commission makes its decision. Click HERE to browse more photos in the archive.

A closeup view of hollows in an unnamed crater. The pits almost always occur within or surrounding impact features. They’re about 100 feet to a couple miles wide and lack rims. Hollows might be volcanic vents or created when sulfur and other volatile materials escape from the surface during solar wind bombardment. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Curiosity’s history-making discovery a big misunderstanding

Bite mark left in the sand dune after Curiosity retrieved soil sample. It’s similar to lava rock found in Hawaii and contains feldspar, pyroxene and olivine. Other materials found in the sample will be revealed next week. Credit: NASA/JPL-Caltech

Do you want the good news or bad news first? OK, the bad news. Remember when we learned last week that Curiosity had made a “history changing” discovery in a Martian soil sample? Many of us speculated that the rover had detected the first organic, carbon-containing compounds on Mars.

Well, it turns out it was just a big misunderstanding between the MPR reporter and Mars Science Laboratory (MSL) project scientist John Grotzinger. During the original interview, Grotzinger explained to reporter Joe Palca that Curiosity had analyzed the first soil sample in its Sample Analysis at Mars instrument. While SAM can detect organics, Grotzinger’s reference to the discovery being “one for the history books” was actually a reference to the entire Mars mission, not a specific finding.

Panoramic view of Curiosity’s digs at the Rocknest site in Gale Crater on Mars. One barren-looking landscape! The photo is a composite of images taken in October and November. Click to enlarge. Credit: NASA-JPL/Caltech

Somehow the NPR reporter misinterpreted the excitement surrounding the first soil analysis with Grotzinger’s description of the mission as history-making. Each thought the other was talking about a different thing. Indeed at the time of the interview, the first sample had only begun to be analyzed, so NASA scientists wouldn’t have even known the details of its chemical contents. Results, described as “interesting” rather than earth-shaking, will be presented next week at a meeting of the American Geophysical Union in San Francisco. More on the topic HERE.

Since it’s still very early in the mission, we shouldn’t be too bothered if some sort of Holy Grail moment has yet to happen. Look at what Curiosity’s found so far – an ancient stream bed filled with water-rounded cobbles, layered buttes of sedimentary rock like a postcard from the Grand Canyon and a most amazing assortment of wind-sculpted rocks. And don’t forget – we got there in the first place and Curiosity couldn’t be healthier.

Does anyone doubt that handfuls of history-making discoveries lie ahead? My only frustration is that NASA didn’t attempt to correct the misunderstanding sooner through one of its many press releases.

View of Mercury’s north pole seen from above. Red denotes areas of permanent shadow as seen by the MESSENGER probe to date. The polar ice deposits imaged by Earth-based radar are in yellow. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory

Now for the good news. Mercury, a planet with a surface temperature hot enough to melt lead has been confirmed by MESSENGER probe to have ice deposits in its polar regions. What the heck? Given that it’s the closest planet to the sun, you’d think it an unlikely place for ice, but the little planet’s axis is tipped less than one degree, so areas around its poles are never exposed to sunlight. Since Mercury has no substantial atmosphere to capture and distribute heat, its surface temperature ranges from 800 degrees F in sunlight to 200 below in the polar regions.

While radio-bright areas likely due to ice have been detected from Earth by the giant Arecibo radio telescope in Puerto Rico as long ago as 1991, new data from NASA’s orbiting MESSENGER spacecraft confirm that water ice is indeed present both exposed on the surface as well as buried beneath dark, tar-like deposits.

The probe uses neutron spectroscopy to measure hydrogen concentrations within Mercury’s radar-bright regions. Based on the amount of hydrogen seen, scientists can estimate the volume of water ice present, because water, or H2O, is two parts hydrogen.

“The new data indicate the water ice in Mercury’s polar regions, if spread over an area the size of Washington, D.C., would be more than 2 miles thick,” said David Lawrence, a MESSENGER participating scientist.

The dark material could be a mix of organic compounds delivered by carbon-rich comets and asteroids several billion years ago during the solar system’s youth. Astronomers believe that Earth was similarly enriched by water and organics. I like the connection, and I like that polar opposites – excuse the pun – find a home together on a most unlikely planet. To read more about the discovery, click HERE.

Mercury makes its move into the evening sky

Three planets and a crescent moon will light up the western sky shortly after sunset this evening (Feb. 22). Created with Stellarium

Move over Jupiter. Move over Venus. It may be the smallest planet, but Mercury is on its way up into the evening sky. Beginning tonight – and with the help of a very young crescent moon – observers with clear skies and a wide open western horizon can seek the innermost planet alongside the 1-day-old moon. As always, take your binoculars to help in case the sky is less than ideal.

The duo will be well below the Venus-Jupiter line just five degrees or three fingers held together at arm’s length above the west-southwest horizon. The best time to look is starting about 20 minutes after sunset.  Don’t wait too long or they’ll set before you get the chance to see them.

As we move into late February and early March, the moon will move up and away from Mercury and pass near Venus  on the 25th and Jupiter on the 26th. Mercury also moves up and away from the sun and will soon become much easier to see. I’ll keep you posted on good viewing opportunities coming up.

Two nearly complete maps of the planet Mercury made from pictures taken by the MESSENGER spacecraft in orbit around the planet. The black and white map is more detailed than the color version, which highlights different types of minerals and terrains. Credit: NASA

NASA’s Mercury MESSENGER (Mercury Surface, Space ENvironment, GEochemistry, and Ranging) mission has nearly completed its initial mission goal of mapping the planet in color and black and white. It’s also made quite a few discoveries including:

* Most of Mercury’s mass – 60-70% vs. 32% for Earth is in the form of metal in its core. Lighter materials were either boiled away from intense solar heat and solar wind bombardment or from heating caused by a major impact long ago.  Mercury is 36 million miles from the sun or 2.5 times closer than the Earth. Surface temperatures are as hot as 800 degrees and sunlight 6.5 times more intense than on Earth.

Shallow, flat-bottomed pits on Mercury may be caused by subatomic particles from the sun zapping away at sulfur-laden minerals. Credit: NASA

* Like Earth, Mercury is surrounded by a magnetic field, but it’s offset far to the north of the planet’s center and fluctuates over time. Compared to the planet’s small size (3032 miles or about 1.5 times the size of the moon), this offset is far more than any other planet. Scientists are still at a loss to explain why.

* A vast expanse of volcanic plains with lavas as thick as 1.2 miles surround the north polar region. According to James Head of Brown University, the deposits appear to be flood lavas or huge volumes of solidified molten rock similar to those  in the Columbia River basin in the northwest United States. “Those on Mercury appear to have poured out from long, linear vents and covered the surrounding areas, flooding them to great depths and burying their source vents,” said Head.

* New, unexpected landforms called ‘hollows’ have been discovered inside some of the planet’s craters. The shallow, rimless pits range from about 100 feet to 2 miles wide are often seen in clusters. They’re very reflective and appear quite fresh. Scientists believe the intense solar wind felt at Mercury’s distance may be eating away at exposed sulfur deposits on the surface to create the depressions.

* Mercury’s surface may look like the moon, but its rocks contain lots more potassium and sulfur than the lunar variety.

If you’d care to learn more about the new findings and see additional photos of Mercury, check out the MESSENGER website. And don’t forget to go out and see the planet with your own eyes in the next few weeks.