Three bright planets gather in the northwestern sky this week. This map shows the sky 30 minutes after sunset from the middle latitudes. Stellarium
Planning a barbecue this weekend? You may want to top it off with a look at three bright planets shuttling about the western sky at dusk. Jupiter, Venus and Mercury gather for nearly a week of delightful alignments including three separate conjunctions staring right now. Mercury and Venus pair up on Friday; Mercury and Jupiter on Sunday and Venus and Jupiter on Monday. All three form a series of ever-changing triangular arrangements as the nights go by.
Three bright planets will highlight the northwestern sky this week and early next. Mercury is shown in pink and Jupiter in yellow. Time is 30 minutes after sunset facing northwest. They’ll be closest together – less than 3 degrees apart – on the night of the 26th. Stellarium
Brightest of the bunch is Venus followed by Jupiter and then Mercury. The key to seeing them all is a clear sky and unobstructed view of the west-northwest horizon. Best time for viewing is a half hour to 45 minutes after sunset. Although the diagrams make the planets look like largish disks, difference in size is a device to show their brightness. Bigger means brighter.
Mercury gradually climbs higher in the coming days, Venus will remain in nearly the same spot and Jupiter slowly drops off toward the horizon. Seeing three planets bunch up isn’t rare, but it is unusual – all the more reason to go for a look if your skies are clear. Alignments like this occur because all 8 planets lie in essentially the same flat plane. As we look across the solar system, sometimes near planets and far planets lie along the same line of sight and appear side-by-side in the sky. They may look close to each other but of course they’re millions of miles apart.
Positions of the planets on May 27. The arrow shows the point of view from Earth. Notice that the line of sight through all three takes our gaze near the sun. That’s why they’re only visible shortly after sunset in a bright sky. Click image to see a cool, interactive planet display. Credit: dd.dynamicdiagrams.com
This week Venus is 154 million miles (248 million km) from Earth, Mercury 113 million (182 million km) and Jupiter a distant 562 million (904 million km). The planet position diagram above will give you a sense of their current arrangement in space.
Whenever you go planet-seeking in bright twilight, I always recommend bringing along a pair of binoculars. They penetrate haze and make finding these bright little dots much easier. Enjoy the show!
An 11-color MESSENGER targeted image of Mercury's Tyagaraja crater
At first glance, the planet Mercury may bear a striking resemblance to our own Moon. True, both are heavily-cratered, airless worlds that hide pockets of ice inside polar shadows… but there the similarities end. In addition to being compositionally different than the Moon, Mercury also has surface features that you won’t find on the lunar surface — or anywhere else in the Solar System.
The picture above, part of an 11-color targeted image acquired by MESSENGER on April 25, 2013, shows the varied terrain found within the 97-kilometer-wide Tyagaraja crater located near Mercury’s equator. The reds, blues, greens, and oranges, much more saturated than anything we’d see with our own eyes, correspond to surface materials of different compositions… and the brightest spots within the crater are features called “hollows” that are truly unique to Mercury, possibly resulting from the planet’s close interaction with the solar wind.
First noted in September of 2011, hollows have been identified across many areas of Mercury. One hypothesis is that they’re formed by the sublimation of subsurface material exposed inside larger craters. Being so close to the Sun and lacking a protective atmosphere, Mercury is constantly being scoured by the solar wind — a relentless stream of charged particles that’s actively “sandblasting” exposed volatiles from the planet’s surface!
A previous MESSENGER image of hollows inside Tyagaraja crater
The reddish spot at the center of the crater in the top image is likely material surrounding a pyroclastic vent, which appear red and orange in MDIS images. The dark material that appears bluish is something called “low reflectance material” (LRM).
The image was acquired as a targeted high-resolution 11-color image set. Acquiring 11-color targets is a new MESSENGER campaign that began in March and utilizes all of the Wide-Angle Camera’s 11 narrow-band color filters. Because of the large data volume involved, only features of special scientific interest are targeted for imaging in all 11 colors.
Full of geologically interesting features the crater was named for Kakarla Tyagabrahmam, an 18th century composer of classical South Indian music.
The first spacecraft to establish orbit around Mercury in summer 2011, MESSENGER is capable of continuing orbital operations until early 2015.
Read more on the Johns Hopkins University APL MESSENGER site here.
Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Mercury's southern polar region as seen from MESSENGER. (Credit: NASA/Johns Hopkins UniversityApplied Physics Laboratory/Carnegie Institution of Washington).
Move over, Tolkien & Tryggvadóttir. Yesterday, an announcement was made that the International Astronomical Union (IAU) approved proposed names for nine new craters on the planet Mercury. The names honor deceased writers, artists and musicians following the convention established by the IAU for naming features on the innermost world.
The announcement comes as NASA’s MESSENGER spacecraft has completed mapping of the surface of Mercury earlier this month. A good majority of these features were established at Mercury’s southern polar region, one of the last areas of the planet to be mapped by MESSENGER.
The craters honored with a newly assigned moniker are:
Donelaitis, named after 18th century Lithuanian poet Kristijonas Donelaitis, author of The Seasons and other tales and fables.
Petofi, named after 19th century Hungarian poet Sandor Petofi, who wrote Nemzeti dal which inspired the Hungarian Revolution of 1848.
Roerich, named after early 20th century Russian philosopher and artist Nicholas Roerich, who created the Roerich Pact of 1935 which asserted the neutrality of scientific, cultural and educational institutions during time of war.
Hurley, named after the 20th century Australian photographer James Francis Hurley, who traveled to Antarctica and served with Australian forces in both World Wars.
Lovecraft, named after 20th century American author H.P. Lovecraft, a pioneer in horror, fantasy and science fiction.
Alver, named after 20th century Estonian author Betti Alver who wrote the 1927 novel Mistress in the Wind.
Flaiano, named after 20th century Italian novelist and screenwriter Ennio Flaiano who was a pioneer Italian cinema and contemporary of Federico Fellini.
Pahinui, named after mid-20th century Hawaiian musician Charles Phillip Kahahawai Pahinui, influential slack-key guitar player and part of the “Hawaiian Renaissance” of island culture in the 1970’s.
L’Engle, named after American author Madeleine L’Engle, who wrote the young adult novels An Acceptable Time, A Swiftly Tilting Planet & A Wind in the Door. L’Engle passed away in 2007.
Five of the newly named craters in the south pole region of Mercury (circled in red). Note that the final portion of the USGS map, although recently released, has yet to be filled in! (Credit: USGS).
The nine new crater names join 95 others named thus far. The MESSENGER surface mapping campaign has been ongoing since the spacecraft’s first flyby of Mercury in January 2008. MESSENGER entered permanent orbit around world on March 18th, 2011.
MESSENGER missions operations engineer Ray Espiritu was instrumental in getting Pahinui’s name in the running.
“I wanted to honor the place where I grew up and still call home,” Espiritu said. ”The Pahinui crater contains a possible volcanic vent, and its name may inspire other scientists as they investigate the volcanic processes that helped to create Mercury, just as investigation of the Hawaiian volcanoes helps us understand the volcanic processes that shape Earth as we know it today.”
Pahinui Crater. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington).
Lovecraft is another interesting selection on the list. The name of the famous horror writer was in the running last month for the naming of Pluto’s moons P4 & P5, and New Horizons principle investigator Alan Stern hinted that Lovecraft may still find a home on a surface feature as New Horizons reveals Pluto & Charon in July 2015. It would be a fitting tribute to a fine writer. Could we end up with Lovecraft marking not only the solar system’s “hubs of hell” on Mercury, but its frozen outer wastelands as well?
There was more news yesterday in the realm of astrogeology and the planet Mercury. The IAU Working Group for Planetary System Nomenclature also made the distinction between features described as valles and catenaeon the surface of Mercury. Catenae are described as crater chains, and MESSENGER has sufficient resolution that several valles have been revealed as such. Catenae on Mercury are named after radio astronomy observatories, while valles are named after abandoned cities of antiquity. Thus, Haystack Vallis is now Haystack Catena, Goldstone Vallis is now Goldstone Catena, and Arecibo Vallis is now Arecibo Catena, and, well, you get the idea.
Arecibo Catenae (formerly known as Arecibo Vallis) as imaged by MESSENGER in 2008. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington).
MESSENGER has proven to be a boon for planetary science. The spacecraft was launched in 2004 and took almost 7 years and 6 flyby assists (one past the Earth, two past Venus and three past Mercury) to become the first spacecraft to orbit the tiniest planet in our solar system. Mercury was first seen up close by Mariner 10 in 1974 and even then we only mapped 45% of its surface. Scientists had to wait until MESSENGER to fill in the remainder of Mercury’s map.
The next mission to Mercury isn’t until the planned arrival of the joint ESA/JAXA BepiColombo mission in 2022.
And don’t forget to watch for Mercury as it reaches greatest elongation on Easter Day low in the dawn sky. I managed to catch sight of it low to the east with binoculars for the first time this apparition this morning about 40 minutes prior to local sunrise. It’s amazing to think that ground-based professional telescopes & even amateur astronomers can actually image fuzzy details on the planet’s surface that match up with what MESSENGER is revealing!
All fascinating stuff to contemplate as we welcome the newest named craters to our ever expanding map of Mercury… now, will there ever be a Miskatonic University within the walls of Lovecraft crater?
Astronomers have found a star system with two planets like Mercury, but bigger. Our own Mercury could supply clues to their composition and formation. (Credit: NASA/Johns Hopkins University/Applied Physics Laboratory.Carnegie Institution of Washington).
A fine apparition of the planet Mercury graces the dawn skies this week, leading up to its greatest elongation from the Sun for 2013.
It seems that nearly every appearance of the planet Mercury is touted as the “best” these days. Such was the case with the inner-most world’s dusk showing early last month. Truth is, all elongations of Mercury (and Venus, for that matter) are not created equal, and visibility of each apparition isn’t the same for observers worldwide. We’ll show you why.
Mercury orbits the Sun once every 88 days. With an orbit interior to our own, it never strays far from the Sun in the sky and thus can only appear low in the dawn or dusk. Its orbit is also elliptical, with an eccentricity of 0.206, the greatest of any planet in our solar system. This means that greatest elongations can vary considerably, from 17.9° away from the Sun in the sky near perihelion of the planet to 28.7° near aphelion. And although reaching greatest elongation near aphelion means the tiny world is above the muck of the horizon, it also means it’s also intrinsically a bit fainter; Mercury can vary in brightness from magnitude -0.2 at a perihelic-elongation to half a magnitude fainter at +0.3 for an aphelic-elongation.
A comparison of elongations of Mercury as seen from the Earth at perihelion versus aphelion. (Created by the author).
But there’s more. Compounding this situation is the angle of the ecliptic, or the imaginary plane of the orbit of the Earth. Near the March equinox the ecliptic rides high in the dusk to the west and low in the dawn to the east for northern hemisphere observers. In the southern hemisphere, the reverse is true. It’s a strange sight for a northerner to head “Down Under” and watch the Sun rise in the east, transit to the north and set to the west!
The path of Mercury looking east ~45 minutes prior to sunrise from latitude 30 degrees north from March 26th through April 30th, (Created by the author using Starry Night).
Thus what may be a terrible apparition of Mercury for one hemisphere may be a grand one for another, as is the case this week. Yes, northern observers can catch the fleeting world, if they know exactly where to look for it. For observers based at longitude 40° north, Mercury will never peak above an altitude of 10° in the dawn sky. Observers based near 35° south will however see the planet reach its maximum possible elevation of over 25° degrees above the horizon.
We would qualify this as “The best dawn appearance of Mercury for 2013… as seen from the southern hemisphere.” Greatest elongations of Mercury occur in pairs, with dusk-to-dawn apparitions about 45 days apart as the planet passes between us and the Sun, followed by a longer period of about 70 days as the world loops back around behind the Sun. The orbit of Mercury is tilted about 7° with respect to our own. Otherwise, we would see a transit of the planetevery inferior conjunction, as last occurred on November 8th, 2006 and will happen next on May 9th, 2016.
The path of Mercury from March 26th through April 26th looking east from latitude 35 degrees south ~45 minutes prior to sunrise. (Created by the author using Starry Night).
Mercury will show a maximum illumination area of 38.5” square arc seconds as seen from the Earth March 30th on just before reaching its greatest elongation west of the Sun on March 31st on Easter Day at 22:00 UT/18:00EDT. Through a telescope, Mercury will display a 7.7” diameter disk with a 50% illuminated “half-Moon” phase. Mercury reaches greatest elongation just 28 hours prior to aphelion which occurs on April 2nd, the closest this has occurred date-wise since April 8th, 2006. This won’t be matched again until March 24th, 2020. Shining at magnitude +0.3, Mercury will then race ahead of the Earth on its inside track and will begin to gradually sink lower on successive mornings in early April. The morning of April 8th may well offer the last good chance to spy the tiny world when the old crescent Moon passes just 8° degrees north of the planet within two days of reaching New phase on April 10th. Mercury reaches superior conjunction opposite to the Earth and on the far side of the Sun on May 11th, 2013, and will again head into the dusk skies for its next greatest eastern elongation on June 12th.
From our Earthly vantage point, Mercury completes 3.15 orbits of the Sun a year. This means that we see 6 greatest elongations on average most years, 3 westerns (dawn) and 3 easterns (dusk). The most elongations of Mercury that you can have in a calendar year are 7, which occurred in 2011 and will happen again in 2015. It’s fascinating to think that until the advent of the Space Age, the orbit and the rough size of Mercury was all we knew about the planet. It would take the first flyby of the Mariner 10 spacecraft to give us a close up view of Mercury in 1974. The precession of the orbit of Mercury was a mystery until explained by Einsteinian physics, and still stands as one of the great proofs of general relativity. Today, we have a permanent ambassador around Mercury, NASA’s MESSENGER spacecraft. MESSENGER has mapped to world in detail, sampled its tenuous exosphere, and observed hints of ancient volcanic activity. MESSENGER will be followed by the joint European Space Agency/Japan Aerospace Exploration Agency mission BepiColombo set to launch in 2015 which will arrive at Mercury in 2022. All fascinating things to ponder as you search for the diminutive world low in the dawn skies this coming Easter weekend!
A high-resolution view of a "silky" surface on Mercury
During its two years in orbit around Mercury — as well as several more years performing flybys — the MESSENGER spacecraft has taken over 150,000 images of the innermost planet, giving us a look at its incredibly rugged, Sun-scoured surface like never before. But not all areas on Mercury appear so harsh — it has its softer sides too, as seen above in an image released earlier today.
Here we see the smooth walls, floor and upper surfaces around an irregular depression on Mercury in high definition. The velvety texture is the result of widespread layering of fine particles, because unlike many features on Mercury’s ancient surface this rimless depression wasn’t caused by an impact from above but rather explosively escaping lava from below — this is the rim of a volcanic vent, not a crater!
Previous images have been acquired of this irregularly-shaped depression but this is the highest resolution view MESSENGER has captured to date — about 26 meters per pixel.
A wide-angle view of the same depression, captured by MESSENGER in July 2012
The full depression, located northeast of the Rachmaninoff basin, is about 36 km (22 miles) across at its widest. It’s surrounded by a smooth blanket of high-reflectance material — explosively ejected volcanic particles from a pyroclastic eruption that spread over the surface like snow.
Other similar vents have been found on Mercury, like this heart-shaped one in Caloris basin. The smooth, bright surface material is a telltale sign of a volcanic outburst, as are the rimless, irregular shapes of the vents.
The numerous small craters that are seen inside the vent and on the smooth surrounding surfaces would be from meteorite impacts that occurred well after the eruption.
On March 17, 2011, MESSENGER became the first spacecraft ever to orbit the planet Mercury. It is capable of continuing orbital operations until early 2015. Find out more about the mission here.
Image credits: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
If you’re reading this then you probably love space exploration, and if you love space exploration then you know how awesome the MESSENGER mission is — the incredibly successful venture by NASA, Johns Hopkins University Applied Physics Laboratory, and the Carnegie Institution of Washington to orbit and study the first rock from the Sun in unprecedented detail. Since entering orbit around Mercury on March 18, 2011, MESSENGER has mapped nearly 100% of the planet’s surface, found unique landforms called hollows residing in many of its craters, and even discovered evidence of water ice at its poles! That’s a lot to get accomplished in just two years!
The video above, assembled by Mark ‘Indy’ Kochte, is a tribute to the many impressive achievements of the MESSENGER mission, featuring orbital animations (love that MESSENGER shimmy!), surface photos, and the approach to the planet. Enjoy!
Images and animation stills courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington. Music: “Mercury Ridge” by Simon Wilkinson. Video creation and time-lapse animations by Mark ‘Indy’ Kochte.
Actor Ed Harris portrayed astronaut John Glenn in The Right Stuff, a 1983 movie following the beginning of the NASA astronaut program. Credit: The Ladd Co. (screenshot)
We’ll be the first to admit that the 1983 movie The Right Stuff takes artistic license when it talks about the Mercury program and other events. It exaggerates problems between the astronauts, portrays the journalists as unthinking buffoons and misrepresents historical events such as breaking the speed of sound.
Late in the three-hour film, the movie turns to astronaut John Glenn‘s first flight in space, which took place on this day in 1962. Glenn was the first American to make an orbital flight of the Earth. He returned a national hero.
Below we’ll highlight a few points of similarity and difference between the movie and John Glenn’s own account of the flight of Friendship 7, which he detailed in his 1999 biography John Glenn: A Memoir. And yes, the rest of this post does contain spoilers for those who haven’t seen the film.
– Visit from Lyndon Johnson. During an aborted launch attempt, the movie shows Lyndon Johnson parked nearby the Glenns’ house in a limousine, ordering an aide to let him inside. Glenn’s wife Annie (through a fellow astronaut wife) keeps informing the hapless assistant that there’s no way Johnson (and the TV cameras he wants to include) can come in. While Glenn’s actual account doesn’t specify where the vice-president of the United States was at that time, he does talk about the request and refusal. “She said she was tired, she had a headache, and she just wasn’t going to allow all those people in her house … I told her whatever she wanted to do, I would back her up 100 percent.”
– Threat to remove Glenn from the flight. In The Right Stuff, Glenn then gets into a shouting argument with a NASA official nearby, who orders him to get on the phone and tell Annie to let the vice-president in. The NASA official threatens to replace Glenn with another astronaut, at which point Glenn’s colleagues surround him and the official backs down. Glenn confirms the incident, but does not mention other astronauts: “I saw red. I said that if they wanted to do that, they’d have a press conference to announce their decision and I’d have one to announce mine, and if they wanted to talk about it anymore, they’d have to wait until I took a shower. When I came back, they were gone and I never heard any more about it.”
John Glenn enters his Friendship 7 spacecraft on On Feb. 20, 1962. Credit: NASA
– Fireflies. An extended sequence in The Right Stuff shows Glenn exclaiming as he sees “fireflies” outside of the spacecraft. The movie doesn’t really explain why they happen, but yes, they actually were there. “I saw around the capsule a huge field of particles that looked like tiny yellow stars,” Glenn wrote in his memoir. “They seemed to travel with the capsule, but more slowly. There were thousands of them, like swirling fireflies.” Glenn added: “They were droplets of frozen water vapor from the capsule’s heat exchanger system, but their fireflylike glow remains a mystery.” However, fellow astronaut Scott Carpenter noted frost flakes from his spacecraft, Aurora 7 on the next Mercury flight after Glenn’s, and floating nearby. They shone when the Sun illuminated the flakes. He also noticed more flakes coming off the side of his spacecraft when he banged the inside.
– Activities in orbit. While allowing that The Right Stuff probably had other priorities in mind, the movie does not show Glenn doing much in orbit besides gazing out the window and talking about the aforementioned fireflies. Glenn’s book shows him doing more than that: taking his blood pressure, snapping pictures of the Canaries and Sahara Desert, testing his vision, and doing exercises with a bungee cord to compare his readings to previous ones taken on the ground.
– Lights on in Perth and Rockingham, Australia. Glenn and a ground station in Australia chat about the residents of Rockingham and Perth turning on their lights for him. This actually did happen (and it happened again when Glenn returned to space in 1998.)
– Decision to bring Glenn down after three orbits. The movie accurately says Glenn was go for at least seven orbits, but then shows Glenn being confused when he’s told to come down after only three. Glenn contradicts that directly in his account: “The mission was planned for three orbits, but it meant that I could go for at least seven if I had to.”
The launch of John Glenn on Mercury 6. Credit: NASA
– Heat shield threat. The movie shows Mission Control grappling with a signal indication that the landing bag deployed, which implies that the heat shield might have cut loose prematurely. They recommend Glenn refrain from removing a retrorocket package that usually was jettisoned after the rockets fire for re-entry, and keep it on the spacecraft to hold the heat shield on. Glenn talks at length about the situation in his book, and expresses frustration that he didn’t receive information quickly: “I was irritated by the cat-and-mouse game they were playing with the information.” It turned out to be a false alarm.
– Humming. Glenn hums a lot in the movie during the re-entry, especially as the gravity forces build up on him. The astronaut makes no mention of doing so in his book. Long-standing New York Times spacejournalist John Noble Wilford unequivocally stated the movie was wrong: “Mr. Glenn did not hum ”The Battle Hymn of the Republic” during re-entry,” he wrote in a 1983 review of the movie.
Color map of Mercury's varied surface. The 1,550-km-wide Caloris Basin can be seen at upper right.
Created by the MESSENGER mission team at the Johns Hopkins University Applied Physics Laboratory and the Carnegie Institution of Washington, this animation gives us a look at the spinning globe of Mercury, its surface color-coded to reflect variations in surface material reflectance.
Thousands of Wide Angle Camera images of Mercury’s surface were stitched together to create the full-planet views.
While the vibrant colors don’t accurately portray Mercury as our eyes would see it, they are valuable to scientists as they highlight the many different types of materials that make up the planet’s surface. Young crater rays surrounding fresh impact craters appear light blue or white. Medium- and dark-blue “low-reflectance material” (LRM) areas are thought to be rich in a dark, opaque mineral. Tan areas are plains formed by eruption of highly fluid lavas. Small orange spots are materials deposited by explosive volcanic eruptions.
At this point, over 99% of the Solar System’s innermost planet has been mapped by MESSENGER. Read more about the ongoing mission here.
Image/video credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Pieces of the Moon and Mars have been found on Earth before, as well as chunks of Vesta and other asteroids, but what about the innermost planet, Mercury? That’s where some researchers think this greenish meteorite may have originated, based on its curious composition and the most recent data from NASA’s MESSENGER spacecraft.
NWA 7325 is the name for a meteorite fall that was spotted in southern Morocco in 2012, comprising 35 fragments totaling about 345 grams. The dark green stones were purchased by meteorite dealer Stefan Ralew (who operates the retail site SR Meteorites) who immediately made note of their deep colors and lustrous, glassy exteriors.
Ralew sent samples of NWA 7325 to researcher Anthony Irving of the University of Washington, a specialist in meteorites of planetary origin. Irving found that the fragments contained surprisingly little iron but considerable amounts of magnesium, aluminum, and calcium silicates — in line with what’s been observed by MESSENGER in the surface crust of Mercury.
And even though the ratio of calcium silicates is higher than what’s found on Mercury today, Irving speculates that the fragments of NWA 7325 could have come from a deeper part of Mercury’s crust, excavated by a powerful impact event and launched into space, eventually finding their way to Earth.
In addition, exposure to solar radiation for an unknown period of time and shock from its formation could have altered the meteorite’s composition somewhat, making it not exactly match up with measurements from MESSENGER. If this is indeed a piece of our Solar System’s innermost planet, it will be the first Mercury meteorite ever confirmed.
But the only way to know for sure, according to Irving’s team’s paper, is further studies on the fragments and, ultimately, sample returns from Mercury.
Irving’s team’s findings on NWA 7325 will be presented at the 44th Lunar and Planetary Science Conference to be held in Houston, TX, on March 18-22. Read more in this Sky & Telescope article by Kelly Beatty.
Inset image: impact craters located within Mercury’s Caloris Basin (NASA/JHUAPL)
A view of Mercury from MESSENGER’s October 2008 flyby (NASA / JHUAPL / Gordan Ugarkovic)
Every now and then a new gem of a color-composite appears in the Flickr photostream of Gordan Ugarkovic, and this one is the latest to materialize.
This is a view of Mercury as seen by NASA’s MESSENGER spacecraft during a flyby in October 2008. The image is a composite of twenty separate frames acquired with MESSENGER’s narrow-angle camera from distances ranging from 18,900 to 17,700 kilometers and colorized with color data from the spacecraft’s wide-angle camera. (North is to the right.)
Click the image for a closer look, and for an even bigger planet-sized version click here. Beautiful!
The images that made up this mosaic were taken two and a half years before MESSENGER entered orbit around Mercury on March 19, 2011 UT, becoming the first spacecraft ever to do so and making Mercury the final “classical” planet to be orbited by a manmade spacecraft.
Since that time MESSENGER has completed well over 1,000 orbits and taken more than 100,000 images of the first planet in the Solar System, which filled in most of our gaps in Mercury’s map and showed us many never-before-seen features of the planet’s Sun-scoured surface. And just this past year MESSENGER’s extended mission helped confirm what could be called its most important discovery of all: water ice on Mercury’s north pole.
With all that’s been achieved by MESSENGER in 2011 and 2012, 2013 is looking to be an interesting year!
“We learned a great deal about Mercury over the past year,” said MESSENGER Principal Investigator Sean Solomon of Columbia University’s Lamont-Doherty Earth Observatory. “The team published three dozen scientific and technical papers and delivered more than 150 presentations at national and international meetings. New measurements continue to stream back from our spacecraft, and we can look forward with excitement to many additional discoveries in 2013.”
And even though the ratio of calcium silicates is higher than what’s found on Mercury today, Irving speculates that the fragments of NWA 7325 could have come from a deeper part of Mercury’s crust, excavated by a powerful impact event and launched into space, eventually finding their way to Earth.
