Mercury Archives

February 4, 2013April 26, 2016 by Jason Major

Is This Meteorite a Piece of Mercury?

The largest fragment of meteorite NWA 7325 (Photo © Stefan Ralew / sr-meteorites.de)

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)

January 15, 2013December 23, 2015 by Jason Major

A Hi-Res Mosaic of Mercury’s Crescent

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.

This was even selected by Scientific American as one of the Top 5 Space Stories of 2012.

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.”

Follow the MESSENGER mission news here and see more of Gordan’s space images here.

Inset image: 12 Mercurial discoveries by MESSENGER in 2012. Click to review.

December 28, 2012December 23, 2015 by Jason Major

How Long is a Day on Mercury?

1/3 the distance from the Sun than Earth, it should be no surprise that a day on Mercury is a real scorcher with temperatures soaring over 400 ºC. But in addition to its solar proximity it also has an extremely slow rotation: a single day on Mercury is 58.6 Earth days long… and you thought your Mondays lasted forever!

To be even more precise, for every 2 Mercury years, 3 Mercury days pass — a 3:2 spin-orbit resonance, caused by the planet’s varying elliptical orbit. (This also makes for some interesting motions of the Sun in Mercury’s sky.)

To illustrate this, UK’s The Open University has published a new video in their 60 Second Adventures in Astronomy series… check it out above (and see more of their excellent and amusing animations here.)

Video: The Open University. Narrated by David Mitchell.

December 19, 2012December 23, 2015 by Jason Major

Evidence for Active Hollows Formation on Mercury

MESSENGER targeted-observation image of the interior of Eminescu crater

A recent image acquired by NASA’s MESSENGER spacecraft shows the interior of Eminescu, a youngish 130-km (80 mile) wide crater just north of Mercury’s equator. Eminescu made science headlines last year with MESSENGER’s discovery of curious eroded blotches called “hollows” scattered across its interior and surrounding its central peak, and now it looks like the spacecraft may have spotted some of these strange features in their earliest stages of formation along the inner edge of the crater’s rim.

First announced in September 2011, hollows have now been identified in many areas across Mercury. They had showed up in previous images as only bright spots, but once MESSENGER established orbit in March 2011 and began its high-resolution imaging of Mercury’s surface it soon became clear that these features were something totally new.

The lack of craters within hollows indicates that they are relatively young. It was suggested that they may be the result of an ongoing process on Mercury — a suggestion supported by this recent image, acquired on November 19, 2012.

In addition to the hollows seen in the smooth central part of the crater and around the base of the central peak, there are also some small bright spots visible within the knobby terrain extending from the base of the crater wall (see detail at right). These bright spots could well be very young hollows, revealing a process in action that is, as far as we know, unique to the planet Mercury.

It’s thought that hollows are formed by the solar wind constantly blasting Mercury’s surface, scouring away deposits of volatile materials in its crust that have been left exposed by impacts.

The image above shows an area about 42 km across. Read more on the MESSENGER mission site here.

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

November 29, 2012December 23, 2015 by Nancy Atkinson

Water Ice and Organics Found at Mercury’s North Pole

A radar image of Mercury’s north polar region is shown superposed on a mosaic of MESSENGER images of the same area. All of the larger polar deposits are located on the floors or walls of impact craters. Deposits farther from the pole are seen to be concentrated on the north-facing sides of craters. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory

Over 20 years ago, radar-bright materials were seen in the north polar region on Mercury, and since then scientists have postulated that water ice could be hiding there in permanently shadowed regions. The latest data from the MESSENGER spacecraft – now orbiting the planet closest to the Sun – confirms that Mercury indeed does hold water ice as well as organic material within permanently shadowed craters at its north pole. Scientists today said that Mercury could hold between 100 billion to 1 trillion tons of water ice at both poles, and the ice could be up to 20 meters deep in places. Additionally, intriguing dark material which covers the ice could hold other volatiles such as organics.

The MESSENGER team published three papers this week in the journal Science, which present three new lines of evidence that water ice dominates the components inside the craters on Mercury’s north pole.

“Water ice passed three challenging tests and we know of no other compound that matches the characteristics we have measured with the MESSENGER spacecraft,” said MESSENGER Principal Investigator Sean Solomon at a briefing today. “These findings reveal a very important chapter of the story of how water ice has been delivered to the inner planets by comets and water rich asteroids over time.”

MESSENGER arrived at Mercury last year and data from the spacecraft’s neutron spectrometer and laser altimeter were used to make the observations at the planet’s north pole.

A layer of water ice several meters thick is illustrated in white. Abundant hydrogen atoms within the ice stop the neutrons from escaping into space. A signature of enhanced hydrogen concentrations (and, by inference, water ice) is a decrease in the rate of MESSENGER’s detection of neutrons from the planet. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Neutron spectroscopy measures average hydrogen concentrations within Mercury’s radar-bright regions, and scientists were able to derive the water ice concentrations from the hydrogen measurements.

“The neutron data indicate that Mercury’s radar-bright polar deposits contain, on average, a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer 10 to 20 centimeters thick that is less rich in hydrogen,” said David Lawrence, a MESSENGER Participating Scientist based at the Johns Hopkins University Applied Physics Laboratory and the lead author of one of the papers. “The buried layer has a hydrogen content consistent with nearly pure water ice.”

This image shows sunlight that reaches the Prokofiev crater floor and rim. The north-facing portions of the rim and interior remain in perpetual shadow, as do those of numerous other craters. Click on the image watch a movie which simulates approximately one half of a Mercury solar day (176 Earth days) and uses the digital terrain model derived from MLA measurements. Credit: NASA Goddard Space Flight Center/Massachusetts Institute of Technology/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

Data from MESSENGER’s Mercury Laser Altimeter (MLA) — which has fired more than 10 million laser pulses at Mercury to make detailed maps of the planet’s topography — corroborate the radar results and Neutron Spectrometer measurements of Mercury’s polar region. Gregory Neumann of the NASA Goddard Flight Center, lead author of the second paper said the team used topographic data to develop illumination models for Mercury north polar craters, revealing irregular dark and bright deposits at near-infrared wavelength near Mercury’s north pole.

“The real surprise is that there were dark areas surrounding bright areas that were more pervasive than radar bright areas,” said Neumann at Thursday’s briefing. “They are a blanket that protects the bright volatiles that lie underneath.”

Neumann said that impacts of comets or volatile-rich asteroids could have provided both the dark and bright deposits, a finding corroborated in a third paper led by David Paige of the University of California, Los Angeles.

Paige and his colleagues provided the first detailed models of the surface and near-surface temperatures of Mercury’s north polar regions that utilize the actual topography of Mercury’s surface measured by MLA. The measurements “show that the spatial distribution of regions of high radar backscatter is well matched by the predicted distribution of thermally stable water ice,” he said.

A map of “permafrost” on Mercury showing the calculated depths below the surface at which water ice is predicted to be thermally stable. The grey areas are regions that are too warm at all depths for stable water ice. The colored regions are sufficiently cold for subsurface ice to be stable, and the white regions are sufficiently cold exposed surface ice to be stable. The thermal model results predict the presence of surface and subsurface water ice at the same locations where they are observed by Earth-based radar and MLA observations. Credit: NASA/UCLA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

According to Paige, the dark material is likely a mix of complex organic compounds delivered to Mercury by the impacts of comets and volatile-rich asteroids, the same objects that likely delivered water to the innermost planet. The organic material may have been darkened further by exposure to the harsh radiation at Mercury’s surface, even in permanently shadowed areas.

This dark insulating material is a new and intriguing piece of the story of Mercury that MESSENGER is seeking to unravel, said Solomon, and raises questions about what types of organics could be found there. Solomon added that Mercury may now become an object of interest for astrobiology, but said in no uncertain terms that none of the scientists think there is life on Mercury. This could, however, provide information about the rise of organics on Earth.

Additionally, the scientist said there is zero chance of liquid water on Mercury, even though temperatures in some regions would be conducive to liquid water. But with no atmosphere on Mercury, water wouldn’t stick around for long. “It would be ice or vapor really fast,” said Paige.

This schematic of MESSENGER’s orbit illustrates some of the challenges to acquiring observations of Mercury’s north polar region. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Solomon said that obtaining these measurements has not been easy and has not been quick. “Even at highest latitudes reached by MESSENGER, the spacecraft must look at an oblique angle to look at the north polar regions,” he said.

During its primary orbital mission, MESSENGER was in a 12-hour orbit and was at an altitude between 244 and 640 km at the northernmost point in its trajectory. Since April 2012, MESSENGER has been in an 8-hour orbit, shown above, and it has been at an altitude between 311 and 442 km at the northernmost point in its trajectory. Even from these high-latitude vantages, Mercury’s polar deposits fill only a small portion of the field of view of many of MESSENGER’s instruments.

But despite the challenges, Solomon said, the one and a half years of MESSENGER in orbit have now yielded clear results.

See more images and videos from the briefing here.

Sources: MESSENGER, NASA

November 27, 2012January 4, 2016 by Jason Major

Lighting Up Mercury’s Shadowy North Pole

Part of a stereographic projection of Mercury’s north pole

Talk about northern exposure! This is a section of a much larger image, released today by the MESSENGER team, showing the heavily-cratered north pole of Mercury as seen by the MESSENGER spacecraft’s Mercury Dual Imaging System (MDIS) instrument.

See the full-size image below:

Many MDIS images were averaged together to create a mosaic of Mercury’s polar region, which this stereographic projection is centered on. MESSENGER is at its lowest altitude as it passes over Mercury’s northern hemisphere — about 200 kilometers (124 miles), which is just a little over half the altitude of the ISS.

The largest centrally-peaked crater near the center is Prokofiev, named after a 20th-century Russian composer. Approximately 110 km (68 mi.) in diameter, its permanently-shadowed interior is home to radar-bright deposits that are thought to contain water ice.

Even though Mercury is almost three times closer to the Sun than Earth is and hosts searing daytime temperatures of 425ºC (800ºF), there’s virtually no atmosphere to hold or transmit that heat. Nighttime temperatures can reach as low as -185ºC (-300ºF), and since a day on Mercury is 176 Earth days long it gets very cold for quite a long time!

Also, because Mercury’s axis of rotation isn’t tilted like Earth’s, low elevation areas near the poles receive literally no sunlight. Unless vaporized by a meteorite impact any ice gathered inside these deep craters would remain permanently frozen.

Here’s an orthographic projection of the image above, showing what the scene would look like on Mercury — that is, if it was ever fully lit by the Sun, which it isn’t.

Many of the craters on Mercury’s north pole have recently been named after famous artists, authors and composers, such as Kandinsky, Stieglitz, Goethe, and even one named after J.R.R. Tolkien. You can see an annotated image showing the names of Mercury’s north polar craters here.

On November 29, NASA will host a news conference at 2 p.m. EST to reveal new observations from MESSENGER, the first spacecraft to orbit Mercury. The news conference will be carried live on NASA Television and the agency’s website… you can tune in on NASA TV here.

Image credits: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

November 6, 2012December 23, 2015 by Elizabeth Howell

How Today’s Election Could Affect the Kansas Cosmosphere

The Kansas Cosmosphere and Space Center. (Elizabeth Howell)

Hutchinson, KS — While the nation is polarized between choosing Barack Obama or Mitt Romney as the next American president, voters going to the polls in this city of 40,000 will have another matter to weigh during elections today.

Along with their ballot, residents will consider whether the Kansas Cosmosphere and Space Center will continue to receive funding from city coffers. Since it represents 18% of revenues for the science museum, Cosmosphere president Jim Remar says his colleagues have been paying close attention.

The city sales tax sets aside 33% of a quarter-cent for the Cosmosphere, and some additional funding for a nearby underground salt museum and other city initiatives. Money to the museum goes for general operations.

“I feel good that it’s going to pass, although we do have some nervous moments,” Remar says. Supporters of the tax have been spreading the word through radio, billboards, editorials in local newspapers and any other means possible to get out the word.

Museum president Jim Remar, inside the Cosmosphere’s restoration facility. (Elizabeth Howell)

Sales tax funding for the Cosmosphere renews every five years, with the current iteration set to expire in 2014. The city tries to get the vote out for the sales tax at the same time as the general election, for convenience and financial sake.

While 18% of the museum’s funding lie in the hands of voters, Remar is trying to increase the share of the remaining 82% under the Cosmosphere’s control.

Getting visitors out to the museum is always a challenge; it’s an hour from the nearest major center (Wichita), a city that itself is many hours’ drive from any city to speak of. Still, the museum brings in 120,000 people every year, an attendance figure that includes space camps, museum visits and other events.

For the city itself, though, the museum is a jewel: “I can’t think of any other town of 40,000 that has such a facility,” says Remar, speaking proudly of how he grew up in the area, left and then chose to come back to help lead the museum’s management. His focus now is on trying to bring in business connections to enhance the Cosmosphere’s power in the community.

One of the most promising aspects is the Cosmosphere’s restoration and fabrication facility. The museum is perhaps most famous for putting the pieces of the Apollo 13 Odyssey spacecraft back together around the same time the movie came out in 1995. This was no easy task, as Odyssey was disassembled and scattered during an investigation into a near-fatal explosion aboard the spacecraft in 1970.

The restored control panel in Apollo 13’s Odyssey spacecraft, which sits in the Cosmosphere. (Elizabeth Howell)

The Cosmosphere required the Smithsonian’s help as the museum hunted through NASA centers, contract facilities and other spots for months in search of missing pieces. More than 85% of the spacecraft, which is on display at the Cosmosphere, was retrieved. The rest of the components came from spares and other odd pieces the Cosmosphere could find.

Restoration capabilities came out of necessity, Remar says. In the mid-1980s, the museum had a need to put spacecraft on display and spiffy them up for visitors. As other museums had the same requirement, the Cosmosphere gradually built out capabilities in restoration.

“It’s not something where somebody can come in a day and do it. It is a lot of trial and error,” Remar says of the employees who work in the facility. The lead mechanic has been around for 14 years, though, and there are two other workers with him who have adapted well over the years.

Cosmosphere officials realized there are only so many spacecraft to restore, and added exhibitions, replication and fabrication to their capabilities. This positioned them well for a surge of Hollywood films and other productions in the 1990s, such as Apollo 13, HBO’s From the Earth to the Moon, a short-lived TV series in the ’90s called The Cape and (in the 2000s) the IMAX film Magnificent Desolation: Walking on the Moon 3D.

An individual project will cost anywhere from $10,000 to $2.5 million to build; overall revenues from this division are 15 to 20% of the museum’s coffers every year. And that could grow bigger very soon.

A tool box inside the Cosmosphere’s restoration facility. (Elizabeth Howell)

On Saturday, a “Science of Aliens” exhibit will open in Taipei at the National Taiwan Science Education Center. One major part is a UFO spacecraft – 19 feet wide by 7 feet tall – that the Cosmosphere built for the exhibit. It includes running lights and some alien-sounding noises.

Asia happens to be a hot economy these days compared with North America and Europe, where the Comosphere’s work historically went.

The Cosmosphere is in discussions with Taipei-based Universal Impression, a broker that negotiated the science museum work, to do more work in the future. Remar says he hopes the Cosmosphere’s presence there will serve as a calling card to other Asian clients.

“International work can explode here,” he says. “There’s a lot of potential.”

October 11, 2012December 23, 2015 by Jenny Winder

BepiColombo – Mission to Mercury

Caption: BepiColombo’s components separating at Mercury. Image Credit: Astrium

BepiColombo, due to launch in 2015, will be only the third spacecraft to visit Mercury and the first to be sent by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). Currently undergoing tests at ESA’s European Space Research and Technology Centre (ESTEC) in the Netherlands. Here are the details and objectives of this joint mission to our innermost planet which hopes to give us the best understanding of Mercury to date

As the innermost of the terrestrial planets Mercury has an important role in showing us how planets form, yet it is the least explored planet in the inner Solar System. NASA sent Mariner 10 in 1974–5 and MESSENGER flew passed the planet 3 times in 2008 and 2009, before going into orbit around it last year. Being in close proximity, the Sun’s enormous gravity makes placing a spacecraft into a stable orbit, a challenge.

Professor Giuseppe (Bepi) Colombo (1920–1984) was the Italian mathematician and scientist who developed the gravity-assist maneuver and helped NASA to devise the trajectory of Mariner 10. The spacecraft that bears his name comprises three components: the Mercury Transfer Module (MTM) and the two probes: Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO) It will take 6 years to make the journey from Earth to Mercury using solar-electric propulsion and gravity assists from the Earth and Venus, before eventual gravity capture at Mercury.

The transfer module will then separate and the orbiters will use rocket engines and a technique called ‘weak stability boundary capture’ to enter polar orbits around Mercury. MPO will enter a 2.3 hour period polar orbit and MMO a 9.3 hour period polar orbit. MPO is a 357 kg spacecraft in the shape of a flat prism will carry an imaging system consisting of a wide-angle and narrow angle camera, an infrared spectrometer, an ultraviolet spectrometer, gamma, X-ray, and neutron spectrometers, a laser altimeter, an ion and neutral spectrometer, a near-Earth object telescope and detection system, and radio science experiments. During the 1 year nominal mission it will map the entire surface in different wavelengths, and hopes to find water ice in polar craters permanently in shadow from the Sun’s rays.MMO is a flat cylinder with a mass of about 250 kg and will carry fluxgate magnetometers, charged particle detectors, a wave receiver, a positive ion emitter, and an imaging system.

The main mission objectives are: to investigate the origin and evolution of a planet close to the parent star; study Mercury’s form, interior structure, geology, composition and craters; examine the composition and dynamics of Mercury’s vestigial atmosphere (exosphere); probe the structure and dynamics of Mercury’s magnetized envelope (magnetosphere); determine the origin of Mercury’s magnetic field; investigate the composition and origin of polar deposits and perform a test of Einstein’s theory of general relativity.

In 1845, Urbain-Jean-Joseph Le Verrier, noticed that at perihelion Mercury was moving around the Sun faster than predicted by Newton’s theory of gravity. It was not understood until 1915 when Albert Einstein overhauled the theory of gravity. BepiColombo will measure Mercury’s motion more accurately than ever before and so provide one of the most rigorous tests ever of Einstein’s theory.

Find out more about the mission at ESA

October 1, 2012December 23, 2015 by Jason Major

Mercury’s Surface is Full of Sulfur

The southern portion of Mercury’s Vivaldi basin and outlying rugged terrain

Named for the 17th-century Venetian composer, the southern half of Mercury’s Vivaldi basin is seen in this image acquired on August 26 by NASA’s MESSENGER spacecraft. The 213-km (132-mile) -wide crater’s smooth floor is contrasted by the incredibly rugged terrain beyond its outermost ring — a result of the ejected material that was flung out from the impact site and emphasized by the low angle of illumination.

The floor of the crater remained relatively smooth due to molten material that erupted in the wake of the impact event, flooding the basin.

Recent findings from the MESSENGER mission have revealed variations in Mercury’s surface composition due to volcanism that occurred at different times, as well as a surprising concentration of elements like magnesium and sulfur — much more so than any of the other terrestrial planets.

In results to be published in the Journal of Geophysical Research, scientists report that Mercury’s volcanic smooth plains differ in composition from older surrounding terrains. The older terrain has higher ratios of magnesium to silicon, sulfur to silicon, and calcium to silicon, but lower ratios of aluminum to silicon, suggesting that the smooth plains material erupted from a magma source that was chemically different from the source of the material in the older regions, according to Shoshana Weider of the Carnegie Institution of Washington, the lead author on the paper.

Mercury’s surface was also found to be high in magnesium and sulfur-enriched minerals.

“None of the other terrestrial planets have such high levels of sulfur. We are seeing about ten times the amount of sulfur than on Earth and Mars,” Weider said. “In terms of magnesium, we do have some materials on Earth that are high in magnesium. They tend to be ancient volcanic rocks that formed from very hot lavas. So this composition on Mercury tells us that eruptions of high-temperature lavas might have formed these high-magnesium materials.”

Read: MESSENGER Reveals Mercury’s Colors

The data was gathered with MESSENGER’s X-Ray Spectrometer (XRS) — one of two instruments designed to measure the abundances of many key elements in the top 2mm of Mercury’s crust. XRS detects emissions from elements in the 1-10 kiloelectron-volt (keV) range – specifically, magnesium, aluminum, silicon, sulfur, calcium, titanium, and iron.

Read more on the MESSENGER mission site here.

Inset image: A global mosaic of Mercury from MESSENGER (2011). Image credits: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington