Universe Today

May 1, 2009December 24, 2015 by Nancy Atkinson

NASA Begins Job Layoffs As Shuttle Retirement Looms

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NASA began the first round of job layoffs today as the space agency prepares to retire its fleet of space shuttles. 160 people were notified today their jobs were being cut, the first of 900 jobs that will evaporate in the next five months. The first wave of layoffs will affect Lockheed Martin and ATK Thiokol, contractors that support the shuttle program building fuel tanks and rocket boosters in Louisiana and Utah. The shuttle program employs about 1,600 NASA civil servants across the space agency and 13,800 contractors around the country. Once the shuttle stops flying, as many as 6,500 jobs could be cut at the Kennedy Space Center alone.

NASA announced the first round of layoffs at a briefing Thursday, where they also announced the launch date for the Hubble Telescope repair mission as May 11, a day earlier than previously planned. Making the two divergent announcements at the same news conference was bittersweet.

Officials at the briefing stressed that without an infusion of money in 2010 — for which a detailed budget is expected to be released next week — they had no choice but to continue the gradual shutdown of shuttle operations.

Bill Gerstenmaier (left), NASAÂ?s associate administrator for space operations, and shuttle-program manager John Shannon announce job cuts Thursday at Kennedy Space Center. Credit: NASA

Shuttle program manager John Shannon said several hundred jobs will be lost to attrition and some employees will transfer to other contractors or projects. The rest will be layoffs.

“Only if we were directed to fly additional missions would we halt that activity,” Shannon said.

Bill Gerstenmaier, associate administrator for space operations, said that if $2.5 billion proposed recently by Congress budget planners materialized, it could allow a few shuttles to fly past the 2010 retirement date if some shuttle flights got delayed and NASA were unable to complete the construction of the international space station.

He added that, although the shuttle program’s plans were clear, it was less certain how quickly jobs would ramp up for the shuttle’s replacement, the Ares I rocket and Orion capsule.

The first launch of Ares I and Orion is planned for March 2015, but that date is not certain.

Source: Orlando Sentinel

May 1, 2009December 24, 2015 by Nancy Atkinson

Why Are Galaxies Smooth? Star Streams

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Look at the disk of any large spiral galaxy, and outwardly it appears smooth, with stars evenly distributed throughout. But when young stars are forming, they are clustered together in dense clouds of dust and gas. So what happens as the galaxy matures to allow for the smooth distribution seen in galaxies like the Milky Way? Using NASA’s Spitzer Space Telescope, an international team of astronomers has discovered streams of young stars flowing from their natal cocoons in distant galaxies. These distant rivers of stars provide an answer to one of astronomy’s most fundamental puzzles.

Astronomers know that the clusters where stars form begin to disappear when their ages reach several hundred million years. A few mechanisms are thought to explain this: some clusters evaporate when random internal motions kick out stars one by one, and other clusters disperse as a result of collisions among the clouds where they were born. Zooming out to mechanisms operating on larger scales still, shearing motions caused by the galaxy’s rotation around its center disperses the clusters of clusters of young stars.

“Our analysis now answers the grand puzzle. By finding a myriad of streams of young stars all over the disks of galaxies we studied, we see that the mechanism for pulling the clusters of young stars apart is shearing motions of the parent galaxy. These streams are the ‘missing link’ we needed to understand how the disks of galaxies evolve to look the way they do,” said team leader David Block of the University of the Witwatersrand in South Africa.

Crucial to this discovery was finding a way to image previously hidden young stellar streams in galaxies millions of light-years away. To do this the team used high-resolution infrared observations from the Spitzer.
Using infrared rather than visible light to look at the galaxies allowed the group to pick out stars at just the right age when the stars are just starting to spread out from their clusters.

“Spitzer observes in the infrared where 100-million-year-old populations of stars dominate the light,” noted co-author Bruce Elmegreen, from IBM’s Research Division in New York. “Younger regions shine more in the visible and ultraviolet parts of the spectrum, and older regions get too faint to see. So we can filter out all the stars we don’t want by taking pictures with an infrared camera.”

Infrared is also important because light in this part of the spectrum can penetrate the dense dust clouds surrounding the clusters where stars form.

“Dust blocks optical starlight very effectively,” said Robert Gehrz of the University of Minnesota, “but infrared light with its longer wavelength goes right around the dust particles blocking our view. This allows the infrared light from young stars to be seen more clearly.”

But even when the images are taken in the infrared, they are still dominated by the light from the smooth older disks of galaxies, not the faint tracks of young dispersing clusters. Special mathematical manipulations were needed to pick out the clusters, whose faint tracks can still be seen precisely because they are not smooth.

Team member Ivanio Puerari of the Instituto Nacional de Astrofisica, Optica y Electronica in Puebla, Mexico used a technique invented by mathematician Jean Baptiste Fourier in the early 1800’s. The technique is effectively a spatial filter that picks out structure on the physical scale where star formation occurs. “The structures cannot be seen on the original Spitzer images with the human eye,” noted Puerari.

“The combination of the Fourier filtering and infrared images highlighted regions of just the right size and the right age. To then unveil so many star streams in the disks of galaxies was unimaginable a year ago. This discovery continues to highlight the enormous potential of the Spitzer Space Telescope to make contributions none of us could have dreamed possible,” commented Giovanni Fazio from the Harvard-Smithsonian Center for Astrophysics, project leader for the Spitzer Infrared Array Camera team used to take the pictures, and co-author of the discovery.

“Galileo, as both astronomer and mathematician, would have been proud. It is a wonderful interplay between the use of astronomical observations and mathematics and computers, exactly 400 years since Galileo used his telescope to examine our Milky Way galaxy in 1609,” Fazio said

Source: Spitzer

May 1, 2009December 24, 2015 by Nancy Atkinson

Coastal Formations Not Result of Asteroid Impact

The black arrows indicate the orientation of chevrons along the southern coast of Madagascar, but the white arrows indicate what computer models say should have been the orientation if they were caused by the impact of a space body in the Indian Ocean. Credit: Robert Weiss

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Coastal formations called chevrons, large U- or V-shaped features found on coastlines around the world were originally thought to be evidence of ancient “megatsunamis” caused by asteroids or comets slamming into the ocean. However, new research using Google Earth and computer models to recreate large wave action refutes that school of thought.

The theory of chevrons being created by tsunamis was proposed in 2006 after the structures were found in Egypt and the Bahamas. Some were, at places, between several hundred meters- and a kilometer-wide. Since they were also found to exist in Australia and Madagascar, some geologists formed the hypothesis that they were sediment cones left behind by large tsunamis, perhaps up to ten times stronger than the devastating tsunami in the Indian Ocean in December 2005.

The theory propsed the only source for such a megatsunami was a meteor impact, occurring about 5,000 years ago.

But a new study, led by Jody Bourgeois, a geologist and tsunami expert at the University of Washington, argues that this theory is simply “nonsense. For example, she said, there are numerous chevrons on Madagascar, but many are parallel to the coastline. Models created by Bourgeois’ colleague Robert Weiss show that if they were created by tsunamis they should point in the direction the waves were travelling, mostly perpendicular to the shore.

Landsat image of the Fenambosy Chevrons in Madagascar by USGS. The open side of these chevrons point directly at a crater at the bottom of the Indian Ocean. They suggest a gigantic meteor impact occurred about 4800 years ago. But new research says chevrons were likely formed by wind.

“And if it really was from an impact, you should find evidence on the coast of Africa too, since it is so near,” she said.

By using Google Earth, Bourgeois and her team searched for chevrons and surprisingly they found some in desert areas, well inland and away from the shores.

“The extraordinary claim of ‘chevron’ genesis by megatsunamis cannot withstand simple but rigorous testing. There are the same forms in the Palouse in eastern Washington state, and those are clearly not from a tsunami,” Bourgeois said.

She believes the structures were formed by wind.

The discovery of marine fossils in some chevron formations seems to support the idea that a wave created the deposit, but Bourgeois discounts that evidence also.

“Marine fossils can get into non-marine deposits. It’s not uncommon. You only have to change sea level a little bit or have them wash up on a beach in a storm,” she said. “And some marine organisms can be carried by the wind. I am convinced these are largely wind-blown deposits.”

She noted that similar deposits have been seen on the Kamchatka Peninsula on Russia’s east coast, where she has conducted research for more than a decade.

“Those are made of volcanic ash, and they are not near the coast at all, yet they look very similar to these coastal chevrons,” Bourgeois said.

Source: Newswise

May 1, 2009December 24, 2015 by Fraser Cain

Spiral Galaxy

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When you think of a galaxy, you’re probably thinking of a spiral galaxy. You know, with the central bulge and grand sweeping arms that spiral outward from the center. In fact, our own Milky Way is a spiral galaxy, and there are many others out there in the Universe. But have you ever thought about how they form in such a beautiful shape?

A spiral galaxy is shaped like a flat disk with a thicker bulge in the center. Bright spiral arms start from the center and then coil outward like a pinwheel. All spiral galaxies rotate, but very slowly; our own Milky Way completes a single revolution once every 250 million years or so.

The spiral arms are actually density waves that move around the disk of the spiral galaxy. As the density wave passes over a region, masses are pulled together, and you get bright pockets of star formation. Then the density wave moves on, and encourages another region to begin star formation.

The central bulge at the center of a spiral galaxy contains older stars, similar to an elliptical galaxy. And at the very center, there’s always a supermassive black hole containing millions of times the mass of the Sun.

Spiral galaxies are also surrounded by a vast spheroidal halo of stars. These stars might not have formed in the galaxy, but were stolen through successive mergers with other galaxies. This galactic halo also contains many globular star clusters.

Astronomers think that spiral galaxies are slowly built over time through the merger of smaller galaxies. As these tiny galaxies came together, their total momentum set the merged galaxy spinning. This spin flattened out the galaxy and set the spiral arms in motion.

We have written many articles about the galaxies for Universe Today. Here’s an article with twin spiral galaxies interacting, and here’s spiral galaxy NGC 2403.

If you’d like more info on galaxies, check out Hubblesite’s News Releases on Galaxies, and here’s NASA’s Science Page on Galaxies.

We have also recorded an episode of Astronomy Cast about galaxies – Episode 97: Galaxies.

May 1, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – May 1-3, 2009

Greetings, fellow StarGazers! Let’s start the weekend off right by taking on a lunar club challenge and then kicking back to enjoy yet another spring meteor shower! (After all, if April showers bring May flowers, you do know what May flowers bring, don’t you? That’s right… Pilgrims!) Now that I’ve got you at least smiling, take out your binoculars, too… Because there’s two asteroids that are ripe for plucking – Hebe and Ceres. If you feel like being a little more serious about your lunar studies, why not do a little photographic map work? Just match the picture to what you see in the eyepiece and log your studies! Are you ready? Then I’ll see you in the back yard…

Friday, May 1, 2009 – This date is a rather special one in history. In 1543 on this date, Copernicus published and distributed the ‘‘ The Little Commentary ,’’ which described his heliocentric beliefs. In 1949, Gerard Kuiper discovered Nereid, a 150-kilometer-wide satellite of Neptune. It’s so distant from the planet that it requires almost one Earth year (360 days) to complete an orbit! At magnitude 18.7, Nereid is beyond the detection point of most average telescopes but can be ‘‘seen’’ using long exposure charge coupled AQ1 device (CCD) image stacking devices. Other sights that can’t be seen are the Van Allen Radiation Belts of our Earth, the discovery of which was announced in 1958 in this day’s copy of the Washington Evening Star. Thanks to James A. Van Allen’s use of the data from the Explorer I and Pioneer III space probes, we know that Earth’s magnetosphere contains concentrations of electrically charged particles. Say Happy Birthday to American astronaut M. Scott Carpenter, who was born on this date in 1925 and was one of the original seven Mercury astronauts to reach space in 1962.

Tonight’s outstanding lunar feature will be crater Maurolycus , just southwest of the three rings of Theophilus, Cyrillus, and Catharina. This Lunar Club Challenge spans 114 kilometers and goes below the lunar surface by 4,730 meters. Be sure to look for Gemma Frisius just to its north!

Now, relax and enjoy the peak of the Phi Bootid meteor shower, whose radiant is near the constellation Hercules. The best time to view most meteor showers is around 2:00 a.m. local time, but you may have good success watching for these meteors as soon as the Moon westers. The average fall rate is only about 6 per hour, but it’s a great way to spend a spring evening out under the stars!

Saturday, May 2, 2009 – Today, let’s start with the 1868 birth on this date of Robert Williams Wood. Although Wood’s primary research was on sound waves, he devised a ‘‘zone plate’’ that could replace the objective lens of a telescope! He also improved the diffraction grating, did research in spectroscopy, and made photographs showing both infrared and ultraviolet radiations. Also, take a moment to note the 1925 passing of the star cataloger, Johann Palisa. Palisa remains the most successful visual discoverer in the history of minor planet research, discovering 122 asteroids with a 600 telescope and no photographic plates!

Why not salute his achievements by looking for the asteroid Hebe, which reaches opposition tonight? Hebe is the 13th largest asteroid by mass and the 5th brightest to observe. If you collect meteorites and have an H chondrite, chances are good you have a physical piece of Hebe, since it is thought to have contributed up to 40% of all recovered chrondites! Hebe is now coming in at 6th magnitude and given its prime location shouldn’t make it fairly easy for even those with just binoculars to find this cool asteroid.

Now, let’s have a look at the Moon! Tonight’s challenges are craters Cassini and Cassini A, which come into view just south of the black slash of the Alpine Valley. The major crater spans 57 kilometers and reaches a floor depth of 1,240 meters. Your assignment, should you decide to accept it, is to spot the central crater A. It only spans 17 kilometers, yet drops down another 2,830 meters below the primary crater’s floor!

Sunday, May 3, 2009 – How about starting the day with the bizarre and unusual? In 1375 BC, the oldest recorded total solar eclipse occurred—if we can believe eighth century Babylonian records! If you have a green laser pointer, or a telrad, you might want to wish Alfred Kastler a happy birthday. Born on this date in 1902, the physicist was very interested in what happened to atoms when excited by light or radio waves. Kastler developed a method called ‘‘optical pumping,’’ where atoms enter a higher energy state. Optical pumping is what makes your laser work!

Tonight notice just how close bright Regulus is to the Moon! If you’d like to try your hand at asteroid Ceres, you’ll find it approximately another 15 degrees north of the ‘‘Little King.’’

Tonight let’s take a long Moonwalk together and do some major crater exploration. Try using mid-range magnification in your telescope and see how many of the craters in this photograph you can identify!.

Ptolemaeus area: (1) Sinus Asperitatis, (2) Theophilus, (3) Cyrillus, (4) Catharina, (5) Rupes Altai, (6) Piccolomini, (7) Sacrobosco, (8) Abulfeda, (9) Almanon, (10) Taylor, (11) Abenezra, (12) Apianus (13) Playfair, (14) Aliacensis, (15) Werner, (16) Blanchinus, (17) Lacaille, (18) Walter, (19) Regiomontanus, (20) Purbach, (21) Thebit, (22) Arzachel, (23) Alphonsus, (24) Ptolemaeus, and (25) Albategnius.

Until next week? Ask for the Moon… But keep on reaching for the stars!

This week’s awesome images are (in order of appearance): M. Scott Carpenter (credit—NASA), Maurolycus (credit—Alan Chu), Johann Palisa (historical image), Hebe Chart (Your Sky), Cassini (credit—Wes Higgins), Alfred Kastler (historical image) and the Ptolemaeus area (credit—Greg Konkel). We thank you so much!

May 1, 2009December 24, 2015 by Anne Minard

Cosmic Rays too Wimpy to Influence Climate

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People looking for new ways to explain climate change on Earth have sometimes turned to cosmic rays, showers of atomic nuclei that emanate from the Sun and other sources in the cosmos.

But new research, in press in the journal Geophysical Research Letters, says cosmic rays are puny compared to other climatic influences, including greenhouse gases — and not likely to impact Earth’s climate much.

Jeffrey Pierce and Peter Adams of Carnegie Mellon University in Pittsburgh, Pennsylvania, point out that cycles in numerous climate phenomena, including tropospheric and stratospheric temperatures, sea-surface temperatures, sea-level pressure, and low level cloud cover have been observed to correlate with the 11-year solar cycle.

However, variation in the Sun’s brightness alone isn’t enough to explain the effects and scientists have speculated for years that cosmic rays could fill the gap.

For example, Henrick Svensmark, a solar researcher at the Danish Space Research Institute, has proposed numerous times, most recently in 2007, that solar cosmic rays can seed clouds on Earth – and he’s seen indications that periods of intense cosmic ray bombardment have yeilded stormy weather patterns in the past.

Others have disagreed.

“Dust and aerosols give us much quicker ways of producing clouds than cosmic rays,” said Mike Lockwood, a solar terrestrial physicist at Southampton University in the UK. “It could be real, but I think it will be very limited in scope.”

To address the debate, Pierce and Adams ran computer simulations using cosmic-ray fluctuations common over the 11-year solar cycle.

“In our simulations, changes in [cloud condensation nuclei concentrations] from changes in cosmic rays during a solar cycle are two orders of magnitude too small to account for the observed changes in cloud properties,” they write, “consequently, we conclude that the hypothesized effect is too small to play a significant role in current climate change.”

The results have met a mixed reception so far with other experts, according to an article in this week’s issue of the journal Science: Jan Kazil of the University of Colorado at Boulder has reported results from a different set of models, confirming that cosmic rays’ influence is similarly weak. But at least one researcher — Fangqun Yu of the University at Albany in New York — has questioned the soundness of Pierce and Adams’ simulations.

And so, the debate isn’t over yet …

Sources: The original paper (available for registered AGU users here) and a news article in the May 1 issue of the journal Science. See links to some of Svensmark’s papers here.

May 1, 2009April 26, 2016 by Nancy Atkinson

A Stunning Look at “The Big Picture”

My friend Carolyn Collins Petersen, a.k.a. The Spacewriter, has just started a new gig with Astrocast.tv. She now has a regular monthly show called “The Astronomer’s Universe.” Her first episode aired today, and it features “The Big Picture,” an image from the Palomar-Quest digital sky survey. It shows the Virgo Cluster of galaxies, and is something akin to the Hubble Deep Field image. Carolyn’s webcast is a stunning and beautiful look at this amazing part of our night sky, and with wonderful background music and Carolyn’s great voice, (can’t find enough superlatives!) this is must-see TV! Thanks to Carolyn and Astrocast.tv for sharing the video.
Continue reading “A Stunning Look at “The Big Picture””

April 30, 2009December 24, 2015 by Fraser Cain

Galaxies

Hello, is there anyone out there? With all of the galaxies in the Universe, is it possible that there is cognizant life somewhere else? Well, I can not answer that question for you, but I can offer you a great deal of information about galaxies so that you can make your own informed decision on the matter.

Our’s is a spiral galaxy. A spiral galaxy is shaped like a flat disk with a thicker bulge in the center. Bright spiral arms start from the center and then coil outward like a pinwheel. All spirals rotate very slowly. The Milky Way completes a single revolution once every 250 million years.

Most galaxies are billions of years old. The youngest known galaxy is 1 Zwicky 18. At an estimated age of a mere 500 million years, it is a babe in diapers compared to the Milky Way at 10-14 billion years, which is the average age of the known galaxies.

Scientists think that galaxy formation was led by dark matter. This invisible material clumped together and it attracted regular mass with its gravity, channeling material together into larger and larger collections. This process of matter accretion led to the first proto-galaxies.

The Canis Major Dwarf Galaxy is the closest galaxy to ours. It is actually contained within the Milky Way and only 42,000 light years form the galactic core.

In the links below you will find thousands of facts, figures, and images that will help you understand many things about galaxies in general and some specific types. Enjoy your reading.

April 30, 2009December 24, 2015 by Nancy Atkinson

It’s Official: Hubble Mission to Launch May 11

[/caption]After today’s Flight Readiness Review for space shuttle Atlantis’ STS-125 mission to the Hubble Space Telescope, mission managers unanimously agreed to set May 11 at 2:01 p.m. EDT as the launch date. This long awaited flight will repair and upgrade Hubble, likely the most significant satellite ever launched. And, for the space shuttle, it’s a final visit to a dear, old friend.

During the 11-day mission’s five spacewalks, astronauts will install two new instruments, repair two inactive ones and perform the component replacements that will keep the telescope functioning into at least 2014.

In addition to the originally scheduled work, Atlantis also will carry a replacement Science Instrument Command and Data Handling Unit for Hubble. Astronauts will install the unit on the telescope, removing the one that stopped working on Sept. 27, 2008, delaying this servicing mission until the replacement was ready.

Veteran astronaut Scott Altman will command the final space shuttle mission to service NASA’s Hubble Space Telescope, and retired Navy Capt. Gregory C. Johnson will serve as pilot. Mission specialists rounding out the crew are: veteran spacewalkers John Grunsfeld and Mike Massimino, and first-time space fliers Andrew Feustel, Michael Good and Megan McArthur.

Source: NASA

April 30, 2009December 24, 2015 by Nancy Atkinson

New Mysteries Unveiled on Mercury

The Rembrandt impact crater basin on Mercury. Credit: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Smithsonian Institution/Carnegie Institution of Washington

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Even though Mercury looks like the Moon at first glance, scientists from the MESSENGER mission say it’s becoming apparent that Mercury is an amazingly dynamic planet, and is actually more like Mars. For example, before this mission, scientists weren’t sure if volcanism even existed on Mercury, but from the spacecraft’s two flybys, they now know it is a very important part of the planet’s history. Additional new findings from the second flyby of Mercury in October 2008 show that the planet’s atmosphere, magnetosphere, and geological past are all characterized by much greater levels of activity than scientists first suspected.

And by the way, isn’t this a stunning picture of an impact basin? It’s one of the new discoveries from MESSENGER.

One of the most exciting results from the second flyby of Mercury is the discovery of a previously unknown large impact basin. The Rembrandt basin is more than 700 kilometers (430 miles) in diameter, and actually, to see the entire basin, it took combined images from both the first and second flyby to create the stunning picture above. Rembrandt is a relatively young impact basin, and forming about 3.9 billion years ago, is younger than any other known impact region on the planet. It shows pristine terrain on the outer portion of the crater, as well as unusual tectonic fault features, not found in any other big crater.

“This is the first time we’ve seen terrain exposed on the floor of an impact basin on Mercury that is preserved from when it formed” says MESSENGER scientist Thomas Watters. “Landforms such as those revealed on the floor of Rembrandt are usually completely buried by volcanic flows. We know that after Rembrandt formed, the planet was still contracting, so it is an exciting and unique new member of planetary craters we can study.”

MESSENGER’s Mercury Atmospheric and Surface Composition Spectrometer, or MASCS, detected significant amounts of magnesium clumped in the planet’s tenuous atmosphere, called the exosphere. Scientists had suspected magnesium would be present, but were surprised at its distribution and abundance.

“Detecting magnesium was not too surprising, but what is surprising is the distribution and amounts of magnesium that was recorded,” said Bill McClintock, a MESSENGER co- investigator.
The instrument also measured other exospheric constituents during the October 6 flyby, including calcium and sodium, and he suspects that additional metallic elements from the surface including aluminum, iron, and silicon also contribute to the exosphere.

The differences in Mercury's magnetosphere in the two flybys by MESSENGER. Credit: Image produced by NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory//Carnegie Institution of Washington. Image reproduced courtesy of Science/AAAS.

MESSENGER observed a radically different magnetosphere at Mercury during its second flyby, compared with its earlier January 14, 2008 encounter. In the first flyby, no dynamic features were found. But the second flyby was a totally different situation, said James Slavin, MESSENGER Co-Investigator.

“MESSENGER measured large magnetic flux leakage through the dayside magnetopause, about a factor of 10 greater than even what is observed at the Earth during its most active intervals. The high rate of solar wind energy input was evident in the great amplitude of the plasma waves and the large magnetic structures measured by the Magnetometer throughout the encounter.”

Slavin said Mercury’s magnetic field bears a marked resemblance to what we have at earth, but it is about 100 times weaker, which implies interior of Mercury is in part molten. “There is a dynamo action that is ongoing which regenerates and maintains the planetary magnetic field,” he said.

A subsurface interpretation of an impact basin on Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington.

Scientists are also learning more abour Mercury’s crustal evolution, and have now mapped about 90% of the planet’s surface. About 40% is covered by smooth plains which are now known to be of volcanic origna. “These plains are globally distributed (in contrast with the Moon, which has a nearside/farside asymmetry in the abundance of volcanic plains),” said Brett Denevi, MESSENGER team member.

Data shows an enhanced iron- and titanium content in an ancient basin studied by MESSENGER, which are exposed on the surface only through impact events, and may formed when dense minerals settled out as they crystallized from a cooling magma. “There are a complex series of events going on here, but we see it everywhere, so this is a microcosm of the entire planet” said Denevi.

These discoveries are more clues to the mystery of the creation of the rocky, bizarre planet that resides closest to the sun.

Source: NASA Press conference, MESSNEGER press release