Scientists using data from the lunar-orbiting twins of NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission are gaining new insight into how the face of the moon received its rugged good looks. A report on the asymmetric distribution of lunar impact basins is published in this week’s edition of the journal Science.
“Since time immemorial, humanity has looked up and wondered what made the man in the moon,” said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge. “We know the dark splotches are large, lava-filled, impact basins that were created by asteroid impacts about four billion years ago. GRAIL data indicate that both the near side and the far side of the moon were bombarded by similarly large impactors, but they reacted to them much differently.”
Understanding lunar impact basins has been hampered by the simple fact that there is a lack of consensus on their size. Most of the largest impact basins on the near side of the moon (the moon’s face) have been filled with lava flows, which hide important clues about the shape of the land that could be used for determining their dimensions. The GRAIL mission measured the internal structure of the moon in unprecedented detail for nine months in 2012. With the data, GRAIL scientists have redefined the sizes of massive impact basins on the moon.
This high-contrast, colorized mosaic from NASA’s Cassini mission shows an infrared view of the Saturn system, backlit by the sun, from July 19, 2013. Exaggerating the contrast of the data brings out subtleties not initially visible. For example, structures in Saturn’s wispy E ring — made from the icy breath of the moon Enceladus — reveal themselves in this exaggerated view.
The image, made from data obtained by Cassini’s visual and infrared mapping spectrometer, covers a swath of Saturn and its rings about 340,000 miles (540,000 kilometers) across that includes the planet and its rings out to the E ring, Saturn’s second most distant ring. The mosaic covers an area about 5,000 miles (8,000 kilometers) from top to bottom.
When Saturn is blocking the direct light of the sun, scientists can get a better look at the fainter rings. When small particles are lit from behind, they show up like fog in the headlights of an oncoming vehicle. Conversely, a ring that is easily seen from Earth because it is densely packed with chunks of bright water ice looks dark in these images because it is so thick that it blocks almost all of the sunlight shining behind it.
Earth’s most eminent emissary to Mars has just proven that those rare Martian visitors that sometimes drop in on Earth — a.k.a. Martian meteorites — really are from the Red Planet. A key new measurement of Mars’ atmosphere by NASA’s Curiosity rover provides the most definitive evidence yet of the origins of Mars meteorites while at the same time providing a way to rule out Martian origins of other meteorites.
The new measurement is a high-precision count of two forms of argon gas—Argon-36 and Argon-38–accomplished by the Sample Analysis at Mars (SAM) instrument on Curiosity. These lighter and heavier forms, or isotopes, of argon exist naturally throughout the solar system. But on Mars the ratio of light to heavy argon is skewed because a lot of that planet’s original atmosphere was lost to space, with the lighter form of argon being taken away more readily because it rises to the top of the atmosphere more easily and requires less energy to escape. That’s left the Martian atmosphere relatively enriched in the heavier Argon-38.
An instrument aboard NASA’s Curiosity rover has sent back to scientists on Earth an ultra high-resolution image of a penny the rover carried to Mars.
The coin was photographed by the Mars Hand Lens Imager (MAHLI) aboard Curiosity in northern Gale crater on Mars. The penny, a 1909 VDB penny minted in Philadelphia during the first year that Lincoln cents became available, is part of the MAHLI calibration target and came from Earth. The images were acquired on Oct. 2, on sol 411 – the 411th Martian day – of the mission.
“I’m so proud of how beautifully this camera has performed on Mars,” said R. Aileen Yingst, Planetary Science Institute Senior Scientist and deputy Principal Investigator for MAHLI. “I can’t wait to apply this newly available capability to real geologic targets on our way to Mt. Sharp.”
A research project led by Joseph R. Michalski, Senior Scientist at the Planetary Science Institute, has identified what could be a supervolcano on Mars – the first discovery of its kind. In a paper published Oct. 3 in the journal Nature, Michalski and co-author Jacob E. Bleacher of NASA Goddard Space Flight Center describe a new type of volcanic construction on Mars that until now has gone unrecognized.
The volcano in question, a vast circular basin on the face of the Red Planet, previously had been classified as an impact crater. Researchers now suggest the basin is actually the remains of an ancient supervolcano eruption. Their assessment is based on images and topographic data from NASA’s Mars Odyssey, Mars Global Surveyor and Mars Reconnaissance Orbiter spacecraft, as well as the European Space Agency’s Mars Express orbiter.
“On Mars, young volcanoes have a very distinctive appearance that allows us to identify them,” Michalski said. “The long-standing question has been what ancient volcanoes on Mars look like. Perhaps they look like this one.”
NASA’s Curiosity rover is revealing a great deal about Mars, from long-ago processes in its interior to the current interaction between the Martian surface and atmosphere.
Examination of loose rocks, sand and dust has provided new understanding of the local and global processes on Mars. Analysis of observations and measurements by the rover’s science instruments during the first four months after the August 2012 landing are detailed in five reports in the Sept. 27 edition of the journal Science.
A key finding is that water molecules are bound to fine-grained soil particles, accounting for about 2 percent of the particles’ weight at Gale Crater where Curiosity landed. This result has global implications, because these materials are likely distributed around the Red Planet.
Curiosity also has completed the first comprehensive mineralogical analysis on another planet using a standard laboratory method for identifying minerals on Earth. The findings about both crystalline and non-crystalline components in soil provide clues to the planet’s volcanic history.
NASA today announced the end of operations for the Deep Impact spacecraft, history’s most traveled deep-space comet hunter, after trying unsuccessfully for more than a month to regain contact with the spacecraft.
UMD scientists – who helped conceive the mission, bring it to reality and keep it going years longer than originally planned—say it is a big loss, but find great satisfaction that Deep Impact exceeded all expectations and that the science derived from it transformed our understanding of comets.
“The impact on comet Tempel 1, the flyby of comet Hartley 2, and the remote sensing of comet Garradd have led to so many surprising results that there is a complete rethinking of our understanding of the formation of comets and of how they work. These small, icy remnants of the formation of our solar system are much more varied, both one from another and even from one part to another of a single comet, than we had ever anticipated,” said University of Maryland astronomer Michael A’Hearn, who led the Deep Impact science team from the successful Deep Impact proposal to its unanticipated completion.
NASA’s Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun.
New and unexpected data indicate Voyager 1 has been traveling for about one year through the plasma, or ionized gas, present in the space between the stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of these new data, an effort led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published this week in the journal Science.
“The crossing is like Voyager leaving the hot, million-degree atmosphere of the sun and entering into a region dominated by the ‘cold,’ 5,000-degree atmosphere of the galaxy,” says APL’s Stamatios (Tom) Krimigis, principal investigator for Voyager’s Low-Energy Charged Particle (LECP) instrument. “It’s like the first time a satellite [Sputnik] went beyond Earth’s atmosphere to an altitude of some 600 miles; Voyager is now leaving the solar bubble at an altitude of 11.3 billion miles. It’s another historic milestone.”
Smart as the Mars Curiosity mission has been about landing and finding its own way on a distant world, the rover is pretty brainless when it comes to doing the science that it was sent 567 million kilometers to carry out. That has to change if future rover missions are to make discoveries further out in the solar system, scientists say.
The change has now begun with the development of a new camera that can do more than just take pictures of alien rocks – it also thinks about what the pictures signify so the rover can decide on its own whether to keep exploring a particular site, or move on.
“We currently have a micromanaging approach to space exploration,” said senior researcher Kiri Wagstaff, a computer scientist and geologist at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “While this suffices for our rovers on Mars, it works less and less well the further you get from the Earth. If you want to get ambitious and go to Europa and asteroids and comets, you need more and more autonomy to even make that feasible.”
Full Story: http://www.agu.org/news/press/pr_archives/2013/2013-43.shtml
Data from NASA’s Interstellar Boundary Explorer (IBEX) spacecraft reveal that neutral interstellar atoms are flowing into the solar system from a different direction than previously observed.
Interstellar atoms flow past the Earth as the solar system passes through the surrounding interstellar cloud at 23 kilometers per second (50,000 miles per hour). The latest IBEX measurements of the interstellar wind direction were discovered to differ from those made by the Ulysses spacecraft in the 1990s. That difference led the IBEX team to compare the IBEX measurements to data gathered by 11 spacecraft between 1972 and 2011. Statistical testing of the Earth-orbiting and interplanetary spacecraft data showed that, over the past 40 years, the longitude of the interstellar helium wind has changed by 6.8 ± 2.4 degrees.
“We concluded it’s highly likely that the direction of the interstellar wind has changed over the past 40 years. It’s also highly unlikely that the direction of the interstellar helium wind has remained constant,” says Dr. Priscilla Frisch, lead author of the study and a senior scientist in the Department of Astronomy and Astrophysics at the University of Chicago.
Full Story: http://www.swri.org/9what/releases/2013/ibex-wind.htm#.UilbyiywUV0