The discovery of manganese oxides in Martian rocks might tell us that the Red Planet was once more Earth-like than previously believed. A new paper in Geophysical Research Letters reveals that NASA's Curiosity rover observed high levels of manganese oxides in Martian rocks, which could indicate that higher levels of atmospheric oxygen once existed on our neighboring planet. This hint of more oxygen in Mars' early atmosphere adds to other Curiosity findings--such as evidence of ancient lakes--revealing how Earth-like our neighboring planet once was.

"The only ways on Earth that we know how to make these manganese materials involve atmospheric oxygen or microbes," said Nina Lanza, a planetary scientist at Los Alamos National Laboratory and lead author on the study published in the American Geophysical Union's journal. "Now we're seeing manganese-oxides on Mars and wondering how the heck these could have formed."

Lanza uses the Los Alamos-developed ChemCam instrument that sits atop Curiosity to "zap" rocks on Mars and analyze their chemical make-up. This work stems from Los Alamos National Laboratory's experience building and operating more than 500 spacecraft instruments for national defense, giving the Laboratory the expertise needed to develop discovery-driven instruments like ChemCam. In less than four years since landing on Mars, ChemCam has analyzed roughly 1,500 rock and soil samples.

Microbes seem a far-fetched explanation for the manganese oxides at this point, said Lanza, but the idea that the Martian atmosphere contained more oxygen in the past than it does now seems possible. "These high-manganese materials can't form without lots of liquid water and strongly oxidizing conditions," said Lanza "Here on Earth, we had lots of water but no widespread deposits of manganese oxides until after the oxygen levels in our atmosphere rose due to photosynthesizing microbes."

In the Earth's geological record, the appearance of high concentrations of manganese is an important marker of a major shift in our atmosphere's composition, from relatively low oxygen abundances to the oxygen-rich atmosphere we see today. The presence of the same types of materials on Mars suggests that something similar happened there. If that's the case, how was that oxygen-rich environment formed?

"One potential way that oxygen could have gotten into the Martian atmosphere is from the breakdown of water when Mars was losing its magnetic field," said Lanza. "It's thought that at this time in Mars' history, water was much more abundant."

Yet without a protective magnetic field to shield the surface from ionizing radiation, that radiation started splitting water molecules into hydrogen and oxygen. Because of Mars' relatively low gravity, it wasn't able to hold onto the very light hydrogen atoms, but the heavier oxygen atoms remained behind. Much of this oxygen went into the rocks, leading to the rusty red dust that covers the surface today. While Mars' famous red iron oxides require only a mildly oxidizing environment to form, manganese oxides require a strongly oxidizing environment. These results suggest that past conditions were far more oxidizing (oxygen-rich) than previously thought.

"It's hard to confirm whether this scenario for Martian atmospheric oxygen actually occurred," Lanza added. "But it's important to note that this idea represents a departure in our understanding for how planetary atmospheres might become oxygenated." So far, abundant atmospheric oxygen has been treated as a so-called biosignature, or a sign of existing life.

The next step in this work is for scientists to better understand the signatures of non-biogenic versus biogenic manganese, which is directly produced by microbes. If it's possible to distinguish between manganese oxides produced by life and those produced in a non-biological setting, that knowledge can be directly applied to Martian manganese observations to better understand their origin.

The high-manganese materials were found in mineral-filled cracks in sandstones in the Kimberley region of Gale crater, which the Curiosity rover has been exploring for the last four years. But that's not the only place on Mars that abundant manganese has been found. The Opportunity rover, which has been exploring Mars since 2004, also recently discovered high-manganese deposits in its landing site thousands of miles from Curiosity, which supports the idea that the conditions needed to form these materials were present well beyond Gale crater. The ,image at the top of the page is an artist's concept of how the "lake" at Gale Crater on Mars may have looked millions of years ago. (credit Kevin Gill).

The Daily Galaxy via Los Alamos National Laboratory

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Over the past two weeks, several milestones occurred that were key to a successful 35-minute burn of its rocket motor, which will place the robotic explorer into a polar orbit around the gas giant. "We have over five years of spaceflight experience and only 10 days to Jupiter orbit insertion," said Rick Nybakken, Juno project manager from NASA's Jet Propulsion Laboratory in Pasadena, California. "It is a great feeling to put all the interplanetary space in the rearview mirror and have the biggest planet in the solar system in our windshield."

On June 11, Juno began transmitting to and receiving data from Earth around the clock. This constant contact will keep the mission team informed on any developments with their spacecraft within tens of minutes of it occurring. On June 20, the protective cover that shields Juno's main engine from micrometeorites and interstellar dust was opened, and the software program that will command the spacecraft through the all-important rocket burn was uplinked.

One of the important near-term events remaining on Juno's pre-burn itinerary is the pressurization of its propulsion system on June 28. The following day, all instrumentation not geared toward the successful insertion of Juno into orbit around Jupiter on July 4 will be turned off.

"If it doesn't help us get into orbit, it is shut down," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "That is how critical this rocket burn is. And while we will not be getting images as we make our final approach to the planet, we have some interesting pictures of what Jupiter and its moons look like from five-plus million miles away."

The mission optical camera, JunoCam, imaged Jupiter on June 21, 2016, at a distance of 6.8 million miles (10.9 million kilometers) from the gas giant. In the image, just to the right of center is Jupiter, with its distinctive swirling bands of orange, brown and white. To the left of Jupiter (from right to left) are the planet's four largest moons -- Europa, Io, Callisto and Ganymede. Juno is approaching over Jupiter's north pole, affording the spacecraft a unique perspective on the Jovian system. Previous missions that imaged Jupiter on approach saw the system from much lower latitudes, closer to the planet's equator.

JunoCam is an outreach instrument -- its inclusion in this mission of exploration was to allow the public to come along for the ride with Juno. JunoCam's optics were designed to acquire high-resolution views of Jupiter's poles while the spacecraft is flying much closer to the planet. Juno will be getting closer to the cloud tops of the planet than any mission before it, and the image resolution of the massive gas giant will be the best ever taken by a spacecraft.

All of Juno's instruments, including JunoCam, are scheduled to be turned back on approximately two days after achieving orbit. JunoCam images are expected to be returned from the spacecraft for processing and release to the public starting in late August or early September.

"This image is the start of something great," said Bolton. "In the future we will see Jupiter's polar auroras from a new perspective. We will see details in rolling bands of orange and white clouds like never before, and even the Great Red Spot.

Stunning new images and the highest-resolution maps to date of Jupiter at thermal infrared wavelengths shown above give a glowing view of Juno's target, a week ahead of the NASA mission's arrival at the giant planet. The maps reveal the present-day temperatures, composition and cloud coverage within Jupiter's dynamic atmosphere, and show how giant storms, vortices and wave patterns shape the appearance of the giant planet. The observations will be presented on Monday 27 June at the National Astronomy Meeting in Nottingham by

The high-resolution maps and images were created from observations with the European Southern Observatory's Very Large Telescope (VLT) in Chile, using a newly-upgraded thermal imager called VISIR. The observations were taken between February and June 2016 to characterise Jupiter's atmosphere ahead of Juno's arrival.

"We used a technique called 'lucky imaging', whereby individual sharp frames are extracted from short movies of Jupiter to 'freeze' the turbulent motions of our own atmosphere, to create a stunning new image of Jupiter's cloud layers," explained Leigh Fletcher of the University of Leicester. "At this wavelength, Jupiter's clouds appear in silhouette against the deep internal glows of the planet. Images of this quality will provide the global context for Juno's close-up views of the planet at the same wavelength."

Fletcher and his team have also used the TEXES spectrograph on NASA's Infrared Telescope Facility (IRTF) in Hawaii regularly to map Jupiter's changing appearance. The team made observations at many different wavelengths, optimised for different features and cloud layers in Jupiter's atmosphere, to create the first global spectral maps of Jupiter taken from Earth.

"These maps will help set the scene for what Juno will witness in the coming months. We have seen new weather phenomena that have been active on Jupiter throughout 2016.

These include a widening of one of the brown belts just north of the equator, which has spawned wave patterns throughout the northern hemisphere, both in the cloud layers and high above in the planet's stratosphere," said Dr Fletcher from the University of Leicester's Department of Physics and Astronomy. "Observations at different wavelengths across the infrared spectrum allow us to piece together a three dimensional picture of how energy and material are transported upwards through the atmosphere."

Both sets of observations were made as part of a campaign using several telescopes in Hawaii and Chile, as well as contributions from amateur astronomers around the world, to understand Jupiter's climate ahead of Juno's arrival. The ground-based campaign in support of Juno is led by Dr Glenn Orton of NASA's Jet Propulsion Laboratory. Once in orbit around Jupiter, Juno will skim just 5000 km above Jupiter's clouds once a fortnight - too close to provide global coverage in a single image. The Earth-based observations supplement the suite of advanced instrumentation on the Juno spacecraft, filling in the gaps in Juno's spectral coverage and providing the wider global and temporal context to Juno's close-in observations.

"The combined efforts of an international team of amateur and professional astronomers have provided us with an incredibly rich dataset over the past eight months," said Dr Orton. "Together with the new results from Juno, this dataset will allow researchers to characterise Jupiter's global thermal structure, cloud cover and distribution of gaseous species. We can then hope to answer questions like what drives Jupiter's atmospheric changes, and how the weather we see is connected to processes hidden deep within the planet."

The Daily Galaxy via NASA and ESO

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Scientists led by Durham University's Institute for Computational Cosmology ran the huge cosmological simulations that can be used to predict the rate at which gravitational waves caused by collisions between the monster black holes might be detected. The amplitude and frequency of these waves could reveal the initial mass of the seeds from which the first black holes grew since they were formed 13 billion years ago and provide further clues about what caused them and where they formed, the researchers said.

The research is being presented today (Monday, June 27, 2016) at the Royal Astronomical Society's National Astronomy Meeting in Nottingham, UK. It was funded by the Science and Technology Facilities Council, the European Research Council and the Belgian Interuniversity Attraction Poles Programme.

The study combined simulations from the EAGLE project - which aims to create a realistic simulation of the known Universe inside a computer - with a model to calculate gravitational wave signals.

Two detections of gravitational waves caused by collisions between supermassive black holes should be possible each year using space-based instruments such as the Evolved Laser Interferometer Space Antenna (eLISA) detector (image below) that is due to launch in 2034, the researchers said.

In February the international LIGO and Virgo collaborations announced that they had detected gravitational waves for the first time using ground-based instruments and in June reported a second detection.

As eLISA will be in space - and will be at least 250,000 times larger than detectors on Earth - it should be able to detect the much lower frequency gravitational waves caused by collisions between supermassive black holes that are up to a million times the mass of our sun.

Current theories suggest that the seeds of these black holes were the result of either the growth and collapse of the first generation of stars in the Universe; collisions between stars in dense stellar clusters; or the direct collapse of extremely massive stars in the early Universe.

As each of these theories predicts different initial masses for the seeds of supermassive black hole seeds, the collisions would produce different gravitational wave signals.

This means that the potential detections by eLISA could help pinpoint the mechanism that helped create supermassive black holes and when in the history of the Universe they formed.

Lead author Jaime Salcido, PhD student in Durham University's Institute for Computational Cosmology, said: "Understanding more about gravitational waves means that we can study the Universe in an entirely different way. These waves are caused by massive collisions between objects with a mass far greater than our sun. By combining the detection of gravitational waves with simulations we could ultimately work out when and how the first seeds of supermassive black holes formed."

Co- author Professor Richard Bower, of Durham University's Institute for Computational Cosmology, added: "Black holes are fundamental to galaxy formation and are thought to sit at the centre of most galaxies, including our very own Milky Way.
Discovering how they came to be where they are is one of the unsolved problems of cosmology and astronomy. Our research has shown how space based detectors will provide new insights into the nature of supermassive black holes."

Gravitational waves were first predicted 100 years ago by Albert Einstein as part of his Theory of General Relativity.The waves are concentric ripples caused by violent events in the Universe that squeeze and stretch the fabric of space time but most are so weak they cannot be detected.

LIGO detected gravitational waves using ground-based instruments, called interferometers, that use laser beams to pick up subtle disturbances caused by the waves. eLISA will work in a similar way, detecting the small changes in distances between three satellites that will orbit the sun in a triangular pattern connected by beams from lasers in each satellite.

In June it was reported that the LISA Pathfinder, the forerunner to eLISA, had successfully demonstrated the technology that opens the door to the development of a large space observatory capable of detecting gravitational waves in space.

The image at the top of the page, shows gas and stars in a slice of the EAGLE simulations at the present day. The intensity shows the gas density, while the color encodes the gas temperature. Researchers used the EAGLE simulations to predict the rate at which gravitational waves caused by collisions between supermassive black holes might be detected.

The Daily Galaxy via Durham University

Image credit: The EAGLE project/Stuart McAlpine

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Martin Puryear, “Drawing for Untitled,” 2009, about 2009, compressed charcoal on paper, Courtesy of the artist. © Martin Puryear, Courtesy Matthew Marks Gallery

Martin Puryear, “Maquette for Bearing Witness,” 1994, pine, Courtesy of the artist. © Martin Puryear, Courtesy Matthew Marks Gallery. (Photography by Jamie Stukenberg, Professional Graphics)

Martin Puryear, “Maquette for Big Bling,” 2014, birch, plywood, maple, and 22k gold leaf, Courtesy of the artist. © Martin Puryear, Courtesy Matthew Marks Gallery. (Photograph by Jamie Stukenberg, Professional Graphics)

Martin Puryear, “Bower,” 1980, Sitka spruce, pine, and copper tacks, Smithsonian American Art Museum, © 1980, Martin Puryear, Courtesy Matthew Marks Gallery

Martin Puryear, “Phrygian,” 2012, soft ground etching with spit bite, drypoint and aquatint on paper, laid down on paper (chine collé), Smithsonian American Art Museum. © 2012, Paulson Bott Press

Martin Puryear, “Vessel,” 19972002, eastern white pine, mesh, and tar, Courtesy of the artist. © Martin Puryear, Courtesy Matthew Marks Gallery