вторник, 26 марта 2019 г.

Light Angle A burst of colour is a universal form of…

Light Angle

A burst of colour is a universal form of communication. We react to it – seeing danger, or maybe calm – it’s also a quick way to monitor changes during medical tests. Scientists and engineers are on the lookout for new ways to split, or refract, white light into its rainbow spectrum on demand. Here dishes of oil droplets display iridescence – illuminated with white light, they appear in different colours from different angles, creating a rainbow shimmer. The secret lies in obstructing the path of the light, a process known as structural colour – in this case two types of particles in the oil meet creating a hemisphere shape which refracts the light into coloured waves. It’s possible to manipulate these patterns, raising the possibility of using similar techniques to create iridescent paints, or perhaps new colorimetric sensors, worn of the body to keep tabs on bodily processes.

Written by John Ankers

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Asteroids, Hydrogen Make Great Recipe for Life on Mars

NASA – Mars Science Laboratory (MSL) logo.

March 26, 2019

A new study reveals asteroid impacts on ancient Mars could have produced key ingredients for life if the Martian atmosphere was rich in hydrogen. An early hydrogen-rich atmosphere on Mars could also explain how the planet remained habitable after its atmosphere thinned. The study used data from NASA’s Curiosity rover on Mars and was conducted by researchers on Curiosity’s Sample Analysis at Mars (SAM) instrument team and international colleagues.

These key ingredients are nitrites (NO2) and nitrates (NO3), fixed forms of nitrogen that are important for the establishment and sustainability of life as we know it. Curiosity discovered them in soil and rock samples it took as it traversed within Gale Crater, the site of ancient lakes and groundwater systems on Mars.

Image above: Data from NASA’s Curiosity Mars rover were used in a new paper studying how asteroids impacting the ancient Martian atmosphere could have produced key ingredients to life. Those data were provided by Curiosity’s Sample Analysis at Mars instrument. Image Credits: NASA/JPL-Caltech/MSSS.

To understand how fixed nitrogen may have been deposited in the crater, researchers needed to recreate the early Martian atmosphere here on Earth. The study, led by Dr. Rafael Navarro-González and his team of scientists at the Institute of Nuclear Sciences of the National Autonomous University of Mexico in Mexico City, used a combination of theoretical models and experimental data to investigate the role hydrogen plays in altering nitrogen into nitrites and nitrates using energy from asteroid impacts. The paper was published in January in the Journal of Geophysical Research: Planets.

In the lab, the group used infrared laser beam pulses to simulate the high-energy shockwaves created by asteroids slamming into the atmosphere. The pulses were focused into a flask containing mixtures of hydrogen, nitrogen and carbon dioxide gases, representing the early Martian atmosphere. After the laser blasts, the resulting concoction was analyzed to determine the amount of nitrates formed. The results were surprising, to say the least.

“The big surprise was that the yield of nitrate increased when hydrogen was included in the laser-shocked experiments that simulated asteroid impacts,” said Navarro-González. “This was counterintuitive as hydrogen leads to an oxygen-deficient environment while the formation of nitrate requires oxygen. However, the presence of hydrogen led to a faster cooling of the shock-heated gas, trapping nitric oxide, the precursor of nitrate, at elevated temperatures where its yield was higher.”

Although these experiments were conducted in a controlled lab environment millions of miles from the Red Planet, the researchers wanted to simulate the results obtained from Curiosity using the SAM instrument on the rover. SAM takes samples drilled from rock or scooped up from the surface by the rover’s mechanical arm and bakes them to look at the chemical fingerprints of the released gases.

Image above: This flask served as part of a laboratory test simulating the effect of asteroids impacting the ancient Martian atmosphere. A high-intensity infrared laser is focused into the flask from a lens (left) to simulate the high-energy shockwaves produced by asteroids entering the Martian atmosphere. The gas is then evacuated from the flask and analyzed to determine the composition and levels of nitrogen fixation. Image Credits: Rafael Navarro-González.

“SAM on Curiosity was the first instrument to detect nitrate on Mars,” said Christopher McKay, a co-author of the paper at NASA’s Ames Research Center in California’s Silicon Valley. “Because of the low levels of nitrogen gas in the atmosphere, nitrate is the only biologically useful form of nitrogen on Mars. Thus, its presence in the soil is of major astrobiological significance. This paper helps us understand the possible sources of that nitrate.”

Why were the effects of hydrogen so fascinating? Although the surface of Mars is cold and inhospitable today, scientists think that a thicker atmosphere enriched in greenhouse gases such as carbon dioxide and water vapor may have warmed the planet in the past. Some climate models show that the addition of hydrogen in the atmosphere may have been necessary to raise temperatures enough to have liquid water at the surface.

“Having more hydrogen as a greenhouse gas in the atmosphere is interesting both for the sake of the climate history of Mars and for habitability,” said Jennifer Stern, a planetary geochemist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and one of the co-investigators of the study. “If you have a link between two things that are good for habitability – a potentially warmer climate with liquid water on the surface and an increase in the production of nitrates, which are necessary for life – it’s very exciting. The results of this study suggest that these two things, which are important for life, fit together and one enhances the presence of the other.”

Even though the composition of the early Martian atmosphere remains a mystery, these results may provide more pieces for solving this climate puzzle.

NASA is exploring our solar system and beyond, uncovering worlds, stars and cosmic mysteries near and far with our powerful fleet of space and ground-based missions. Experimental and theoretical work by Navarro-González was funded by the National Autonomous University of Mexico in Mexico City and the National Council of Science and Technology of Mexico. American co-authors received funding from NASA’s Mars Science Laboratory project and French co-authors received funding from the National Center for Space Studies (CNES), Paris, France. NASA’s Mars Exploration Program for the agency’s Science Mission Directorate (SMD) in Washington funded all work related to the operation of the Curiosity rover, the SAM instrument, and the use of NASA facilities and resources to retrieve and analyze the data. Goddard provided the SAM instrument. NASA’s Jet Propulsion Laboratory in Pasadena, California, built the rover and manages the project for SMD.

Mars Science Laboratory (MSL) or “Curiosity”: https://www.nasa.gov/mission_pages/msl/index.html

Images (mentioned), Text, Credits: NASA/JPL/Andrew Good/GSFC/Nancy Neal Jones, written by Timothy Childers.

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The Swiss who takes you to the Moon

NASA – Apollo Program patch.

March 26, 2019

Passionate about the Apollo adventure, this airline pilot met most of his astronauts. He paints an astonishing portrait in a book that comes out this Tuesday.

Image above: Buzz Aldrin and the solar wind experiment which contains, perhaps, as the book suggests, the image of the Swiss flag in its foot. Image Credit: NASA.

This year marks the fiftieth anniversary of the first step on the moon. But it is also 47 years since no man has visited our satellite. They were twelve in all, all Americans. And if the name of Neil Armstrong, the first of them, remains known in the general public, with sometimes also that Buzz Aldrin, who accompanied him on July 20, 1969, the other ten are much less famous. Not to mention the third man from each mission, the one who remained in lunar orbit.

These names, a Swiss knows them all. Better still, Lukas Viglietti met most of the Apollo astronauts and even managed to forge strong bonds with some, even those belonging to the world’s most exclusive club, the Moon Walkers. An intimacy that allows him to publish today this great book, “Apollo Confidential”.

Born the year of the first step on the Moon

Failing perhaps to be born under a lucky star, Lukas Viglietti was born in 1969, year of the conquest of the Moon. This is perhaps why, as a child fascinated by his brother’s Apollo 11 poster, he reads “Pioneers of the cosmos” published in the Green Library. “But the click happens in 1981, he tells us. My brother Dimitri, who was 18 years old and was much more familiar than I at the time, then took me to a lecture by James Irwin near Tramelan (BE), where we lived. “Listening to this Apollo 15 astronaut, 12-year-old Lukas is fascinated: yes, men have managed the feat of walking on the moon.

This will only confirm his desire to become a pilot. But why not astronaut? “Because I, Tramelan’s kid, I thought it was not for me, that it was out of my reach. I did not have the courage to believe in my dreams. I had a conception of elitist success. Even becoming a pilot at Swissair, I thought it was an impossible dream. But these astronauts who have all had to go through trials that were thought insurmountable for them, inspired me and it was thanks to them that I was able to become captain. “

Image above: Lukas Viglietti with Charlie Duke. Image Credit: Lukas Viglietti.

His entrance into the closed circle of lunar walkers, he will do it by dint of tenacity. He takes advantage of his flights to the United States to get in touch with astronauts. He will see them every time one of them passes through Switzerland. And maybe because he’s a pilot and he’s passionate, it works. He befriends Charlie Duke, Al Worden, Alan Bean or Edgar Mitchell, who becomes his son’s godfather. Swiss astronaut Claude Nicollier is helping him open a few more doors. Günter Wendt, the engineer who was the last face astronauts saw when the capsule door closed on them, will tell Lukas Viglietti about the missions and their secrets. To share these experiences and bring as many astronauts as possible to Switzerland, the child of Tramelan created in 2009, with his wife Bettina, Swiss Apollo including Charlie Duke, the youngest man to have walked the lunar ground, made party today. It is the latter who signs the preface to this “confidential Apollo” whose human dimension he rightly points out.

The Swiss flag on the Moon?

Each chapter of the book tells a mission, from Apollo 11 to Apollo 17. The author begins with an anecdote and then attaches to astronauts, describing the journey that brought them here and their personality. Because everyone had a strong character and these daredevils have made beautiful during and alongside the missions. It’s exciting, well written and reads like a thrilling adventure novel. We discover often endearing characters who, all, have been deeply marked by their adventure. The book contains some surprising revelations. Thus, the first flag on the moon may not be that of the United States but that of Switzerland. Inside the foot of the Helvetic experience on the solar wind, the first deployed by Armstrong and Aldrin even before they plant the stars and stripes, would indeed be engraved the red flag with white cross.

Today, four of the twelve lunar walkers are still alive. Who will be the next to walk on the moon? “It will definitely be a woman,” says Lukas Viglietti, American or Chinese. The Chinese have just put a craft on the hidden side of our satellite, a form of dress rehearsal before an inhabited flight. The professor who gave geology lessons to the Apollo astronauts still teaches in Boston and told me that almost all his students are Chinese. In the culture of China, the moon occupies a very important place and a Chinese or a Chinese woman walking there would be a very strong symbol, not to mention all the political, economic and technological fallout for the country. ” not finished making men dream. And women.

Image above: Claude Nicollier on Twitter: My deepest respect and admiration for these heroes of a magnificent adventure! This superb photo was taken by Felix Kunze – congratulations Felix, a real winner!

Claude Nicollier is also an admirer of the Apollo program. He just posted this message and this photo taken on March 16 from eight of its members still alive, from left to right: Charles Duke (Apollo 16), Buzz Aldrin (Apollo 11), Walter Cunningham (Apollo 7), Al Worden (Apollo 15), Rusty Schweickart (Apollo 9), Harrison Schmitt (Apollo 17), Michael Collins (Apollo 11) and Fred Haise (Apollo 13).

Related links:

SwissApollo on Facebook: https://www.facebook.com/SWISSAPOLLO/

The book “Apollo Confidentiel” (in French) can be ordered online on this website:

Images (mentioned), Text, Credits: Le Matin/Orbiter.ch Aerospace/Roland Berga.

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2019 March 26 AE Aurigae and the Flaming Star Nebula Image…

2019 March 26

AE Aurigae and the Flaming Star Nebula
Image Credit & Copyright: Amir Abolfath (TWAN)

Explanation: Is star AE Aurigae on fire? No. Even though AE Aurigae is named the flaming star, the surrounding nebula IC 405 is named the Flaming Star Nebula, and the region shape gives the appearance of fire, there is no fire. Fire, typically defined as the rapid molecular acquisition of oxygen, happens only when sufficient oxygen is present and is not important in such high-energy, low-oxygen environments such as stars. The material that appears as smoke is mostly interstellar hydrogen, but does contain smoke-like dark filaments of carbon-rich dust grains. The bright star AE Aurigae, visible just to the lower right of the image center, is so hot it glows blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, light is emitted, as seen in the surrounding emission nebula. Featured here, the Flaming Star nebula lies about 1,500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga).

∞ Source: apod.nasa.gov/apod/ap190326.html

NASA Updates Spacewalk Assignments, Announces Final Preview Briefing

ISS – Expedition 59 Mission patch.

March 25, 2019

With the first in a series of three spacewalks successfully completed at the International Space Station, NASA has updated astronaut assignments for the remaining two spacewalks and will preview the third in an upcoming news conference on NASA Television and the agency’s website.

NASA astronauts Nick Hague and Anne McClain conducted the first spacewalk in this series on March 22. Hague and fellow NASA astronaut Christina Koch now are preparing to conduct the second spacewalk Friday, March 29, during which they will continue work started on the first spacewalk to install powerful lithium-ion batteries for one pair of the station’s solar arrays.

Image above: NASA astronaut Christina Koch (center) assists spacewalkers Nick Hague (left) and Anne McClain in their U.S. spacesuits shortly before they begin the first spacewalk of their careers. Hague and McClain would work outside in the vacuum of space for six hours and 39 minutes to upgrade the International Space Station’s power storage capacity. Image Credit: NASA.

Koch had been scheduled to conduct this spacewalk with astronaut McClain, in what would have been the first all-female spacewalk. However, after consulting with McClain and Hague following the first spacewalk, mission managers decided to adjust the assignments, due in part to spacesuit availability on the station. McClain learned during her first spacewalk that a medium-size hard upper torso – essentially the shirt of the spacesuit – fits her best. Because only one medium-size torso can be made ready by Friday, March 29, Koch will wear it.

Mission experts previewed the tasks for the first two spacewalks during a March 19 news conference.

McClain now is tentatively scheduled to perform her next spacewalk – the third in this series – on Monday, April 8 with Canadian Space Agency astronaut David Saint-Jacques. Assignments for this spacewalk will be finalized following completion of the second spacewalk.

Image above: NASA astronauts Nick Hague (top) and Anne McClain work to swap batteries in the Port-4 truss structure during March 22 spacewalk. Image Credit: NASA TV.

Experts will discuss the work to be performed on the April 8 spacewalk during a news conference at 2 p.m. EDT Tuesday, April 2, at NASA’s Johnson Space Center in Houston. Live coverage of the briefing and spacewalks will air on NASA Television and the agency’s website.

Media wishing to attend the briefing in person must request credentials from the Johnson newsroom at 281-483-5111 no later than 4 p.m. Monday, April 1. Media interested in participating by phone must contact the newsroom by 1:45 p.m. April 2.

Participants in the briefing will be:

– Kenny Todd, International Space Station manager for Operations and Integration
– Rick Henfling, spacewalk flight director
– John Mularski, lead spacewalk officer

McClain and Saint-Jacques will lay out jumper cables between the Unity module and the S0 truss, at the midpoint of the station’s backbone, during their April 8 spacewalk. This work will establish a redundant path of power to the Canadian-built robotic arm, known as Canadarm2. They also will install cables to provide for more expansive wireless communications coverage outside the orbital complex, as well as for enhanced hardwired computer network capability.

International Space Station (ISS). Animation Credit: NASA

Live coverage of both spacewalks will begin at 6:30 a.m., and each is expected to last about 6.5 hours. The March 29 spacewalk is scheduled to start at 8:20 a.m., while the April 8 spacewalk is set to start at 8:05 a.m.

These will be the 215th and 216th spacewalks in the history of International Space Station assembly and maintenance. During the first spacewalk of the series, on March 22, McClain became the 13th woman to perform a spacewalk. Koch will become the 14th on March 29.

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/future.html

NASA Television: https://www.nasa.gov/live

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.

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Bryn Gwyn Prehistoric Standing Stones, Anglesey, North Wales, 23.3.19.

Bryn Gwyn Prehistoric Standing Stones, Anglesey, North Wales, 23.3.19.

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Hubble Tracks the Lifecycle of Giant Storms on Neptune

NASA – Hubble Space Telescope patch.

March 25, 2019

In 1989, NASA’s Voyager 2 zipped past Neptune—its final planetary target before speeding to the outer limits of the solar system. It was the first time a spacecraft had visited the remote world. As the craft zoomed by, it snapped pictures of two giant storms brewing in Neptune’s southern hemisphere. Scientists dubbed the storms “The Great Dark Spot” and “Dark Spot 2.”

Just five years later, in 1994, NASA’s Hubble Space Telescope took sharp images of Neptune from Earth’s distance of 2.7 billion miles (4.3 billion kilometers). Scientists were eager to get another look at the storms. Instead, Hubble’s photos revealed that both the Earth-sized Great Dark Spot and the smaller Dark Spot 2 had vanished.

Image above: This is a composite picture showing images of storms on Neptune from the Hubble Space Telescope (left) and the Voyager 2 spacecraft (right). The Hubble Wide Field Camera 3 image of Neptune, taken in Sept. and Nov. 2018, shows a new dark storm (top center). In the Voyager image, a storm known as the Great Dark Spot is seen at the center. It is about 13,000 km by 6,600 km (approximately 8,000 miles by 4,100 miles) in size — as large along its longer dimension as the Earth. The white clouds seen hovering in the vicinity of the storms are higher in altitude than the dark material. Image Credits: NASA/ESA/GSFC/JPL.

“It was certainly a surprise,” recalls Amy Simon, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We were used to looking at Jupiter’s Great Red Spot, which presumably had been there for more than a hundred years.” Planetary scientists immediately began constructing computer simulations in order to understand the Great Dark Spot’s mysterious disappearance.

Now part of the Outer Planet Atmospheres Legacy (OPAL) project, Simon and her colleagues are beginning to answer these questions. Thanks to images captured by Hubble, the team has not only witnessed a storm’s formation for the first time but developed constraints that pinpoint the frequency and duration of the storm systems.

The Birth of a Storm

In 2015, the OPAL team began a yearly mission to analyze images of Neptune captured by Hubble and detected a small dark spot in the southern hemisphere. Each year since, Simon and her colleagues have viewed the planet and monitored the storm as it dissipated. In 2018, a new dark spot emerged, hovering at 23 degrees north latitude.

“We were so busy tracking this smaller storm from 2015, that we weren’t necessarily expecting to see another big one so soon,” says Simon about the storm, which is similar in size to the Great Dark Spot. “That was a pleasant surprise. Every time we get new images from Hubble, something is different than what we expected.”

What’s more, the storm’s birth was caught on camera. While analyzing Hubble images of Neptune taken from 2015 to 2017, the team discovered that several small, white clouds formed in the region where the most recent dark spot would later appear. They published their findings March 25 in the journal Geophysical Research Letters.

The high-altitude clouds are made up of methane ice crystals, which give them their characteristic bright, white appearance. These companion clouds are thought to hover above the storms, similar to the way that lenticular clouds cap tall mountains on Earth. Their presence several years before a new storm was spotted suggests that dark spots may originate much deeper in the atmosphere than previously thought.

“In the same way a terrestrial Earth satellite would watch Earth’s weather, we observe the weather on Neptune,” says Glenn Orton, a planetary scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who also serves on the OPAL project. Just as hurricanes are tracked on Earth, Hubble’s images revealed the dark spot’s meandering path. In a span of nearly 20 hours, the storm drifted westward, moving slightly slower than Neptune’s high-speed winds.

But these Neptunian storms are different from the cyclones we see on Earth or Jupiter. So are the wind patterns that propel them. Similar to the rails that keep errant bowling balls from bounding into the gutters, thin bands of wind currents on Jupiter keep the Great Red Spot on a set path. On Neptune, wind currents operate in much wider bands around the planet, allowing storms like the Great Dark Spot to slowly drift across latitudes. The storms typically hover between westward equatorial wind jets and eastward-blowing currents in the higher latitudes before strong winds pull them apart.

Still more observations are needed. “We want to be able to study how the winds are changing over time,” says Simon.

Average Lifespan?

Simon is also part of a team of scientists led by undergraduate student Andrew Hsu of the University of California, Berkeley, who pinpointed how long these storms last and how frequently they occur.

They suspect that new storms crop up on Neptune every four to six years. Each storm may last up to six years, though two-year lifespans were more likely, according to findings published March 25 in the Astronomical Journal.

A total of six storm systems have been spotted since scientists first set their sights on Neptune. Voyager 2 identified two storms in 1989. Since Hubble launched in 1990, it has viewed four more of these storms.

In addition to analyzing data collected by Hubble and Voyager 2, the team ran computer simulations that charted a total of 8,000 dark spots swirling across the icy planet. When matched to 256 archival images, these simulations revealed that Hubble likely would have spotted approximately 70 percent of the simulated storms that occurred over the course of a year and roughly 85 to 95 percent of storms with a two-year lifespan.

Still, Questions Swirl.

Conditions on Neptune are still largely a mystery. Planetary scientists hope to next study changes in the shape of the vortex and wind speed in the storms. “We have never directly measured winds within Neptune’s dark vortices, but we estimate the wind speeds are in the ballpark of 328 feet (100 meters) per second, quite similar to wind speeds within Jupiter’s Great Red Spot,” says Michael Wong, a planetary scientist at the University of California, Berkeley. More frequent observations using the Hubble telescope, he notes, will help paint a clearer picture of how storm systems on Neptune evolve.

Simon says that discoveries on Neptune will have implications for those studying exoplanets in our galaxy that are similar in size to the ice giants. “If you study the exoplanets and you want to understand how they work, you really need to understand our planets first,” says Simon. “We have so little information on Uranus and Neptune.”

All agree that these recent findings have spurred a desire to track our furthest major planetary neighbor in even greater detail. “The more you know, the more you realize you don’t know,” says Orton.

Hubble Space Telescope (HST)

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C. The researchers used data acquired from the Hubble Space Telescope associated with the OPAL program and archived by the STScI.

Related article:

Hubble Reveals Dynamic Atmospheres of Uranus, Neptune

For more information about Hubble, visit:




NASA’s Goddard Space Flight Center (GSFC): http://www.nasa.gov/goddard

Outer Planet Atmospheres Legacy (OPAL): https://archive.stsci.edu/prepds/opal/

Image (mentioned), Animation, Text, Credits: NASA/Bill Steigerwald/Goddard Space Flight Center, by Jennifer Leman.

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Building Biofilms If you could watch a city develop through…

Building Biofilms

If you could watch a city develop through the ages you’d see small buildings spread and grow, pushing up against the city limits and eventually sprouting skyscrapers. You’d be witnessing the global mechanics of a growing city. Watch bacteria grow and you’ll sometimes see them coalesce into sheets called biofilms. Over time these bacterial cities change shape and structure too. Researchers observed these changes in dishes of Vibrio cholerae – the pathogen that causes cholera – using a variety of imaging techniques, including scanning electron microscopy. Quantifying these observations enabled them to deduce what was going on at a mechanical level. The team found global mechanics at play, with biofilms producing wrinkles and blisters (pictured) in response to instabilities in their structure. Biofilms are notoriously harder to destroy than lone bacteria and so new drugs targeting the mechanics of biofilm growth could prove useful in fighting the diseases they cause.

Written by Lux Fatimathas

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Comet C/2020 F3 (NEOWISE) on 13 July 2020 Live video from night vision device The recently discovered comet which is called C/2020 or NE...