пятница, 29 марта 2019 г.

Snake Care Lots of people are scared of snakes. For those of…


Snake Care


Lots of people are scared of snakes. For those of us in the UK, it’s a phobia unlikely to pose much practical threat, but around the world there are five million bites each year. Permanent muscle damage is one possible consequence of a bite, but the precise mechanism of this damage is poorly understood. To investigate, researchers purified one harmful component of viper venom: metalloproteases. To see how they causes lasting problems, they observed how muscle structure changes in the days after a bite. They found that viper venom damages structural scaffold proteins around the bite, such as collagen (red in undamaged mouse muscle, left, and deteriorating muscle 10 days after a simulated bite, right) and laminin (green). With these supporting structures impaired, future recovery and growth was halted. Studies like this aim to ultimately improve treatments and reduce the threat of snakes, wherever you live.


Written by Anthony Lewis



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NASA’s Cassini Finds Saturn’s Rings Coat Tiny Moons


NASA – Cassini Mission to Saturn patch.


March 29, 2019


New findings have emerged about five tiny moons nestled in and near Saturn’s rings. The closest-ever flybys by NASA’s Cassini spacecraft reveal that the surfaces of these unusual moons are covered with material from the planet’s rings – and from icy particles blasting out of Saturn’s larger moon Enceladus. The work paints a picture of the competing processes shaping these mini-moons.



Image above: This graphic shows the ring moons inspected by NASA’s Cassini spacecraft in super-close flybys. The rings and moons depicted are not to scale. Image Credits: NASA-JPL/Caltech.


“The daring, close flybys of these odd little moons let us peer into how they interact with Saturn’s rings,” said Bonnie Buratti of NASA’s Jet Propulsion Laboratory in Pasadena, California. Buratti led a team of 35 co-authors that published their work in the journal Science on March 28. “We’re seeing more evidence of how extremely active and dynamic the Saturn ring and moon system is.”


The new research, from data gathered by six of Cassini’s instruments before its mission ended in 2017, is a clear confirmation that dust and ice from the rings accretes onto the moons embedded within and near the rings.


Scientists also found the moon surfaces to be highly porous, further confirming that they were formed in multiple stages as ring material settled onto denser cores that might be remnants of a larger object that broke apart. The porosity also helps explain their shape: Rather than being spherical, they are blobby and ravioli-like, with material stuck around their equators.


“We found these moons are scooping up particles of ice and dust from the rings to form the little skirts around their equators,” Buratti said. “A denser body would be more ball-shaped because gravity would pull the material in.”


“Perhaps this process is going on throughout the rings, and the largest ring particles are also accreting ring material around them. Detailed views of these tiny ring moons may tell us more about the behavior of the ring particles themselves,” said Cassini Project Scientist Linda Spilker, also at JPL.


Of the satellites studied, the surfaces of those closest to Saturn – Daphnis and Pan – are the most altered by ring materials. The surfaces of the moons Atlas, Prometheus and Pandora, farther out from Saturn, have ring material as well – but they’re also coated with the bright icy particles and water vapor from the plume spraying out of Enceladus. (A broad outer ring of Saturn, known as the E ring, is formed by the icy material that fans out from Enceladus’ plume.)


The key puzzle piece was a data set from Cassini’s Visible and Infrared Mapping Spectrometer (VIMS), which collected light visible to the human eye and also infrared light of longer wavelengths. It was the first time Cassini was close enough to create a spectral map of the surface of the innermost moon Pan. By analyzing the spectra, VIMS was able to learn about the composition of materials on all five moons.



Image above: This montage of views from NASA’s Cassini spacecraft shows three of the small, ring moons inspected during close flybys: Atlas, Daphnis and Pan. They’re shown here at the same scale. Image Credits: NASA/JPL-Caltech/Space Science Institute.


VIMS saw that the ring moons closest to Saturn appear the reddest, similar to the color of the main rings. Scientists don’t yet know the exact composition of the material that appears red, but they believe it’s likely a mix of organics and iron.


The moons just outside the main rings, on the other hand, appear more blue, similar to the light from Enceladus’ icy plumes.


The six uber-close flybys of the ring moons, performed between December 2016 and April 2017, engaged all of Cassini’s optical remote sensing instruments that study the electromagnetic spectrum. They worked alongside the instruments that examined the dust, plasma and magnetic fields and how those elements interact with the moons.


Questions remain, including what triggered the moons to form. Scientists will use the new data to model scenarios and could apply the insights to small moons around other planets and possibly even to asteroids.


“Do any of the moons of the ice giant planets Uranus and Neptune interact with their thinner rings to form features similar to those on Saturn’s ring moons?” Buratti asked. “These are questions to be answered by future missions.”


Cassini’s mission ended in September 2017, when it was low on fuel. Mission controllers deliberately plunged Cassini into Saturn’s atmosphere rather than risk crashing the spacecraft into the planet’s moons. More science from the last orbits, known as the Grand Finale, will be published in the coming months.


The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA’s JPL, a division of Caltech in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington. JPL designed, developed and assembled the Cassini orbiter. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries.


More information about Cassini can be found here: https://solarsystem.nasa.gov/cassini


Images (mentioned), Text, Credits: NASA/JoAnna Wendel/JPL/Gretchen McCartney.


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Fireball over US Northern East Coast on March 28th, 2019

Over 260 reports from 14 states


The AMS has received over 260 reports so far about of a bright fireball seen above the Ashokan Reservoir, NY on Thursday, March 28th 2019 around 6:13pm EST (10:13 Universal Time). The event was mainly seen from Connecticut and Pennsylvania but we also received reports from Washington DC, Delaware, Massachusetts, Maryland, Maine, New Hampshire, New York, Rhode Island, Vermont and West Virginia.


If you witnessed this event and/or if you have a video or a photo of this event, please

Submit an Official Fireball Report


If you want to learn more about Fireballs: read our Fireball FAQ.



AMS Event #1414-2019 – Witness location and estimated ground trajectory

Trajectory


The preliminary 3D trajectory computed based on all the reports submitted to the AMS shows that the fireball was traveling from South-East to North-West and ended its flight North-West of Pine Hill, NY.


AMS Event #1414-2019 – Estimated 3D trajectory

Video


We received one video of the event caught by Peter Deterline from Douglassville, PA on an AMS AllSky6 camera system:




Below is a “stack” picture obtained from the video


AMS Event #1414-2019 – Stack picture from Peter Deterline’s video

Fireball?


Several thousand meteors of fireball magnitude occur in the Earth’s atmosphere each day. The vast majority of these, however, occur over the oceans and uninhabited regions, and a good many are masked by daylight. Those that occur at night also stand little chance of being detected due to the relatively low numbers of persons out to notice them.


Additionally, the brighter the fireball, the more rare is the event. As a general thumb rule, there are only about 1/3 as many fireballs present for each successively brighter magnitude class, following an exponential decrease. Experienced observers can expect to see only about 1 fireball of magnitude -6 or better for every 200 hours of meteor observing, while a fireball of magnitude -4 can be expected about once every 20 hours or so.


AMS TERMINOLOGY

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Simulating nature’s cosmic laboratory, one helium droplet at a time




Two astronomers from the Max Planck Institute for Astronomy and from the University of Jena have found an elegant new method to measure the energy of simple chemical reactions, under similar conditions as those encountered by atoms and molecules in the early solar system. Their method promises accurate measurements of reaction energies that can be used to understand chemical reactions under space conditions – in cluding those reactions that were responsible of creating organic chemicals as the raw material for the development of life.


In order for life to form, nature needed plenty raw materials in the shape of complex organic molecules. Some of those molecules are likely to have formed long before, in space, during the birth of the Solar System. Systematic studies of the necessary chemical reactions, which take place on the craggy and convoluted surfaces of dust grains, were and are hampered by a lack of data. Which elementary reactions, involving which individual reactants are possible? What temperature is required for a reaction to take place? Which molecules are produced in those reactions? Now, Thomas Henning, director at the Max Planck Institute for Astronomy (MPIA), and Sergiy Krasnokutskiy of the MPIA’s Laboratory Astrophysics Group at the University of Jena have developed an elegant method to study such elementary surface reactions – using minute liquid helium droplets.


In the early solar system, long before the formation of Earth, complex chemical reaction took place, creating substantial amounts of organic molecules. The cosmic laboratory for these works of chemical synthesis was provided by grains of dust – clusters of mostly silicates and carbon, covered with a mantle of ice, with complicated and delicate tendrils and ramifications, and on this basis with one crucial property: A comparatively large surface on which chemical reactions could take place. In the millions of years that follows, many of those dust grains would cluster together for form ever larger structures, until finally, solid planets emerged, orbiting the young Sun.

Creating the raw ingredients for life


While all of the organic compounds synthesized on the grain surfaces would be destroyed by the unavoidable heat during planet formation, some of the molecules remained in waiting, encapsulated in, or clinging to the surface of, smallish grains or lumps of rock, as well as in the icy bodies of the comets. By one account of the history of life, once Earth’s surface had cooled sufficiently for liquid water to form, it was these grains and rocks, hitting Earth’s surface in the shape of meteorites, some of them landing in warm, small, ponds, that provided the chemical basis for life to form on our home planet.


In order to understand the early natural chemical experiments in our universe, we need to know the properties of the various reactions. For instance, do certain reactions need a specific activation energy to happen? What is the eventual product of a given reaction? Those parameters determine which reactions can happen under what conditions in the early Solar system, and they are key for any realistic reconstruction of early Solar system chemistry.


Scarce data about low-temperature surface reactions


Yet precise data on these reactions is surprisingly scarce. Instead, a substantial part of chemical research is dedicated to the study of such reactions in the gaseous phase, with the atoms and molecules floating freely, colliding, and forming compounds. But the crucial chemical reactions in space needed to build up larger organic molecules take place under markedly different conditions – on the surfaces of dust grains. This changes even the basic physics of the situation: When a new molecule is formed, the energy of the chemical bond formation is stored in the newly created molecule. If this energy is not passed on to the environment, the new molecule will quickly be destroyed. This prevents the formation of many species of in the gas phase. On a surface, or in a medium, where energy can readily be absorbed by the additional matter present, the conditions for certain types of reactions building complex molecules, step by step, are much more favorable.


Henning and Krasnokutskiy developed an elegant method for measuring the energetics of such reactions. Their mock-ups of cosmic laboratories are miniature helium droplets, a few nanometers in size, drifting in a high vacuum. The reactants – that is, the atoms or molecules meant to take part in the reaction – are brought into the vacuum chamber as gases, but in such minute amounts that helium droplets are overwhelmingly likely to pick up either a single molecule of each required species or none, but not more. The helium droplets act as a medium that, similar to the surface of a dust grain, can absorb reaction energy, allowing reactions to happen under similar conditions to those in the early Solar system. This reproduces a key feature of the relevant surface chemistry (although other properties, such as catalytic properties of a specific dust surface, are not modelled).

Nanodrops as measuring devices


Furthermore, the two astronomers used the helium nanodrops as energy measuring devices (calorimeters). As reaction energy is released into the drop, some of the Helium atoms will evaporate in a predictable fashion. The remaining drop is now smaller than before – a difference in size that can be measured using two alternative methods: an electron beam (a larger drop is easier to hit than a smaller one!) or a precise measurement of the pressure in the vacuum chamber created by Helium droplets hitting the wall, where larger droplets produce greater pressure. By calibrating their method using reactions that had been studied in detail beforehand, and whose properties are well-known, the two astronomers were able to increase the method’s accuracy considerably. All in all, the new method provides an elegant new way of investigating the formation pathway of complex organic molecules in space. This should enable researchers to be more specific about the raw materials nature had to work with in the run-up of the emergence of life on Earth. But there is more:


The first measurements using the new technique confirm a trend that had already been visible in other recent experiments: On surfaces, at low temperatures, carbon atoms are surprisingly reactive. The researchers found a surprisingly high number – almost a dozen – of reactions involving carbon atoms which are barrierless, that is, which do not require extra energy input to proceed, and hence can occur at very low temperatures. Evidently, the condensation of atomic gas at low temperatures is bound to lead to the formation of a large variety of organic molecules. But that large possible variety also means that molecules of each specific species will be very rare.


This, in turn, suggests that astronomers might be drastically underestimating the amount of organic molecules in outer space. When it comes to estimating abundances, astronomical observations examine the trace signatures (spectral lines) of each molecular species separately. If there are many different species of organic molecules out there, each separate species can “fly under the radar.” Its molecules might be present only in amounts too minute for astronomers to detect, and in addition, even the tell-tale signatures of the molecules (more generally those of specific functional groups common to different types of molecules) could be slightly altered, making the molecule evade detection. But added up, it is possible that all these separate species of molecule together could make up a substantial amount of matter in outer space – a hidden outer-space world of organic chemistry.

Background information


The results presented here have been published as Henning, Th. & S. A. Krasnokutski 2019, “Experimental Characterization of the Energetics of Low-temperature Surface Reactions” in the journal Nature Astronomy.

Journal article



Science contact


Sergiy Krasnokutskiy
Email: sergiy.krasnokutskiy@uni-jena.de


PR contact

Markus Pössel
Public Information Officer
Phone:+49 6221 528-261
Email: pr@mpia.de





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Be Glad You Don’t Have to Dust in Space!

Throw open the windows

and break out the feather duster, because spring is here and it’s time to do a

little cleaning! Fortunately, no one has to tidy up the dust in space — because

there’s a lot of it — around 100 tons rain down on Earth alone

every day! And there’s even more swirling around the solar system, our Milky Way galaxy, other galaxies

and the spaces in between. 


image

By studying the contents of the dust in your

house — which can include skin cells, pet fur, furniture fibers, pollen,

concrete particles and more — scientists learn a lot about your environment. In the same way, scientists can

learn a lot by looking at space dust. Also called cosmic dust, a fleck of space dust is usually smaller

than a grain of sand and is made of rock, ice, minerals or organic compounds.

Scientists can study cosmic dust to learn about how it formed and how the

universe recycles material.


image

“We are made of star-stuff,” Carl Sagan

famously said. And it’s true! When a star dies, it sheds clouds of gas in

strong stellar winds or in an explosion called a supernova. As the gas cools,

minerals condense. Recent observations by our SOFIA mission suggest that

in the wake of a supernova shockwave, dust may form more rapidly than scientists previously

thought
. These clouds of gas and dust created by the

deaths of stars can sprawl across light-years and form

new stars
— like the Horsehead

Nebula
pictured above. Disks of dust and gas form around

new stars and produce planets, moons, asteroids and comets. Here on Earth, some

of that space dust eventually became included in living organisms — like

us! Billions of years from now, our Sun will die too. The gas and

dust it sheds will be recycled into new stars and planets and so on and so

forth, in perpetuity!


image

Astronomers originally thought dust was a

nuisance that got in the way of seeing the objects it surrounded. Dust scatters

and absorbs light from stars and emits heat as infrared light. Once we started using infrared

telescopes, we began to understand just how important dust is in the universe

and how beautiful it can be. The picture of the Andromeda galaxy above was taken in

the infrared by our Spitzer Space Telescope and reveals

detailed spirals of dust that we can’t see in an optical image.


image

We also see plenty of dust right here in our

solar system. Saturn’s rings are made of mostly

ice particles and some dust, but scientists think that dust from meteorites may

be darkening the rings over time. Jupiter also has faint dusty rings,

although they’re hard to see — Voyager 1 only discovered them when it

saw them backlit by the Sun. Astronomers think the rings formed when meteorite impacts on Jupiter’s

moons released dust into orbit. The Juno spacecraft took the above picture in 2016 from inside the

rings, looking out at the bright star Betelgeuse.


image


Copyright Josh Calcino, used with permission



And some space dust you can see from right

here on Earth! In spring or autumn, right before sunrise or after sunset, you

may be able to catch a glimpse of a hazy cone of light above the horizon

created when the Sun’s rays are scattered by dust in the inner solar system.

You can see an example in the image

above, extending from above the tree on the horizon toward a spectacular view

of the Milky Way. This phenomenon is called zodiacal light — and the dust

that’s reflecting the sunlight probably comes from icy comets. Those comets

were created by the same dusty disk that that formed our planets and eventually

you and the dust under your couch!


Make

sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com


Dark dust devil tracks on Mars


ESA – Mars Express Mission patch.


28 March 2019


The winds of Mars are responsible for myriad features across the planet’s surface – including the dark dunes and wispy, filament-like streaks seen in this image from ESA’s Mars Express.



Dust devils in Chalcoporos Rupes

The intriguing features shown here are ‘dust devil’ tracks: as the Sun heats up the martian ground during the day, vortices form that lift warm air from near the surface, whipping up dust as they do so, shaping and sculpting it into swirling, column-shaped, tornado-like whirlwinds (click here for videos of dust devils made by NASA’s Mars rover Spirit).


These dust devils range across the entire planet, lifting the top, brighter layer of dust from the surface, and leaving darker paths in their wake. They are most often seen in the martian spring and summer, lasting for a few months at most before their tracks become obscured by dust that has been buffeted around by storms and winds.



Mars Express

These Mars Express images show a curving, looping, crisscrossing web of dust devil tracks in the southern hemisphere of the planet, around an escarpment feature known as Chalcoporos Rupes. This area is covered in a thick layer of dust and is not unfrequently home to wind-related activity.



Context view

Areas of Mars that most regularly see dust devils include Amazonis Planitia, Argyre Planitia, Hellas Basin, and two impact craters that lie close to the region shown here: Proctor and Russell.


Proctor, Russell, and Chalcoproros Rupes are based in Mars’ Noachis quadrangle, an area so thickly pockmarked with impact craters that it is thought to be one of the oldest parts of the planet.


Both the craters visible in this frame boast dense, dark, eye-catching patches of rippling sand dunes, while the surrounding terrain is decorated with a broad web of dunes and signs of past dust devil activity.



Topographic view of Chalcoporos Rupes

Martian dust devils are similar to those seen on Earth in especially dry, arid, desert landscapes – but they are far larger. They can tower up to eight kilometres high on the Red Planet, creating paths that are hundreds of metres wide and stretch out for a few kilometres.


Their colossal size makes them highly effective at carrying dust high up into Mars’ atmosphere – in fact, these devils may lift as much material as a martian global dust storm does at its peak.



Perspective view

Such dust storms are immense and impressive. Mars Express captured signs of a burgeoning storm near Mars’ north pole in April of last year, highlighting an intense boundary between the planet’s usual, calm, ochre-hued surface and an incoming wall of dust clouds – and this was a somewhat modest dust storm compared to those that blanket the entirety of Mars and rage on for months.


Dust devils have been seen often on Mars, both by Mars Express and other missions – including the ESA-Roscosmos ExoMars Trace Gas Orbiter, which recently imaged an impressive pattern of dust devil tracks in the Terra Sabaea region of Mars that may be the result of hundreds or even thousands of small martian tornadoes coming together and leaving their mark on the planet’s surface.



Chalcoporos Rupes in 3D

The Trace Gas Orbiter will be joined by a rover – recently named Rosalind Franklin – and a surface science platform, due to launch in 2020. These will allow the ExoMars mission to explore the Red Planet in even greater detail in coming years.


Related links:


Mars Express: http://www.esa.int/Our_Activities/Space_Science/Mars_Express


ESA-Roscosmos ExoMars: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars


Images, Text, Credits: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO.


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The Voyage to Interstellar Space


NASA – Voyager 1 & 2 Mission patch.


March 28, 2019


By all means, Voyager 1 and Voyager 2 shouldn’t even be here. Now in interstellar space, they are pushing the limits of spacecraft and exploration, journeying through the cosmic neighborhood, giving us our first direct look into the space beyond our star.


But when they launched in 1977, Voyager 1 and Voyager 2 had a different mission: to explore the outer solar system and gather observations directly at the source, from outer planets we had only seen with remote studies. But now, four decades after launch, they’ve journeyed farther than any other spacecraft from Earth; into the cold, quiet world of interstellar space.



Voyager spacecraft travel in interstellar space. Animation Credits: NASA/JPL

Originally designed to measure the properties of the giant planets, the instruments on both spacecraft have spent the past few decades painting a picture of the propagation of solar events from our Sun. And the Voyagers’ new mission focuses not only on effects on space from within our heliosphere — the giant bubble around the Sun filled up by the constant outflow of solar particles called the solar wind — but from outside of it. Though they once helped us look closer at the planets and their relationship to the Sun, they now give us clues about the nature of interstellar space as the spacecraft continue their journey.


The environment they explore is colder, subtler and more tenuous than ever before, and yet the Voyagers continue on, exploring and measuring the interstellar medium, a smorgasbord of gas, plasma and particles from stars and gas regions not originating from our system. Three of the spacecraft’s 10 instruments are the major players that study how space inside the heliosphere differs from interstellar space. Looking at this data together allows scientist to piece together our best-yet picture of the edge of the heliosphere and the interstellar medium. Here are the stories they tell.


The Magnetometer




Image above: Illustration of NASA’s Voyager spacecraft, with the Magnetometer (MAG) instrument and its boom displayed. Image Credits: NASA’s Goddard Space Flight Center/Jet Propulsion Laboratory/Mary Pat Hrybyk-Keith.


On the Sun Spot, we have been exploring the various instruments on Voyager 2 one at a time, and analyzing how scientists read the individual sets of data sent to Earth from the far-reaching spacecraft. But one instrument we have not yet talked about is Voyager 2’s Magnetometer, or MAG for short.


During the Voyagers’ first planetary mission, the MAG was designed to investigate the magnetospheres of planets and their moons, determining the physical mechanics and processes of the interactions of those magnetic fields and the solar wind. After that mission ended, the Voyager spacecraft studied the magnetic field of the heliosphere and beyond, observing the magnetic reach of the Sun and the changes that occur within that reach during solar activity.


Getting the magnetic data as we travel further into space requires an interesting trick. Voyager spins itself around, in a calibration maneuver that allows Voyager to differentiate between the spacecraft’s own magnetic field — that goes along for the ride as it spins — and the magnetic fields of the space it’s traveling through.


The initial peek into the magnetic field beyond the Sun’s influence happened when Voyager 1 crossed the heliopause in 2012. Scientists saw that within the heliosphere, the strength of the magnetic field was quite variable, changing and jumping as Voyager 1 moved through the heliosphere. These changes are due to solar activity. But once Voyager 1 crossed into interstellar space, that variability was silenced. Although the strength of the field was similar to what it was inside the heliosphere, it no longer had the variability associated with the Sun’s outbursts.



Graphic above: Magnetometer (MAG) data taken from Voyager 1 during its transition into interstellar space in 2012. Graphic Credits: NASA’s Goddard Space Flight Center/Jet Propulsion Laboratory.


This graph shows the magnitude, or the strength, of the magnetic field around the heliopause from January 2012 out to May 2014. Before encountering the heliopause, marked by the orange line, the magnetic strength fluctuates quite a bit. After a bumpy ride through the heliopause in 2012, the magnetic strength stops fluctuating and begins to stabilize in 2013, once the spacecraft is far enough out into the interstellar medium.


In November 2018, Voyager 2 also crossed the heliopause and similarly experienced quite the bumpy ride out of the heliopause. Scientists are excited to see how its journey differs from its twin spacecraft.


Scientists are still working through the MAG data from Voyager 2, and are excited to see how Voyager 2’s journey differed from Voyager 1.


The Cosmic Ray Subsystem



Image above: Illustration of NASA’s Voyager spacecraft, with the Cosmic Ray Subsystem (CRS) highlighted. Image Credits: NASA’s Goddard Space Flight Center/Jet Propulsion Laboratory/Mary Pat Hrybyk-Keith.


Much like the MAG, the Cosmic Ray Subsystem — called CRS — was originally designed to measure planetary systems. The CRS focused on the compositions of energetic particles in the magnetospheres of Jupiter, Saturn, Uranus and Neptune. Scientists used it to study the charged particles within the solar system and their distribution between the planets. Since it passed the planets, however, the CRS has been studying the heliosphere’s charged particles and — now — the particles in the interstellar medium.


The CRS measures the count rate, or how many particles detected per second. It does this by using two telescopes: the High Energy Telescope, which measures high energy particles (70MeV) identifiable as interstellar particles, and the Low Energy Telescope, which measures low-energy particles (5MeV) that originate from our Sun. You can think of these particles like a bowling ball hitting a bowling pin versus a bullet hitting the same pin — both will make a measurable impact on the detector, but they’re moving at vastly different speeds. By measuring the amounts of the two kinds of particles, Voyager can provide a sense of the space environment it’s traveling through.



Graphic above: Scientists compared data from Voyager 1 with its 2012 crossing of the heliopause to watch for clue for when Voyager 2 would cross. In November 2018, the first clues came from the Cosmic Ray Subsystem! Graphic Credits: NASA’s Jet Propulsion Laboratory/NASA Headquarters/Patrick Koehn.


These graphs show the count rate — how many particles per second are interacting with the CRS on average each day — of the galactic ray particles measured by the High Energy Telescope (top graph) and the heliospheric particles measured by the Low Energy Telescope (bottom graph). The line in red shows the data from Voyager 1, time shifted forward 6.32 years from 2012 to match up with the data from Voyager around November 2018, shown in blue.


CRS data from Voyager 2 on Nov. 5, 2018, showed the interstellar particle count rate of the High Energy Telescope increasing to count rates similar to what Voyager 1 saw then leveling out. Similarly, the Low Energy Telescope shows a severe decrease in heliospheric originating particles. This was a key indication that Voyager 2 had moved into interstellar space. Scientists can keep watching these counts to see if the composition of interstellar space particles changes along the journey.


The Plasma Instrument



Image above: Illustration of NASA’s Voyager spacecraft, with the Plasma Science Instrument (PLS) displayed. Image Credits: NASA’s Goddard Space Flight Center/Jet Propulsion Laboratory/Mary Pat Hrybyk-Keith.


The Plasma Science instrument, or PLS, was made to measure plasma and ionized particles around the outer planets and to measure the solar wind’s influence on those planets. The PLS is made up of four Faraday cups, an instrument that measures the plasma as it passes through the cups and calculates the plasma’s speed, direction and density.


The plasma instrument on Voyager 1 was damaged during a fly-by of Saturn and had to be shut off long before Voyager 1 exited the heliosphere, making it unable to measure the interstellar medium’s plasma properties. With Voyager 2’s crossing, scientists will get the first-ever plasma measurements of the interstellar medium.


Scientists predicted that interstellar plasma measured by Voyager 2 would be higher in density but lower in temperature and speed than plasma inside the heliosphere. And in November 2018, the instrument saw just that for the first time. This suggests that the plasma in this region is getting colder and slower, and, like cars slowing down on a freeway, is beginning to pile up around the heliopause and into the interstellar medium.


And now, thanks to Voyager 2’s PLS, we have a never-before-seen perspective on our heliosphere: The plasma velocity from Earth to the heliopause.



Graphic above: With Voyager 2 crossing the heliopause, scientists now have a new view of solar wind plasma across the heliosphere. Graphic Credits: NASA’s Jet Propulsion Laboratory/ Michigan Institute of Technology/John Richardson.


These three graphs tell an amazing story, summarizing a journey of 42 years in one plot. The top section of this graph shows the plasma velocity, how fast the plasma across the heliosphere is moving, against the distance out from Earth. The distance is in astronomical units; one astronomical unit is the average distance between the Sun and Earth, about 93 million miles. For context, Saturn is 10 AU from Earth, while Pluto is about 40 AU away.


The heliopause crossing happened at 120 AU, when the velocity of plasma coming out from the Sun drops to zero (seen on the top graph), and the outward flow of the plasma is diverted — seen in the increase in the two bottom graphs, which show the upwards and downward speeds (the normal velocity, middle graph) and the sideways speed of the solar wind (the tangential velocity, bottom graph) of the solar wind plasma, respectively. This means as the solar wind begins to interact with the interstellar medium, it is pushed out and away, like a wave hitting the side of a cliff. 


Looking at each instrument in isolation, however, does not tell the full story of what interstellar space at the heliopause looks like. Together, these instruments tell a story of the transition from the turbulent, active space within our Sun’s influence to the relatively calm waters on the edge of interstellar space.


The MAG shows that the magnetic field strength decreases sharply in the interstellar medium. The CRS data shows an increase in interstellar cosmic rays, and a decrease in heliospheric particles. And finally, the PLS shows that there’s no longer any detectable solar wind.


Now that the Voyagers are outside of the heliosphere, their new perspective will provide new information about the formation and state of our Sun and how it interacts with interstellar space, along with insight into how other stars interact with the interstellar medium.


Voyager 1 and Voyager 2 are providing our first look at the space we would have to pass through if humanity ever were to travel beyond our home star — a glimpse of our neighborhood in space. 


Related links:


Video: “NASA Science Live: Going Interstellar”: https://www.youtube.com/watch?v=4UD21rCcPpU


Explore Voyager 2 data on “The Sun Spot” blog: https://blogs.nasa.gov/sunspot/


Voyager: https://www.nasa.gov/mission_pages/voyager/index.html


Images (mentioned), Graphics (mentioned), Animation (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Susannah Darling.



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Astronauts Ready After Robotics Sets Up Worksite for Friday Spacewalk


ISS – Expedition 59 Mission patch.


March 28, 2019


Astronauts Nick Hague and Christina Koch have configured their spacesuits and reviewed procedures for tomorrow’s spacewalk at the International Space Station. Robotics controllers also readied the Port-4 (P4) truss structure so the spacewalkers can continue battery swaps and power upgrades outside the orbital lab.


Hague and Koch will set their spacesuits to battery power Friday around 8:20 a.m. inside the Quest airlock. They will exit Quest to swap old nickel-hydrogen batteries with new lithium-ion batteries on the P4 truss. NASA TV will begin its live coverage of the scheduled 6.5-hour spacewalk Friday at 6:30 a.m.



Image above: NASA astronaut Nick Hague is tethered to the International Space Station during a six-hour, 39-minute spacewalk to upgrade the orbital complex’s power storage capacity. Image Credit: NASA TV.


Ground specialists in Mission Control remotely commanded the Canadarm2 robotic arm and its “robotic hand” Dextre to set up the P4 worksite throughout week. The fine-tuned robotics maneuvers transferred the batteries between an external pallet and the P4 worksite over several days.


NASA astronaut Anne McClain is tentatively scheduled to join Canadian Space Agency astronaut David Saint-Jacques on April 8 for another spacewalk. The spacewalkers will install truss jumpers to provide secondary power to the Canadarm2.



The International Space Station seen from Soyuz MS-08

Meanwhile, McClain collected her blood and urine samples today for ongoing human research. She spun the samples in a centrifuge and stowed them in a science freezer for later analysis. Saint-Jacques worked on computer electronics maintenance throughout the day.


Expedition 59 commander Oleg Kononenko and Alexey Ovchinin, both of Roscosmos, stayed focused on activities in the station’s Russian segment on Thursday. The duo spent the morning on life support maintenance before checking docked vehicle communications and photographing windows in the Zvezda service module.


NASA TV Broadcasts Live Spacewalk Coverage Friday Morning


Expedition 59 Flight Engineers Nick Hague and Christina Koch will exit the Quest airlock Friday for about 6.5 hours of battery swaps to upgrade the station’s power storage capacity. The duo will set their spacesuits to battery power about 8:20 a.m. EDT Friday signifying the start of their spacewalk. Coverage will begin its live coverage at 6:30 a.m.


Watch the spacewalk on NASA TV and on the agency’s website: http://www.nasa.gov/ntv


This will be the 215th spacewalk in support of space station assembly and maintenance. Hague will be designated extravehicular crew member 1 (EV 1), wearing the suit with red stripes. Koch will be designated extravehicular crew member 2 (EV 2), wearing the suit with no stripes.


Hague and Koch have configured their spacesuits and reviewed procedures for tomorrow’s spacewalk at the space station. Robotics controllers also readied the Port-4 (P4) truss structure so the spacewalkers can continue battery swaps and power upgrades outside the orbital lab.



Image above: NASA astronaut Anne McClain takes a “space-selfie” with her helmet visor up 260 miles above the Earth’s surface during a spacewalk on March 22, 2019. Image Credit: NASA TV.


This is the second battery replacement spacewalks this month. Hague and Koch will work on a second set of battery replacements on a different power channel in the same area of the station from the recent spacewalk on March 22.


During that spacewalk, NASA Flight Engineer Anne McClain and Hague replaced some nickel-hydrogen batteries with newer, more powerful lithium-ion batteries for the power channel on one pair of the station’s solar arrays. The batteries were transported to the station in September aboard the Japanese H-II Transfer Vehicle. The spacewalking work continues the overall upgrade of the station’s power system that began with similar battery replacement during spacewalks in January 2017.


Related links:


Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html


Spacewalk: https://www.nasa.gov/mission_pages/station/spacewalks/


Quest airlock: https://www.nasa.gov/mission_pages/station/structure/elements/joint-quest-airlock


Canadarm2 robotic arm: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html


Zvezda service module: https://www.nasa.gov/mission_pages/station/structure/elements/zvezda-service-module.html


Port-4 (P4) truss structure: https://cms.nasa.gov/mission_pages/station/structure/elements/truss-structure


H-II Transfer Vehicle: https://cms.nasa.gov/feature/kounotori-htv-launches-arrivals-and-departures


Human research: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?


Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html


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


Images (mentioned), Video, Text, Credits: NASA/Mark Garcia/NASA TV/SciNews.


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Marcasite | #Geology #GeologyPage #Mineral Locality: Cap…


Marcasite | #Geology #GeologyPage #Mineral


Locality: Cap Blanc-Nez, Pas-de-Calais, Nord-Pas-de-Calais, France


Size: 38mm x 35mm x 26mm


Photo Copyright © Quebul Fine Minerals


Geology Page

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Fluorite crystals with phantoms inside the cubes and Quartz |…


Fluorite crystals with phantoms inside the cubes and Quartz | #Geology #GeologyPage #Mineral


Locality: Okorusu Mine (Okarusu Mine), Otjiwarongo District, Otjozondjupa Region, Namibia


Size: 42mm x 32mm x 35mm


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Elbaite var Indicolite | #Geology #GeologyPage…


Elbaite var Indicolite | #Geology #GeologyPage #Mineral


Locality: Konar Valley, Konar Province, Afghanistan, Asia


Dimensions: 4.5 × 2.6 × 2.0 cm


Photo Copyright © Crystal Classics


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Folding 😍😍 | #Geology #GeologyPage #Folds #Greece Folds in…


Folding 😍😍 | #Geology #GeologyPage #Folds #Greece


Folds in alternating layers of limestone and chert in Crete, Ágios Pávlos in the south of Crete, Greece


Geology Page

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Vanadinite on Baryte | #Geology #GeologyPage #Mineral Locality:…


Vanadinite on Baryte | #Geology #GeologyPage #Mineral


Locality: Mibladen Mining District, Midelt, Khenifra Province, Meknes-Tafilalet Region, Morocco, Africa


Dimensions: 6.5 × 5.3 × 4.4 cm


Photo Copyright © Crystal Classics


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Hubble Captures Rare Active Asteroid


ESA – Hubble Space Telescope logo.


28 March 2019


Thanks to an impressive collaboration bringing together data from ground-based telescopes, all-sky surveys and space-based facilities — including the NASA/ESA Hubble Space Telescope — a rare self-destructing asteroid called 6478 Gault has been observed.



Asteroid 6478 Gault

Clear images from the NASA/ESA Hubble Space Telescope have provided researchers with new insight into asteroid Gault’s unusual past. The object is 4–9 kilometres wide and has two narrow, comet-like tails of debris that tell us that the asteroid is slowly undergoing self-destruction. Each tail is evidence of an active event that released material into space.


Gault was discovered in 1988. However, this observation of two debris tails is the first indication of the asteroid’s instability. This asteroid one of only a handful to be caught disintegrating by a process known as a YORP torque. When sunlight heats an asteroid, the infrared radiation that escapes from its warmed surface carries off both heat and momentum. This creates a small force that can cause the asteroid to spin faster. If this centrifugal force eventually overcomes gravity, the asteroid becomes unstable. Landslides on the object can release rubble and dust into space, leaving behind a tail of debris, as seen here with asteroid Gault.


“This self-destruction event is rare”, explained Olivier Hainaut (European Southern Observatory, Germany). “Active and unstable asteroids such as Gault are only now being detected by means of new survey telescopes that scan the entire sky, which means asteroids such as Gault that are misbehaving cannot escape detection any more.”



Gault within the solar system

Astronomers estimate that among the 800,000 known asteroids that occupy the Asteroid Belt between Mars and Jupiter, YORP disruptions occur roughly once per year. The direct observation of this activity by the Hubble Space Telescope has provided astronomers with a special opportunity to study the composition of asteroids. By researching the material that this unstable asteroid releases into space, astronomers can get a glimpse into the history of planet formation in the early ages of the Solar System.


Understanding the nature of this active and self-destructive object has been a collaborative effort involving researchers and facilities around the world. The asteroid’s debris tail was first detected by the University of Hawaiʻi/NASA ATLAS (Asteroid Terrestrial-Impact Last Alert System) telescopes in the Hawaiian Islands on 5 January 2019. Upon review of archival data from ATLAS and UH/NASA Pan-STARRS (Panoramic Survey Telescope and Rapid Response System), it was found that the object’s larger tail of debris had been observed earlier in December 2018. Shortly thereafter, in January 2019, a second, shorter tail was seen by various telescopes, including the Isaac Newton, William Herschel, and ESA OGS Telescopes in La Palma and Tenerife, Spain; the Himalayan Chandra Telescope in India; and the CFHT in Hawaiʻi. Subsequent analysis of these observations suggested that the two events that produced these debris trails occurred around 28 October and 30 December 2018, respectively. These tails will only be visible for only a few months, after which the dust will have dispersed into interplanetary space.


Follow-up observations were then made by various ground-based telescopes. These data were used to deduce a two-hour rotation period for Gault, which is very close to the critical speed at which material will begin to tumble and slide across the asteroid’s surface before drifting off into space.



Pan across the Gault asteroid

“Gault is the best ‘smoking-gun’ example of a fast rotator right at the two-hour limit”, explained lead author Jan Kleyna (University of Hawaiʻi, USA). “It could have been on the brink of instability for 10 million years. Even a tiny disturbance, like a small impact from a pebble, might have triggered the recent outbursts.”


Hubble’s sharp imaging provided valuable detail regarding the asteroid’s activity. From the narrow width of the streaming tails, researchers inferred that the release of material took place in short episodes lasting from a few hours to a couple of days. From the absence of excess dust in the immediate vicinity of the asteroid, they concluded that the asteroid’s activity was not caused by a collision with another massive object. Researchers hope that further observations will provide even more insight into this rare and curious object.



Hubble Space Telescope (HST)

The team’s results have been accepted for publication in The Astrophysical Journal Letters: https://iopscience.iop.org/journal/0004-637X


More information:


The Hubble Space Telescope is a project of international cooperation between ESA and NASA.


The research team’s work is presented in the scientific paper “The Sporadic Activity of (6478) Gault: A YORP driven event?”, which will be published in The Astrophysical Journal Letters.


ATLAS (Asteroid Terrestrial-impact Last Alert System) is an asteroid impact early warning system being developed by the University of Hawai’i and funded by NASA. It consists of two telescopes, 100 miles apart, which automatically scan the whole sky several times every night looking for moving objects.


The international team of astronomers in this study consists of Jan T. Kleyna (University of Hawai’i Institute for Astronomy, USA), Olivier R. Hainaut(European Southern Observatory, Germany), Karen J. Meech (University of Hawai’i Institute for Astronomy, USA), Henry H. Hsieh (Planetary Science Institute, USA, & Academia Sinica Institute of Astronomy and Astrophysics, Taiwan), Alan Fitzsimmons (Queen’s University Belfast Astrophysics Research Centre, UK), Marco Micheli (European Space Agency Near Earth Object Coordination Centre, Italy, & National Institute for Astrophysics – Osservatorio Astronomico di Roma, Italy), Jacqueline V. Keane (University of Hawai’i Institute for Astronomy, USA), Larry Denneau (University of Hawai’i Institute for Astronomy, USA), John Tonry (University of Hawai’i Institute for Astronomy, USA), Aren Heinze (University of Hawai’i Institute for Astronomy, USA), Bhuwan C. Bhatt(Indian Institute for Astrophysics, India), Devendra K. Sahu (Indian Institute for Astrophysics, India),


Detlef Koschny (European Space Agency European Space Research and Technology Centre, the Netherlands & Near Earth Object Coordination Centre, Italy, & Technical University of Munich, Germany), Ken W. Smith (Queen’s University Belfast Astrophysics Research Centre, UK), Harald Ebeling (University of Hawai’i Institute for Astronomy, USA), Robert Weryk (University of Hawai’i Institute for Astronomy, USA), Heather Flewelling (University of Hawai’i Institute for Astronomy, USA), and Richard J. Wainscoat (University of Hawai’i Institute for Astronomy, USA).


Links:


Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/


Hubblesite release: http://hubblesite.org/news_release/news/2019-22


The science paper by J. Kleyna et al.: http://imgsrc.hubblesite.org/hvi/uploads/science_paper/file_attachment/366/Gault_Paper1.pdf


NASA/ESA Hubble Space Telescope (HST): https://www.spacetelescope.org/


Image, Animation, Text, Credits: NASA, ESA, NASA, ESA, K. Meech and J. Kleyna (University of Hawaii), O. Hainaut (European Southern Observatory), L. Calçada/Videos: ESA/Hubble, L. Calçada / spaceengine.org/K. Meech and J. Kleyna (University of Hawaii), O. Hainaut (European Southern Observatory)/Music: James Creasey — Space Drone (creaseyproductions.com).


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Stubborn Cells When you buy a second-hand car, sometimes it…


Stubborn Cells


When you buy a second-hand car, sometimes it bears traces of its previous owner – lingering smells or forgotten belongings. And when patients receive an organ transplant, they also accept some of the previous owners’ molecular residue. Tissue-resident memory T cells are immune cells restricted to one organ, that come along inside a transplant. Since they don’t flow around the body like other immune cells, we’ve had limited opportunities to study them in humans until a new study looking at 20 lung transplant recipients. They found these specialised residents – highlighted in green in the transplanted lung section pictured – persisting up to a year after transplantation, long after other donor immune cells have gone. Higher levels of these stubborn cells correlated with better patient outcomes, so the study might have found a new indicator of transplant health for doctors, as well as revealing key details about this little-understood facet of the immune system.


Written by Anthony Lewis



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