пятница, 19 апреля 2019 г.

Astronaut Commands Robotic Arm to Capture Cygnus NG-11 Cargo Craft and Attached to...


ISS — Expedition 59 Mission patch.


April 19, 2019


At 5:28 a.m. EDT, Expedition 59 Flight Engineer Anne McClain of NASA used the International Space Station’s robotic Canadarm2 to grapple the Northrop Grumman Cygnus spacecraft as David Saint-Jacques of the Canadian Space Agency monitored Cygnus systems during its approach. Next, ground controllers will command the station’s arm to rotate and install Cygnus, dubbed the S.S. Roger Chaffee, on the bottom of the station’s Unity module.



Image above: The Cygnus spacecraft from Northrop Grumman approaches the International Space Station for a robotic capture. Image Credit: NASA TV.


The station was flying over northeast France at an altitude of 254 miles when it was captured.


NASA Television coverage of installation will begin at 7 a.m., and installation of the Cygnus spacecraft to the space station is expected to be completed later this morning. Cygnus will remain at the orbiting laboratory for a three-month stay.


Cygnus Cargo Craft Attached to Station Until July



Image above: April 19, 2019: International Space Station Configuration. Five spaceships are docked at the space station including Northrop Grumman’s Cygnus space freighter and Russia’s Progress 71 and 72 resupply ships and the Soyuz MS-11 and MS-12 crew ships. Image Credit: NASA.


After its capture this morning at 5:28 a.m. EDT, the Northrop Grumman Cygnus spacecraft was bolted into place on the International Space Station’s Earth-facing port of the Unity module at 7:31 a.m. At the time of installation, Cygnus was flying 255 miles above the Indian Ocean just south of Singapore.


Cygnus will remain at the space station until July 23, when the spacecraft will depart the station, deploy NanoRacks customer CubeSats, then have an extended mission of nine months before it will dispose of several tons of trash during a fiery reentry into Earth’s atmosphere.


The spacecraft’s arrival brings close to 7,600 pounds of research and supplies to space station. Highlights of NASA-sponsored research to advance exploration goals and enable future missions to the Moon and Mars include:


Models for growing increasingly complex materials


Advanced Colloids Experiment-Temperature-10 (ACE-T-10) will test gels in a microgravity environment. This research could aid in the development of increasingly complex materials that may serve as the building blocks for a range of applications on Earth including foods, drugs, and electronic devices. The process also may provide an efficient method to build new materials and equipment in space.


Better life science research in a few drops


Although the space station is well equipped for health and life sciences research, the equipment available for cellular and molecular biology still is limited compared to capabilities found in laboratories on Earth. To address this limitation, CSA designed Bio-Analyzer, a new tool the size of a video game console that astronauts on station easily can use to test body fluids such as blood, saliva, and urine, with just a few drops. It returns key analyses, such as blood cell counts, in just two to three hours, eliminating the need to freeze and store samples.


Analyzing aging of the arteries in astronauts


The Vascular Aging investigation uses ultrasounds, blood samples, oral glucose tolerance tests, and wearable sensors to study aging-like changes that occur in many astronauts during their stay on the space station. It’s one of three Canadian experiments exploring the effects of weightlessness on the blood vessels and heart, and the links between these effects and bone health, blood biomarkers, insulin resistance, and radiation exposure. Increased understanding of these mechanisms can be used to address vascular aging in both astronauts and the aging Earth population.


Testing immune response in space


Spaceflight is known to have a dramatic influence on an astronaut’s immune response, but there is little research on its effect following an actual challenge to the body’s immune system. The rodent immune system closely parallels that of humans, and Rodent Research-12: Tetanus Antibody Response by B cells in Space (TARBIS) will examine the effects of spaceflight on the function of antibody production and immune memory. This investigation aims to advance the development of measures to counter these effects and help maintain crew health during future long-duration space missions. On Earth, it could advance research to improve the effectiveness of vaccines and therapies for treating diseases and cancers.


Big buzz for new robot


A fleet of small robots is set to take on big jobs aboard the space station. Building on the success of SPHERES, NASA will test Astrobee, a robotic system comprised of three cube-shaped robots and a docking station for recharging; the first two are aboard Cygnus. The free-flying robots use electric fans for propulsion and cameras and sensors help them navigate their surroundings. The robots also have an arm to grasp station handrails or grab and hold items. Astrobee can operate in automated mode or under remote control from the ground as it assists with routine chores on station, and requires no supervision from the crew. This has the potential to free up astronauts to conduct more research.


Related links:


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


Advanced Colloids Experiment-Temperature-10 (ACE-T-10): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7881


Bio-Analyzer: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=7393


Vascular Aging: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7644


Canadian experiments: https://urldefense.proofpoint.com/v2/url?u=http-3A__asc-2Dcsa.gc.ca_eng_sciences_vascular.asp


Rodent Research-12: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7868


Astrobee: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=303


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), Text, Credits: NASA/Mark Garcia.


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Orange Scolecite, Chalcedony | #Geology #GeologyPage…


Orange Scolecite, Chalcedony | #Geology #GeologyPage #Mineral


Locality: Chandanapuri, Samgamner, Ahmadnagar District, Maharashtra, India


Size: 41mm x 30mm x 20mm


Photo Copyright © Quebul Fine Minerals


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Azurite, Quartz with Hematite Coating | #Geology #GeologyPage…


Azurite, Quartz with Hematite Coating | #Geology #GeologyPage #Mineral


Locality: Mecissi (Mcissi), Er Rachidia Province, Meknes-Tafilalet Region, Morocco


Size: 45mm x 37mm x 31mm


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Beautiful Orpheus Agate | #Geology #GeologyPage #Agate…


Beautiful Orpheus Agate | #Geology #GeologyPage #Agate #Mineral


Locality: Rhodope Mts, Kardzali (Kurdzhali; Kardjali; Kurdjali) Oblast, Bulgaria


Size: 52mm x 38mm x 14mm


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Azurite with Cerussite | #Geology #GeologyPage…


Azurite with Cerussite | #Geology #GeologyPage #Mineral


Locality: Mas Dieu, Mercoirol, Alès, Gard, Occitanie France


Specimen size: 5.7 × 4.8 × 2.4 cm


Main crystal size: 1 × 0,9 cm


Photo Copyright © Fabre Minerals


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Meteor Activity Outlook for 20-26 April 2019

Roger Craig Smith captured this beautiful green fireball on 06 April 2019 from Bear Valley Springs, California USA. © Roger Craig Smith @RogerCraigSmith

During this period the moon will reach its last quarter phase on Friday April 26th. This weekend the nearly full moon will lie above the horizon nearly all night long. The glare from the bright moon will make meteor observing difficult at best. The lunar glare will obscure all but the brighter meteors. The glare will lessen which each passing night but will still be a hindrance all week long. Hourly meteor rates for evening observers this week are near 2 as seen from mid-northern latitudes (45N) and 3 as seen from tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 5 as seen from mid-northern latitudes and 6 from the southern tropics. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Rates are reduced during this period due to interfering moonlight. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brighter meteors will be visible from such locations.The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning April 20/21 . These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year. Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies near the edge and not the center. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located far below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.





Radiant Positions at 21:00 Local Summer Time







Radiant Positions at 1:00 Local Summer Time







Radiant Positions at 5:00 Local Summer Time





These sources of meteoric activity are expected to be active this week.


Descriptions of each source continue next week when viewing conditions are more favorable




































































SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Summer Time North-South
pi Puppids (PUP) Apr 24 07:16 (109) -45 15 18:00 <1 -<1 III
h Virginids (HVI) Apr 30 13:05 (196) -08 17 00:00 <1 -<1 IV
Anthelion (ANT) 14:52 (223) -16 30 02:00 1 – 1 II
Lyrids (LYR) Apr 23 18:04 (271) +33 46 06:00 1 -<1 I
eta Aquariids (ETA) May 07 21:34 (323) -07 66 09:00 <1 -<1 I

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Caption Spotlight (18 April 2019): Abstract Art in Ius…


Caption Spotlight (18 April 2019): Abstract Art in Ius Chasma


Sometimes Mars’ surface is just beautiful as seen through the eyes of HiRISE.


This is one example on the floor of Ius Chasma, part of Valles Marineris. The region has had a complex history of sediment deposition, deformation, erosion, and alteration.


NASA/JPL/University of Arizona


2019 April 19 Milky Way in Northern Spring Image Credit &…


2019 April 19


Milky Way in Northern Spring
Image Credit & Copyright: Taha Ghouchkanlu (TWAN)


Explanation: A postcard from planet Earth, this springtime night skyscape looks over Alandan lake in the Alborz mountains. Taken after local midnight on April 17, the central Milky Way is rising over the region’s southeast horizon. Its luminous track of stars and nebulae along the plane of our galaxy are reflected in the mirror-like lake. The brightest celestial beacon mingled with the diffuse galactic starlight is Jupiter. Slightly dimmer, Saturn is below and left just above the mountains. As spring brought leaves to the trees and the galactic center to the northern night the photographer found it also gave frogs their voices, heard like a melody across the calm water.


∞ Source: apod.nasa.gov/apod/ap190419.html


Gobihadros, a new species of Mongolian hadrosaur…


Gobihadros, a new species of Mongolian hadrosaur http://www.geologypage.com/2019/04/gobihadros-a-new-species-of-mongolian-hadrosaur.html


Folding faults and seismic risk in the Kunlun range, Northwest…


Folding faults and seismic risk in the Kunlun range, Northwest Tibet http://www.geologypage.com/2019/04/folding-faults-and-seismic-risk-in-the-kunlun-range-northwest-tibet.html


Scientists identify almost two million previously ‘hidden’…


Scientists identify almost two million previously ‘hidden’ earthquakes http://www.geologypage.com/2019/04/scientists-identify-almost-two-million-previously-hidden-earthquakes.html


Fossils found in museum drawer in Kenya belong to gigantic…


Fossils found in museum drawer in Kenya belong to gigantic carnivore http://www.geologypage.com/2019/04/fossils-found-in-museum-drawer-in-kenya-belong-to-gigantic-carnivore.html


These beetles have successfully freeloaded for 100 million years…


These beetles have successfully freeloaded for 100 million years http://www.geologypage.com/2019/04/these-beetles-have-successfully-freeloaded-for-100-million-years.html


Planck reveals link between active galaxies and their dark matter environment


ESA — Planck Mission patch.


18 April 2019


Scientists have used the tiny distortions imprinted on the cosmic microwave background by the gravity of matter throughout the Universe, recorded by ESA’s Planck satellite, to uncover the connection between the luminosity of quasars – the bright cores of active galaxies – and the mass of the much larger ‘halos’ of dark matter in which they sit. The result is an important confirmation for our understanding of how galaxies evolve across cosmic history.



Image above: Gravitational deflection by quasar-hosting dark matter halos. Image Credits: David Tree, Professor Peter Richardson, Games and Visual Effects Research Lab, University of Hertfordshire.


Most galaxies in the Universe are known to host supermassive black holes, with masses of millions to billions of times the Sun’s mass, at their cores. The majority of these cosmic monsters are ‘dormant’, with little or no activity going on near them, but about one percent are classified as ‘active’, accreting matter from their surroundings at very intense rates. This accretion process causes material in the black hole’s vicinity to shine brightly across the electromagnetic spectrum, making these active galaxies, or quasars, some of the brightest sources in the cosmos.


While it is still unclear what activates these black holes, switching on and off their phase of intense accretion, it is likely that quasars play an important role in regulating the evolution of galaxies across cosmic history. For this reason, it is crucial to understand the relationship between quasars, their host galaxies, and their environment on even larger scales.


In a recent study led by James Geach of the University of Hertfordshire, UK, scientists have combined data from ESA’s Planck mission with the largest survey of quasars available to date to shed light on this fascinating topic.



Planck. Image Credit: ESA

According to the leading scenario of structure formation in the Universe, galaxies take shape out of ordinary matter in the densest knots of the cosmic web – a filamentary network, made up primarily of the invisible dark matter, that pervades the cosmos. In turn, the complex distribution of both ordinary and dark matter originates from tiny fluctuations in the primordial Universe, which leave an imprint in the Cosmic Microwave Background (CMB), the most ancient light in the history of the Universe.


The Planck satellite has been scanning the sky between 2009 and 2013 to create the most precise all-sky map of the CMB, enabling scientists to refine our knowledge of the age, expansion, history, and contents of the Universe to unprecedented levels of accuracy.


And there is more: as predicted by Albert Einstein’s general theory of relativity, massive objects bend the fabric of spacetime around them, distorting the path of everything – even light – that passes nearby. This phenomenon, known as gravitational lensing, affects also Planck’s measurements of the CMB, which carry an imprint of the large-scale distribution of matter that the most ancient cosmic light encountered along its way to the satellite.



Image above: Gravitational lensing of the Cosmic Microwave Background. (See also the animated version of this image.) Image Credits: ESA and the Planck Collaboration.


«We know that galaxies form and evolve within an invisible ‘scaffolding’ of dark matter that we cannot directly observe, but we can exploit the gravitational lensing distortions imprinted on the cosmic microwave background to learn about the dark matter structures around galaxies,» says James Geach.


Gravitational lensing distortions of the CMB are small, rearranging the CMB sky picture on scales of about 10 minutes of arc – equivalent to just one third the diameter of the full Moon. But many tiny deflections from across the sky can be combined, with the help of statistical methods, to obtain a stronger signal, piling up the data gathered around many quasars.


In their research, Geach and colleagues analysed the latest gravitational lensing map obtained by the Planck team, made public as part of the Planck Legacy Release in 2018, in combination with 200 000 quasars drawn from the largest sample ever compiled, the more than half-a-million quasars that comprise Data Release 14 of the Sloan Digital Sky Survey quasar catalogue.


«By combining the Planck data with such a large sample of quasars, we could measure the mass of the dark matter halos in which the quasar host galaxies are embedded, and investigate how this varies for quasars of different luminosity,» says Geach.


The analysis hints that that the more luminous a quasar is, the more massive its halo of dark matter.


«This is compelling evidence that a correlation exists between the luminosity of a quasar, energy that is released in the immediate vicinity of a supermassive black hole – a region spanning perhaps a few light days – and the mass of the encompassing halo of dark matter and surrounding environment, which extends for tens of millions of light years around the quasar,» Geach explains.



Image above: Gravitational deflection by quasar-hosting dark matter halos. Image Credits: David Tree, Professor Peter Richardson, Games and Visual Effects Research Lab, University of Hertfordshire.


«We’re using the cosmic microwave background as a kind of ‘backlight’ to the Universe. That backlight has been gravitationally lensed by foreground matter, and so by correlating galaxies with the Planck lensing map, we have a new way to study galaxies and their evolution.»


The finding supports theoretical models of quasar formation, which predict a correlation between quasar luminosity and halo mass, in particular for the most luminous quasars, where the black holes are accreting matter at close to the maximum rate.


The study focused on distant quasars that are observed as they were when the Universe was about four billion years old – about one third of its current age of nearly 14 billion years. This is close to the peak era of supermassive black hole growth. In combination with deeper quasar surveys in the future, the Planck data could enable scientists to push these investigations to even earlier times in cosmic history, up to the epoch when the first quasars formed.


«This result shows the power of Planck’s gravitational lensing measurements, which make it possible for us to measure the invisible structures of dark matter in which galaxies form and evolve,» says Jan Tauber, Planck project scientist at ESA.


«The legacy of Planck is quite astonishing, with data that are being used for a much wider range of scientific applications than originally conceived for.»


Notes for editors


«The halo mass of optically-luminous quasars at z~1–2 measured via gravitational deflection of the cosmic microwave background» by J. E. Geach et al. is published in The Astrophysical Journal, Volume 874, Number 1: https://doi.org/10.3847/1538-4357/ab0894


Launched in 2009, Planck was designed to map the sky in nine frequencies using two state-of-the-art instruments: the Low Frequency Instrument (LFI), which includes three frequency bands in the range 30-70 GHz, and the High Frequency Instrument (HFI), which includes six frequency bands in the range 100-857 GHz. Seven of Planck’s nine frequency channels were equipped with polarisation-sensitive detectors. HFI completed its survey in January 2012, while LFI continued to make science observations until October 2013.


ESA Planck: http://sci.esa.int/planck/


Images (mentioned), Text, Credit: ESA/Jan Tauber/Centre for Astrophysics Research/University of Hertfordshire/James E. Geach.


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TESS finds its first Earth-sized planet

A nearby system hosts the first Earth-sized planet discovered by NASA’s Transiting Exoplanets Survey Satellite, as well as a warm sub-Neptune-sized world, according to a new paper from a team of astronomers that includes Carnegie’s Johanna Teske, Paul Butler, Steve Shectman, Jeff Crane, and Sharon Wang. Their work is published in the Astrophysical Journal Letters.











TESS finds its first Earth-sized planet
Artist’s conception of HD 21749c, the first Earth-sized planet found by NASA’s Transiting Exoplanets
Survey Satellite (TESS), as well as its sibling, HD 21749b, a warm sub-Neptune-sized world
[Credit: Robin Dienel/Carnegie Institution for Science]

«It’s so exciting that TESS, which launched just about a year ago, is already a game-changer in the planet-hunting business,» said Teske, who is second author on the paper. «The spacecraft surveys the sky and we collaborate with the TESS follow-up community to flag potentially interesting targets for additional observations using ground-based telescopes and instruments.»


One such tool, the Planet Finder Spectrograph on the Magellan II telescope at Carnegie’s Las Campanas Observatory in Chile, was a crucial component of this effort. It helped confirm the planetary nature of the TESS signal, and to measure the mass of the newly discovered sub-Neptune.


The PFS — built by Shectman and Crane using a method pioneered by Butler and his collaborators — works using a technique called the radial velocity method, which is currently the only way for astronomers to measure the masses of individual planets. Without known masses, it is very challenging to determine a planet’s density or its general chemical composition.


This method takes advantage of that fact that not only does a star’s gravity influence the planet orbiting it, but the planet’s gravity also affects the star in turn. The PFS enables astronomers to detect these tiny wobbles that the planet’s gravity induces in the star’s orbit.


«PFS is one of the only instruments in the Southern Hemisphere that can do these types of measurements,» Teske added. «So, it will be a very important part of further characterizing the planets found by the TESS mission.»


With an orbit that takes about 36 days to complete, the sub-Neptune, HD 21749b, has the longest period of any of the TESS discoveries published so far. Because of the technique that TESS employs, it is predicted that most of the planets the mission finds will have orbital periods of fewer than 10 days, so HD 21749b is unusual in this regard. In fact, this also made the detection of the planet in the TESS data an extra challenge.


«There was quite some detective work involved, and the right people were there at the right time,» said lead author Diana Dragomir of MIT’s Kavli Institute for Astrophysics and Space Research. «But we were lucky, and we caught the signals, and they were really clear.»


Its host star has about 80 percent of the mass of our Sun and is found about 53 light-years distant from Earth. HD 21749b has about 23 times Earth’s mass and a radius of about 2.7 times Earth’s. Its density indicates the planet has substantial atmosphere but is not rocky, so it could potentially help astronomers understand the composition and evolution of cooler sub-Neptune planet atmospheres.


Excitingly, the longer period sub-Neptune planet in this system is not alone. It has a sibling planet, HD 21749c, which takes about eight days to orbit the host star and is much smaller — similar in size to Earth.


«Measuring the exact mass and composition of such a small planet will be challenging, but important for comparing HD 21749c to Earth,» said Wang. «Carnegie’s PFS team is continuing to collect data on this object with this goal in mind.»


Thanks to TESS, astronomers will be able to measure the masses, atmospheric compositions, and other properties of many smaller exoplanets for the first time. Although small exoplanets are common in our galaxy, there is still much to learn about their diversity and about how they compare to the planets in our own Solar System.


«For stars that are very close by and very bright, we expected to find up to a couple dozen Earth-sized planets,» said Dragomir. «And here we are — this would be our first one, and it’s a milestone for TESS. It sets the path for finding smaller planets around even smaller stars, and those planets may potentially be habitable.»


Source: Carnegie Institution for Science [April 15, 2019]




TANN



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Asteroids help scientists to measure the diameters of faraway stars

Using the unique capabilities of telescopes specialised on cosmic gamma rays, scientists have measured the smallest apparent size of a star on the night sky to date. The measurements with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) reveal the diameters of a giant star 2674 light-years away and of a sun-like star at a distance of 700 light-years. The study establishes a new method for astronomers to determine the size of stars, as the international team led by Tarek Hassan from DESY and Michael Daniel from the Smithsonian Astrophysical Observatory (SAO) reports in the journal Nature Astronomy.











Asteroids help scientists to measure the diameters of faraway stars
When an asteroid passes in front of a star, the resulting diffraction pattern (here greatly exaggerated)
can reveal the star’s angular size [Credit: DESY, Lucid Berlin]

Almost any star in the sky is too far away to be resolved by even the best optical telescopes. To overcome this limitation, the scientists used an optical phenomenon called diffraction to measure the star’s diameter. This effect illustrates the wave nature of light, and occurs when an object, such as an asteroid, passes in front of a star. «The incredibly faint shadows of asteroids pass over us everyday,» explained Hassan. «But the rim of their shadow isn’t perfectly sharp. Instead, wrinkles of light surround the central shadow, like water ripples.» This is a general optical phenomenon called a diffraction pattern and can be reproduced in any school lab with a laser hitting a sharp edge.


The researchers used the fact that the shape of the pattern can reveal the angular size of the light source. However, different from the school lab, the diffraction pattern of a star occulted by an asteroid is very hard to measure. «These asteroid occultations are hard to predict,» said Daniel. «And the only chance to catch the diffraction pattern is to make very fast snapshots when the shadow sweeps across the telescope.» Astronomers have measured the angular size of stars this way that were occulted by the moon. This method works right down to angular diameters of about one milliarcsecond, which is about the apparent size of a two-cent coin atop the Eiffel Tower in Paris as seen from New York.


However, not many stars in the sky are that «big.» To resolve even smaller angular diameters, the team employed Cherenkov telescopes. These instruments normally watch out for the extremely short and faint bluish glow that high-energy particles and gamma rays from the cosmos produce when they encounter and race through Earth’s atmosphere. Cherenkov telescopes do not produce the best optical images. But thanks to their huge mirror surface, usually segmented in hexagons like a fly’s eye, they are extremely sensitive to fast variations of light, including starlight.


Using the four large VERITAS telescopes at the Fred Lawrence Whipple Observatory in Arizona, the team could clearly detect the diffraction pattern of the star TYC 5517-227-1 sweep past as it was occulted by the 60-kilometre asteroid Imprinetta on 22 February 2018. The VERITAS telescopes allowed to take 300 snapshots every second. From these data, the brightness profile of the diffraction pattern could be reconstructed with high accuracy, resulting in an angular, or apparent, diameter of the star of 0.125 milliarcseconds. Together with its distance of 2674 light-years, this means the star’s true diameter is eleven times that of our sun. Interestingly, this result categorises the star whose class was ambiguous before as a red giant star.


The researchers repeated the feat three months later on 22 May 2018, when asteroid Penelope with a diameter of 88 kilometres occulted the star TYC 278-748-1. The measurements resulted in an angular size of 0.094 milliarcseconds and a true diameter of 2.17 times that of our sun. This time the team could compare the diameter to an earlier estimate based on other characteristics of the star that had placed its diameter at 2.173 times the solar diameter — an excellent match, although the earlier estimate was not based on a direct measurement.


«This is the smallest angular size of a star ever measured directly,» Daniel emphasised. «Profiling asteroid occultations of stars with Cherenkov telescopes delivers a ten times better resolution than the standard lunar occultation method. Also, it is at least twice as sharp as available interferometric size measurements.» The uncertainty of these measurements are about ten per cent, as the authors write. «We expect this can be notably improved by optimising the set-up, for example narrowing the wavelength of the colours recorded,» said Daniel. Since different wavelengths are diffracted differently, the pattern is smeared out if too many colours are recorded at the same time.


«Our pilot study establishes a new method to determine the true diameter of stars,» Hassan summarised. The scientists estimate that suitable telescopes could view more than one asteroid occultation per week. «Since the same star looks smaller the farther away it is, moving to smaller angular diameters also means extending the observation range,» explained Hassan. «We estimate that our method can analyse stars up to ten times as far away as the standard lunar occultation method allows. All together, the technique can deliver enough data for population studies.»


Author: Tracey Bryant | Source: Deutsches Elektronen-Synchrotron DESY [April 15, 2019]




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Historic logging site shows first human-caused bedrock erosion along an entire river

Geologic time is supposed to be slow, and the most solid object should be bedrock. But new University of Washington research upends both concepts: Effects of logging show that human activity can significantly erode bedrock, causing geology to fast forward.











Historic logging site shows first human-caused bedrock erosion along an entire river
This 1920 photo of the Teanaway River shows how logs traveled down the river to the mills and railway
[Credit: Frederick Krueger Photographs 376/Central Washington University Archives]

The study, published in the Proceedings of the National Academy of Sciences, focuses on the Teanaway River, a picturesque river in central Washington state.


«In the last century, we have more river incision in this area than expected. Something caused these rivers to start eroding a lot more,» said lead author Sarah Schanz, a former UW doctoral student who is now a postdoctoral researcher at Indiana University. «We know the Teanaway River has eroded into bedrock before, naturally — it has some terraces that are 1,800 years old. But this current cycle is anthropogenic, or human-driven.»


Results show that practices related to logging caused bedrock incision of up to 2 meters (6 feet) along the riverbed. As much as a half of what had been a floodplain was transformed into a new terrace abutting the river.


«This is the first time that we’ve been able to pinpoint erosion into bedrock due to human action,» Schanz said. «Most rivers are eroding at about a tenth of a millimeter per year. This is about 100 times that amount.»


The discovery means this beautiful riverbank resulted from human action, not natural forces. It could change how geologists think about landscapes in other parts of the world, such as Taiwan, with its long history of intense human activity.


The study began 20 years ago when co-author Brian Collins, a UW senior lecturer in river geology, was curious why there was so much exposed bedrock in the Teanaway.











Historic logging site shows first human-caused bedrock erosion along an entire river
Fluting and pothole formation in the bed of the channel. The survey rod in the foreground is 1.1 meters long
[Credit: Brian Collins/University of Washington]

Collins also noticed unusual river terraces, the stepped structures along the river bank resulting from cycles of the river flooding and then running more quickly, cutting a new channel deeper into the sediment. He led a 2016 study that calculated short-term changes in the Teanaway’s western fork and suggested logging may have caused the river to cut a new channel.


This site in a community forest offered good access for regular visits by the research team and undergraduate assistants to all three forks. By combining newspaper records, material from the UW Libraries Special Collections, Central Washington University and the local Kittitas County historical society, the researchers were able to piece together and confirm the full history.


Before logging roads existed, companies built temporary «splash dams» high up on the slope with all the logs and then broke up the dam with tools or explosives. Released water helped send logs shooting down to the mills.


«It was such an event that schools closed, and newspaper records show it really well,» Schanz said. «People who are still alive today, some of their earliest memories are of going to see it.»


Key to the process is that loggers would clear away debris to give the logs a clear shot down the river. This removed barriers that held back sediment and cleared out much of the gravel from the riverbed. Such events, the authors believe, caused the erosion to change dramatically.


«If you have too much sediment, you’re basically protecting the river from erosion. But if you have not enough sediment, as that sediment is moving along, it starts to hit the bedrock and erode it,» Schanz said.











Historic logging site shows first human-caused bedrock erosion along an entire river
The author’s 45-pound dog gives a sense of the size of the bedrock boulders being eroded from the side
of the Teanaway River. The previous floodplain is just visible at the top of the frame
[Credit: Sarah Schanz/Indiana University]

David Montgomery, a UW professor of Earth and space sciences, and the other two co-authors used many techniques to analyze the four youngest terraces on the river’s edge, including LIDAR maps, carbon dating of rocks and computer models. In 1999 the team even hammered nails into the bedrock and measured the erosion rates directly.


Many rivers, including the Teanaway, have individual features that show evidence of human impact on areas of bedrock. But this is the first time an entire river basin is found to have been transformed by human activity.


«This is a direct topographic signature of the Anthropocene, the ‘age of humans’ that we now live in,» Montgomery said. «The finding that terrace surfaces in the Teanaway are recently-abandoned floodplains suggests that similar landforms around the world may also reflect the influence of human activity.»


The UW team recently published an overview paper looking at where river terraces have formed worldwide over the past 4,000 years. The authors showed that in many cases, river terrace formation coincided with deforestation.


«It’s sort of a hand-wavey linkage at this point, but I think this could be prevalent worldwide,» said Schanz. «It’s just not a signal that we’ve known to look for before.»


Schanz will start a faculty position in August at Colorado College, where she plans also to explore what the finding means for how river canyons form through natural processes.


«I think the human part is really interesting, but what has broader implications, for me, is the proof that if you change how sediment moves through a river, you can change erosion rates,» Schanz said.


Source: University of Washington [April 15, 2019]



TANN



Archive


North Atlantic warming hole impacts jet stream

The North Atlantic warming hole (NAWH), a region of reduced warming located in the North Atlantic Ocean, significantly affects the North Atlantic jet stream in climate simulations of the future, according to a team of researchers.











North Atlantic warming hole impacts jet stream
Floating iceberg in Labrador Sea south of Greenland
[Credit: Melissa Gervais/Penn State]

Sea surface temperatures (SST) are projected to increase in most of the world’s oceans as the result of global climate change. However, within an area of rotating ocean currents just south of Greenland an anomaly exists where colder sea-surface temperatures were documented in both global climate-model projections and in observations.


«It’s called a hole because there is a lack of warming,» said Melissa Gervais, assistant professor of meteorology and atmospheric science, Penn State, who used the Community Earth System model (CESM) to investigate the impact of the NAWH on atmospheric circulation and midlatitude jets. «We found that this region of the ocean is a really important place for forcing the jet stream that goes across the North Atlantic Ocean.»


Development of the NAWH is linked to a slowdown of the Atlantic Meridional Overturning Circulation, a large system of ocean currents that carry warm water from the tropics northwards into the North Atlantic, and is thought to be caused by an influx of fresh water coming from melting Arctic sea ice.


Previous research by Gervais and her team demonstrated that this increase in fresh water to the ocean changes circulation patterns and leads to surface cooling.


«With more Arctic sea ice melting, more fresh water flows into the Labrador Sea, which leads to a reduction in deep convection,» said Gervais who also is an Institute for CyberScience co-hire. «That changes the ocean circulation, allowing it to cool in that region south of Greenland.»











North Atlantic warming hole impacts jet stream
Floating iceberg in Labrador Sea south of Greenland
[Credit: Melissa Gervais/Penn State]

This cooling pattern, relative to global average SST increase, is predicted to become greater and more apparent relative to the internal ocean variability as the 21st century progresses.


«These changes in SST patterns occur as the result of changes in ocean circulation and could have a significant impact on atmospheric circulation and the North Atlantic storm track in the future,» said Gervais.


Jet streams, high altitude currents of wind flowing above the Earth, transport air masses and drive weather patterns. The relationship between climate change and jet streams is complex and understanding the potential impact of climate change on jet streams is crucial for understanding changes in weather patterns and storm tracks.


«With climate change we have some ideas about how the jets are going to change. In general, we expect to see a poleward shift and eastward elongation of the jet,» said Gervais. «Right now, it’s sort of a tug of war between impacts of the tropics and impacts of the arctic. So those two things are competing to shift where the jet is located.»


Most climate models seem to agree that the Pacific jet stream is going to shift poleward but there is a lot of variability in predictions for the Atlantic, said Gervais.











North Atlantic warming hole impacts jet stream
The Greenland coast taken from the Knorr WHOI research vessel
[Credit: Melissa Gervais/Penn State]

To investigate how the development of the NAWH impacts the jet stream, the team conducted a series of large-ensemble, atmospheric model experiments in the CESM with prescribed SST and sea ice levels over three different time periods.


«We ran three simulations,» said Gervais. «One with current warming-hole conditions; one where the ocean temperature was increased to fill in the warming hole; and one where its size was twice as deep, to simulate more freshwater from melting ice sheets.»


Their results indicate that the NAWH plays an important role in midlatitude atmospheric circulation changes in the model’s future climate simulations.


«We found that it’s really quite important for that region,» said Gervais. «The NAWH seems to be elongating the jet even further and shifting it a little bit north. Instead of just thinking about how the tropics and arctic amplification are influencing the jet, we now also need to think about how this warming hole is going to influence the jet. These local changes in the North Atlantic jet are of a similar magnitude to the full climate-change response in the region, indicating that the North Atlantic warming hole could be an important additional factor in the tug of war on midlatitude circulation, that has received little attention.»


The researchers published their findings in the Journal of Climate.


Source: Pennsylvania State University [April 15, 2019]



TANN



Archive


Ancient lakes: Eyes into the past, and the future

«A lake is a landscape’s most beautiful and expressive feature. It is Earth’s eye; looking into which the beholder measures the depth of his own nature.» — Henry David Thoreau, Walden











Ancient lakes: Eyes into the past, and the future
Siberia in winter: Russia’s Lake Baikal. This ancient lake is on the cusp of change
[Credit: Sergey Pesterev/WikiCommons]

Baikal, Biwa and Bosuntwi. Maracaibo, Malawi and Matano. Tule, Tahoe and Titicaca. Ancient lakes, they’re called: waterbodies more than 130,000 years old. Over their long histories, they’ve seen countless changes — warming and cooling cycles, wet and dry periods, altered biology and chemistry.


These age-old lakes have long tolerated the presence of humans, supporting some of the earliest known settlements and playing key roles in our cultural evolution and development, state Stephanie Hampton and co-authors in a recent paper in the journal Limnology and Oceanography. Hampton is a limnologist (lake scientist) at Washington State University.


Despite covering less than one percent of Earth’s surface area, ancient lakes contain almost half the world’s fresh surface water and a large share of its freshwater biodiversity.


The lakes also support major economies, including fisheries and tourism. But it’s these very uses that are degrading the ecological, socioeconomic and scientific value of many ancient lakes, found Hampton and colleagues. The research was supported in part by an award to Michael Meyer at Washington State University from the National Science Foundation’s Graduate Research Fellowship Program.


Looking into 29 ancient eyes


The researchers peered into the waters of 29 ancient lakes around the world. The lakes are dotted across almost every continent, and located in areas with a range of land uses and socioeconomic conditions.











Ancient lakes: Eyes into the past, and the future
As part of the ancient lakes research, scientist Stephanie Hampton prepares to explore Lake Baikal
[Credit: Washington State University]

Some cross political boundaries, such as the Caspian Sea, which is shared by Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. Others, such as Lake Baikal in Russia, are UNESCO World Heritage Sites. Still others — California’s Lake Tahoe, for example — support thriving tourism industries.
«The intent of this review is to evaluate major anthropogenic [human-caused] threats faced by these unique ecosystems, as well as the ecological changes that have been documented,» write Hampton and colleagues. «In doing so, we hope to encourage future comparative ecological studies across ancient lakes worldwide.»


A lake’s eye closing


Ancient lakes are threatened by invasive species, warming waters and a host of other maladies. Among the most pervasive is pollution by nutrients, usually nitrogen or phosphorus from fertilizers.











Ancient lakes: Eyes into the past, and the future
California’s Lake Tahoe, an ancient lake, is an example of an oligotrophic, or low nutrient, lake
[Credit: WikiCommons]

Freshwater lakes range from oligotrophic, with see-to-the-bottom clear waters and low nutrient levels, to eutrophic, with an overgrowth of algae fueled by an excess of nutrients. Runoff from the land carries nutrients into rivers and streams and eventually into larger waterbodies.
Continued eutrophication essentially kills a lake, with an overgrowth of algae starving its waters of oxygen and leaving fish and other freshwater species unable to breathe. Harmful algae blooms and resulting dead zones signal that a lake is in trouble.


Unfortunately, states Hampton’s team, «increasing nutrient concentrations and the consequences of eutrophication have been recorded for most of the ancient lakes, including Victoria [on the border of Kenya, Tanzania and Uganda], Baikal [Russia], Valencia [Venezuela], Titicaca [Peru] and Ohrid [Macedonia], among others.»











Ancient lakes: Eyes into the past, and the future
Peru’s Lake Titicaca looks pristine from a distance, but is showing signs of eutrophication
[Credit: WikiCommons]

A major effect of eutrophication, Hampton says, «is a loss of biodiversity. In Lake Victoria, for example, decreased water clarity has affected the reproduction of endemic cichlid fish, leading to the disappearance of dozens of species.» These colorful fish are prized around the world.
In Lake Baikal, algae blooms threaten what scientists call an extraordinary biodiversity of the nearshore benthos, or bottom zone. In Lake Tahoe, impaired water clarity has precipitated declines in populations of deep-water invertebrates and other species.


Ancient lakes’ futures


Ancient lakes’ long histories make them invaluable to science and society, the scientists say.











Ancient lakes: Eyes into the past, and the future
Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan share the Caspian Sea, an ancient lake
[Credit: WikiCommons]

«These lakes not only record long histories of environmental variation and human resource use, they also harbor high rates of endemism and biodiversity,» write the researchers. «Many of the biota in ancient lakes may be especially sensitive to threats and may be less likely to recover following collapses» of their populations.


A major concern, says Hampton, is that biodiversity loss in the lakes is happening on comparatively short time scales.


Tens of thousands of years after these lakes formed, «they’re still with us,» Hampton says. «Long into the future, will they remain?» The answer, she says, may be up to us.


Author: Cheryl Dybas | Source: National Science Foundation [April 15, 2019]



TANN



Archive


What makes a jellyfish?

Translucent jellyfish, colorful corals and waving sea anemones have very different bodies but all fall on the same big branch in the animal family tree. Jellyfish actually start out anchored to the sea floor, just like corals and anemones. Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) recently uncovered which genes allow jellyfish to graduate from this stationary stage and swim off into the sea.











What makes a jellyfish?
Jellyfish start out in a stationary polyp stage and later develop into jellyfish, when environmental conditions are right.
The Morbakka virulenta, pictured here, is beginning to develop into a full-fledged jelly
[Credit: OIST]

Early in their life cycles, jellyfish develop from larvae into polyps—immobile, stalk-like structures rooted into the sediment. Anemones and coral live out their lives in this state, which earned them the name anthozoa or «flower animals» in Greek. Jellyfish set themselves apart from anthozoans by being able to develop from the polyp stage to the medusa stage, blossoming into the luminous, bell-like creatures we know and love.


The new study, published in Nature Ecology & Evolution, reports the genomes of two jellyfish species and investigated why some creatures can enter the medusa stage while others remain frozen as polyps. The genomes can be browsed online and compared to other species on the OIST BLAST server.


OIST researchers and colleagues from Japan and Germany compared the genomes of a moon jellyfish (Aurelia aurita) and a giant box jellyfish (Morbakka virulenta). In Japanese, these species are known as the «water jellyfish» and «fire jellyfish», respectively. The fire jellyfish is highly venomous and owes its name to its painful, burning sting.


«By comparing two different types of jellyfish we expected to identify some universal rules on how to make a medusa stage,» said Dr. Konstantin Khalturin, first author of the study and a scientist in the OIST Marine Genomics Unit led by Prof. Noriyuki Satoh. As a jellyfish exits its polyp stage and leaves the sandy sea floor, different genes switch on to drive its development. To identify these special genes, the researchers first had to catalogue all the genes present in their sample jellyfish species.











What makes a jellyfish?
Research by the Marine Genomics Unit revealed that the genome of the moon jellyfish (Aurelia aurita)
is more similar to a coral or sea anemone than another jellyfish, Morbakka virulenta
[Credit: OIST]

«We then looked at how these genes behaved in the polyp and jellyfish stages of their lifecycles,» Khalturin said.


The researchers sequenced the complete genome of a moon jellyfish from the Baltic Sea and giant box jellyfish from Japan. Genomes contain all the instructions to build and maintain an organism, encoded in individual building blocks known as genes. Along with a creature’s genetic composition, the order in which these building blocks are lain helps determine how a creature develops. The researchers compared their freshly decoded jellyfish genomes to those from corals and anemones, pinpointing which genes appeared in each animal and in what sequence.


«We expected that the genome organization in the two jellyfish would be more similar to each other than to the genomes of sea anemones or corals,» said Khalturin. Surprisingly, the gene order in the moon jelly genome resembled anthozoans much more closely than fire jellyfish. In contrast, the genetic composition of the two jellyfish hardly overlapped; their genomes differ as drastically as humans do from sea urchins.


The results suggest that the giant box jellyfish genome must have been vigorously reshuffled at some point in its evolution. The dearth of similarities between moon and giant box jellies convinced the researchers that there is no universal region within jellyfish genomes responsible for orchestrating the medusa stage formation.











What makes a jellyfish?
The OIST Marine Genomics Unit is now sequencing the genome of a local Okinawan box jellyfish to compare
to the giant box jellyfish pictured here. Comparing the two should shed light on how box jellyfish originally
 evolved and what sets them apart from other jellies [Credit: Dr. Sho Toshino]

One question remained: why can’t corals and anemones enter the jellyfish stage? To solve this mystery, the researchers assessed which genes were active in the polyp and medusa stages of both jellyfish. They compared these distinct patterns of gene expression to those observed in 11 different cnidarian species—the taxonomic group that encompasses medusozoans and anthozoans. Remarkably, they found that coral and anemones contain about two-thirds of the genes active in the moon jellyfish’s medusa stage.
But moon jellyfish have a special genetic toolkit: an elite arsenal of genes that activate during their medusa stage but are absent in anthozoans. Devoid of a jellyfish stage, corals and anemones lack the genes to grow certain organs and tissues, such as eyes and specialized swimming muscles. The researchers found that water and fire jellyfish share about 100 of these species-specific genes that only switch on in their jellyfish stages. A large proportion of these genes code for transcription factors, proteins that fine tune which genes are expressed, when and in what quantities.


Looking forward, the researchers plan to sequence the genome of a local box jellyfish called the Okinawan sea wasp (Chironex yamaguchii, «habu-kurage»), which will provide a closer comparison to the fire jellyfish. Future studies could advance our understanding of how jellyfish evolve and what sets them apart from their blobby brethren and other creatures of the deep.


Source: Okinawa Institute of Science and Technology [April 15, 2019]



TANN



Archive


Early chariot drivers of Transcaucasia came from…

I’m finding it increasingly difficult nowadays to fully appreciate all of the ancient DNA samples that are accumulating in my dataset. But it’s not entirely my fault.
Among the hundreds of ancient samples published last year there was a couple of Middle Bronze Age (MBA) individuals from what is now Armenia labeled «Lchashen Metsamor» (see here). I wasn’t planning to do much with these samples because, even after reading the Nature paper that they came with a couple times over, I didn’t have a clue what they were about. But after some digging around, I now know that their people, those associated with the Lchashen Metsamor archeological culture, were among the earliest in Transcaucasia, and indeed the Near East, to use the revolutionary spoked-wheel horse chariot. How awesome is that?
The invention of the spoked-wheel chariot is generally credited to the Middle Bronze Age Sintashta culture of the Trans-Ural steppe in Central Asia, and its rapid spread is often associated with the early expansions of Indo-European languages deep into Asia. On the other hand, some have argued that this type of chariot was first developed in the Near East, and directly derived from solid-wheeled wagons pulled by donkeys.
It’s now obvious, thanks to ancient DNA, that the Sintashta people were by and large migrants to Central Asia from somewhere deep in Eastern Europe, and that they didn’t harbor any recent ancestry from the Near East. So if chariot technology spread into the steppes from the Near East, then it did so without any accompanying gene flow, which is possible but not entirely convincing. This begs the question of whether the Lchashen Metsamor population was of Sintashta-related origin, because if it was, then this would corroborate the consensus that spoked-wheel chariots were introduced into Transcaucasia from the steppes to the north.
Below is a Principal Component Analysis (PCA) of West Eurasian genetic variation. It does suggest that the Lchashen Metsamor pair (labeled Armenia_MBA_Lchashen), as well as most of the other currently available samples from what is now Armenia dating to the Middle to Late Bronze Age (MLBA), harbor some steppe ancestry. That’s because they appear to form a cline between samples associated with the Sintashta and Kura-Araxes cultures. Of course, the Kura-Araxes culture was a major Early Bronze Age (EBA) archeological phenomenon centered on Transcaucasia and surrounds, so its population can be reasonably assumed to have formed the genetic base of most subsequent populations in the region. The relevant PCA datasheet is available here.



To investigate the possibility of Sintashta-related admixture in Lchashen Metsamor with formal methods, I ran a series of mixture models with the qpAdm software. Here are the three statistically most sound outcomes that I was able to come up with for Lchashen Metsamor:



Armenia_MBA_Lchashen
CWC_Kuyavia 0.183±0.036
Kura-Araxes_Kaps 0.817±0.036
chisq 13.941
tail prob 0.378021
Full output
Armenia_MBA_Lchashen
Balkans_BA_I2163 0.193±0.045
Kura-Araxes_Kaps 0.807±0.045

chisq 14.780
tail prob 0.321267
Full output
Armenia_MBA_Lchashen
Kura-Araxes_Kaps 0.788±0.043
Sintashta_MLBA 0.212±0.043

chisq 14.871
tail prob 0.315451
Full output



I sorted the output by «tail prob», but the fact that Sintashta_MLBA is in third place isn’t a problem because the stats in all of these models are basically identical. Indeed, CWC_Kuyavia (Corded Ware culture samples from present-day Kuyavia, North-Central Poland) and Balkans_BA_I2163 (a Bronze Age singleton from what is now Bulgaria) are both very similar and probably closely related to each other and to the Sintashta samples.
Interestingly, and, I’d say, importantly, ancients from the steppe that are closest to Lchashen Metsamor in both space and time, but not particularly closely related to the Sintashta people, don’t work too well as a mixture source in such models.



Armenia_MBA_Lchashen
Kubano-Tersk 0.184±0.046
Kura-Araxes_Kaps 0.816±0.046

chisq 22.179
tail prob 0.0526526
Full output



A couple of months ago I suggested that populations associated with the Early to Middle Bronze Age (EMBA) Catacomb culture were the vector for the spread of steppe ancestry into what is now Armenia during the MLBA (see here). After taking a closer look at the Lchashen Metsamor samples, I now think that the peoples of the Sintashta and related cultures were also important in this process. If so, they may have moved from the steppe into Transcaucasia both from the west via the Balkans and the east via Central Asia, and brought spoked-wheel chariots. I don’t have a clue what language they spoke, but I’m guessing that it may have been something Indo-European.
See also…
The mystery of the Sintashta people
A potentially violent end to the Kura-Araxes Culture (Alizadeh et al. 2018)
Late PIE ground zero now obvious; location of PIE homeland still uncertain, but…

Source


We Found the Universe’s First Type of Molecule

image

For decades, astronomers searched the cosmos for what is thought to be the first kind of molecule to have formed after the Big Bang. Now, it has finally been found. The molecule is called helium hydride. It’s made of a combination of hydrogen and helium. Astronomers think the molecule appeared more than 13 billion years ago and was the beginning step in the evolution of the universe. Only a few kinds of atoms existed when the universe was very young. Over time, the universe transformed from a primordial soup of simple molecules to the complex place it is today — filled with a seemingly infinite number of planets, stars and galaxies. Using SOFIA, the world’s largest airborne observatory, scientists observed newly formed helium hydride in a planetary nebula 3,000 light-years away. It was the first ever detection of the molecule in the modern universe. Learn more about the discovery:


Helium hydride is created when hydrogen and helium combine. 


image

Since the 1970s, scientists thought planetary nebula NGC 7027—a giant cloud of gas and dust in the constellation Cygnus—had the right environment for helium hydride to exist. 


image

But space telescopes could not pick out its chemical signal from a medley of molecules. 


image


Enter SOFIA, the world’s largest flying observatory! 


image

By pointing the aircraft’s 106-inch telescope at the planetary nebula and using a tool that works like a radio receiver to tune in to the “frequency” of helium hydride, similar to tuning a radio to a favorite station…


image

…the molecule’s chemical signal came through loud and clear, bringing a decades-long search to a happy end.


image

The discovery serves as proof that helium hydride can, in fact, exist in space. This confirms a key part of our basic understanding of the chemistry of the early universe, and how it evolved into today’s complexity. SOFIA is a modified Boeing 747SP aircraft that allows astronomers to study the solar system and beyond in ways that are not possible with ground-based telescopes. Find out more about the mission at www.nasa.gov/SOFIA


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