вторник, 17 июля 2018 г.

VLA Gives Tantalizing Clues About Source of Energetic Cosmic Neutrino



Supermassive black hole at core of galaxy accelerates particles in jets moving outward at nearly the speed of light. In a Blazar, one of these jets is pointed nearly straight at Earth. Credit: Sophia Dagnello, NRAO/AUI/NSF


Astronomers pinpoint likely source of high-energy cosmic rays for first time


A single, ghostly subatomic particle that traveled some 4 billion light-years before reaching Earth has helped astronomers pinpoint a likely source of high-energy cosmic rays for the first time. Subsequent observations with the National Science Foundation’s (NSF) Karl G. Jansky Very Large Array (VLA) have given the scientists some tantalizing clues about how such energetic cosmic rays may be formed at the cores of distant galaxies.


On September 22, 2017, an observatory called IceCube, made up of sensors distributed through a square kilometer of ice under the South Pole, recorded the effects of a high-energy neutrino coming from far beyond our Milky Way Galaxy. Neutrinos are subatomic particles with no electrical charge and very little mass. Since they interact only very rarely with ordinary matter, neutrinos can travel unimpeded for great distances through space.


Follow-up observations with orbiting and ground-based telescopes from around the world soon showed that the neutrino likely was coming from the location of a known cosmic object — a blazar called TXS 0506+056, about 4 billion light-years from Earth. Like most galaxies, blazars contain supermassive black holes at their cores. The powerful gravity of the black hole draws in material that forms a hot rotating disk. Jets of particles traveling at nearly the speed of light are ejected perpendicular to the disk. Blazars are a special class of galaxies, because in a blazar, one of the jets is pointed almost directly at Earth.


Theorists had suggested that these powerful jets could greatly accelerate protons, electrons, or atomic nuclei, turning them into the most energetic particles known in the Universe, called ultra-high energy cosmic rays. The cosmic rays then could interact with material near the jet and produce high-energy photons and neutrinos, such as the neutrino detected by IceCube.


Cosmic rays were discovered in 1912 by physicist Victor Hess, who carried instruments in a balloon flight. Subsequent research showed that cosmic rays are either protons, electrons, or atomic nuclei that have been accelerated to speeds approaching that of light, giving some of them energies much greater than those of even the most energetic electromagnetic waves. In addition to the active cores of galaxies, supernova explosions are probable sites where cosmic rays are formed. The galactic black-hole engines, however, have been the prime candidate for the source of the highest-energy cosmic rays, and thus of the high-energy neutrinos resulting from their interactions with other matter.


“Tracking that high-energy neutrino detected by IceCube back to TXS 0506+056 makes this the first time we’ve been able to identify a specific object as the probable source of such a high-energy neutrino,” said Gregory Sivakoff, of the University of Alberta in Canada.


Following the IceCube detection, astronomers looked at TXS 0506+056 with numerous telescopes and found that it had brightened at wavelengths including gamma rays, X-rays, and visible light. The blazar was observed with the VLA six times between October 5 and November 21, 2017.


“The VLA data show that the radio emission from this blazar was varying greatly at the time of the neutrino detection and for two months afterward. The radio frequency with the brightest radio emission also was changing,” Sivakoff said.


TXS 0506+056 has been monitored over a number of years with the NSF’s Very Long Baseline Array (VLBA), a continent-wide radio telescope system that produces extremely detailed images. The high-resolution VLBA images have shown bright knots of radio emission that travel outward within the jets at speeds nearly that of light. The knots presumably are caused by denser material ejected sporadically through the jet.


“The behavior we saw with the VLA is consistent with the emission of at least one of these knots. It’s an intriguing possibility that such knots may be associated with generating high-energy cosmic rays and thus the kind of high-energy neutrino that IceCube found,” Sivakoff said.


The scientists continue to study TXS 0506+056. “There are a lot of exciting phenomena going on in this object,” Sivakoff concluded.


“The era of multi-messenger astrophysics is here,” said NSF Director France Córdova. “Each messenger — from electromagnetic radiation, gravitational waves and now neutrinos — gives us a more complete understanding of the Universe, and important new insights into the most powerful objects and events in the sky. Such breakthroughs are only possible through a long-term commitment to fundamental research and investment in superb research facilities.”


Sivakoff and numerous colleagues from institutions around the world are reporting their findings in the journal Science.


The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.


Media Contact:

Dave Finley, 
Public Information Officer
(575) 835-7302
dfinley@nrao.edu



Paper:


“Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A”, http://science.sciencemag.org/cgi/doi/10.1126/science.aat1378






Archive link


https://xissufotoday.space/2018/07/vla-gives-tantalizing-clues-about-source-of-energetic-cosmic-neutrino/

Astronomers Find a Famous Exoplanet’s Doppelgänger


Direct Wircam image of 2MASS 0249 system taken wiht CFHT’s infrared camera WIRCam. 2MASS 0249c is located 2000 astronomical units from the host brown dwarfs that are unresolved in this image. Credits: T. Dupuy, M. Liu



The infrared spectra of 2MASS 0249c and beta Pictoris b are similar, as expected for two objects of comparable mass that formed in the same stellar nursery. Unlike 2MASS 0249c, beta Pictoris b orbits much closer to its massive host star and is imbedded in a bright circumstellar disk. Credits: T. Dupuy, ESO/A.-M. Lagrange et al.


When it comes to extrasolar planets, appearances can be deceiving. Astronomers have imaged a new planet, and it appears nearly identical to one of the best studied gas-giant planets. But this doppelgänger differs in one very important way: its origin. “We have found a gas-giant planet that is a virtual twin of a previously known planet, but it looks like the two objects formed in different ways,” said Trent Dupuy, astronomer at the Gemini Observatory and leader of the study.


Emerging from stellar nurseries of gas and dust, stars are born like kittens in a litter, in bunches and inevitably wandering away from their birthplace. These litters comprise stars that vary greatly, ranging from tiny runts incapable of generating their own energy (called brown dwarfs) to massive stars that end their lives with supernova explosions. In the midst of this turmoil, planets form around these new stars. And once the stellar nursery exhausts its gas, the stars (with their planets) leave their birthplace and freely wander the Galaxy. Because of this exodus, astronomers believe there should be planets born at the same time from the same stellar nursery, but orbiting stars that have moved far away from each other over the eons, like long-lost siblings.


“To date, exoplanets found by direct imaging have basically been individuals, each distinct from the other in their appearance and age. Finding two exoplanets with almost identical appearances and yet having formed so differently opens a new window for understanding these objects,” said Michael Liu, astronomer at the University of Hawai`i Institute for Astronomy, and a collaborator on this work.


Dupuy, Liu, and their collaborators have identified the first case of such a planetary doppelgänger. One object has long been known: the 13-Jupiter-mass planet beta Pictoris b, one of the first planets discovered by direct imaging, back in 2009. The new object, dubbed 2MASS 0249 c, has the same mass, brightness, and spectrum as beta Pictoris b.


After discovering this object with the Canada-France-Hawaii Telescope (CFHT), Dupuy and collaborators then determined that 2MASS 0249 c and beta Pictoris b were born in the same stellar nursery. On the surface, this makes the two objects not just look-alikes but genuine siblings.


However, the planets have vastly different living situations, namely the types of stars they orbit. The host for beta Pictoris b is a star 10 times brighter than the Sun, while 2MASS 0249 c orbits a pair of brown dwarfs that are 2000 times fainter than the Sun. Furthermore, beta Pictoris b is relatively close to its host, about 9 astronomical units (AU, the distance from the Earth to the Sun), while 2MASS 0249 c is 2000 AU from its binary host.


These drastically different arrangements suggest that the planets’ upbringings were not at all alike. The traditional picture of gas-giant formation, where planets start as small rocky cores around their host star and grow by accumulating gas from the star’s disk, likely created beta Pictoris b. In contrast, the host of 2MASS 0249 c did not have enough of a disk to make a gas giant, so the planet likely formed by directly accumulating gas from the original stellar nursery.


“2MASS 0249 c and beta Pictoris b show us that nature has more than one way to make very similar looking exoplanets,” says Kaitlin Kratter, astronomer at the University of Arizona and a collaborator on this work. “beta Pictoris b probably formed like we think most gas giants do, starting from tiny dust grains. In contrast, 2MASS 0249 c looks like an underweight brown dwarf that formed from the collapse of a gas cloud. They’re both considered exoplanets, but 2MASS 0249 c illustrates that such a simple classification can obscure a complicated reality.”


The team first identified 2MASS 0249 c using images from CFHT, and their repeated observations revealed this object is orbiting at a large distance from its host. The system belongs to the beta Pictoris moving group, a widely dispersed set of stars named for its famous planet-hosting star. The team’s observations with the W. M. Keck Telescope determined that the host is actually a closely separated pair of brown dwarfs. So altogether, the 2MASS 0249 system comprises two brown dwarfs and one gas-giant planet. Follow-up spectroscopy of 2MASS 0249 c with the NASA Infrared Telescope Facility and the Astrophysical Research Consortium 3.5-meter Telescope at Apache Point Telescope demonstrated that it shares a remarkable resemblance to beta Pictoris b.


The 2MASS 0249 system is an appealing target for future studies. Most directly imaged planets are very close to their host stars, inhibiting detailed studies of the planets due to the bright light from the stars. In contrast, the very wide separation of 2MASS 0249 c from its host binary will make measurements of properties like its surface weather and composition much easier, leading to a better understanding of the characteristics and origins of gas-giant planets.


This work is accepted for publication in the Astronomical Journal.


This work has been supported by the National Science Foundation under Grant No. AST-1518339. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.



Additional information : arXiv link to the Paper


Contact Information:


Media contacts

Mary Beth Laychak, Outreach manager
Canada-France-Hawaii Telescope
mary@cfht.hawaii.edu


Science contacts

Trent Dupuy
Gemini Observatory
tdupuy@gemini.edu


Michael Liu
UH Institute for Astronomy
mliu@ifa.hawaii.edu





Archive link


https://xissufotoday.space/2018/07/astronomers-find-a-famous-exoplanets-doppelganger/

HiPOD (17 July 2017): Monitoring Slopes in Gale Crater   – This…



HiPOD (17 July 2017): Monitoring Slopes in Gale Crater


   – This part of Gale Crater is south of where the rover Curiosity is.


NASA/JPL/University of Arizona (271 km above the surface. Black and white is less than 5 km across; enhanced color is less than 1 km)


https://xissufotoday.space/2018/07/hipod-17-july-2017-monitoring-slopes-in-gale-crater-this/

Temple Wood Stone Circle 2, Kilmartin Glen, Argyll, Scotland,…









Temple Wood Stone Circle 2, Kilmartin Glen, Argyll, Scotland, 14.7.18.


Source link


https://xissufotoday.space/2018/07/temple-wood-stone-circle-2-kilmartin-glen-argyll-scotland/

Giant’s Causeway, Ireland…


Giant’s Causeway, Ireland http://www.geologypage.com/2018/07/giants-causeway-ireland.html


https://xissufotoday.space/2018/07/giants-causeway-ireland/

Study finds deep subterranean connection between two Japan…


Study finds deep subterranean connection between two Japan volcanoes http://www.geologypage.com/2018/07/study-finds-deep-subterranean-connection-between-two-japan-volcanoes.html


https://xissufotoday.space/2018/07/study-finds-deep-subterranean-connection-between-two-japan/

Sound waves reveal enormous diamond cache deep in Earth’s…


Sound waves reveal enormous diamond cache deep in Earth’s interior http://www.geologypage.com/2018/07/sound-waves-reveal-enormous-diamond-cache-deep-in-earths-interior.html


https://xissufotoday.space/2018/07/sound-waves-reveal-enormous-diamond-cache-deep-in-earths/

2018 July 17 Moon and Venus over Cannon Beach Image Credit…


2018 July 17


Moon and Venus over Cannon Beach
Image Credit & Copyright: James W. Young


Explanation: What’s that spot next to the Moon? Venus. Two days ago, the crescent Moon slowly drifted past Venus, appearing within just two degrees at its closest. This conjunction, though, was just one of several photographic adventures for our Moon this month (moon-th), because, for one, a partial solar eclipse occurred just a few days before, on July 12. Currently, the Moon appears to be brightening, as seen from the Earth, as the fraction of its face illuminated by the Sun continues to increase. In a few days, the Moon will appear more than half full, and therefore be in its gibbous phase. Next week the face of the Moon that always faces the Earth will become, as viewed from the Earth, completely illuminated by the Sun. Even this full phase will bring an adventure, though, as a total eclipse of this Thunder Moon will occur on July 27. Don’t worry about our Luna getting tired, though, because she’ll be new again next month (moon-th) – August 11 to be exact – just as she causes another partial eclipse of the Sun. Pictured, Venus and the Moon were captured from Cannon Beach above a rock formation off the Oregon (USA) coast known as the Needles. About an hour after this image was taken, the spin of the Earth caused both Venus and the Moon to set.


∞ Source: apod.nasa.gov/apod/ap180717.html


https://xissufotoday.space/2018/07/2018-july-17-moon-and-venus-over-cannon-beach-image-credit/

Space Station Science Highlights: Week of July 9, 2018


ISS – Expedition 56 Mission patch.


July 16, 2018


Last week, Progress, a Russian resupply spacecraft, delivered more than 5,700 pounds of crew supplies and cargo to the crew members aboard the International Space Station. Monday’s arrival of the spacecraft set a milestone for station operations by arriving with its cargo in just 3 hours and 40 minutes, or only two Earth orbits.



Image above: The Progress 43 spacecraft launched from the Baikonur Cosmodrome in Kazakhstan, headed for the International Space Station. Image Credit: NASA.


Read more details about scientific work last week aboard your orbiting laboratory:


Blood samples collected in support of JAXA investigations


Blood carries molecular signals released from cells inside the body. For the Cell-Free Epigenome (CFE) study, blood samples are collected from astronauts and cellular genes are analyzed. The results provide insight into how human bodies function during spaceflight. The Medical Proteomics investigation evaluates changes of proteins in blood serum, bone and skeletal muscles after space flight, and also supports identification of osteopenia-related proteins.



Image above: The Plant Habitat-1 compares differences in genetics, metabolism, photosynthesis, and gravity sensing between plants grown in space and on Earth. This investigation provides key insights on major changes occurring in plants exposed to microgravity. Image Credit: NASA.


By combining research results for mice, astronauts and ground patients, proteins related to osteopenia can be identified using the latest proteome analysis technique. It is anticipated that the use of the marker proteins related to osteopenia will be of benefit in the future for assessing the health of astronauts as well as osteoporosis patients on ground.


Last week, crewmembers collected blood samples in support of both investigations.


Experiment investigates protein associated with various diseases


Amyloid fibril is the protein aggregation that is known to be associated with various diseases including Alzheimer’s disease and diabetes. To develop treatments for Alzheimer’s disease, it is important to clarify the mechanism of amyloid fibril formation. In the Characterization of Amyloid Formation Under Microgravity Environment: Toward Understanding the Mechanisms of Neurodegenerative Diseases (Amyloid) investigation, researchers prepare the high-quality homogeneous amyloid fibrils using the microgravity environment, and bring back the samples to characterize the fibrillation process and intermediate structure.



Image above: Mt. Rainier as seen from the vantage point of the space station. Image Credit: NASA.


Last week, crew members transferred the Amyloid samples from a -95 degree Celsius container within the Minus Eighty Degree Celsius Laboratory Freezer for ISS (MELFI) to a 2 degree Celsius container, then attached to the Cell Biology Experiment Facility (CBEF) to incubate before being placed back into MELFI.


Study examines spaceflight impact on sperm cells


The survival of multiple generations of organisms beyond the Earth requires proper function of normal sperm and eggs cells. There exists a significant knowledge gap on impacts of spaceflight conditions on the fertility-dependent functions of sperm. The goal of the Spaceflight-Altered Motility Activation and Fertility-Dependent Responses in Sperm (Micro-11) investigation is to study how sperm cells are affected by the spaceflight environment.



Image above: NASA astronaut Serena M. Auñón-Chancellor conducts Micro-11 operations in the Microgravity Science Glovebox (MSG). Image Credit: NASA.


Last week, the crew performed five runs of the Micro-11 investigation. For each run, the Micro-11 microscope was checked out, configured and calibrated before samples were fixed and loaded into the device for imaging. Finally, the samples were stored in MELFI. There will be 13 runs conducted for the Micro-11 investigation.


Other work was done on these investigations:, CEO, HDEV, Probiotics, Space Algae, HREP-HICO, HREP-RAIDS, Biomolecule Sequencer, MICS, ACE-M-2, Made in Space-Fiber Optics, Rodent Research-7, LMM Biophysics-4, Neuromapping, MagVector, MICS, Food Acceptability, MELFI, Angiex Cancer Therapy, Biochem Profile, Repository, Atomization, SAMS-II and Manufacturing Device.



Space to Ground: Same Day Delivery: 07/13/2018

Related links:


Cell-Free Epigenome (CFE): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7555


Medical Proteomics: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7590


Minus Eighty Degree Celsius Laboratory Freezer for ISS (MELFI): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=56


Cell Biology Experiment Facility (CBEF): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=333


Spaceflight-Altered Motility Activation and Fertility-Dependent Responses in Sperm (Micro-11): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1922


CEO: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=84


HDEV: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=892


Probiotics: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2047


Space Algae: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7446


HREP-HICO: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=678


HREP-RAIDS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=680


Biomolecule Sequencer: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1917


MICS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7658


ACE-M-2: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1197


Made in Space-Fiber Optics: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7388


Rodent Research-7: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7425


LMM Biophysics-4: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7741


Neuromapping: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=979


MagVector: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1070


MICS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7658


Food Acceptability: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7562


MELFI: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=56


Angiex Cancer Therapy: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7502


Biochem Profile: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=980


Repository: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=954


Atomization: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=282


SAMS-II: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=963


Manufacturing Device: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1934


Expedition 56: https://cms.nasa.gov/mission_pages/station/expeditions/expedition56/index.html


Spot the Station: https://spotthestation.nasa.gov/


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 (NASA), Text, Credits: NASA/Michael Johnson/Yuri Guinart-Ramirez, Lead Increment Scientist Expeditions 55 & 56.


Best regards, Orbiter.chArchive link


https://xissufotoday.space/2018/07/space-station-science-highlights-week-of-july-9-2018/

A Merger of Stars


NASA – Spitzer Space Telescope patch.


July 16, 2018



Launched nearly 15 years ago on August 25, 2003, the Spitzer Space Telescope is the final mission in NASA’s Great Observatories Program – a family of four space-based observatories, each observing the universe in a different kind of light. The other missions in the program include the visible-light Hubble Space Telescope, Compton Gamma-Ray Observatory, and the Chandra X-Ray Observatory.


Over the years, Spitzer, which makes observations in the infrared spectrum, has made a plethora of discoveries, including this detection of the faint afterglow of the explosive merger of two neutron stars in the galaxy NGC 4993 on September 29, 2017. The event, labeled GW170817, was initially detected nearly simultaneously in gravitational waves and gamma rays, but subsequent observations by many dozens of telescopes have monitored its afterglow across the entire spectrum of light. Spitzer’s observation came late in the game, just over six weeks after the event was first seen, but this played an important role in helping astronomers understand how many of the heaviest elements in the periodic table are created in explosive neutron star mergers.



Spitzer Space Telescope

The telescope was named after Lyman Spitzer, Jr. (1914-1997), one of the 20th century’s great astrophysicists, who made major contributions in the areas of stellar dynamics, plasma physics, thermonuclear fusion, and space astronomy. He was laos the first person to propose the idea of placing a large telescope in space and was instrumental in the development of the Hubble Space Telescope.


Spitzer Space Telescope: http://www.nasa.gov/mission_pages/spitzer/main/index.html


Image, Animation, Text, Credits: NASA/Yvette Smith/JPL-Caltech.


Greetings, Orbiter.chArchive link


https://xissufotoday.space/2018/07/a-merger-of-stars/

Dusk for Dawn: Mission of Many Firsts to Gather More Data in Home Stretch


NASA – Dawn Mission patch.


July 16, 2018



Image above: This mosaic of Cerealia Facula in Occator Crater is based on images obtained by NASA’s Dawn spacecraft in its second extended mission, from an altitude as low as about 21 miles (34 kilometers). Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.


Pasadena Conference to Include New Insight into Dwarf Planet Ceres


As NASA’s Dawn spacecraft prepares to wrap up its groundbreaking 11-year mission, which has included two successful extended missions at Ceres, it will continue to explore — collecting images and other data.


Within a few months, Dawn is expected to run out of a key fuel, hydrazine, which feeds thrusters that control its orientation and keeps it communicating with Earth. When that happens, sometime between August and October, the spacecraft will stop operating, but it will remain in orbit around dwarf planet Ceres.


Dawn is the only spacecraft to orbit two deep-space destinations. It has given us new, up-close views of Ceres and Vesta, the largest bodies between Mars and Jupiter. During 14 months in orbit from 2011 to 2012, Dawn studied Vesta from its surface to its core. It then pulled off an unprecedented maneuver by leaving orbit and traveling through the main asteroid belt for more than two years to reach and orbit Ceres, which it has been investigating since 2015.


At Ceres, the spacecraft discovered brilliant, salty deposits decorating the dwarf planet like a smattering of diamonds. The science behind these bright spots is even more compelling: they are mainly sodium carbonate and ammonium chloride that somehow made their way to the surface in a slushy brine from within or below the crust.


These discoveries were fueled by the tremendous efficiency of ion propulsion. Dawn wasn’t the first spacecraft to use ion propulsion, familiar to science-fiction fans as well as space enthusiasts, but it pushed the limits of this advanced propulsion’s capabilities and stamina.



Image above: This close-up image of the Vinalia Faculae in Occator Crater was obtained by NASA’s Dawn spacecraft in its second extended mission, from an altitude as low as 21 miles (34 kilometers). Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.


“Dawn’s unique mission to orbit and explore two strange new worlds would have been impossible without ion propulsion,” said Marc Rayman of NASA’s Jet Propulsion Laboratory, Pasadena, California, who has served as Dawn’s mission director, chief engineer and project manager. “Dawn is truly an interplanetary spaceship, and it has been outstandingly productive as it introduced these fascinating and mysterious worlds to Earth.”


These days, near the end of Dawn’s second extended mission at Ceres, the spacecraft continues to wow us week after week, with very close photos shot from only 22 miles (35 kilometers) above the dwarf planet — about three times the altitude of a passenger jet.


But Wait, There’s More: New Science to Come


Although the Dawn mission is winding down, the science is not. Besides the high-resolution images, the spacecraft is collecting gamma ray and neutron spectra, infrared and visible spectra, and gravity data. The observations focus on the area around Occator and Urvara craters, with the main goal of understanding the evolution of Ceres, and testing for possible ongoing geology.


“The new images of Occator Crater and the surrounding areas have exceeded expectations, revealing beautiful, alien landscapes,” said Carol Raymond of JPL, principal investigator of the Dawn mission. “Ceres’ unique surface appears to be shaped by impacts into its volatile-rich crust, resulting in intriguing, complex geology, as we can see in the new high-resolution mosaics of Cerealia Facula and Vinalia Faculae.”


The first results of this mission phase, which started in early June, are being presented this week at the Committee on SPAce Research (COSPAR) meeting in Pasadena. Raymond and JPL scientist Jennifer Scully will offer new information on the relationships between bright and dark materials on the floor of Occator Crater, which show impact processes, landslides and cryovolcanism.



Dawn orbiting Ceres. Image Credit: NASA

Dawn scientists are using new high-resolution data from Dawn to test and refine hypotheses about Occator crater’s formation and evolution.  “Observations, modeling and laboratory studies helped us conclude that the bright spots are either formed by impacts interacting with the crust, or that a reservoir of briny melt contributed to their formation,” said Scully.


The new images so far support the hypothesis that exposure of subsurface material in that region is ongoing, and that it is geologically active, feeding from a deep reservoir. Eleonora Ammannito of the Italian Space Agency, deputy lead for the Dawn visible and infrared mapping spectrometer, will present updated maps at the conference showing the distribution of briny materials across Ceres’ surface.


Also at COSPAR, Dawn flight team member Dan Grebow of JPL will describe Dawn’s final orbit, designed to abide by NASA’s planetary protection protocols.


Low-altitude images collected by Dawn are posted regularly to the mission’s web page here: https://dawn.jpl.nasa.gov/multimedia/images/


The Dawn mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. JPL is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.


For a complete list of mission participants, visit:


https://dawn.jpl.nasa.gov/mission


More information about Dawn is available at the following sites:


https://www.nasa.gov/dawn


https://dawn.jpl.nasa.gov


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


Best regards, Orbiter.chArchive link


https://xissufotoday.space/2018/07/dusk-for-dawn-mission-of-many-firsts-to-gather-more-data-in-home-stretch/

A Scientist’s Final Paper Looks Toward Earth’s Future Climate


NASA – Goddard Space Flight Center logo.


July 16, 2018


A NASA scientist’s final scientific paper, published posthumously this month, reveals new insights into one of the most complex challenges of Earth’s climate: understanding and predicting future atmospheric levels of greenhouse gases and the role of the ocean and land in determining those levels.


A paper published in the Proceedings of the National Academy of Sciences was led by Piers J. Sellers, former director of the Earth Sciences Division at NASA’s Goddard Space Flight Center, who died in December 2016. Sellers was an Earth scientist at NASA Goddard and later an astronaut who flew on three space shuttle missions.


The paper includes a significant overarching message: The current international fleet of satellites is making real improvements in accurately measuring greenhouse gases from space, but in the future a more sophisticated system of observations will be necessary to understand and predict Earth’s changing climate at the level of accuracy needed by society.


Sellers wrote the paper along with colleagues at NASA’s Jet Propulsion Laboratory and the University of Oklahoma. Work on the paper began in 2015, and Sellers continued working with his collaborators up until about six weeks before he died. They carried on the research and writing of the paper until its publication this week.


The paper focuses on the topic that was at the center of Sellers’ research career: Earth’s biosphere and its interactions with the planet’s climate. In the 1980s he helped pioneer computer modeling of Earth’s vegetation. In the new paper, Sellers and co-authors investigated “carbon cycle–climate feedbacks” – the potential response of natural systems to climate change caused by human emissions – and laid out a vision for how to best measure this response on a global scale from space.



Animation above: From space, satellites can see Earth breathe. A new NASA visualization shows 20 years of continuous observations of plant life on land and at the ocean’s surface, from September 1997 to September. 2017. On land, vegetation appears on a scale from brown (low vegetation) to dark green (lots of vegetation); at the ocean surface, phytoplankton are indicated on a scale from purple (low) to yellow (high). This visualization was created with data from satellites including SeaWiFS, and instruments including the NASA/NOAA Visible Infrared Imaging Radiometer Suite and the Moderate Resolution Imaging Spectroradiometer. Image Credit: NASA.


The exchange of carbon between the land, ocean and air plays a huge role in determining the amount of greenhouse gases in the atmosphere, which will largely determine Earth’s future climate. But, there are complex interactions at play. While human-caused emissions of greenhouses gases are building up in the atmosphere, land ecosystems and the ocean still offset about 50 percent of all those emissions. As the climate warms scientists are unsure whether forests and the ocean will continue to absorb roughly half of the emissions – acting as a carbon sink – or if this offset becomes lower, or if the sinks become carbon sources.


Paper co-author David Schimel, a scientist at JPL and a longtime scientific collaborator of Sellers’, said the paper captured how he, Sellers and the other co-authors saw this scientific problem as one of the critical research targets for NASA Earth science.


“We all saw understanding the future of carbon cycle feedbacks as one of the grand challenges of climate change science,” Schimel said.


Scientists’ understanding of how Earth’s living systems interact with rising atmospheric levels of greenhouse gases has changed tremendously in recent decades, said co-author Berrien Moore III, of the University of Oklahoma. Moore has been a scientific collaborator with Sellers and Schimel since the 1980s. He said that back then, scientists thought the ocean absorbed about half of annual carbon emissions, while plants on land played a minimal role. Scientists now understand the ocean and land together absorb about half of all emissions, with the terrestrial system’s role being affected greatly by large-scale weather patterns such as El Niño and La Niña. Moore is also the principal investigator of a NASA mission called GeoCarb, scheduled to launch in 2022, that will monitor greenhouse gases over much of the Western Hemisphere from a geostationary orbit.


NASA launched the Orbiting Carbon Observatory-2 (OCO-2) in 2014, and with the advancement of measurement and computer modeling techniques, scientists are gaining a better understanding of how carbon moves through the land, ocean and atmosphere. This new paper builds on previous research and focuses on a curious chain of events in 2015. While human emissions of carbon dioxide leveled off for the first time in decades during that year, the growth rate in atmospheric concentrations of carbon dioxide actually spiked at the same time.


This was further evidence of what scientists had been piecing together for years – that a complex combination of factors, including weather, drought, fires and more, contributes to greenhouse gas levels in the atmosphere.



Piers Sellers Reflects on NASA Goddard

Video above: In a 2016 interview, Piers Sellers talked about his enthusiasm and appreciation for working at NASA’s Goddard Space Flight Center. Video Credits: NASA Goddard.


However, with the new combination of OCO-2 observations and space-based measurements of plant fluorescence (essentially a measure of photosynthesis), researchers have begun producing more accurate estimates of where carbon was absorbed and released around the planet during 2015, when an intense El Niño was in effect, compared to other years.


The paper follows a report from a 2015 workshop on the carbon cycle led by Sellers, Schimel, and Moore. Schimel and Moore both pointed out that every one of the more than 40 participants in the workshop contributed to a final scientific report from the meeting – a rare occurrence. They attributed this, in part, to the inspirational role Sellers played in spurring thought and action.


“When you have someone like Piers in the room, there’s a magnetic effect,” Moore said. “Piers had his shoulder to the wheel, so everyone had to have their shoulders to the wheel.”


Schimel and Moore said the workshop paper lays out a vision for what’s needed in a future space-based observing system to measure, understand, and predict carbon cycle feedbacks: active and passive instruments, and satellites both in low-Earth and geostationary orbits around the world. In the coming years, NASA and space agencies in Europe, Japan, and China, will all launch new greenhouse-gas monitoring missions.


“Piers thought it’s absolutely essential to get it right,” said Schimel, “and essential to more or less get it right the first time.”


The authors dedicated the paper’s publication to Sellers, and in their dedication referenced a Winston Churchill quote often cited by the British-born scientist. They wrote: “P.J.S. approached the challenge of carbon science in the spirt of a favorite Churchill quote, ‘Difficulties mastered are opportunities won,’ and he aimed to resolve the carbon–climate problem by rising to the difficulties and seizing the opportunities.”


For more: http://www.pnas.org/content/early/2018/07/05/1716613115


Climate: https://www.nasa.gov/subject/3127/climate


Animation, Video. Text, Credits: NASA/Sara Blumberg/Goddard Space Flight Center, by Patrick Lynch.


Greetings, Orbiter.chArchive link


https://xissufotoday.space/2018/07/a-scientists-final-paper-looks-toward-earths-future-climate/

Ballymeanoch Standing Stones, Kilmartin Glen, Argyll, Scotland,…






Ballymeanoch Standing Stones, Kilmartin Glen, Argyll, Scotland, 14.7.18.


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