Assembled using raw uncalibrated red, green, and violet filtered images of Saturn taken by the Cassini spacecraft on August 12, 2017.
Credit: NASA/JPL-Caltech/Space Science Institute/Kevin M. Gill
Image Date: August 12, 2017
Release Date: August 14, 2017#NASA #Astronomy #Science #Space #Saturn #Planet #Rings #Moon #Gravity #DensityWaves #SolarSystem #Exploration #Cassini #Spacecraft #JPL #Pasadena #California #UnitedStates #ESA #ASI #STEM #Education
A substantial coronal hole rotated into a position where it is facing Earth (Aug. 9-11, 2017). Coronal holes are areas of open magnetic field that spew out charged particles as solar wind that spreads into space. If that solar wind interacts with our own magnetosphere it can generate aurora. In this view of the sun in extreme ultraviolet light, the coronal hole appears as the dark stretch near the center of the sun. It was the most distinctive feature on the sun over the past week.
Credit: Solar Dynamics Observatory, NASA
Capture Date: August 9, 2017
Release Date: August 14, 2017#NASA #Astronomy #Science #Space #SpaceWeather #Sun #Solar #Corona #CoronalHole #Plasma #MagneticField #Earth #Magnetosphere #Aurora #Astrophysics #Spacecraft #SDO #Goddard #GSFC #Greenbelt #Maryland #UnitedStates #STEM #Education
Greenland is best known for its ice, but some remote sensing scientists found themselves closely tracking a sizable wildfire burning along the island’s coast in August 2017. The fire burned in western Greenland, about 150 kilometers (90 miles) northeast of Sisimiut.
Satellites first detected evidence of the fire on July 31, 2017. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP collected daily images of smoke streaming from the fire over the next week. The Operational Land Imager (OLI) on Landsat 8 captured this more detailed image of the fire on August 3, 2017.
While it is not unprecedented for satellites to observe fire activity in Greenland, a preliminary analysis by Stef Lhermitte of Delft University of Technology in the Netherlands suggests that MODIS has detected far more fire activity in Greenland in 2017 than it did during any other year since the sensor began collecting data in 2000.
Fires detected in Greenland by MODIS are usually small, most likely campfires lit by hunters or backpackers. But Landsat did capture imagery of another sizable fire in August 2015. According to Ruth Mottram of the Danish Meteorological Institute (DNI), neither DNI nor other scientific groups maintain detailed records of fire activity in Greenland, but many meteorologists at the institute have heard anecdotal reports of fires.
The blaze appears to be burning through peat, noted Miami University scientist Jessica McCarty. That would mean the fire likely produced a sharp increase in wildfire-caused carbon dioxide emissions in Greenland for 2017, noted atmospheric scientist Mark Parrington of the European Commission’s
Copernicus program.
It is not clear what triggered this fire, though a lack of documented lightning prior to its ignition suggests the fire was probably triggered by human activity. The area is regularly used by reindeer hunters, and is not too far from a town with a population of 5,500 people.
The summer has been quite dry. Sisimiut saw almost no rain in June and half of the usual amount in July. That may have parched dwarf willows, shrubs, grasses, mosses, and other vegetation that commonly live in Greenland’s coastal areas and made them more likely to burn.
Fires emit a soot-like material called black carbon. It is likely that winds will transport some of this material east to the ice sheet where it will contribute to a line of darkened snow and ice along the western edge of Greenland’s ice sheet. This area is of interest to climate scientists because darkened snow and ice tends to melt more rapidly than when it is clean.
Image Credit: NASA Earth Observatory image by Jesse Allen, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland, with information from Ruth Mottram (Danish Meteorological Institute), Jessica McCarty (Miami University), Mark Parrington (COPERNICUS), and Stef Lhermitte (Delft University of Technology).
Instrument(s): Landsat 8 - OLI
Image Date: August 3, 2017
Release Date: August 7, 2017#NASA #Earth #Science #Satellite #Greenland #Grønland #Wildfire #Smoke #Sisimiut #Island #Landsat #Landsat8 #OLI #USGS #EarthObservation #ClimateChange #Climate #Environment #Denmark #Danmark #STEM #Education
Aug. 9, 2017: Given adequate sunlight and nutrients, phytoplankton populations can swell into blooms large enough to be visible from space. On August 3, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image of several blooms in the Caspian Sea.
Phytoplankton blooms are often harmless, and are an important food source for marine life. Other times, blooms can be harmful; they can deplete the water’s oxygen and suffocate marine life, and produce toxins that can be harmful to both aquatic creatures and humans.
Lake Urmia is visible west of the Caspian Sea. Microscopic organisms periodically turn the lake’s salty water striking shades of red and orange.
The Caspian Sea is the largest enclosed inland body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. It is in an endorheic basin (a basin without outflows) located between Europe and Asia. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the west, Iran to the south, and Turkmenistan to the southeast.
(Source: Wikipedia)
Image Credit: NASA images by Norman Kuring, NASA’s Ocean Color web Caption Credit: Adam Voiland
Instrument(s): Aqua - MODIS
Image Date: August 3, 2017
Release Date: August 9, 2017#NASA #Earth #Science #Satellite #CaspianSea #Phytoplankton #Bloom #LakeUrmia #Asia #Europe #EarthObservation #Aqua #MODIS #Goddard #GSFC #UnitedStates #STEM #Education
The aurora and the night sky above Earth’s atmosphere are pictured from the International Space Station. A portion of the station’s solar arrays and a pair of nitrogen/oxygen recharge system tanks are pictured in the foreground.
Credit: NASA/JSC
Image Date: June 19, 2017
#NASA #ISS #Earth #Science #Aurora #Planet #Atmosphere #EarthObservation #Photography #Astronaut #Human #Spaceflight #Expedition52 #UnitedStates #JSC #OverviewEffect #OrbitalPerspective #STEM
#Education
Aug. 10, 2017: In 1887, American astronomer Lewis Swift discovered a glowing cloud, or nebula, that turned out to be a small galaxy about 2.2 billion light years from Earth. Today, it is known as the “starburst” galaxy IC 10, referring to the intense star formation activity occurring there.
More than a hundred years after Swift’s discovery, astronomers are studying IC 10 with the most powerful telescopes of the 21st century. New observations with NASA’s Chandra X-ray Observatory reveal many pairs of stars that may one day become sources of perhaps the most exciting cosmic phenomenon observed in recent years: gravitational waves.
By analyzing Chandra observations of IC 10 spanning a decade, astronomers found over a dozen black holes and neutron stars feeding off gas from young, massive stellar companions. Such double star systems are known as “X-ray binaries” because they emit large amounts of X-ray light. As a massive star orbits around its compact companion, either a black hole or neutron star, material can be pulled away from the giant star to form a disk of material around the compact object. Frictional forces heat the infalling material to millions of degrees, producing a bright X-ray source.
When the massive companion star runs out fuel, it will undergo a catastrophic collapse that will produce a supernova explosion, and leave behind a black hole or neutron star. The end result is two compact objects: either a pair of black holes, a pair of neutron stars, or a black hole and neutron star. If the separation between the compact objects becomes small enough as time passes, they will produce gravitational waves. Over time, the size of their orbit will shrink until they merge. LIGO has found three examples of black hole pairs merging in this way in the past two years.
Starburst galaxies like IC 10 are excellent places to search for X-ray binaries because they are churning out stars rapidly. Many of these newly born stars will be pairs of young and massive stars. The most massive of the pair will evolve more quickly and leave behind a black hole or a neutron star partnered with the remaining massive star. If the separation of the stars is small enough, an X-ray binary system will be produced.
This new composite image of IC 10 combines X-ray data from Chandra (blue) with an optical image (red, green, blue) taken by amateur astronomer Bill Snyder from the Heavens Mirror Observatory in Sierra Nevada, California. The X-ray sources detected by Chandra appear as a darker blue than the stars detected in optical light.
The young stars in IC 10 appear to be just the right age to give a maximum amount of interaction between the massive stars and their compact companions, producing the most X-ray sources. If the systems were younger, then the massive stars would not have had time to go supernova and produce a neutron star or black hole, or the orbit of the massive star and the compact object would not have had time to shrink enough for mass transfer to begin. If the star system were much older, then both compact objects would probably have already formed. In this case transfer of matter between the compact objects is unlikely, preventing the formation of an X-ray emitting disk.
Chandra detected 110 X-ray sources in IC 10. Of these, over forty are also seen in optical light and 16 of these contain “blue supergiants”, which are the type of young, massive, hot stars described earlier. Most of the other sources are X-ray binaries containing less massive stars. Several of the objects show strong variability in their X-ray output, indicative of violent interactions between the compact stars and their companions.
A pair of papers describing these results were published in the February 10th, 2017 issue of The Astrophysical Journal. The papers are available online here:
https://arxiv.org/abs/1611.08611
https://arxiv.org/abs/1701.03803
The authors of the study are Silas Laycock from the UMass Lowell’s Center for Space Science and Technology (UML); Rigel Capallo, a graduate student at UML; Dimitris Christodoulou from UML; Benjamin Williams from the University of Washington in Seattle; Breanna Binder from the California State Polytechnic University in Pomona; and, Andrea Prestwich from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
Credit: X-ray: NASA/CXC/UMass Lowell/S. Laycock et al.; Optical: Bill Snyder
Release Date: August 10, 2017
#NASA #Astronomy #Science #Space #Galaxy #IC10 #Starburst #Cassiopeia #Cosmos #Universe #Gravitational #Waves #Chandra #Xray #Observatory #MSFC #Marshall #STEM #Education
Aug. 3, 2017: A dynamic storm at the southern edge of Jupiter’s northern polar region dominates this Jovian cloudscape, courtesy of NASA’s Juno spacecraft.
This storm is a long-lived anticyclonic oval named North North Temperate Little Red Spot 1 (NN-LRS-1); it has been tracked at least since 1993, and may be older still. An anticyclone is a weather phenomenon where winds around the storm flow in the direction opposite to that of the flow around a region of low pressure. It is the third largest anticyclonic oval on the planet, typically around 3,700 miles (6,000 kilometers) long. The color varies between red and off-white (as it is now), but this JunoCam image shows that it still has a pale reddish core within the radius of maximum wind speeds.
Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager. The image has been rotated so that the top of the image is actually the equatorial regions while the bottom of the image is of the northern polar regions of the planet.
The image was taken on July 10, 2017 at 6:42 p.m. PDT (9:42 p.m. EDT), as the Juno spacecraft performed its seventh close flyby of Jupiter. At the time the image was taken, the spacecraft was about 7,111 miles (11,444 kilometers) from the tops of the clouds of the planet at a latitude of 44.5 degrees.
JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena.
More information about Juno is online at http://www.nasa.gov/juno and http://missionjuno.swri.edu.
JunoCam's raw images are available for the public to peruse and process into image products at: www.missionjuno.swri.edu/junocam
Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran
Release Date: August 3, 2017#NASA #Astronomy #Space #Science #Jupiter #Planet #Atmosphere #LittleRedSpot #LRS #NNLRS1 #Juno #Spacecraft #SwRI #JPL #Pasadena #California #UnitedStates #STEM #Education
#CitizenScience
Closeup of sunspot showing coils arcing over active region
Aug. 4, 2017: On July 5, 2017, NASA’s Solar Dynamics Observatory watched an active region—an area of intense and complex magnetic fields—rotate into view on the Sun. The satellite continued to track the region as it grew and eventually rotated across the Sun and out of view on July 17.
With their complex magnetic fields, sunspots are often the source of interesting solar activity. During its 13-day trip across the face of the Sun, the active region—dubbed AR12665—put on a show for NASA’s Sun-watching satellites, producing several solar flares, a coronal mass ejection and a solar energetic particle event. Watch the video below to learn how NASA’s satellites tracked the sunspot over the course of these two weeks.
This image shows a blended view of the sunspot in visible and extreme ultraviolet light, revealing bright coils arcing over the active region—particles spiraling along magnetic field lines.
Credit: NASA’s Goddard Space Flight Center/SDO
Image Date: July 5, 2017
Release Date: August 4, 2017 #NASA #Astronomy #Science #Space #SpaceWeather #Sun #Solar #Sunspot #ActiveRegion #AR12665 #Plasma #MagneticField #Astrophysics #Spacecraft #SDO #Goddard #GSFC #Greenbelt #Maryland #UnitedStates #STEM #Education
Image: Super typhoon photographed from low Earth orbit with Soyuz spacecraft in left of frame | Aug. 2, 2017: NASA astronaut Randy Bresnik photographed Super Typhoon Noru in the Northwestern Pacific Ocean on August 1, 2017, as the International Space Station passed overhead. He shared images of the massive storm on social media, writing, "Super Typhoon #Noru, amazing the size of this weather phenomenon, you can almost sense its power from 250 miles above."
As of 11 a.m. EDT on August 1, the storm was centered near 24.7 degrees north latitude and 137.0 degrees east longitude, with maximum sustained winds near 90 knots. By August 2 at 5 a.m. EDT, the maximum sustained winds were near 100 knots. NASA satellites are keeping track of the typhoon as it continues its slow trek through the Pacific toward southwestern Japan.
Credit: NASA
Release Date: August 2, 2017#NASA #ISS #Earth #Science #Weather #Typhoon #SuperTyphoon #Storm #PacificOcean #Japan #日本 #Soyuz #SoyuzMS05 #Astronaut #RandyBresnik #Russia #Россия #Human #Spaceflight #Expedition52 #UnitedStates #JSC #STEM
#Education
Image: The planetary nebula IC 4406 seen with MUSE and the AOF
Spectacular improvement in the sharpness of MUSE images
August 2, 2017: The Unit Telescope 4 (Yepun) of ESO’s Very Large Telescope (VLT) has now been transformed into a fully adaptive telescope. After more than a decade of planning, construction and testing, the new Adaptive Optics Facility (AOF) has seen first light with the instrument MUSE, capturing amazingly sharp views of planetary nebulae and galaxies. The coupling of the AOF and MUSE forms one of the most advanced and powerful technological systems ever built for ground-based astronomy.
The Adaptive Optics Facility (AOF) is a long-term project on ESO’s Very Large Telescope (VLT) to provide an adaptive optics system for the instruments on Unit Telescope 4 (UT4), the first of which is MUSE (the Multi Unit Spectroscopic Explorer) [1]. Adaptive optics works to compensate for the blurring effect of the Earth’s atmosphere, enabling MUSE to obtain much sharper images and resulting in twice the contrast previously achievable. MUSE can now study even fainter objects in the Universe.
“Now, even when the weather conditions are not perfect, astronomers can still get superb image quality thanks to the AOF,” explains Harald Kuntschner, AOF Project Scientist at ESO.
Following a battery of tests on the new system, the team of astronomers and engineers were rewarded with a series of spectacular images. Astronomers were able to observe the planetary nebulae IC 4406, located in the constellation Lupus (The Wolf), and NGC 6369, located in the constellation Ophiuchus (The Serpent Bearer). The MUSE observations using the AOF showed dramatic improvements in the sharpness of the images, revealing never before seen shell structures in IC 4406 [2].
The AOF, which made these observations possible, is composed of many parts working together. They include the Four Laser Guide Star Facility (4LGSF) and the very thin deformable secondary mirror of UT4 [3] [4]. The 4LGSF shines four 22-watt laser beams into the sky to make sodium atoms in the upper atmosphere glow, producing spots of light on the sky that mimic stars. Sensors in the adaptive optics module GALACSI (Ground Atmospheric Layer Adaptive Corrector for Spectroscopic Imaging) use these artificial guide stars to determine the atmospheric conditions.
One thousand times per second, the AOF system calculates the correction that must be applied to change the shape of the telescope’s deformable secondary mirror to compensate for atmospheric disturbances. In particular, GALACSI corrects for the turbulence in the layer of atmosphere up to one kilometer above the telescope. Depending on the conditions, atmospheric turbulence can vary with altitude, but studies have shown that the majority of atmospheric disturbance occurs in this “ground layer” of the atmosphere.
“The AOF system is essentially equivalent to raising the VLT about 900 meters higher in the air, above the most turbulent layer of atmosphere,” explains Robin Arsenault, AOF Project Manager. “In the past, if we wanted sharper images, we would have had to find a better site or use a space telescope—but now with the AOF, we can create much better conditions right where we are, for a fraction of the cost!”
The corrections applied by the AOF rapidly and continuously improve the image quality by concentrating the light to form sharper images, allowing MUSE to resolve finer details and detect fainter stars than previously possible. GALACSI currently provides a correction over a wide field of view, but this is only the first step in bringing adaptive optics to MUSE. A second mode of GALACSI is in preparation and is expected to see first light early 2018. This narrow-field mode will correct for turbulence at any altitude, allowing observations of smaller fields of view to be made with even higher resolution.
“Sixteen years ago, when we proposed building the revolutionary MUSE instrument, our vision was to couple it with another very advanced system, the AOF,” says Roland Bacon, project lead for MUSE. “The discovery potential of MUSE, already large, is now enhanced still further. Our dream is becoming true.”
One of the main science goals of the system is to observe faint objects in the distant Universe with the best possible image quality, which will require exposures of many hours. Joël Vernet, ESO MUSE and GALACSI Project Scientist, comments: “In particular, we are interested in observing the smallest, faintest galaxies at the largest distances. These are galaxies in the making—still in their infancy—and are key to understanding how galaxies form.”
Furthermore, MUSE is not the only instrument that will benefit from the AOF. In the near future, another adaptive optics system called GRAAL will come online with the existing infrared instrument HAWK-I, sharpening its view of the Universe. That will be followed later by the powerful new instrument ERIS.
“ESO is driving the development of these adaptive optics systems, and the AOF is also a pathfinder for ESO’s Extremely Large Telescope,” adds Arsenault. “Working on the AOF has equipped us—scientists, engineers and industry alike—with invaluable experience and expertise that we will now use to overcome the challenges of building the ELT.”
Notes
[1] MUSE is an integral-field spectrograph, a powerful instrument that produces a 3D data set of a target object, where each pixel of the image corresponds to a spectrum of the light from the object. This essentially means that the instrument creates thousands of images of the object at the same time, each at a different wavelength of light, capturing a wealth of information.
[2] IC 4406 has previously been observed with the VLT (eso9827a).
[3] At just over one meter in diameter, this is the largest adaptive optics mirror ever produced and demanded cutting-edge technology. It was mounted on UT4 in 2016 (ann16078) to replace the telescope’s original conventional secondary mirror.
[4] Other tools to optimize the operation of the AOF have been developed and are now operational. These include an extension of the Astronomical Site Monitor software that monitors the atmosphere to determine the altitude at which the turbulence is occurring, and the Laser Traffic Control System (LTCS) that prevents other telescopes looking into the laser beams or at the artificial stars themselves and potentially affecting their observations.
Credit: European Southern Observatory (ESO)
Release Date: August 2, 2017#ESO #Astronomy #Science #Space #Cosmos #Universe #Stars #Nebulae #IC4406 #VLT #Telescope #AdaptiveOptics #AOF #MUSE #Chile #Atacama#SouthAmerica #Europe #STEM #Education
Roughly 20,000 years ago, during the peak of the last Ice Age, the area that is now Hudson Bay sat beneath a layer of ice thousands of feet thick. As the climate warmed, the Laurentide Ice Sheet thinned and glacial lakes in Canada’s interior merged with the Arctic Ocean to form the large inland bay. It is now a haven for polar bears, whales, orcas, walruses, seals, and other wildlife.
Shallow and surrounded by land, Hudson Bay freezes over completely in the winter but thaws for periods in the summer. Usually all of the sea ice is gone by August, and the bay begins to freeze over in October or November. In between, as the sea ice is breaking up, winds and currents cause flotillas of pack ice to cluster in certain parts of the bay.
That is what was happening on June 29, 2017, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image. (It is a mosaic, composed from multiple satellite passes over the region.) Note how much of the sea ice is drifting along the western coastline.
One of the most noticeable features in the image is the Belcher Islands, a curved set of islands in the southeastern part of the bay that is rich with hunting and fishing grounds for the Inuit communities who live on them. We can also see the D-shaped Akimiski Island, which is to the south in James Bay. The island has no permanent human residents, but it is the site of a sanctuary for hundreds of thousands of migratory birds each year.
The rhythms of sea ice play a central role in the lives of the animals of Hudson Bay, particularly polar bears. When the bay is topped with ice, polar bears head out to hunt for seals and other prey. When the ice melts in the summer, the bears swim to shore, where they fast until sea ice returns.
University of Alberta scientist Andrew Derocher is part of a group that monitors Hudson Bay polar bear populations with information gleaned from tagged bears and GPS satellites. Via email, he offered an update on sea ice conditions and polar bear populations in late June, around the time that this image was acquired.
“The sea ice melt was well advanced by June 29, but polar bears were still hunting along the remanent ice lingering along the western part of the bay. Bears farther south and in James Bay were already moving to land,” he said. “The break-up this spring was a bit unusual, and the bears in western Hudson Bay responded by remaining offshore longer than normal. We typically expect the bears to come ashore about three weeks after the Bay reaches 50 percent ice cover, but the bears we were tracking found patches of ice that worked for them.”
Ice conditions are closely watched by researchers who study polar bears. Most experts think that the retreat in Arctic sea ice cover in recent decades puts these bear populations at risk. While populations have been stable in the northern part of the Hudson Bay, bears in the western part have seen populations decline by 30 percent over the past decade. “Sea ice loss is simply habitat loss for polar bears,” said Derocher. “Once the ice-free period is too long, then an area can no longer support a viable population of polar bears.”
Image Credit: NASA image by Norman Kuring, NASA’s Ocean Color web.
Story Credit: Adam Voiland
Instrument(s): Aqua - MODIS
Image Date: June 29, 2017
Release Date: July 28, 2017#Earth #Science #Space #Satellite #HudsonBay #JamesBay #Canada #Ice #Belcher #Islands #Akimiski #Aqua #MODIS #GSFC #Goddard #UnitedStates #STEM #Education
