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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
New findings using data from NASA’s IXPE (Imaging X-ray Polarimetry Explorer) mission offer unprecedented insight into the shape and nature of a structure important to black holes called a corona.
A corona is a shifting plasma region that is part of the flow of matter onto a black hole, about which scientists have only a theoretical understanding. The new results reveal the corona’s shape for the first time, and may aid scientists’ understanding of the corona’s role in feeding and sustaining black holes.
This illustration of material swirling around a black hole highlights a particular feature, called the “corona,” that shines brightly in X-ray light. In this depiction, the corona can be seen as a purple haze floating above the underlying accretion disk, and extending slightly inside of its inner edge. The material within the inner accretion disk is incredibly hot and would glow with a blinding blue-white light, but here has been reduced in brightness to make the corona stand out with better contrast. Its purple color is purely illustrative, standing in for the X-ray glow that would not be obvious in visible light. The warp in the disk is a realistic representation of how the black hole’s immense gravity acts like an optical lens, distorting our view of the flat disk that encircles it. NASA/Caltech-IPAC/Robert Hurt Many black holes, so named because not even light can escape their titanic gravity, are surrounded by accretion disks, debris-cluttered whirlpools of gas. Some black holes also have relativistic jets – ultra-powerful outbursts of matter hurled into space at high speed by black holes that are actively eating material in their surroundings.
Less well known, perhaps, is that snacking black holes, much like Earth’s Sun and other stars, also possess a superheated corona. While the Sun’s corona, which is the star’s outermost atmosphere, burns at roughly 1.8 million degrees Fahrenheit, the temperature of a black hole corona is estimated at billions of degrees.
Astrophysicists previously identified coronae among stellar-mass black holes – those formed by a star’s collapse – and supermassive black holes such as the one at the heart of the Milky Way galaxy.
“Scientists have long speculated on the makeup and geometry of the corona,” said Lynne Saade, a postdoctoral researcher at NASA’s Marshall Space Flight Center in Huntsville, Alabama, and lead author of the new findings. “Is it a sphere above and below the black hole, or an atmosphere generated by the accretion disk, or perhaps plasma located at the base of the jets?”
Enter IXPE, which specializes in X-ray polarization, the characteristic of light that helps map the shape and structure of even the most powerful energy sources, illuminating their inner workings even when the objects are too small, bright, or distant to see directly. Just as we can safely observe the Sun’s corona during a total solar eclipse, IXPE provides the means to clearly study the black hole’s accretion geometry, or the shape and structure of its accretion disk and related structures, including the corona.
“X-ray polarization provides a new way to examine black hole accretion geometry,” Saade said. “If the accretion geometry of black holes is similar regardless of mass, we expect the same to be true of their polarization properties.”
IXPE demonstrated that, among all black holes for which coronal properties could be directly measured via polarization, the corona was found to be extended in the same direction as the accretion disk – providing, for the first time, clues to the corona’s shape and clear evidence of its relationship to the accretion disk. The results rule out the possibility that the corona is shaped like a lamppost hovering over the disk.
The research team studied data from IXPE’s observations of 12 black holes, among them Cygnus X-1 and Cygnus X-3, stellar-mass binary black hole systems about 7,000 and 37,000 light-years from Earth, respectively, and LMC X-1 and LMC X-3, stellar-mass black holes in the Large Magellanic Cloud more than 165,000 light-years away. IXPE also observed a number of supermassive black holes, including the one at the center of the Circinus galaxy, 13 million light-years from Earth, and those in galaxies NGC 1068 and NGC 4151, 47 million light-years away and nearly 62 million light-years away, respectively.
Stellar mass black holes typically have a mass roughly 10 to 30 times that of Earth’s Sun, whereas supermassive black holes may have a mass that is millions to tens of billions of times larger. Despite these vast differences in scale, IXPE data suggests both types of black holes create accretion disks of similar geometry.
That’s surprising, said Marshall astrophysicist Philip Kaaret, principal investigator for the IXPE mission, because the way the two types are fed is completely different.
“Stellar-mass black holes rip mass from their companion stars, whereas supermassive black holes devour everything around them,” he said. “Yet the accretion mechanism functions much the same way.”
That’s an exciting prospect, Saade said, because it suggests that studies of stellar-mass black holes – typically much closer to Earth than their much more massive cousins – can help shed new light on properties of supermassive black holes as well.
The team next hopes to make additional examinations of both types.
Saade anticipates there’s much more to glean from X-ray studies of these behemoths. “IXPE has provided the first opportunity in a long time for X-ray astronomy to reveal the underlying processes of accretion and unlock new findings about black holes,” she said.
The complete findings are available in the latest issue of The Astrophysical Journal.
More about IXPE
IXPE, which continues to provide unprecedented data enabling groundbreaking discoveries about celestial objects across the universe, is a joint NASA and Italian Space Agency mission with partners and science collaborators in 12 countries. IXPE is led by Marshall. Ball Aerospace, headquartered in Broomfield, Colorado, manages spacecraft operations together with the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder.
Learn more about IXPE’s ongoing mission here:
https://www.nasa.gov/ixpe
Elizabeth Landau
NASA Headquarters
elizabeth.r.landau@nasa.gov
202-358-0845
Lane Figueroa
NASA’s Marshall Space Flight Center
256-544-0034
lane.e.figueroa@nasa.gov
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Last Updated Oct 17, 2024 EditorBeth RidgewayLocationMarshall Space Flight Center Related Terms
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By NASA
Due to launch in the early 2030s, NASA’s DAVINCI mission will investigate whether Venus — a sweltering world wrapped in an atmosphere of noxious gases — once had oceans and continents like Earth.
Consisting of a flyby spacecraft and descent probe, DAVINCI will focus on a mountainous region called Alpha Regio, a possible ancient continent. Though a handful of international spacecraft plunged through Venus’ atmosphere between 1970 and 1985, DAVINCI’s probe will be the first to capture images of this intriguing terrain ever taken from below Venus’ thick and opaque clouds.
But how does a team prepare for a mission to a planet that hasn’t seen an atmospheric probe in nearly 50 years, and that tends to crush or melt its spacecraft visitors?
Scientists leading the DAVINCI mission started by using modern data-analysis techniques to pore over decades-old data from previous Venus missions. Their goal is to arrive at our neighboring planet with as much detail as possible. This will allow scientists to most effectively use the probe’s descent time to collect new information that can help answer longstanding questions about Venus’ evolutionary path and why it diverged drastically from Earth’s.
On the left, a new and more detailed view of Venus’ Alpha Regio region developed by scientists on NASA’s DAVINCI mission to Venus, due to launch in the early 2030s. On the right is a less detailed map created using radar altimeter data collected by NASA’s Magellan spacecraft in the early 1990s. The colors on the maps depict topography, with dark blues identifying low elevations and browns identifying high elevations. To make the map on the left, the DAVINCI science team re-analyzed Magellan data and supplemented it with radar data collected on three occasions from the Arecibo Observatory in Puerto Rico, and used machine vision computer models to scrutinize the data and fill in gaps in information. The red ellipses on each image mark the area DAVINCI’s probe will descend over as it collects data on its way toward the surface. Jim Garvin/NASA’s Goddard Space Flight Center Between 1990 and 1994, NASA’s Magellan spacecraft used radar imaging and altimetry to map the topography of Alpha Regio from Venus’ orbit. Recently, NASA’s DAVINICI’s team sought more detail from these maps, so scientists applied new techniques to analyze Magellan’s radar altimeter data. They then supplemented this data with radar images taken on three occasions from the former Arecibo Observatory in Puerto Rico and used machine vision computer models to scrutinize the data and fill in gaps in information at new scales (less than 0.6 miles, or 1 kilometer).
As a result, scientists improved the resolution of Alpha Regio maps tenfold, predicting new geologic patterns on the surface and prompting questions about how these patterns could have formed in Alpha Regio’s mountains.
Benefits of Looking Backward
Old data offers many benefits to new missions, including information about what frequencies, parts of spectrum, or particle sizes earlier instruments covered so that new instruments can fill in the gaps.
At NASA Space Science Data Coordinated Archive, which is managed out of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, staff restore and digitize data from old spacecraft. That vintage data, when compared with modern observations, can show how a planet changes over time, and can even lead to new discoveries long after missions end. Thanks to new looks at Magellan observations, for instance, scientists recently found evidence of modern-day volcanic activity on Venus.
The three images in this carousel were taken in March 2024 at NASA Space Science Data Coordinated Archive at NASA’s Goddard Space Flight Center in Greenbelt, Md. The first shows stacked boxes of microfilm with data from Apollo missions. The middle image shows miniaturized records from NASA’s 1964 Mariner 4 flyby mission to Mars. And the final image shows a view of Jupiter from NASA’s Pioneer 10 flyby mission to the outer planets, which launched on March 2, 1972. The three images in this carousel were taken in March 2024 at NASA Space Science Data Coordinated Archive at NASA’s Goddard Space Flight Center in Greenbelt, Md. The first shows stacked boxes of microfilm with data from Apollo missions. The middle image shows miniaturized records from NASA’s 1964 Mariner 4 flyby mission to Mars. And the final image shows a view of Jupiter from NASA’s Pioneer 10 flyby mission to the outer planets, which launched on March 2, 1972. The three images in this carousel were taken in March 2024 at NASA Space Science Data Coordinated Archive at NASA’s Goddard Space Flight Center in Greenbelt, Md. The first shows stacked boxes of microfilm with data from Apollo missions. The middle image shows miniaturized records from NASA’s 1964 Mariner 4 flyby mission to Mars. And the final image shows a view of Jupiter from NASA’s Pioneer 10 flyby mission to the outer planets, which launched on March 2, 1972.
Magellan was among the first missions to be digitally archived in NASA’s publicly accessible online repository of planetary mission data. But the agency has reams of data — much of it not yet digitized — dating back to 1958, when the U.S. launched its first satellite, Explorer 1.
Data restoration is a complex and resource-intensive job, and NASA prioritizes digitizing data that scientists need. With three forthcoming missions to Venus — NASA’s DAVINCI and VERITAS, plus ESA’s (European Space Agency) Envision — space data archive staff are helping scientists access data from Pioneer Venus, NASA’s last mission to drop probes into Venus’ atmosphere in 1978.
Mosaic of Venus
Alpha Regio is one of the most mysterious spots on Venus. Its terrain, known as “tessera,” is similar in appearance to rugged Earth mountains, but more irregular and disorderly.
So called because they resemble a geometric parquet floor pattern, tesserae have been found only on Venus, and DAVINCI will be the first mission to explore such terrain in detail and to map its topography.
DAVINCI’s probe will begin photographing Alpha Regio — collecting the highest-resolution images yet — once it descends below the planet’s clouds, starting at about 25 miles, or 40 kilometers, altitude. But even there, gases in the atmosphere scatter light, as does the surface, such that these images will appear blurred.
Could Venus once have been a habitable world with liquid water oceans — like Earth? This is one of the many mysteries associated with our shrouded sister world. Credit: NASA’s Goddard Space Flight Center DAVINCI scientists are working on a solution. Recently, scientists re-analyzed old Venus imaging data using a new artificial-intelligence technique that can sharpen the images and use them to compute three-dimensional topographic maps. This technique ultimately will help the team optimize DAVINCI’s images and maps of Alpha Regio’s mountains. The upgraded images will give scientists the most detailed view ever — down to a resolution of 3 feet, or nearly 1 meter, per pixel — possibly allowing them to detect small features such as rocks, rivers, and gullies for the first time in history.
“All this old mission data is part of a mosaic that tells the story of Venus,” said Jim Garvin, DAVINCI principal investigator and chief scientist at NASA Goddard. “A story that is a masterpiece in the making but incomplete.”
By analyzing the surface texture and rock types at Alpha Regio, scientists hope to determine if Venusian tesserae formed through the same processes that create mountains and certain volcanoes on Earth.
By Lonnie Shekhtman
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Get to know Venus
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Last Updated Oct 17, 2024 Editor Lonnie Shekhtman Contact Lonnie Shekhtman lonnie.shekhtman@nasa.gov Location Goddard Space Flight Center Related Terms
DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) Pioneer Venus Planetary Science Planetary Science Division Planets Science & Research Science Mission Directorate The Solar System Venus VERITAS (Venus Emissivity, Radio Science, InSAR, Topography & Spectroscopy) View the full article
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Researchers think meltwater beneath Martian ice could support microbial life.
The white material seen within this Martian gully is believed to be dusty water ice. Scientists believe this kind of ice could be an excellent place to look for microbial life on Mars today. This image, showing part of a region called Dao Vallis, was captured by NASA’s Mars Reconnaissance Orbiter in 2009.NASA/JPL-Caltech/University of Arizona These holes, captured on Alaska’s Matanuska Glacier in 2012, are formed by cryoconite — dust particles that melt into the ice over time, eventually forming small pockets of water below the glacier’s surface. Scientists believe similar pockets of water could form within dusty water ice on Mars.Kimberly Casey CC BY-NC-SA 4.0 While actual evidence for life on Mars has never been found, a new NASA study proposes microbes could find a potential home beneath frozen water on the planet’s surface.
Through computer modeling, the study’s authors have shown that the amount of sunlight that can shine through water ice would be enough for photosynthesis to occur in shallow pools of meltwater below the surface of that ice. Similar pools of water that form within ice on Earth have been found to teem with life, including algae, fungi, and microscopic cyanobacteria, all of which derive energy from photosynthesis.
“If we’re trying to find life anywhere in the universe today, Martian ice exposures are probably one of the most accessible places we should be looking,” said the paper’s lead author, Aditya Khuller of NASA’s Jet Propulsion Laboratory in Southern California.
Mars has two kinds of ice: frozen water and frozen carbon dioxide. For their paper, published in Nature Communications Earth & Environment, Khuller and colleagues looked at water ice, large amounts of which formed from snow mixed with dust that fell on the surface during a series of Martian ice ages in the past million years. That ancient snow has since solidified into ice, still peppered with specks of dust.
Although dust particles may obscure light in deeper layers of the ice, they are key to explaining how subsurface pools of water could form within ice when exposed to the Sun: Dark dust absorbs more sunlight than the surrounding ice, potentially causing the ice to warm up and melt up to a few feet below the surface.
The white edges along these gullies in Mars’ Terra Sirenum are believed to be dusty water ice. Scientists think meltwater could form beneath the surface of this kind of ice, providing a place for possible photosynthesis. This is an enhanced-color image; the blue color would not actually be perceptible to the human eye.NASA/JPL-Caltech/University of Arizona Mars scientists are divided about whether ice can actually melt when exposed to the Martian surface. That’s due to the planet’s thin, dry atmosphere, where water ice is believed to sublimate — turn directly into gas — the way dry ice does on Earth. But the atmospheric effects that make melting difficult on the Martian surface wouldn’t apply below the surface of a dusty snowpack or glacier.
Thriving Microcosms
On Earth, dust within ice can create what are called cryoconite holes — small cavities that form in ice when particles of windblown dust (called cryoconite) land there, absorb sunlight, and melt farther into the ice each summer. Eventually, as these dust particles travel farther from the Sun’s rays, they stop sinking, but they still generate enough warmth to create a pocket of meltwater around them. The pockets can nourish a thriving ecosystem for simple lifeforms..
“This is a common phenomenon on Earth,” said co-author Phil Christensen of Arizona State University in Tempe, referring to ice melting from within. “Dense snow and ice can melt from the inside out, letting in sunlight that warms it like a greenhouse, rather than melting from the top down.”
Christensen has studied ice on Mars for decades. He leads operations for a heat-sensitive camera called THEMIS (Thermal Emission Imaging System) aboard NASA’s 2001 Mars Odyssey orbiter. In past research, Christensen and Gary Clow of the University of Colorado Boulder used modeling to demonstrate how liquid water could form within dusty snowpack on the Red Planet. That work, in turn, provided a foundation for the new paper focused on whether photosynthesis could be possible on Mars.
In 2021, Christensen and Khuller co-authored a paper on the discovery of dusty water ice exposed within gullies on Mars, proposing that many Martian gullies form by erosion caused by the ice melting to form liquid water.
This new paper suggests that dusty ice lets in enough light for photosynthesis to occur as deep as 9 feet (3 meters) below the surface. In this scenario, the upper layers of ice prevent the shallow subsurface pools of water from evaporating while also providing protection from harmful radiation. That’s important, because unlike Earth, Mars lacks a protective magnetic field to shield it from both the Sun and radioactive cosmic ray particles zipping around space.
The study authors say the water ice that would be most likely to form subsurface pools would exist in Mars’ tropics, between 30 degrees and 60 degrees latitude, in both the northern and southern hemispheres.
Khuller next hopes to re-create some of Mars’ dusty ice in a lab to study it up close. Meanwhile, he and other scientists are beginning to map out the most likely spots on Mars to look for shallow meltwater — locations that could be scientific targets for possible human and robotic missions in the future.
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Last Updated Oct 17, 2024 Related Terms
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By NASA
NASA astronaut and Expedition 72 Flight Engineer Nick Hague in the space station cupola. (Credit: NASA) Students from Iowa will have the opportunity to hear NASA astronaut Nick Hague answer their prerecorded questions while he’s serving an expedition aboard the International Space Station on Monday, Oct. 21.
Watch the 20-minute space-to-Earth call at 11:40 a.m. EDT on NASA+. Students from Iowa State University in Ames, First Robotics Clubs, World Food Prize Global Youth Institute, and Plant the Moon teams will focus on food production in space. Learn how to watch NASA content on various platforms, including social media.
Media interested in covering the event must contact Angie Hunt by 5 p.m., Friday, Oct.18 at amhunt@iastate.edu or 515-294-8986.
For more than 23 years, astronauts have continuously lived and worked aboard the space station, testing technologies, performing science, and developing skills needed to explore farther from Earth. Astronauts aboard the orbiting laboratory communicate with NASA’s Mission Control Center in Houston 24 hours a day through SCaN’s (Space Communications and Navigation) Near Space Network.
Important research and technology investigations taking place aboard the space station benefit people on Earth and lays the groundwork for other agency missions. As part of NASA’s Artemis campaign, the agency will send astronauts to the Moon to prepare for future human exploration of Mars; inspiring Artemis Generation explorers and ensuring the United States continues to lead in space exploration and discovery.
See videos and lesson plans highlighting space station research at:
https://www.nasa.gov/stemonstation
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Abbey Donaldson
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By European Space Agency
Video: 00:03:27 On Saturday 5 and Sunday 6 October 2024, the European Space Agency opened the doors to the European Space Research and Technology Centre, ESTEC, in the Netherlands, welcoming some 9000 visitors to its 13th annual Open Day. As in previous years, ESA’s largest establishment in Europe invited the public to meet space engineers, astronauts and to see actual space hardware. Attendees explored state-of-the-art facilities, interacted with ESA and NASA astronauts and discovered various job opportunities at ESA. There was also a full schedule of talks from Space Rocks, celebrating the art and culture of science and space.
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