SPACE
The moon is shrinking, causing landslides and instability in lunar south pole
New paper identifies potential landing sites for Artemis mission that are particularly vulnerable to quakes and landslides.
VIDEO:
SIMULATED GROUND MOTION GENERATED BY A SHALLOW MOONQUAKE LOCATED BY THE LUNAR SOUTH POLE. STRONG TO MODERATE GROUND SHAKING IS PREDICTED AT A DISTANCE OF AT LEAST ~40KM FROM THE SOURCE.
view moreCREDIT: NICHOLAS SCHMERR, UNIVERSITY OF MARYLAND
Earth’s moon shrank more than 150 feet in circumference as its core gradually cooled over the last few hundred million years. In much the same way a grape wrinkles when it shrinks down to a raisin, the moon also develops creases as it shrinks. But unlike the flexible skin on a grape, the moon’s surface is brittle, causing faults to form where sections of crust push against one another.
A team of scientists discovered evidence that this continuing shrinkage of the moon led to notable surface warping in its south polar region—including areas that NASA proposed for crewed Artemis III landings. Because fault formation caused by the moon’s shrinking is often accompanied by seismic activity like moonquakes, locations near or within such fault zones could pose dangers to future human exploration efforts.
In a new paper published in The Planetary Science Journal, the team linked a group of faults located in the moon’s south polar region to one of the most powerful moonquakes recorded by Apollo seismometers over 50 years ago. Using models to simulate the stability of surface slopes in the region, the team found that some areas were particularly vulnerable to landslides from seismic shaking.
“Our modeling suggests that shallow moonquakes capable of producing strong ground shaking in the south polar region are possible from slip events on existing faults or the formation of new thrust faults,” said the study’s lead author Thomas R. Watters, a senior scientist emeritus in the National Air and Space Museum’s Center for Earth and Planetary Studies. “The global distribution of young thrust faults, their potential to be active and the potential to form new thrust faults from ongoing global contraction should be considered when planning the location and stability of permanent outposts on the moon.”
Shallow moonquakes occur near the surface of the moon, just a hundred or so miles deep into the crust. Similar to earthquakes, shallow moonquakes are caused by faults in the moon’s interior and can be strong enough to damage buildings, equipment and other human-made structures. But unlike earthquakes, which tend to last only a few seconds or minutes, shallow moonquakes can last for hours and even a whole afternoon—like the magnitude 5 moonquake recorded by the Apollo Passive Seismic Network in the 1970s, which the research team connected to a group of faults detected by the Lunar Reconnaissance Orbiter more recently.
According to Nicholas Schmerr, a co-author of the paper and an associate professor of geology at the University of Maryland, this means that shallow moonquakes can devastate hypothetical human settlements on the moon.
“You can think of the moon’s surface as being dry, grounded gravel and dust. Over billions of years, the surface has been hit by asteroids and comets, with the resulting angular fragments constantly getting ejected from the impacts,” Schmerr explained. “As a result, the reworked surface material can be micron-sized to boulder-sized, but all very loosely consolidated. Loose sediments make it very possible for shaking and landslides to occur.”
The researchers continue to map out the moon and its seismic activity, hoping to identify more locations that may be dangerous for human exploration. NASA’s Artemis missions, which are set to launch their first crewed flight in late 2024, ultimately hope to establish a long-term presence on the moon and eventually learn to live and work on another world through moon-based observatories, outposts and settlements.
“As we get closer to the crewed Artemis mission’s launch date, it’s important to keep our astronauts, our equipment and infrastructure as safe as possible,” Schmerr said. “This work is helping us prepare for what awaits us on the moon—whether that’s engineering structures that can better withstand lunar seismic activity or protecting people from really dangerous zones.”
The epicenter of one of the strongest moonquakes recorded by the Apollo Passive Seismic Experiment was located in the lunar south polar region. However, the exact location of the epicenter could not be accurately determined. A cloud of possible locations (magenta dots and light blue polygon) of the strong shallow moonquake using a relocation algorithm specifically adapted for very sparse seismic networks are distributed near the pole. Blue boxes show the locations of proposed Artemis III landing regions. Lobate thrust fault scarps are shown by small red lines. The cloud of epicenter locations encompasses a number of lobate scarps and many of the Artemis III landing regions.
CREDIT
Credit: NASA/LRO/LROC/ASU/Smithsonian Institution
JOURNAL
The Planetary Science Journal
ARTICLE TITLE
Tectonics and Seismicity of the Lunar South Polar Region
ARTICLE PUBLICATION DATE
25-Jan-2024
New satellite capable of measuring Earth precipitation from space
IMAGE:
VERTICAL AND SPATIAL DISTRIBUTION OF PRECIPITATION WELL CAPTURED BY FY-3G PMR
view moreCREDIT: DR. PENG ZHANG, NATIONAL SATELLITE METEOROLOGICAL CENTER
Measuring the amount of precipitation that falls in a specific location is simple if that location has a device designed to accurately record and transmit precipitation data. In contrast, measuring the amount and type of precipitation that falls to Earth in every location is logistically quite difficult. Importantly, this information could provide a wealth of data for characterizing and predicting Earth’s water, energy and biogeochemical cycles. Researchers from China recently deployed a satellite, FengYun 3G (FY-3G), that is successfully collecting Earth precipitation data from space.
Scientists from the China Meteorological Administration developed and launched a satellite created to measure Earth precipitation with radar while orbiting in space. This is the first of two precipitation missions planned by the team to accurately measure the occurrence, type and intensity of any precipitation across the world, including over oceans and complex terrain. Specifically, the FY-3G satellite is designed to assess the 3-dimensional (3D) form of rainfall and other precipitation for weather systems at Earth’s middle and lower latitudes.
The team published their results in the 19 December 2023 issue of the Journal of Remote Sensing.
“The first active precipitation measurement satellite in China (FY-3G) was developed and successfully launched, and the commission test of the satellite platform and the instruments [was] completed, illustrating excellent performance. The active and passive microwave instruments combined with optical imaging instruments… obtain high-precision observation data of global precipitation. The satellite can also cooperate with the on-orbit Global Position Measurement (GPM) satellite to enhance the ability of scientists to study the structure and mechanism of global precipitation as well as carry out water cycle research,” said Peng Zhang, first author of the review paper and leading scientist of the FY-3 polar orbiting meteorological satellite program at the National Satellite Meteorological Center in Beijing, China.
FY-3G marks the first rainfall satellite mission from China and the third such mission in the world. The satellite can measure clouds, precipitation and atmospheric profiles with the complement of remote sensing instruments built into the satellite.
Specifically, the active remote sensing precipitation measurement radar (PMR) works in tandem with a passive microwave imager MWRI-RM, which has been optimized to improve the detection of weaker precipitation over land and solid forms of precipitation. An optical imaging instrument, the MERSI-RM, assists other microwave instruments in measuring clouds and precipitation to facilitate low-orbit precipitation measurement and high-orbit infrared precipitation estimation.
The GNOS-II instrument, also included on the satellite, uses variations in global navigation satellite system (GNSS) data to accurately measure temperature, humidity and sea surface speed from space. The FY-3G also houses an short-wave infrared polarized multi-angle imager (PMAI) and high radiometric accuracy on-board calibrator (HAOC).
As a precipitation measurement device, the primary instrument of the FY-3G satellite is the active precipitation measurement radar PMR, which creates a 3D rendering of falling precipitation. Data collected by the instrument can then be used to calculate precipitation intensity and type, improving the accuracy of measurements taken from space.
“China has successfully launched a precipitation measurement satellite [FY-3G], and the commission test results show that its measurement performance is superior, and high-precision 3D precipitation measurement information can be obtained. FY-3G and GPM can form a virtual constellation in orbit, which greatly enhances the ability to measure and study global precipitation. FY-3G global observation data are [freely available] to… worldwide users through the Fengyun Satellite Data Center,” said Zhang.
Importantly, FY-3G has improved our understanding of global precipitation, which will help scientists better interpret and predict our planet’s water and energy cycles. This data will be used to enhance forecasting of extreme weather events and inform the development of the program’s next generation precipitation satellite, FY-5.
The team is encouraged by the data they have received from FY-3G, but more data processing work is required to fully grasp the satellite’s capacity and future applications. “Next, we will accelerate the development of precipitation event database and precipitation data set based on FY-3G satellite data. We also plan to improve the quantitative inversion accuracy of active radar precipitation and strengthen the global data service of the FY-3G satellite. We will also continue to promote the follow-up satellite development plan to ensure continuous precipitation observation,” said Zhang.
Other contributors include Songyan Gu, Lin Chen, Jian Shang, Manyun Lin, Aijun Zhu, Honggang Yin, Qiong Wu, Yixuan Shou, Fenglin Sun, Hanlie Xu, Guanglin Yang, Haofei Wang, Lu Li, Sijie Chen and Naimeng Lu from the Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites at the National Satellite Meteorological Center (National Center for Space Weather) from the China Meteorological Administration in Beijing, China and the Innovation Center for FengYun Meteorological Satellite in Beijing, China; and HongWei Zhang from the Shanghai Academy of Spaceflight Technology in Shanghai, China.
This work was supported by the FY3-03 meteorological satellite project ground application system and the International Space Water Cycle Observation Constellation Program (grant no. 183311KYSB20200015).
JOURNAL
Journal of Remote Sensing
METHOD OF RESEARCH
Data/statistical analysis
ARTICLE TITLE
FY-3G Satellite Instruments and Precipitation Products: First Report of China’s Fengyun Rainfall Mission In-Orbit
UTSA researchers reveal faint features in galaxy NGC 5728 though JWST image techniques
IMAGE:
JWST OBSERVED NGC 5728 AT FIVE DISTINCT WAVELENGTHS. IN THESE OBSERVATIONS, A FAINT EXTENDED FEATURE WAS SEEN IN ONLY ONE WAVELENGTH. AS LEIST DECONVOLVED THE DATA, THE FAINT EXTENDED EMISSION FEATURE WAS REVEALED IN ALL WAVELENGTHS, DEMONSTRATING THE EFFECTIVENESS OF KRAKEN DECONVOLUTION TO IMPROVE JWST IMAGE QUALITY AND ENHANCE FAINT EXTENDED EMISSION FEATURES.
view moreCREDIT: THE UNIVERSITY OF TEXAS AT SAN ANTONIO
(SAN ANTONIO, TEXAS) — Mason Leist is working remotely—127 million light-years from Earth—on images of a supermassive black hole in his office at the UTSA Department of Physics and Astronomy.
The UTSA Graduate Research Assistant led a study, published in The Astronomical Journal, on the best method to improve images obtained by the James Webb Science Telescope (JWST) using a mathematical approach called deconvolution. He was tasked by the Galactic Activity, Torus, and Outflow Survey (GATOS), an international team of scientists, to enhance JWST observations of the galaxy NGC 5728.
The GATOS team, co-led by UTSA Professor and Leist’s doctoral advisor Chris Packham, was awarded time on the JWST for its research on black holes.
“It’s incredibly humbling,” Leist said. “Not just working with JWST data, which is a great opportunity and a crazy amount of science, but working with our collaborators. It’s a very incredible experience to collaborate with other members of the GATOS on this. I like to tell people that this work represents the efforts of 35 individuals from institutes in 14 countries.”
Leist deconvolved simulated and observed images of an active galactic nucleus (AGN), a region at the center of the galaxy NGC 5728. The central engine of an active galactic nucleus, comprised of a hot and turbulent accretion disk orbiting a central supermassive black hole enshrouded by a thick torus of gas and dust, plays a key role in feedback between the AGN, host galaxy and intergalactic medium.
He tested five deconvolution algorithms over two years on simulated observations of an AGN. Of the five methods tested, the Kraken algorithm improved the simulated AGN model image quality the most and was therefore applied to JWST observations of NGC 5728. Kraken is a high-performance multi-frame deconvolution algorithm developed by a team of researchers led by Douglas Hope and Stuart Jefferies at Georgia State University.
JWST observed NGC 5728 at five distinct wavelengths. In these observations, a faint extended feature was seen in only one wavelength. As Leist deconvolved the data, the faint extended emission feature was revealed in all wavelengths, demonstrating the effectiveness of Kraken deconvolution to improve JWST image quality and enhance faint extended emission features.
“We believe the extension could be part of an outflow from a supermassive black hole that could be interacting with the host galaxy. There’s a lot more science that needs to be done,” Leist said. “It is difficult to distinguish the extended structure in all of the JWST images, but by using deconvolution techniques, we reduced the image data to reveal the hidden faint emission feature.”
The process was also a collaboration with Willie Schaefer, UTSA’s Adobe Creative Cloud support specialist, who helped create a scientifically accurate set of color images for the study.
Leist’s work demonstrates deconvolution is an efficient and accurate tool for image processing. Similar methods, he and Packham said, can be applied to broader science cases using JWST observations. The approach has garnered significant interest from fellow scientists working on JWST image processing.
“We’re doing important work using JWST data,” Packham said. “But it’s important because we can improve on the raw data and get better image quality to see those fainter details by using this approach. It shows the strength of collaboration within the GATOS, which is co-led from UTSA.”
Leist’s work to enhance the JWST observations of the galaxy NGC 5728 is a new piece in the puzzle that further demystifies the origins of the universe. The full scope of the deconvolved images and other astrophysical results will be described in forthcoming studies currently underway by the GATOS.
“It goes back to the generation of galaxies shortly after the Big Bang,” Packham explained. “If we really want to understand our place within our own galaxy, within our own solar system and within the universe in general, we have to understand what’s going on within black holes in our galaxy and, indeed, other galaxies. We can understand the formation of our galaxy, our solar system, the earth and life on earth. It’s really part of that big picture question.”
Explore Further
Discover the UTSA Department of Physics and Astronomy and the UTSA College of Sciences.
Read about previous JWST work at UTSA.
JOURNAL
The Astronomical Journal
ARTICLE TITLE
Deconvolution of JWST/MIRI Images: Applications to an AGN Model and GATOS Observations of NGC 5728
No comments:
Post a Comment