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An Ancient Partnership: Co-Evolution of Earth Environments and Microbial LifeAn Ancient Partnership:
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By European Space Agency
Image: The Copernicus Sentinel-2 mission shows us what is left of the Aral Sea, once the fourth largest lake in the world. View the full article
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By European Space Agency
Image: The Copernicus Sentinel-2 mission captures the striking landscape surrounding the Waza National Park in Cameroon. View the full article
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By NASA
X-ray: NASA/CXC/Technion/N. Keshet et al.; Illustration: NASA/CXC/SAO/M. Weiss People often think about archaeology happening deep in jungles or inside ancient pyramids. However, a team of astronomers has shown that they can use stars and the remains they leave behind to conduct a special kind of archaeology in space.
Mining data from NASA’s Chandra X-ray Observatory, the team of astronomers studied the relics that one star left behind after it exploded. This “supernova archaeology” uncovered important clues about a star that self-destructed – probably more than a million years ago.
Today, the system called GRO J1655-40 contains a black hole with nearly seven times the mass of the Sun and a star with about half as much mass. However, this was not always the case.
Originally GRO J1655-40 had two shining stars. The more massive of the two stars, however, burned through all of its nuclear fuel and then exploded in what astronomers call a supernova. The debris from the destroyed star then rained onto the companion star in orbit around it, as shown in the artist’s concept.
This artist’s impression shows the effects of the collapse and supernova explosion of a massive star. A black hole (right) was formed in the collapse and debris from the supernova explosion is raining down onto a companion star (left), polluting its atmosphere.CXC/SAO/M. Weiss With its outer layers expelled, including some striking its neighbor, the rest of the exploded star collapsed onto itself and formed the black hole that exists today. The separation between the black hole and its companion would have shrunk over time because of energy being lost from the system, mainly through the production of gravitational waves. When the separation became small enough, the black hole, with its strong gravitational pull, began pulling matter from its companion, wrenching back some of the material its exploded parent star originally deposited.
While most of this material sank into the black hole, a small amount of it fell into a disk that orbits around the black hole. Through the effects of powerful magnetic fields and friction in the disk, material is being sent out into interstellar space in the form of powerful winds.
This is where the X-ray archaeological hunt enters the story. Astronomers used Chandra to observe the GRO J1655-40 system in 2005 when it was particularly bright in X-rays. Chandra detected signatures of individual elements found in the black hole’s winds by getting detailed spectra – giving X-ray brightness at different wavelengths – embedded in the X-ray light. Some of these elements are highlighted in the spectrum shown in the inset.
The team of astronomers digging through the Chandra data were able to reconstruct key physical characteristics of the star that exploded from the clues imprinted in the X-ray light by comparing the spectra with computer models of stars that explode as supernovae. They discovered that, based on the amounts of 18 different elements in the wind, the long-gone star destroyed in the supernova was about 25 times the mass of the Sun, and was much richer in elements heavier than helium in comparison with the Sun.
This analysis paves the way for more supernova archaeology studies using other outbursts of double star systems.
A paper describing these results titled “Supernova Archaeology with X-Ray Binary Winds: The Case of GRO J1655−40” was published in The Astrophysical Journal in May 2024. The authors of this study are Noa Keshet (Technion — Israel Institute of Technology), Ehud Behar (Technion), and Timothy Kallman (NASA’s Goddard Space Flight Center).
NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
Read more from NASA’s Chandra X-ray Observatory.
Learn more about the Chandra X-ray Observatory and its mission here:
https://www.nasa.gov/chandra
https://chandra.si.edu
Visual Description
This release features an artist’s rendering of a supernova explosion, inset with a spectrum graph.
The artist’s illustration features a star and a black hole in a system called GRO J1655-40. Here, the black hole is represented by a black sphere to our upper right of center. The star is represented by a bright yellow sphere to our lower left of center. In this illustration, the artist captures the immensely powerful supernova as a black hole is created from the collapse of a massive star, with an intense burst of blurred beams radiating from the black sphere. The blurred beams of red, orange, and yellow light show debris from the supernova streaking across the entire image in rippling waves. These beams rain debris on the bright yellow star.
When astronomers used the Chandra X-ray Observatory to observe the system in 2005, they detected signatures of individual elements embedded in the X-ray light. Some of those elements are highlighted in the spectrum graph shown in the inset, positioned at our upper lefthand corner.
The graph’s vertical axis, on our left, indicates X-ray brightness from 0.0 up to 0.7 in intensity units. The horizontal axis, at the bottom of the graph, indicates Wavelength from 6 to 12 in units of Angstroms. On the graph, a tight zigzagging line begins near the top of the vertical axis, and slopes down toward the far end of the horizontal axis. The sharp dips show wavelengths where the light has been absorbed by different elements, decreasing the X-ray brightness. Some of the elements causing these dips have been labeled, including Silicon, Magnesium, Iron, Nickel, Neon, and Cobalt.
News Media Contact
Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu
Lane Figueroa
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
lane.e.figueroa@nasa.gov
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By European Space Agency
Image: The Copernicus Sentinel-2 mission takes us over the Sequoia and Kings Canyon National Parks in California’s Sierra Nevada mountains. View the full article
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By NASA
Explore This Section Earth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives 11 min read
The Earth Observer Editor’s Corner: January–March 2025
NASA’s Earth Observing fleet continues to age gracefully. While several new missions have joined the fleet in the past year, scientists and engineers work to extend the life of existing missions and maximize their science along the way. The crowning example is the first Earth Observing System (EOS) Flagship mission, Terra, which celebrated a quarter-century in orbit on December 18, 2024.
Terra, continues to collect daily morning Earth observations using five different instruments: Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Clouds and the Earth’s Radiant Energy System (CERES), Multi-angle Imaging SpectroRadiometer (MISR), Moderate Resolution Imaging Spectroradiometer (MODIS), and Measurement of Pollution in the Troposphere (MOPITT). Collectively, these observations have established a robust satellite record of global scientific processes to track changes in temperature, glaciers, clouds, vegetation, land-use, air quality, and natural hazards such as hurricanes, wildfires, and volcanic eruptions.
Originally designed for a six-year prime mission, Terra continues to deliver data used by emergency managers, researchers, and modelers over a quarter-of-a-century later. On December 18th, 2024, NASA celebrated the 25th anniversary of Terra’s launch with a celebration at the Goddard Space Flight Center (GSFC) Visitor’s Center. NASA Senior management [from NASA Headquarters and GSFC] as well as other key figures from Terra’s long history gave brief remarks and perspectives on Terra’s development and achievements. To read a review of the celebration, see “Celebrating 25 Years of Terra.”
Terra-related sessions (poster and oral) during the Fall American Geophysical Union (AGU) meeting were well-attended. The Terra team took advantage of the meeting to have a celebratory anniversary dinner that included attendees representing each of the five instruments.
Another mission to recently reach a longevity milestone is NASA’s Orbiting Carbon Observatory-2 (OCO-2), which celebrated 10 years in space last summer. OCO-2, which launched on July 2, 2014, from the Vandenburg Air Force (now Space Force) Base in California, was originally designed as a pathfinder mission to measure carbon dioxide (CO2) with the precision and accuracy needed to quantify where, when, and how the Earth inhales and exhales this important greenhouse gas seasonally. OCO-2 was part of the international Afternoon Constellation, or “A-Train,” which also included Aqua, Aura, CloudSat, and CALIPSO, as well as international partner missions.
Since its launch, OCO-2 data have revealed unprecedented insights into how the carbon cycle operates – from observing the impact and recovery of tropical land and ocean ecosystems during El Niño events to revealing the outsized impacts of extreme events, such as floods, droughts, and fires on ecosystem health and functioning. Researchers from around the world use OCO-2 data, opening new opportunities for understanding the response of the carbon cycle to human-driven perturbations, such as the impact of COVID lockdowns on atmospheric CO2 and improved quantification of emissions from large power plants and cities.
OCO-2 also maps vegetation fluorescence, which shows promise as a reliable early warning indicator of flash drought. During photosynthesis, plants “leak” unused photons, producing a faint glow known as solar-induced fluorescence (SIF). The stronger the fluorescence, the more CO2 a plant is taking from the atmosphere to power its growth. Ancillary SIF measurements from OCO-2 will help scientists better predict flash droughts, and understand how these impact carbon emissions.
Ten years into the mission, OCO-2 has become the gold standard for CO2 measurements from space. The spacecraft and instrument continue to perform nominally, producing data leading to new scientific discoveries.
OCO–3, built from spare parts during the build of OCO-2 and launched to the International Space Station (ISS) in 2019, also celebrated a milestone, marking five years in orbit on May 4, 2024. While the follow-on has the same instrument sensitivity and makes essentially the same measurements as OCO-2, the vantage point on the ISS as opposed to OCO-2’s polar orbit and the use of a new pointing mirror assembly (PMA) results in significant day-to-day spatial and temporal sampling differences that allows CO2 tracking for diurnal variability. In addition, the flexible PMA system allows for a much more dynamic observation-mode schedule.
Further out in space, about 1 million mi (~1.1 million km) from Earth, orbiting the “L1” Lagrange point between Earth and Sun, the Deep Space Climate Observatory (DSCOVR) celebrated the 10th anniversary of its launch on February 11, 2025. The two NASA Earth observing instruments on DSCOVR are the Earth Polychromatic Camera (EPIC) and National Institute of Standards and Technology (NIST) Advanced Radiometer [NISTAR].
The 10th DSCOVR EPIC NISTAR Science Team Meeting was held October 16–18, 2024 at Goddard Space Flight Center. Former U.S. Vice President Al Gore opened the meeting with remarks that focused on remote sensing and the future of Earth observations. Following Gore’s remarks, DSCOVR mission leadership and representatives from GSFC and the National Oceanic and Atmospheric Administration (NOAA) gave presentations on DSCOVR operations, EPIC calibration, and NISTAR Status and Science.
The meeting provided an opportunity for participants to learn the status of DSCOVR’s Earth-observing instruments, the status of recently released Level-2 (geophysical) data products, and the resulting science. As more people use DSCOVR data worldwide, the science team hopes to hear from users and team members at its next meeting. The latest updates from the mission can be found on the EPIC website. For more details, see the Summary of the 10th DSCOVR EPIC and NISTAR Science Team Meeting.
Flying in the space between satellites and ground-based observations, NASA’s Airborne Science Program operates a fleet of aircraft, unpiloted aerial vehicles, and even kites to study Earth and space science. Since 1987, a highly modified McDonnell Douglas DC-8 aircraft has been a mainstay of ASP’s fleet – see Photo 1. The aircraft, located at NASA’s Armstrong Flight Research Center (AFRC) in California, flew countless missions as a science laboratory, producing science data for the national and global scientific communities. NASA decided to retire the venerable DC-8 aircraft, which made its last science flight in April 2024. The DC-8 is being replaced with a similarly refurbished Boeing 777 aircraft, which will be even more capable than the DC-8 and is located at the NASA Langley Research Center (LaRC).
The NASA History Office and NASA Earth Science Division cohosted a workshop, titled “Contributions of the DC-8 to Earth System Science at NASA,” on October 24–25, 2024 at the Mary W. Jackson NASA Headquarters (HQ) Building in Washington, DC – for more details on the DC-8 event, see the article The NASA DC-8 Retires: Reflections on its Contributions to Earth System Science.
Photo 1. NASA’s DC-8 flying laboratory flew Earth science missions from 1987 to 2024. Expert maintenance allowed the aircraft to conduct research on six continents and study ice fields on the seventh, Antarctica. Image Credit: Lori Losey/NASA There are also updates from three recent NASA field campaigns – where ground observations are timed and coordinated with aircraft flights (often at more than one altitude) and with satellite overpasses to gain a comprehensive (i.e., multilayered, multiscale) picture of the atmosphere over a certain area.
The Westcoast & Heartland Hyperspectral Microwave Sensor Intensive Experiment (WHyMSIE) campaign was held from October 17- November 18, 2024. Serving as a future NASA planetary boundary-layer (PBL) mission prototype, WHyMSIE aimed to capture a wide variety of thermodynamic, moisture, and PBL regimes across a variety of surface types. WHyMSIE was an initial step towards an integrated and affordable PBL observing system of systems, with multiple observing nodes – i.e., space, suborbital, and ground – from passive and active sensors to enable a comprehensive and coherent picture of essential PBL variables and hydrometeors that is not possible with any single sensor, observational approach, or scale. As a partnership between NASA and NOAA, this field campaign flew a first-of-its-kind hyperspectral microwave airborne measurements (CoSMIR-H) that was complemented by other passive (thermal emission, solar reflectance) and active (lidar, radar) sensors flying onboard the NASA ER-2 (AFRC) and G-III (LaRC), with coordination over a variety of ground-based sensor facilities.
The GSFC Lidar Observation and Validation Experiment (GLOVE) was conducted in February 2025 at Edwards Air Force Base, California – see photo 2. GLOVE flew the Cloud Physics Lidar (CPL), Roscoe lidar, enhanced MODIS Airborne Simulator (eMAS) imaging scanner, and Cloud Radar System (CRS) on the ER-2 to validate NASA ICESat-2 atmospheric data products and validate ESA’s recently launched EarthCARE lidar, radar, and spectrometer products.
NASA’s Earth Science Division FireSense project focuses on delivering NASA’s unique Earth science and technological capabilities to operational agencies, striving to address challenges in US wildland fire management. Together with agency, academic, and private partners, FireSense completed an airborne campaign in a wildfire smoke-impacted airshed in Missoula, MT on August 27–29, 2024. During the three-day campaign, a NASA Uninhabited Aerial System (UAS) team conducted eight data-collection flights, partnering these launches with weather balloon launches.
FireSense uses airborne campaigns to evaluate capabilities and technologies to support decision making in wildland fire management and air quality forecasting. Targeted data collection produces better forecasts and more successful technology transfer to wildland fire operations. In the future, the FireSense Program will coordinate two airborne campaigns for spring 2025 at Geneva State Forest, Alabama and Kennedy Space Center located within Merritt Island National Wildlife Refuge, Florida. Both 2025 campaigns will incorporate data collection before, during, and after prescribed fire operations. Beyond NASA, the campaign works in close partnership with the U.S. Forest Service, National Weather Service, U.S. Fish and Wildlife Service, Department of Defense, as well as partners in academia and the private sector. For more information on FireSense’s most recent campaign in Montana see the Editor’s Corner supplemental summary of “The FireSense Project.”
Photo 2. NASA personnel stand in front of theNASA ER-2 at Edwards Air Force Base, California, during the GSFC Lidar Observation and Validation Experiment (GLOVE) in February 2025. Image credit: John Yorks/NASA Congratulations to Jack Kaye, Associate Director for research with the Earth Science Division within NASA’s Science Mission Directorate, who has received the William T. Pecora Award for his vision and creative leadership in multidisciplinary Earth science research, as well as spurring advancements in the investigator community, supporting development of sensors, and shaping NASA satellite and aircraft missions and research programs at the highest levels. To read more about this accomplishment, see “Kaye Honored with Pecora Award.”
On the outreach front, AGU returned to Washington, DC, for its annual meeting from December 9–14, 2024. NASA continued to uphold its long-standing tradition as an AGU partner and exhibitor, leveraging the meeting as an opportunity to share the agency’s cutting-edge research, data, and technology with the largest collection of Earth and planetary science professionals in the world. Many of the estimated 25,000 students, scientists, and industry personnel who attended the conference visited the NASA Science exhibit, interacting with NASA subject matter experts and listening to Hyperwall presentations throughout the week.
As the final event in a busy calendar of annual scientific conferences, AGU is often an opportunity for NASA scientists to publish findings from the previous year and set goals for the year ahead. The agency’s robust portfolio of missions and programs will continue to set new records, such as NASA’s Parker Solar Probe pass of the Sun, and conduct fundamental research in Earth and space science. To read more about AGU 2024, see the article: AGU 2024: NASA Science on Display in the Nation’s Capital.
Ending on a somber note, we recently posted three notable obituaries. Each of these individuals made significant contributions to EOS history, which are highlighted in the In Memoriam articles linked below.
Jeff Dozier, an environmental scientist, snow hydrologist, researcher, academic, and former EOS Project Scientist, died on November 17, 2024. Jeff embraced remote sensing with satellites to measure snow properties and energy balance. As a Project Scientist with the Earth Observing System Data and Information System (EOSDIS), he contributed to the design and management of very large information systems that would impact spatial modeling and environmental informatics.
Berrien Moore, Dean of the College of Atmospheric and Geographic Sciences at the University of Oklahoma (OU), died on December 17, 2024. Berrien served in several roles with NASA, including as a committee member and later chair of the organization’s Space and Earth Science Advisory Committee, Chair of the Earth Observing System Payload Advisory Committee, member and Chair of NASA’s Earth Science and Applications Committee, and member of the NASA Advisory Council. Berrien received NASA’s highest civilian honor, the Distinguished Public Service Medal, for outstanding service and the NOAA Administrator’s Recognition Award.
Pierre Morel, the first director of the World Climate Research Programme (WCRP) and founding member of WCRP’s Global Energy and Water Exchanges (GEWEX) Core project, died on December 10, 2024. Pierre’s work played an integral role in the development of tools used to study the atmosphere, many of which are still active today. Pierre was the recipient of the 2008 Alfred Wegener Medal & Honorary Membership for his outstanding contributions to geophysical fluid dynamics, his leadership in the development of climate research, and the applications of space observation to meteorology and the Earth system science.
Steve Platnick
EOS Senior Project Scientist
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