Members Can Post Anonymously On This Site
Arctic coastal sea ice thinning twice as fast than thought
-
Similar Topics
-
By NASA
This illustration shows a red, early-universe dwarf galaxy that hosts a rapidly feeding black hole at its center. Using data from NASA’s James Webb Space Telescope and Chandra X-ray Observatory, a team of astronomers have discovered this low-mass supermassive black hole at the center of a galaxy just 1.5 billion years after the Big Bang. It is pulling in matter at a phenomenal rate — over 40 times the theoretical limit. While short lived, this black hole’s “feast” could help astronomers explain how supermassive black holes grew so quickly in the early universe.NOIRLab/NSF/AURA/J. da Silva/M. Zamani A rapidly feeding black hole at the center of a dwarf galaxy in the early universe, shown in this artist’s concept, may hold important clues to the evolution of supermassive black holes in general.
Using data from NASA’s James Webb Space Telescope and Chandra X-ray Observatory, a team of astronomers discovered this low-mass supermassive black hole just 1.5 billion years after the big bang. The black hole is pulling in matter at a phenomenal rate — over 40 times the theoretical limit. While short lived, this black hole’s “feast” could help astronomers explain how supermassive black holes grew so quickly in the early universe.
Supermassive black holes exist at the center of most galaxies, and modern telescopes continue to observe them at surprisingly early times in the universe’s evolution. It’s difficult to understand how these black holes were able to grow so big so rapidly. But with the discovery of a low-mass supermassive black hole feasting on material at an extreme rate so soon after the birth of the universe, astronomers now have valuable new insights into the mechanisms of rapidly growing black holes in the early universe.
The black hole, called LID-568, was hidden among thousands of objects in the Chandra X-ray Observatory’s COSMOS legacy survey, a catalog resulting from some 4.6 million Chandra observations. This population of galaxies is very bright in the X-ray light, but invisible in optical and previous near-infrared observations. By following up with Webb, astronomers could use the observatory’s unique infrared sensitivity to detect these faint counterpart emissions, which led to the discovery of the black hole.
The speed and size of these outflows led the team to infer that a substantial fraction of the mass growth of LID-568 may have occurred in a single episode of rapid accretion.
LID-568 appears to be feeding on matter at a rate 40 times its Eddington limit. This limit relates to the maximum amount of light that material surrounding a black hole can emit, as well as how fast it can absorb matter, such that its inward gravitational force and outward pressure generated from the heat of the compressed, infalling matter remain in balance.
These results provide new insights into the formation of supermassive black holes from smaller black hole “seeds,” which current theories suggest arise either from the death of the universe’s first stars (light seeds) or the direct collapse of gas clouds (heavy seeds). Until now, these theories lacked observational confirmation.
The new discovery suggests that “a significant portion of mass growth can occur during a single episode of rapid feeding, regardless of whether the black hole originated from a light or heavy seed,” said International Gemini Observatory/NSF NOIRLab astronomer Hyewon Suh, who led the research team.
A paper describing these results (“A super-Eddington-accreting black hole ~1.5 Gyr after the Big Bang observed with JWST”) appears in the journal Nature Astronomy.
About the Missions
NASA’s Marshall Space Flight Center 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.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
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
News Media Contact
Elizabeth Laundau
NASA Headquarters
Washington, DC
202-923-0167
elizabeth.r.landau@nasa.gov
Lane Figueroa
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
lane.e.figueroa@nasa.gov
View the full article
-
By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Coastal locations, such as Drakes Bay on the Point Reyes peninsula in Northern California, are increasingly vulnerable to sea level rise.NOAA/NMFS/WCR/CCO The information will help people who live in coastal areas prepare for impacts caused by rising sea levels.
Earth’s ocean is rising, disrupting livelihoods and infrastructure in coastal communities around the world. Agencies and organizations are working to prepare people as their world changes around them, and NASA information is helping these efforts.
The agency’s global data is now available in the sea level section of the Earth Information Center. NASA developed the global sea level change website in collaboration with the U.S. Department of Defense, the World Bank, the U.S. Department of State, and the United Nations Development Programme.
The site includes information on projected sea level rise through the year 2150 for coastlines around the world, as well as estimates of how much flooding a coastal community or region can expect to see in the next 30 years. The projections come from data collected by NASA and its partners and from computer models of ice sheets and the ocean, as well as the latest sea level assessment from the Intergovernmental Panel on Climate Change, and other sources.
“NASA innovates for the benefit of humanity. Our cutting-edge instruments and data-driven information tools help communities and organizations respond to natural hazards and extreme weather, and inform critical coastal infrastructure planning decisions,” said Karen St. Germain, director of the Earth science division at NASA Headquarters in Washington.
Information to Action
International organizations such as the World Bank will use the data from the global sea level change site for tasks including the creation of Climate Risk Profiles for countries especially vulnerable to sea level rise.
The Defense Department will continue to incorporate sea level rise data into its plans to anticipate and respond to hazards posed to its facilities by the effects of rising oceans. Similarly, the State Department uses the information for activities ranging from disaster preparedness to long-term adaptation planning to supporting partners around the world in related efforts.
“We are at a moment of truth in our fight against the climate crisis. The science is unequivocal and must serve as the bedrock upon which decision-making is built. With many communities around the world already facing severe impacts from sea-level rise, this new resource provides a vital tool to help them protect lives and livelihoods. It also illustrates what is at stake between a 1.5-degree-Celsius world and a current-policies trajectory for all coastal communities worldwide,” said Assistant Secretary-General Selwin Hart, special adviser to the United Nations secretary-general on climate action and just transition.
Rising Faster
NASA-led data analyses have revealed that between 1970 and 2023, 96% of countries with coastlines have experienced sea level rise. The rate of that global rise has also accelerated, more than doubling from 0.08 inches (0.21 centimeters) per year in 1993 to about 0.18 inches (0.45 centimeters) per year in 2023.
As the rate of sea level rise increases, millions of people could face the related effects sooner than previously projected, including larger storm surges, more saltwater intrusion into groundwater, and additional high-tide flood days — also known as nuisance floods or sunny day floods.
“This new platform shows the timing of future floods and the magnitude of rising waters in all coastal countries worldwide, connecting science and physics to impacts on people’s livelihoods and safety,” said Nadya Vinogradova Shiffer, director of the ocean physics program at NASA Headquarters in Washington.
Data released earlier this year found that Pacific Island nations will experience at least 6 inches (15 centimeters) of sea level rise in the next 30 years. The number of high-tide flood days will increase by an order of magnitude for nearly all Pacific Island nations by the 2050s.
“The data is clear: Sea levels are rising around the world, and they’re rising faster and faster,” said Ben Hamlington, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California and head of the agency’s sea level change science team. “Having the best information to make decisions about how to plan for rising seas is more crucial than ever.”
To explore the global sea level change site:
https://earth.gov/sealevel
News Media Contacts
Karen Fox / Elizabeth Vlock
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / elizabeth.a.vlock@nasa.gov
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
2024-158
Share
Details
Last Updated Nov 13, 2024 Related Terms
Oceans Climate Change Earth Jet Propulsion Laboratory Natural Disasters Explore More
5 min read JPL Workforce Update
Article 17 hours ago 6 min read Inia Soto Ramos, From the Mountains of Puerto Rico to Mountains of NASA Earth Data
Dr. Inia Soto Ramos became fascinated by the mysteries of the ocean while growing up…
Article 22 hours ago 4 min read NASA-developed Technology Supports Ocean Wind Speed Measurements from Commercial Satellite
A science antenna developed with support from NASA’s Earth Science Technology Office (ESTO) is now…
Article 1 day ago Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By European Space Agency
The 2025 ESA internship opportunities are now live! Positions are open in a wide range of fields, including engineering, science, IT, natural and social sciences, business, economics, and administrative services. This is your chance to launch your career in the extraordinary world of space exploration—don't miss out on this incredible opportunity to gain hands-on experience with one of the world’s leading space organisations!
View the full article
-
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.
News Media Contacts
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
2024-142
Share
Details
Last Updated Oct 17, 2024 Related Terms
Mars Astrobiology Jet Propulsion Laboratory Explore More
4 min read New Team to Assess NASA’s Mars Sample Return Architecture Proposals
NASA announced Wednesday a new strategy review team will assess potential architecture adjustments for the…
Article 20 hours ago 6 min read Christine Knudson Uses Earthly Experience to Study Martian Geology
Geologist Christine Knudson works with the Curiosity rover to explore Mars — from about 250…
Article 1 day ago 5 min read Snippet of Euclid Mission’s Cosmic Atlas Released by ESA
Article 2 days ago Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By NASA
5 min read
NASA’s LRO: Lunar Ice Deposits are Widespread
Deposits of ice in lunar dust and rock (regolith) are more extensive than previously thought, according to a new analysis of data from NASA’s LRO (Lunar Reconnaissance Orbiter) mission. Ice would be a valuable resource for future lunar expeditions. Water could be used for radiation protection and supporting human explorers, or broken into its hydrogen and oxygen components to make rocket fuel, energy, and breathable air.
Prior studies found signs of ice in the larger permanently shadowed regions (PSRs) near the lunar South Pole, including areas within Cabeus, Haworth, Shoemaker and Faustini craters. In the new work, “We find that there is widespread evidence of water ice within PSRs outside the South Pole, towards at least 77 degrees south latitude,” said Dr. Timothy P. McClanahan of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of a paper on this research published October 2 in the Planetary Science Journal.
The study further aids lunar mission planners by providing maps and identifying the surface characteristics that show where ice is likely and less likely to be found, with evidence for why that should be. “Our model and analysis show that greatest ice concentrations are expected to occur near the PSRs’ coldest locations below 75 Kelvin (-198°C or -325°F) and near the base of the PSRs’ poleward-facing slopes,” said McClanahan.
This illustration shows the distribution of permanently shadowed regions (in blue) on the Moon poleward of 80 degrees South latitude. They are superimposed on a digital elevation map of the lunar surface (grey) from the Lunar Orbiter Laser Altimeter instrument on board NASA’s Lunar Reconnaissance Orbiter spacecraft. NASA/GSFC/Timothy P. McClanahan “We can’t accurately determine the volume of the PSRs’ ice deposits or identify if they might be buried under a dry layer of regolith. However, we expect that for each surface 1.2 square yards (square meter) residing over these deposits there should be at least about five more quarts (five more liters) of ice within the surface top 3.3 feet (meter), as compared to their surrounding areas,” said McClanahan. The study also mapped where fewer, smaller, or lower-concentration ice deposits would be expected, occurring primarily towards warmer, periodically illuminated areas.
Ice could become implanted in lunar regolith through comet and meteor impacts, released as vapor (gas) from the lunar interior, or be formed by chemical reactions between hydrogen in the solar wind and oxygen in the regolith. PSRs typically occur in topographic depressions near the lunar poles. Because of the low Sun angle, these areas haven’t seen sunlight for up to billions of years, so are perpetually in extreme cold. Ice molecules are thought to be repeatedly dislodged from the regolith by meteorites, space radiation, or sunlight and travel across the lunar surface until they land in a PSR where they are entrapped by extreme cold. The PSR’s continuously cold surfaces can preserve ice molecules near the surface for perhaps billions of years, where they may accumulate into a deposit that is rich enough to mine. Ice is thought to be quickly lost on surfaces that are exposed to direct sunlight, which precludes their accumulations.
The team used LRO’s Lunar Exploration Neutron Detector (LEND) instrument to detect signs of ice deposits by measuring moderate-energy, “epithermal” neutrons. Specifically, the team used LEND’s Collimated Sensor for Epithermal Neutrons (CSETN) that has a fixed 18.6-mile (30-kilometer) diameter field-of-view. Neutrons are created by high-energy galactic cosmic rays that come from powerful deep-space events such as exploding stars, that impact the lunar surface, break up regolith atoms, and scatter subatomic particles called neutrons. The neutrons, which can originate from up to about a 3.3-foot (meter’s) depth, ping-pong their way through the regolith, running into other atoms. Some get directed into space, where they can be detected by LEND. Since hydrogen is about the same mass as a neutron, a collision with hydrogen causes the neutron to lose relatively more energy than a collision with most common regolith elements. So, where hydrogen is present in regolith, its concentration creates a corresponding reduction in the observed number of moderate-energy neutrons.
“We hypothesized that if all PSRs have the same hydrogen concentration, then CSETN should proportionally detect their hydrogen concentrations as a function of their areas. So, more hydrogen should be observed towards the larger-area PSRs,” said McClanahan.
The model was developed from a theoretical study that demonstrated how similarly hydrogen-enhanced PSRs would be detected by CSETNs fixed-area field-of-view. The correlation was demonstrated using the neutron emissions from 502 PSRs with areas ranging from 1.5 square miles (4 km2) to 417 square miles (1079 km2) that contrasted against their surrounding less hydrogen-enhanced areas. The correlation was expectedly weak for the small PSRs but increased towards the larger-area PSRs.
The research was sponsored by the LRO project science team, NASA’s Goddard Space Flight Center’s Artificial Intelligence Working Group, and NASA grant award number 80GSFC21M0002. The study was conducted using NASA’s LRO Diviner radiometer and Lunar Orbiter Laser Altimeter instruments. The LEND instrument was developed by the Russian Space Agency, Roscosmos by its Space Research Institute (IKI). LEND was integrated to the LRO spacecraft at the NASA Goddard Space Flight Center. LRO is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at NASA Headquarters in Washington.
Share
Details
Last Updated Oct 03, 2024 Editor wasteigerwald Contact wasteigerwald william.a.steigerwald@nasa.gov Location Goddard Space Flight Center Related Terms
Earth’s Moon Lunar Reconnaissance Orbiter (LRO) Uncategorized Explore More
6 min read NASA’s LRO Discovers Lunar Hydrogen More Abundant on Moon’s Pole-Facing Slopes
Space travel is difficult and expensive – it would cost thousands of dollars to launch…
Article
10 years ago
4 min read NASA’s LRO Finds Lunar Pits Harbor Comfortable Temperatures
NASA-funded scientists have discovered shaded locations within pits on the Moon that always hover around…
Article
2 years ago
4 min read NASA’s LRO Spacecraft Captures Images of LADEE’s Impact Crater
NASA’S Lunar Reconnaissance Orbiter (LRO) spacecraft has spied a new crater on the lunar surface;…
Article
10 years ago
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.