Jump to content

Recommended Posts

Posted
low_keystone.png

Now you see it, now you don't. Douglas Clowe of Ohio University in Athens, Ohio, is reporting on new Hubble observations that do not find an unusually dense clump of dark matter in the universe that a different Hubble team reported on earlier this year. The region of interest lies at the center of a collision among massive galaxy clusters in Abell 520, located 2.4 billion light-years away. "The earlier result presented a mystery. But in our observations we didn't see anything surprising in the core," said Clowe. "Our measurements are in complete agreement with how we would expect dark matter to behave." Because dark matter is not visible, its presence and distribution is found indirectly through its gravitational effects. The gravity from both dark and luminous matter warps space, bending and distorting light from galaxies and clusters behind it like a giant magnifying glass. Astronomers can use this effect, called gravitational lensing, to infer the presence of dark matter in massive galaxy clusters. Both teams used this technique to map the dark matter in the merging cluster. Clowe is encouraging other scientists to study the Hubble data and conduct their own analysis on the cluster.

View the full article

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.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By European Space Agency
      Iceland is one of the most active volcanic regions in the world, but its seismic nature is part of a much broader geological history.
      In a groundbreaking discovery, scientists, supported by an ESA-funded project, have uncovered the underlying forces that forged the North Atlantic’s fiery volcanic past – shedding light on the vast geological region that spans from Greenland to western Europe, which is home to iconic natural wonders like the Giant’s Causeway in Northern Ireland. 
      View the full article
    • By USH
      Since November 2024, strange blinking lights have been reported worldwide, an unexplained phenomenon that’s left many puzzled. MrMBB333 believes he may have found a connection. 

      Also known as electrical pollution, dirty electricity refers to high-frequency voltage spikes that ride along standard power lines. These rogue signals, forms of electromagnetic interference (EMI), can spread through our infrastructure, causing devices to glitch or behave unpredictably. 
      If this interference is appearing globally, the source might be something massive, possibly deep within Earth’s core. Rogue frequencies from the core could travel up and interact with power grids, solar systems, and transmission lines, triggering widespread anomalies. 
      Supporting this idea is a discovery from NASA’s ANITA project in Antarctica. While searching for cosmic neutrinos, scientists instead detected impossible radio signals rising from deep within Earth, signals that defy current physics.  
      According to current science, these waves should have been absorbed by the Earth’s crust long before reaching the detectors. But they weren’t. 
      When researchers checked their findings against other experiments, nothing lined up. This means they didn’t detect neutrinos, but something entirely unknown. Could this be a new kind of particle? A glitch in reality? Or something even stranger? 
      Although it is not known whether the strange radio signals detected deep beneath the Antarctic ice are related to the rogue signals believed to originate from Earth's core, MrMBB333 suggests there could be a connection. He proposes that similar forms of electromagnetic interference (EMI) might be disrupting global electronics and even contributing to the mysterious blinking light phenomenon. 
      Another possible factor at play is that the magnetic field is weakening as well as Solar Cycle 25 — the current 11-year cycle of solar activity marked by the Sun’s magnetic field reversal and increasing sunspot activity. This cycle began in December 2019 and is expected to reach its peak in 2025. 
      Therefore, could this solar phenomenon be interfering with the rogue electromagnetic signals from the Earth’s core are behind the strange blinking lights observed around the world? 
      If that’s the case, although I don’t recall the blinking light phenomenon ever appearing this intensely before, then the strange lights may begin to fade as Solar Cycle 25 winds down. Still, that doesn’t explain the origin of the mysterious radio signals rising from deep beneath Antarctica’s ice.
        View the full article
    • By Space Force
      Second Lt. Katherine Hendl escorted the remains of her great-great-uncle, a U.S. Army Air Forces gunner killed in action during World War II, home to Massachusetts nearly 80 years after he was declared missing in action.

      View the full article
    • By NASA
      A funky effect Einstein predicted, known as gravitational lensing — when a foreground galaxy magnifies more distant galaxies behind it — will soon become common when NASA’s Nancy Grace Roman Space Telescope begins science operations in 2027 and produces vast surveys of the cosmos.
      This image shows a simulated observation from NASA’s Nancy Grace Roman Space Telescope with an overlay of its Wide Field Instrument’s field of view. More than 20 gravitational lenses, with examples shown at left and right, are expected to pop out in every one of Roman’s vast observations. A journal paper led by Bryce Wedig, a graduate student at Washington University in St. Louis, Missouri, estimates that of those Roman detects, about 500 from the telescope’s High-Latitude Wide-Area Survey will be suitable for dark matter studies. By examining such a large population of gravitational lenses, the researchers hope to learn a lot more about the mysterious nature of dark matter.Credit: NASA, Bryce Wedig (Washington University), Tansu Daylan (Washington University), Joseph DePasquale (STScI) A particular subset of gravitational lenses, known as strong lenses, is the focus of a new paper published in the Astrophysical Journal led by Bryce Wedig, a graduate student at Washington University in St. Louis. The research team has calculated that over 160,000 gravitational lenses, including hundreds suitable for this study, are expected to pop up in Roman’s vast images. Each Roman image will be 200 times larger than infrared snapshots from NASA’s Hubble Space Telescope, and its upcoming “wealth” of lenses will vastly outpace the hundreds studied by Hubble to date.
      Roman will conduct three core surveys, providing expansive views of the universe. This science team’s work is based on a previous version of Roman’s now fully defined High-Latitude Wide-Area Survey. The researchers are working on a follow-up paper that will align with the final survey’s specifications to fully support the research community.
      “The current sample size of these objects from other telescopes is fairly small because we’re relying on two galaxies to be lined up nearly perfectly along our line of sight,” Wedig said. “Other telescopes are either limited to a smaller field of view or less precise observations, making gravitational lenses harder to detect.”
      Gravitational lenses are made up of at least two cosmic objects. In some cases, a single foreground galaxy has enough mass to act like a lens, magnifying a galaxy that is almost perfectly behind it. Light from the background galaxy curves around the foreground galaxy along more than one path, appearing in observations as warped arcs and crescents. Of the 160,000 lensed galaxies Roman may identify, the team expects to narrow that down to about 500 that are suitable for studying the structure of dark matter at scales smaller than those galaxies.
      “Roman will not only significantly increase our sample size — its sharp, high-resolution images will also allow us to discover gravitational lenses that appear smaller on the sky,” said Tansu Daylan, the principal investigator of the science team conducting this research program. Daylan is an assistant professor and a faculty fellow at the McDonnell Center for the Space Sciences at Washington University in St. Louis. “Ultimately, both the alignment and the brightness of the background galaxies need to meet a certain threshold so we can characterize the dark matter within the foreground galaxies.”
      To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video
      This video shows how a background galaxy’s light is lensed or magnified by a massive foreground galaxy, seen at center, before reaching NASA’s Roman Space Telescope. Light from the background galaxy is distorted, curving around the foreground galaxy and appearing more than once as warped arcs and crescents. Researchers studying these objects, known as gravitational lenses, can better characterize the mass of the foreground galaxy, which offers clues about the particle nature of dark matter.Credit: NASA, Joseph Olmsted (STScI) What Is Dark Matter?
      Not all mass in galaxies is made up of objects we can see, like star clusters. A significant fraction of a galaxy’s mass is made up of dark matter, so called because it doesn’t emit, reflect, or absorb light. Dark matter does, however, possess mass, and like anything else with mass, it can cause gravitational lensing.
      When the gravity of a foreground galaxy bends the path of a background galaxy’s light, its light is routed onto multiple paths. “This effect produces multiple images of the background galaxy that are magnified and distorted differently,” Daylan said. These “duplicates” are a huge advantage for researchers — they allow multiple measurements of the lensing galaxy’s mass distribution, ensuring that the resulting measurement is far more precise.
      Roman’s 300-megapixel camera, known as its Wide Field Instrument, will allow researchers to accurately determine the bending of the background galaxies’ light by as little as 50 milliarcseconds, which is like measuring the diameter of a human hair from the distance of more than two and a half American football fields or soccer pitches.
      The amount of gravitational lensing that the background light experiences depends on the intervening mass. Less massive clumps of dark matter cause smaller distortions. As a result, if researchers are able to measure tinier amounts of bending, they can detect and characterize smaller, less massive dark matter structures — the types of structures that gradually merged over time to build up the galaxies we see today.
      With Roman, the team will accumulate overwhelming statistics about the size and structures of early galaxies. “Finding gravitational lenses and being able to detect clumps of dark matter in them is a game of tiny odds. With Roman, we can cast a wide net and expect to get lucky often,” Wedig said. “We won’t see dark matter in the images — it’s invisible — but we can measure its effects.”
      “Ultimately, the question we’re trying to address is: What particle or particles constitute dark matter?” Daylan added. “While some properties of dark matter are known, we essentially have no idea what makes up dark matter. Roman will help us to distinguish how dark matter is distributed on small scales and, hence, its particle nature.”
      Preparations Continue
      Before Roman launches, the team will also search for more candidates in observations from ESA’s (the European Space Agency’s) Euclid mission and the upcoming ground-based Vera C. Rubin Observatory in Chile, which will begin its full-scale operations in a few weeks. Once Roman’s infrared images are in hand, the researchers will combine them with complementary visible light images from Euclid, Rubin, and Hubble to maximize what’s known about these galaxies.
      “We will push the limits of what we can observe, and use every gravitational lens we detect with Roman to pin down the particle nature of dark matter,” Daylan said.
      The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory in Southern California; Caltech/IPAC in Pasadena, California; the Space Telescope Science Institute in Baltimore; and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems, Inc. in Boulder, Colorado; L3Harris Technologies in Melbourne, Florida; and Teledyne Scientific & Imaging in Thousand Oaks, California.
      By Claire Blome
      Space Telescope Science Institute, Baltimore, Md.
      Share
      Details
      Last Updated Jun 12, 2025 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationNASA Goddard Space Flight Center Related Terms
      Nancy Grace Roman Space Telescope Astrophysics Dark Matter Galaxies Galaxies, Stars, & Black Holes Galaxies, Stars, & Black Holes Research The Universe Explore More
      6 min read NASA’s Roman Mission Shares Detailed Plans to Scour Skies
      Article 2 months ago 5 min read Millions of Galaxies Emerge in New Simulated Images From NASA’s Roman
      Article 2 years ago 6 min read Team Preps to Study Dark Energy via Exploding Stars With NASA’s Roman
      Article 3 months ago View the full article
    • By NASA
      Jack Kaye [NASA HQ—Associate Director for Research, Earth Science Division (ESD)] has decided to retire on April 30, 2025, following 42 years of service to NASA – see Photo 1. Most recently, Kaye served as associate director for research of the Earth Science Division (ESD) within NASA’s Science Mission Directorate (SMD). In this position, he was responsible for the research and data analysis programs for Earth System Science that addressed the broad spectrum of scientific disciplines from the stratopause to the poles to the oceans.
      Photo 1. Jack Kaye [NASA HQ—Associate Director for Research, Earth Science Division (ESD)] retired from NASA on April 30, 2025, after a 42-year career. Photo credit: Public Domain A New York native, Kaye’s interest in space was piqued as a child watching early NASA manned space launches on television. He would often write to NASA to get pictures of the astronauts. In high school, he started an after school astronomy club. Despite a youthful interest in Earth science, as he explained in a 2014 “Maniac Talk” at NASA’s Goddard Space Flight Center, Kaye pursued a slightly different academic path. He obtained a Bachelor’s of Science in chemistry from Adelphi University in 1976 and a Ph.D. in theoretical physical chemistry at the California Institute of Technology in 1982. For his graduate studies, he focused on the quantum mechanics of chemical reactions with an aim toward being able to understand and calculate the activity.
      Following graduate school, Kaye secured a post-doctoral position at the U.S. Naval Research Laboratory, where he studied the chemistry of Earth’s atmosphere with a focus on stratospheric ozone. It was while working in a group of meteorologists at NASA’s Goddard Space Flight Center that Kaye returned to his roots and refocused his scientific energy on studying Earth.
      “NASA had a mandate to study stratospheric ozone,” Kaye said in an interview in 2009. “I got involved in looking at satellite observations and especially trying to interpret satellite observations of stratospheric composition and building models to simulate things, to look both ways, to use the models and use the data.”
      Kaye has held numerous science and leadership positions at NASA. He began his career at GSFC as a researcher for the Stratospheric General Circulation and Chemistry Modeling Project (SGCCP) from 1983–1990 working on stratospheric modeling.  In this role, he also worked on an Earth Observing System Interdisciplinary proposal.  His first role at NASA HQ was managing  as program scientist for the Atmospheric Chemistry Modeling and Analysis Program (ACMAP), as well as numerous other missions. In this role, he was a project scientist for the Atmospheric Laboratory for Applications and Science (ATLAS) series of Shuttle missions. While managing ATLAS, Kaye oversaw the science carried out by a dozen instruments from several different countries. He also managed several other Earth Science missions during this time. See the link to Kaye’s “Maniac Talk.”
      Kaye entered the Senior Executive Service in 1999, where he continued to contribute to the agency by managing NASA’s Earth Science Research Program. In addition, Kaye has held temporary acting positions as deputy director of ESD and deputy chief scientist for Earth Science within SMD. Throughout his career he has focused on helping early-career investigators secure their first awards to establish their career path—see Photo 2.
      Photo 2. Throughout his career, Jack Kaye has been an advocate for young scientists, helping them get established in their careers. Here, Kaye speaks with the Climate Change Research Initiative cohort at the Mary W. Jackson NASA Headquarters building in Washington, DC on August 7, 2024. The Earth Science Division’s Early Career Research Program’s Climate Change Research Initiative is a year-long STEM engagement and experiential learning opportunity for educators and students from high school to graduate level. Photo Credit: NASA/Joel Kowsky On numerous occasions, Kaye spoke to different groups emphasizing the agency’s unique role in both developing and utilizing cutting-edge technology, especially remote observations of Earth with different satellite platforms – see Photo 3. With the launch of five new NASA Earth science campaigns in 2020, Kaye stated, “These innovative investigations tackle difficult scientific questions that require detailed, targeted field observations combined with data collected by our fleet of Earth-observing satellites.”
      Photo 3. Jack Kaye hands out eclipse posters and other outreach materials to attendees at Eclipse Fest 2024. Photo credit: GRC https://science.nasa.gov/science-research/earth-science/looking-back-on-looking-up-the-2024-total-solar-eclipse/ Kaye has also represented NASA in interagency and international activities and has been an active participant in the U.S. Global Change Research Program (USGCRP), where he has served for many years as NASA principal of the Subcommittee on Global Change Research. He served as NASA’s representative to the Subcommittee on Ocean Science and Technology and chaired the World Meteorological Organization Expert Team on Satellite Systems. Kaye was named an honorary member of the Asia Oceania Geoscience Society in 2015. He previously completed a six-year term as a member of the Steering Committee for the Global Climate Observing System and currently serves an ex officio member of the National Research Council’s Roundtable on Science and Technology for Sustainability and the Chemical Sciences Roundtable, as well as a member of the Roundtable on Global Science Diplomacy.
      NASA has honored Kaye with numerous awards, including the Distinguished Service Medal in 2022 and the Meritorious Executive in the Senior Executive Service in 2004, 2010, and 2021. In 2024 he was awarded the NASA-USGS Pecora Individual Award honoring excellence in Earth Observation. He was named a Fellow by the American Meteorological Society in 2010 and by the American Association of the Advancement of Science (AAAS) in 2014. Kaye was elected to serve as an office of the Atmospheric and Hydrospheric Science section of the AAAS (2015–2018). AGU has recognized him on two occasions with a Citation for Excellence in Refereeing.
      Over the course of his career Kaye has published more than 50 papers, contributed to numerous reports, books, and encyclopedias, and edited the book Isotope Effects in Gas-Phase Chemistry for the American Chemical Society. In addition, he has attended the Leadership for Democratic Society program at the Federal Executive Institute and the Harvard Senior Managers in Government Program at the John F. Kennedy School of Government at Harvard University.
      “The vantage point of space provides a way to look at the Earth globally, with the ability to observe Earth’s interacting components of air, water, land and ice, and both naturally occurring and human-induced processes,” Kaye said in a November 2024 article published by Penn State University. “It lets us look at variability on a broad range of spatial and temporal scales and given the decades of accomplishments, has allowed us to characterize and document Earth system variability on time scales from minutes to decades.”
      View the full article
  • Check out these Videos

×
×
  • Create New...