Jump to content

NASA Researchers Discover More Dark Comets


Recommended Posts

  • Publishers
Posted
This artist’s concept shows interstellar object 1I/2017 U1 (‘Oumuamua) after its discovery in 2017. While itself not a dark comet, ‘Oumuamua’s motion through the solar system has helped researchers better understand the nature of the 14 dark comets discovered so far.
This artist’s concept shows interstellar object 1I/2017 U1 (‘Oumuamua) after its discovery in 2017. While itself not a dark comet, ‘Oumuamua’s motion through the solar system has helped researchers better understand the nature of the 14 dark comets discovered so far.
European Southern Observatory / M. Kornmesser

These celestial objects look like asteroids but act like comets now come in two flavors.

The first dark comet — a celestial object that looks like an asteroid but moves through space like a comet — was reported less than two years ago. Soon after, another six were found. In a new paper, researchers announce the discovery of seven more, doubling the number of known dark comets, and find that they fall into two distinct populations: larger ones that reside in the outer solar system and smaller ones in the inner solar system, with various other traits that set them apart.

The findings were published on Monday, Dec. 9, in the Proceedings of the National Academy of Sciences.

Scientists got their first inkling that dark comets exist when they noted in a March 2016 study that the trajectory of “asteroid” 2003 RM had moved ever so slightly from its expected orbit. That deviation couldn’t be explained by the typical accelerations of asteroids, like the small acceleration known as the Yarkovsky effect.

“When you see that kind of perturbation on a celestial object, it usually means it’s a comet, with volatile material outgassing from its surface giving it a little thrust,” said study coauthor Davide Farnocchia of NASA’s Jet Propulsion Laboratory in Southern California. “But try as we might, we couldn’t find any signs of a comet’s tail. It looked like any other asteroid — just a pinpoint of light. So, for a short while, we had this one weird celestial object that we couldn’t fully figure out.”

Weird Celestial Objects

Farnocchia and the astronomical community didn’t have to wait long for another piece of the puzzle. The next year, in 2017, a NASA-sponsored telescope discovered history’s first documented celestial object that originated outside our solar system. Not only did 1I/2017 U1 (‘Oumuamua) appear as a single point of light, like an asteroid, its trajectory changed as if it were outgassing volatile material from its surface, like a comet.

“‘Oumuamua was surprising in several ways,” said Farnocchia. “The fact that the first object we discovered from interstellar space exhibited similar behaviors to 2003 RM made 2003 RM even more intriguing.”

By 2023, researchers had identified seven solar system objects that looked like asteroids but acted like comets. That was enough for the astronomical community to bestow upon them their own celestial object category: “dark comets.” Now, with the finding of seven more of these objects, researchers could start on a new set of questions.

“We had a big enough number of dark comets that we could begin asking if there was anything that would differentiate them,” said Darryl Seligman, a postdoctoral fellow in the department of Physics at Michigan State University, East Lansing, and lead author of the new paper. “By analyzing the reflectivity,” or albedo, “and the orbits, we found that our solar system contains two different types of dark comets.”

Two Kinds of Dark Comets

The study’s authors found that one kind, which they call outer dark comets, have similar characteristics to Jupiter-family comets: They have highly eccentric (or elliptical) orbits and are on the larger side (hundreds of meters or more across).

The second group, inner dark comets, reside in the inner solar system (which includes Mercury, Venus, Earth, and Mars), travel in nearly circular orbits, and are on the smaller side (tens of meters or less).

Like so many astronomical discoveries, Seligman and Farnocchia’s research not only expands on our knowledge of dark comets, but it also raises several additional questions: Where did dark comets originate? What causes their anomalous acceleration? Could they contain ice?

“Dark comets are a new potential source for having delivered the materials to Earth that were necessary for the development of life,” said Seligman. “The more we can learn about them, the better we can understand their role in our planet’s origin.”

For more information about asteroids and comets, visit:

https://www.jpl.nasa.gov/topics/asteroids/

News Media Contacts

Ian J. O’Neill
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-2649
ian.j.oneill@jpl.nasa.gov

Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov

Bethany Mauger
Michigan State University, East Lansing
maugerbe@msu.edu

2024-168

Share

Details

Last Updated
Dec 09, 2024
Keep Exploring

Discover More Topics From NASA

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 NASA
      1 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      NASA Marshall will hold a candle-lighting ceremony and wreath placement at 9:30 a.m. CST. The ceremony will include remarks from Larry Leopard, associate director, and Bill Hill, director of Marshall’s Office of Safety and Mission Assurance. NASA/ Krisdon Manecke NASA’s Marshall Space Flight Center in Huntsville, Alabama, invites media to attend its observance of the agency’s Day of Remembrance at 9:30 a.m. CST Thursday, Jan. 23, in the lobby of Building 4221.
      Day of Remembrance honors the members of the NASA family who lost their lives while furthering the cause of exploration and discovery. 
      The event will include brief remarks from NASA Marshall leaders, followed by a candle lighting and moment of silence for the crews of Apollo 1 and space shuttles Challenger and Columbia. Speakers will include:
      Larry Leopard, associate director, technical. Bill Hill, director, Office of Safety and Mission Assurance. Media interested in attending the event must confirm by 12 p.m. Wednesday, Jan. 22, with Molly Porter at: molly.a.porter@nasa.gov.
      The agency will also pay tribute to its fallen astronauts with special online content, updated on NASA’s Day of Remembrance, at: 
      https://www.nasa.gov/dor/
      Molly Porter
      Marshall Space Flight Center, Huntsville, Ala.
      256-424-5158
      molly.a.porter@nasa.gov
      Share
      Details
      Last Updated Jan 21, 2025 EditorBeth RidgewayContactMolly Portermolly.a.porter@nasa.govLocationMarshall Space Flight Center Related Terms
      Marshall Space Flight Center Explore More
      5 min read Exoplanets Need to Be Prepared for Extreme Space Weather, Chandra Finds
      Article 5 days ago 4 min read NASA Instrument on Firefly’s Blue Ghost Lander to Study Lunar Interior
      Article 2 weeks ago 3 min read NASA to Test Solution for Radiation-Tolerant Computing in Space
      Article 2 weeks ago Keep Exploring Discover Related Topics
      Missions
      Humans in Space
      Climate Change
      Solar System
      View the full article
    • By NASA
      NASA’s Jet Propulsion Laboratory used radar data taken by ESA’s Sentinel-1A satellite before and after the 2015 eruption of the Calbuco volcano in Chile to create this inter-ferogram showing land deformation. The color bands west of the volcano indicate land sinking. NISAR will produce similar images.ESA/NASA/JPL-Caltech A SAR image — like ones NISAR will produce — shows land cover on Mount Okmok on Alaska’s Umnak Island . Created with data taken in August 2011 by NASA’s UAVSAR instrument, it is an example of polarimetry, which measures return waves’ orientation relative to that of transmitted signals.NASA/JPL-Caltech Data from NASA’s Magellan spacecraft, which launched in 1989, was used to create this image of Crater Isabella, a 108-mile-wide (175-kilometer-wide) impact crater on Venus’ surface. NISAR will use the same basic SAR principles to measure properties and characteristics of Earth’s solid surfaces.NASA/JPL-Caltech Set to launch within a few months, NISAR will use a technique called synthetic aperture radar to produce incredibly detailed maps of surface change on our planet.
      When NASA and the Indian Space Research Organization’s (ISRO) new Earth satellite NISAR (NASA-ISRO Synthetic Aperture Radar) launches in coming months, it will capture images of Earth’s surface so detailed they will show how much small plots of land and ice are moving, down to fractions of an inch. Imaging nearly all of Earth’s solid surfaces twice every 12 days, it will see the flex of Earth’s crust before and after natural disasters such as earthquakes; it will monitor the motion of glaciers and ice sheets; and it will track ecosystem changes, including forest growth and deforestation.  
      The mission’s extraordinary capabilities come from the technique noted in its name: synthetic aperture radar, or SAR. Pioneered by NASA for use in space, SAR combines multiple measurements, taken as a radar flies overhead, to sharpen the scene below. It works like conventional radar, which uses microwaves to detect distant surfaces and objects, but steps up the data processing to reveal properties and characteristics at high resolution.
      To get such detail without SAR, radar satellites would need antennas too enormous to launch, much less operate. At 39 feet (12 meters) wide when deployed, NISAR’s radar antenna reflector is as wide as a city bus is long. Yet it would have to be 12 miles (19 kilometers) in diameter for the mission’s L-band instrument, using traditional radar techniques, to image pixels of Earth down to 30 feet (10 meters) across.
      Synthetic aperture radar “allows us to refine things very accurately,” said Charles Elachi, who led NASA spaceborne SAR missions before serving as director of NASA’s Jet Propulsion Laboratory in Southern California from 2001 to 2016. “The NISAR mission will open a whole new realm to learn about our planet as a dynamic system.”
      Data from NASA’s Magellan spacecraft, which launched in 1989, was used to create this image of Crater Isabella, a 108-mile-wide (175-kilometer-wide) impact crater on Venus’ surface. NISAR will use the same basic SAR principles to measure properties and characteristics of Earth’s solid surfaces.NASA/JPL-Caltech How SAR Works
      Elachi arrived at JPL in 1971 after graduating from Caltech, joining a group of engineers developing a radar to study Venus’ surface. Then, as now, radar’s allure was simple: It could collect measurements day and night and see through clouds. The team’s work led to the Magellan mission to Venus in 1989 and several NASA space shuttle radar missions.
      An orbiting radar operates on the same principles as one tracking planes at an airport. The spaceborne antenna emits microwave pulses toward Earth. When the pulses hit something — a volcanic cone, for example — they scatter. The antenna receives those signals that echo back to the instrument, which measures their strength, change in frequency, how long they took to return, and if they bounced off of multiple surfaces, such as buildings.
      This information can help detect the presence of an object or surface, its distance away, and its speed, but the resolution is too low to generate a clear picture. First conceived at Goodyear Aircraft Corp. in 1952, SAR addresses that issue.
      “It’s a technique to create high-resolution images from a low-resolution system,” said Paul Rosen, NISAR’s project scientist at JPL.
      As the radar travels, its antenna continuously transmits microwaves and receives echoes from the surface. Because the instrument is moving relative to Earth, there are slight changes in frequency in the return signals. Called the Doppler shift, it’s the same effect that causes a siren’s pitch to rise as a fire engine approaches then fall as it departs.
      Computer processing of those signals is like a camera lens redirecting and focusing light to produce a sharp photograph. With SAR, the spacecraft’s path forms the “lens,” and the processing adjusts for the Doppler shifts, allowing the echoes to be aggregated into a single, focused image.
      Using SAR
      One type of SAR-based visualization is an interferogram, a composite of two images taken at separate times that reveals the differences by measuring the change in the delay of echoes. Though they may look like modern art to the untrained eye, the multicolor concentric bands of interferograms show how far land surfaces have moved: The closer the bands, the greater the motion. Seismologists use these visualizations to measure land deformation from earthquakes.
      Another type of SAR analysis, called polarimetry, measures the vertical or horizontal orientation of return waves relative to that of transmitted signals. Waves bouncing off linear structures like buildings tend to return in the same orientation, while those bouncing off irregular features, like tree canopies, return in another orientation. By mapping the differences and the strength of the return signals, researchers can identify an area’s land cover, which is useful for studying deforestation and flooding.
      Such analyses are examples of ways NISAR will help researchers better understand processes that affect billions of lives.
      “This mission packs in a wide range of science toward a common goal of studying our changing planet and the impacts of natural hazards,” said Deepak Putrevu, co-lead of the ISRO science team at the Space Applications Centre in Ahmedabad, India.
      Learn more about NISAR at:
      https://nisar.jpl.nasa.gov
      News Media Contacts
      Andrew Wang / Jane J. Lee
      Jet Propulsion Laboratory, Pasadena, Calif.
      626-379-6874 / 818-354-0307
      andrew.wang@jpl.nasa.gov / jane.j.lee@jpl.nasa.gov
      2025-006
      Share
      Details
      Last Updated Jan 21, 2025 Related Terms
      NISAR (NASA-ISRO Synthetic Aperture Radar) Earth Earth Science Earth Science Division Jet Propulsion Laboratory Explore More
      4 min read NASA Scientists, Engineers Receive Presidential Early Career Awards 
      Article 4 days ago 6 min read NASA International Space Apps Challenge Announces 2024 Global Winners
      Article 5 days ago 3 min read NASA Scientists Find New Human-Caused Shifts in Global Water Cycle
      Article 5 days ago Keep Exploring Discover More Topics From NASA
      Missions
      Humans in Space
      Climate Change
      Solar System
      View the full article
    • By NASA
      Credit: NASA With Finland’s signing of the Artemis Accords on Tuesday, NASA celebrates the 53rd nation committing to the safe and responsible exploration of space that benefits humanity. The signing ceremony took place on the margins of the Aalto University’s Winter Satellite Workshop 2025 in Espoo, Finland.
      “Today, Finland is joining a community of nations that want to share scientific data freely, operate safely, and preserve the space environment for the Artemis Generation,” said NASA Associate Administrator Jim Free, who provided pre-recorded virtual remarks for the ceremony. “By signing the Artemis Accords, Finland builds on its rich history in space, excelling in science, navigation, and Earth observation. Forging strong partnerships between our nations and among the international community is critical for advancing our shared space exploration goals.”
      Wille Rydman, Finland’s minister of economic affairs, signed the Artemis Accords in front of an audience of Finnish space officials and workshop attendees.
      “Finland has been part of the space exploration community for decades with innovations and technology produced by Finnish companies and research institutions,” said Rydman. “The signing of the Artemis Accords is in line with Finland’s newly updated space strategy that highlights the importance of international cooperation and of strengthening partnerships with the Unites States and other allies. We aim for this cooperation to open great opportunities for the Finnish space sector in the new era of space exploration and in the Artemis program.”
      NASA and Finland have a long history of collaboration, and most recently, Finland is contributing to the upcoming Intuitive Machines-2 delivery to the Moon under NASA’s Artemis campaign and CLPS (Commercial Lunar Payload Services) initiative. Intuitive Machines will deliver a lunar LTE/4G communications system developed by Finnish company, Nokia. Its U.S. subsidiary, Nokia of America, was selected as part of NASA’s Tipping Point opportunity through the agency’s Space Technology Mission Directorate, to advance a lunar surface communications system that could help humans and robots explore more of the Moon than ever before.
      The Finnish Meteorological Institute also provided the pressure and humidity measurement instruments for the Environmental Monitoring Station instrument suite aboard the Curiosity Rover, operating on Mars now.
      In 2020, the United States, led by NASA and the U.S. Department of State, and seven other initial signatory nations established the Artemis Accords, a set of principles promoting the beneficial use of space for humanity.
      The Artemis Accords are grounded in the Outer Space Treaty and other agreements including the Registration Convention, the Rescue and Return Agreement, as well as best practices for responsible behavior that NASA and its partners have supported, including the public release of scientific data. 
      Learn more about the Artemis Accords at:
      https://www.nasa.gov/artemis-accords
      -end-
      Kathryn Hambleton / Elizabeth Shaw
      Headquarters, Washington
      202-358-1600
      kathryn.a.hambleton@nasa.gov / elizabeth.a.shaw@nasa.gov
      Share
      Details
      Last Updated Jan 21, 2025 LocationNASA Headquarters Related Terms
      artemis accords NASA Headquarters Office of International and Interagency Relations (OIIR) View the full article
    • By NASA
      4 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      A test rover with shape memory alloy spring tires traverses rocky, Martian-simulated terrain.Credit: NASA The mystique of Mars has been studied for centuries. The fourth planet from the Sun is reminiscent of a rich, red desert and features a rugged surface challenging to traverse. While several robotic missions have landed on Mars, NASA has only explored 1% of its surface. Ahead of future human and robotic missions to the Red Planet, NASA recently completed rigorous rover testing on Martian-simulated terrain, featuring revolutionary shape memory alloy spring tire technology developed at the agency’s Glenn Research Center in Cleveland in partnership with Goodyear Tire & Rubber.

      Rovers — mobile robots that explore lunar or planetary surfaces — must be equipped with adequate tires for the environments they’re exploring. As Mars has an uneven, rocky surface, durable tires are essential for mobility. Shape memory alloy (SMA) spring tires help make that possible.

      Shape memory alloys are metals that can return to their original shape after being bent, stretched, heated, and cooled. NASA has used them for decades, but applying this technology to tires is a fairly new concept.
      “We at Glenn are one of the world leaders in bringing the science and understanding of how you change the alloy compositions, how you change the processing of the material, and how you model these systems in a way that we can control and stabilize the behaviors so that they can actually be utilized in real applications,” said Dr. Santo Padula II, materials research engineer at NASA Glenn.
      Researchers from NASA’s Glenn Research Center and Airbus Defence & Space pose with a test rover on Martian-simulated terrain.Credit: NASA Padula and his team have tested several applications for SMAs, but his epiphany of the possibilities for tires came about because of a chance encounter.
      While leaving a meeting, Padula encountered Colin Creager, a mechanical engineer at NASA Glenn whom he hadn’t seen in years. Creager used the opportunity to tell him about the work he was doing in the NASA Glenn Simulated Lunar Operations (SLOPE) Laboratory, which can simulate the surfaces of the Moon and Mars to help scientists test rover performance. He brought Padula to the lab, where Padula immediately took note of the spring tires. At the time, they were made of steel.
      Padula remarked, “The minute I saw the tire, I said, aren’t you having problems with those plasticizing?” Plasticizing refers to a metal undergoing deformation that isn’t reversible and can lead to damage or failure of the component.
      “Colin told me, ‘That’s the only problem we can’t solve.’” Padula continued, “I said, I have your solution. I’m developing a new alloy that will solve that. And that’s how SMA tires started.”
      From there, Padula, Creager, and their teams joined forces to improve NASA’s existing spring tires with a game-changing material: nickel-titanium SMAs. The metal can accommodate deformation despite extreme stress, permitting the tires to return to their original shape even with rigorous impact, which is not possible for spring tires made with conventional metal.

      Credit: NASA Since then, research has been abundant, and in the fall of 2024, teams from NASA Glenn traveled to Airbus Defence and Space in Stevenage, United Kingdom, to test NASA’s innovative SMA spring tires. Testing took place at the Airbus Mars Yard — an enclosed facility created to simulate the harsh conditions of Martian terrain.
      “We went out there with the team, we brought our motion tracking system and did different tests uphill and back downhill,” Creager said. “We conducted a lot of cross slope tests over rocks and sand where the focus was on understanding stability because this was something we had never tested before.”
      During the tests, researchers monitored rovers as the wheels went over rocks, paying close attention to how much the crowns of the tires shifted, any damage, and downhill sliding. The team expected sliding and shifting, but it was very minimal, and testing met all expectations. Researchers also gathered insights about the tires’ stability, maneuverability, and rock traversal capabilities.
      As NASA continues to advance systems for deep space exploration, the agency’s Extravehicular Activity and Human Surface Mobility program enlisted Padula to research additional ways to improve the properties of SMAs for future rover tires and other potential uses, including lunar environments.
      “My goal is to extend the operating temperature capability of SMAs for applications like tires, and to look at applying these materials for habitat protection,” Padula said. “We need new materials for extreme environments that can provide energy absorption for micrometeorite strikes that happen on the Moon to enable things like habitat structures for large numbers of astronauts and scientists to do work on the Moon and Mars.”
      Researchers say shape memory alloy spring tires are just the beginning.
      Explore More
      4 min read NASA Scientists, Engineers Receive Presidential Early Career Awards 
      Article 4 days ago 3 min read NASA Scientists Find New Human-Caused Shifts in Global Water Cycle
      Article 5 days ago 6 min read New Simulated Universe Previews Panoramas From NASA’s Roman Telescope
      Article 7 days ago View the full article
    • By NASA
      This image from NASA’s James Webb Space Telescope shows the dwarf galaxy NGC 4449. ESA/Webb, NASA & CSA, A. Adamo (Stockholm University) and the FEAST JWST team President Biden has named 19 researchers who contribute to NASA’s mission as recipients of the Presidential Early Career Award for Scientists and Engineers (PECASE). These recipients are among nearly 400 federally funded researchers receiving the honor.  
      Established in 1996 by the National Science and Technology Council, the PECASE Award is the highest honor given by the U.S. government to scientists and engineers who are beginning their research careers. The award recognizes recipients’ potential to advance the frontiers of scientific knowledge and their commitment to community service, as demonstrated through professional leadership, education or community outreach. 
      “I am so impressed with these winners and what they have accomplished,” said Kate Calvin, chief scientist, NASA Headquarters in Washington. “They have made valuable contributions to NASA science and engineering, and I can’t wait to see what they do in the future.” 
      The following NASA recipients were nominated by the agency: 
      Natasha Batalha, NASA Ames Research Center, Silicon Valley, California – for transformational scientific research in the development of open-source systems for the modeling of exoplanet atmospheres and observations  Elizabeth Blaber, Rensselaer Polytechnic Institute, Troy, New York – for transformative spaceflight and ground-based space biology research  James Burns, University of Virginia, Charlottesville – for innovative research at the intersection of metallurgy, solid mechanics and chemistry   Egle Cekanaviciute, NASA Ames Research Center – for producing transformational research to enable long-duration human exploration on the Moon and Mars  Nacer Chahat, NASA Jet Propulsion Laboratory, Pasadena, California – for leading the innovation of spacecraft antennas that enable NASA deep space and earth science missions  Ellyn Enderlin, Boise State University, Idaho – for innovative methods to study glaciers using a wide variety of satellite datasets  David Estrada, Boise State University, Idaho – for innovative research in the areas of printed electronics for in space manufacturing and sensors for harsh environments  Burcu Gurkan, Case Western Reserve University, Cleveland, Ohio – for transforming contemporary approaches to energy storage and carbon capture to be safer and more economical, for applications in space and on Earth  Elliott Hawkes, University of California, Santa Barbara – for highly creative innovations in bio-inspired robotics that advance science and support NASA’s mission  John Hwang, University of California, San Diego – for innovative approach to air taxi design and key contributions to the urban air mobility industry   James Tuttle Keane, NASA Jet Propulsion Laboratory – for innovative and groundbreaking planetary geophysics research, and renowned planetary science illustrations  Kaitlin Kratter, University of Arizona, Tucson – for leadership in research about the formation and evolution of stellar and planetary systems beyond our own   Lyndsey McMillon-Brown, NASA Glenn Research Center, Cleveland, Ohio – for leadership in photovoltaic research, development, and demonstrations  Debbie Senesky, Stanford University, California – for research that has made it possible to operate sensing and electronic devices in high-temperature and radiation-rich environments  Hélène Seroussi, Dartmouth College, Hanover, New Hampshire  – for leading the cryosphere science community in new research directions about the role of ocean circulation in the destabilization of major parts of Antarctica’s ice sheets  Timothy Smith, NASA Glenn Research Center – for achievements in materials science research, specifically in high temperature alloy innovation  Mitchell Spearrin, University of California, Los Angeles – for pioneering scientific and technological advancements in multiple areas critical to NASA’s current and future space missions including rocket propulsion, planetary entry, and sensor systems  Michelle Thompson, Purdue University, West Lafayette, Indiana  – for research in planetary science and dedication to training the next generation of STEM leaders  Mary Beth Wilhelm, NASA Ames Research Center – for achievements in science, technology, and community outreach through her work in the fields of space science and astrobiology  The PECASE awards were created to highlight the importance of science and technology for America’s future. These early career awards foster innovative developments in science and technology, increase awareness of careers in science and engineering, provide recognition to the scientific missions of participating agencies, and enhance connections between research and challenges facing the nation. For a complete list of award winners, visit: 
      https://www.whitehouse.gov/ostp/news-updates/2025/01/14/president-biden-honors-nearly-400-federally-funded-early-career-scientists

      View the full article
  • Check out these Videos

×
×
  • Create New...