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What are Transmedium Objects? Avi Loeb, Ph.D. on the possibility of life beyond Earth
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The mystery of why life uses molecules with specific orientations has deepened with a NASA-funded discovery that RNA — a key molecule thought to have potentially held the instructions for life before DNA emerged — can favor making the building blocks of proteins in either the left-hand or the right-hand orientation. Resolving this mystery could provide clues to the origin of life. The findings appear in research recently published in Nature Communications.
Proteins are the workhorse molecules of life, used in everything from structures like hair to enzymes (catalysts that speed up or regulate chemical reactions). Just as the 26 letters of the alphabet are arranged in limitless combinations to make words, life uses 20 different amino acid building blocks in a huge variety of arrangements to make millions of different proteins. Some amino acid molecules can be built in two ways, such that mirror-image versions exist, like your hands, and life uses the left-handed variety of these amino acids. Although life based on right-handed amino acids would presumably work fine, the two mirror images are rarely mixed in biology, a characteristic of life called homochirality. It is a mystery to scientists why life chose the left-handed variety over the right-handed one.
A diagram of left-handed and right-handed versions of the amino acid isovaline, found in the Murchison meteorite.NASA DNA (deoxyribonucleic acid) is the molecule that holds the instructions for building and running a living organism. However, DNA is complex and specialized; it “subcontracts” the work of reading the instructions to RNA (ribonucleic acid) molecules and building proteins to ribosome molecules. DNA’s specialization and complexity lead scientists to think that something simpler should have preceded it billions of years ago during the early evolution of life. A leading candidate for this is RNA, which can both store genetic information and build proteins. The hypothesis that RNA may have preceded DNA is called the “RNA world” hypothesis.
If the RNA world proposition is correct, then perhaps something about RNA caused it to favor building left-handed proteins over right-handed ones. However, the new work did not support this idea, deepening the mystery of why life went with left-handed proteins.
The experiment tested RNA molecules that act like enzymes to build proteins, called ribozymes. “The experiment demonstrated that ribozymes can favor either left- or right-handed amino acids, indicating that RNA worlds, in general, would not necessarily have a strong bias for the form of amino acids we observe in biology now,” said Irene Chen, of the University of California, Los Angeles (UCLA) Samueli School of Engineering, corresponding author of the Nature Communications paper.
In the experiment, the researchers simulated what could have been early-Earth conditions of the RNA world. They incubated a solution containing ribozymes and amino acid precursors to see the relative percentages of the right-handed and left-handed amino acid, phenylalanine, that it would help produce. They tested 15 different ribozyme combinations and found that ribozymes can favor either left-handed or right-handed amino acids. This suggested that RNA did not initially have a predisposed chemical bias for one form of amino acids. This lack of preference challenges the notion that early life was predisposed to select left-handed-amino acids, which dominate in modern proteins.
“The findings suggest that life’s eventual homochirality might not be a result of chemical determinism but could have emerged through later evolutionary pressures,” said co-author Alberto Vázquez-Salazar, a UCLA postdoctoral scholar and member of Chen’s research group.
Earth’s prebiotic history lies beyond the oldest part of the fossil record, which has been erased by plate tectonics, the slow churning of Earth’s crust. During that time, the planet was likely bombarded by asteroids, which may have delivered some of life’s building blocks, such as amino acids. In parallel to chemical experiments, other origin-of-life researchers have been looking at molecular evidence from meteorites and asteroids.
“Understanding the chemical properties of life helps us know what to look for in our search for life across the solar system,” said co-author Jason Dworkin, senior scientist for astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and director of Goddard’s Astrobiology Analytical Laboratory.
Dworkin is the project scientist on NASA’s OSIRIS-REx mission, which extracted samples from the asteroid Bennu and delivered them to Earth last year for further study.
“We are analyzing OSIRIS-REx samples for the chirality (handedness) of individual amino acids, and in the future, samples from Mars will also be tested in laboratories for evidence of life including ribozymes and proteins,” said Dworkin.
The research was supported by grants from NASA, the Simons Foundation Collaboration on the Origin of Life, and the National Science Foundation. Vázquez-Salazar acknowledges support through the NASA Postdoctoral Program, which is administered by Oak Ridge Associated Universities under contract with NASA.
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Last Updated Nov 21, 2024 EditorWilliam SteigerwaldContactNancy N. Jonesnancy.n.jones@nasa.govLocationGoddard Space Flight Center Related Terms
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By NASA
Earth Observer Earth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives 9 min read
The Earth Observer Editor’s Corner: Fall 2024
On September 18, 2024, the National Oceanic and Atmospheric Administration (NOAA) shared the first images of the Western Hemisphere from the GOES-19 satellite, its newest geostationary satellite launched on June 25, 2024 onboard a Falcon Heavy rocket from NASA’s Kennedy Space Center. Previously known as GOES-U, the satellite was renamed GOES-19 upon reaching geostationary orbit on July 7, 2024. GOES-19 orbits about 35,785 km above the equator at the same speed the Earth rotates, allowing the satellite to constantly view the same area of the planet and track weather conditions and hazards as they happen. The satellite’s Advanced Baseline Imager (ABI) instrument recently captured stunning views of Earth in 16 spectral channels. This data provides researchers information about Earth’s atmosphere, land, and ocean for short-term forecasts and tracking severe weather – see Figure. ABI data is also used for detecting and monitoring environmental hazards, such as wildfires, smoke, dust storms, volcanic eruptions, turbulence, and fog. Data from multiple ABI channels can be combined to create imagery that approximates what the human eye would see from space referred to as GeoColor (see Figure).
Figure. [Left] The GOES-19 images show the contiguous U.S. observed by each of the Advanced Baseline Imager’s (ABI) 16 channels on August 30, 2024, at 6:00 PM UTC. This 16-panel image [progressing left to right, across each row] shows the ABI’s two visible (gray scale), four near-infrared (IR) (gray scale), and 10 infrared channels (warmer brightness temperatures of the IR bands map to warmer colors). Each band’s appearance illustrates how it reflects or absorbs radiation. [Right] The GOES-19 full disk GeoColor image combines data from multiple ABI channels to approximate what the human eye would see from space. Figure Credit: NOAA GOES-19 is the final satellite in NOAA’s GOES-R series and serves as a bridge to a new age of advanced satellite technology. NOAA and NASA are currently developing NOAA’s next generation geostationary satellites, called Geostationary Extended Observations (GeoXO), to advance operational geostationary Earth observations.
NASA Earth sciences celebrated several satellite milestone anniversaries in 2024. The Global Precipitation Measurement (GPM) Core Observatory (CO) celebrated its 10th anniversary in February while Aura and Orbiting Carbon Observatory–2 (OCO–2) celebrated their 20th and 10th anniversaries, respectively, in July. Here, we focus on GPM and Aura.
The GPM CO launched on February 27, 2024, aboard a Japanese H-IIA rocket from Tanegashima Space Center in southern Japan, as a joint Earth-observing mission between NASA and the Japan Aerospace Exploration Agency (JAXA). To celebrate its 10th anniversary, GPM has been hosting special outreach activities. One example is the GPM 10-in-10 webinar series that began on February 8, 2024. This series of 10 public webinars explores GPM and the story behind the mission, which is aimed at anyone interested in science, technology, engineering, mathematics, and the synergy of these disciplines to better understand and protect our home planet.
Now over 10 years into the mission, GPM continues to provide important data on precipitation around the globe leading to new scientific discoveries and contributing data to help society, from monitoring storms to supporting weather forecasts and aiding water-borne disease public health alerts.
As an example, GPM made several passes of Hurricane Milton, which made landfall near Siesta Key, FL on October 9, 2024 as a Category 3 storm. As a complement to GPM CO observations, a multi-satellite sensor IMERG animation shows rainfall rates and accumulation over the course of Milton’s history.
To read more about how GPM continues to observe important precipitation characteristics and gain physical insights into precipitation processes, please see the article “GPM Celebrates Ten Years of Observing Precipitation for Science and Society” in The Earth Observer.
The last of NASA’s three EOS Flagships – Aura – marked 20 years in orbit on July 15, 2024, with a celebration on September 18, 2024, at Goddard Space Flight Center’s (GSFC) Recreational Center. The 120 attendees – including about 40 participating virtually – reminisced about Aura’s (originally named EOS-CHEM) tumultuous beginning, from the instrument and Principal Investigator (PI) selections up until the delayed launch at Vandenberg Space Force Base (then Air Force Base) in California. They remembered how Bill Townsend, who was Deputy Director of GSFC at the time, and Ghassem Asrar, who was NASA’s Associate Administrator for Earth Science, spent many hours on site negotiating with the Vandenberg and Boeing launch teams in preparation for launch (after several delays and aborts). Photo 1 shows the Aura mission program scientist, project scientists (PS), and several instrument principal investigators (PI) at Vandenberg shortly before launch.
Photo 1. The Aura (formerly EOS CHEM) mission program scientist, project scientists (PS), and several of instrument principal investigators (PI) at Vandenberg Space Force Base (then Air Force Base) shortly before launch on July 15, 2004. The individuals pictured [left to right] are Reinhold Beer [NASA/Jet Propulsion Laboratory (JPL)—Tropospheric Emission Spectrometer (TES) PI]; John Gille [University of Colorado, Boulder/National Center for Atmospheric Research (NCAR)—High Resolution Dynamics Limb Sounder (HIRDLS) PI]; Pieternel Levelt [Koninklijk Nederlands Meteorologisch Instituut (KNMI), Royal Netherlands Meteorological Institute—Ozone Monitoring Instrument (OMI) PI]; Ernest Hilsenrath [NASA’s Goddard Space Flight Center (GSFC)—Aura Deputy Scientist and U.S. OMI Co-PI]; Anne Douglass [GSFC—Aura Deputy PS]; Mark Schoeberl [GSFC—Aura Project Scientist];Joe Waters [NASA/JPL—Microwave Limb Sounder (MLS) PI]; P.K. Bhartia [GSFC—OMI Science Team Leader and former Aura Project Scientist]; and Phil DeCola [NASA Headquarters—Aura Program Scientist]. NOTE: Affiliations/titles listed for individuals named were those at the time of launch. Photo Credit: Ernest Hilsenrath At the anniversary event, Bryan Duncan [GSFC—Aura Project Scientist] gave formal opening remarks. Aura’s datasets have given a generation of scientists the most comprehensive global view of gases in Earth’s atmosphere to better understand the chemical and dynamic processes that shape their concentrations. Aura’s objective was to gather data to monitor Earth’s ozone layer, examine trends in global air pollutants, and measure the concentration of atmospheric constituents contributing to climate forcing. To read more about Aura’s incredible 20 years of accomplished air quality and climate science, see the anniversary article “Aura at 20 Years” in The Earth Observer.
To read more about the anniversary event, see Summary of Aura 20th Anniversary Event.
It has been over a year and a half since the Surface Water and Ocean Topography (SWOT) mission began collecting data on the height of nearly all water on Earth’s surface, including oceans, lakes, rivers, and reservoirs. During that time, data collected by the satellite has started to improve our understanding of energy in the ocean, yielding insights on surface currents and waves, internal tides, the vertical mixing of seawater, as well as atmosphere–ocean interactions. Notably, SWOT has been measuring the amplitude of solitary internal waves in the ocean. These waves reflect the dynamics of internal tides (tides that occur deep in the ocean rather than at the surface) that can influence biological productivity as well as ocean energy exchanges through their contribution to mixing and general oceanic circulation.
SWOT measurements are also being used to study inland and coastal flooding to inform water management strategies. Earlier this year, researchers used SWOT data to measure the total volume of water during major floods in southern Brazil in April to improve understanding of these events and prepare for the future. In addition, the Water Ministry of Bangladesh is working to incorporate SWOT water elevation maps, along with other near-real time satellite data, into their flood forecasts. Researchers at Alexandria University, Egypt are using SWOT data in the Nile River Basin to improve dam operations. A detailed account of SWOT Significant Events since launch is available online. To learn more about project status and explore the many facets of operational and applied uses of SWOT data, please see The Earth Observer article, “Summary of the 10th SWOT Applications Workshop.”
In September 2024, the Plankton, Aerosol, Cloud, ocean Ecosystem–Postlaunch Airborne eXperiment (PACE–PAX) gathered data for the validation of the PACE mission, which launched in February 2024. The operations spanned Southern and Central California and nearby coastal regions, logging 81 flight hours for the NASA ER-2, which operated out of NASA’s Armstrong Flight Research Center (AFRC) in Edwards, CA, and 60 hours for Twin Otter aircraft, which was operated by the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) at the Naval Postgraduate School (Monterey, CA) out of Marina Municipal Airport in Marina, CA – see Photo 2.
Photo 2. The Twin Otter aircraft operated out of the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) during the Plankton, Aerosol, Cloud, ocean Ecosystem–Postlaunch Airborne eXperiment (PACE–PAX) campaign. The image shows the Twin Otter aircraft missing the approach at Marina Airport to check instrument performance on the aircraft against identical instrumentation on an airport control tower. Photo credit: ???TBD ??? Congratulations to PACE-PAX leads Kirk Knobelspiesse [GSFC], Brian Cairns [NASA Goddard Institute for Space Studies (GISS)], and Ivona Cetinić [GSFC/Morgan State University] for successfully executing and planning this campaign. PACE–PAX data will be available in March 2025 via NASA’s Langley Research Center Suborbital Science Data for Atmospheric Composition website and NASA’s SeaWiFS Bio-optical Archive and Storage System (SeaBASS).
Photo 3. Clockwise from top left: Mike Ondrusek (NOAA), mission scientist of the R/V Shearwater, waves to the Naval Postgraduate School (NPS) Twin Otter as it samples at low altitude. Bridge fire in San Gabriel mountains, September 10, 2024. Photo by NASA ER-2 pilot Kirt Stallings. Carl Goodwin (JPL) performs calibration reference measurements at Ivanpah Playa, California. Scott Freeman (GSFC) and Harrison Smith (GSFC) deploy instrumentation from the R/V Shearwater in the Santa Barbara Channel. Instrument integration on the NASA ER-2 in preparation for PACE-PAX. San Francisco observed by the NPS Twin Otter as it samples at low altitude over the San Francisco Bay. The R/V Shearwater seen from the NPS Twin Otter. Photo credit: ???TBD ??? Shifting venues, NASA’s BlueFlux Campaign conducted a series of ground-based and airborne fieldwork missions out of the Miami Homestead Air Reserve Base and the Miami Executive Airport in Miami-Dade County, which are adjacent to the eastern border of the Everglades National Park. The full study region – broadly referred to as South Florida – is narrowly defined by the wetland ecosystems that extend from Lake Okeechobee and its Northern estuaries to the saltwater marshland and mangrove forests along the state’s southernmost shore.
Glenn Wolfe [GSFC] and Erin Delaria [GSFC/UMD] organized more than 34 flights across 5 separate fieldwork deployments during the campaign. The data during BlueFlux are intended to contribute to a more robust understanding of how Florida’s coastal ecology fits into the carbon cycle. The article, “NASA’s BlueFlux Campaign Supports Blue Carbon Management in South Florida,” provides additional information about this program, which was made possible by David Lagomasino [East Carolina University], Cheryl Doughty [GSFC/UMD], Lola Fatoyinbo [GSFC], and Peter Raymond [Yale University].
To learn more about PACE-PAX and BlueFlux, see: Updates on NASA Field Campaigns.
Notable recent Science Support Office (SSO) outreach activities include the 2024 Eclipse outreach and engagement efforts on April 7, 2024, in Kerrville, TX and Cleveland, OH. The two locations are among a dozen that NASA set up along path of totality. To read about the 2024 Total Solar Eclipse through the eyes of NASA outreach and engagement activities, please see The Earth Observer feature article, “Looking Back on Looking Up: The 2024 Total Solar Eclipse.”
The SSO also supported the United Nations (UN) Summit of the Future event and the 79th General Assembly High Level week, September 19–27, 2024 at UN Headquarters (HQ) in New York City, NY. SSO supported the NASA Sea Level Change Team (N-SLCT) during the High-level Meeting on Sea-Level Rise by having Hyperwall content available for the release of the new Pacific Flooding Analysis Tool. NASA Administrator Bill Nelson visited the Hyperwall on September 23 with Aarti Holla-Maini [UN Office for Outer Space Affairs (UNOOSA)—Director]. Karen St. Germain [NASA HQ—Director of the Earth Science Division], Julie Robinson [NASA HQ—Deputy Director of the Earth Science Division], Kate Calvin [NASA HQ—NASA Chief Scientist], Lesley Ott [GSFC— Climate Scientist], and Anjali Tripathi [NASA/Jet Propulsion Laboratory (JPL)—Astrophysicist] talked with delegates and members about NASA Science and accessed NASA global datasets. Photos from the event are available at the SSO Flickr Page.
Looking ahead, the SSO is once again leading the planning and logistics for the NASA exhibit at the American Geophysical Union (AGU) Fall Meeting, which will be held December 9–13, 2024 in Washington, DC. Nearly 40 NASA projects and missions will have hands-on activities within the perimeter of the NASA Science exhibit, from the James Webb Space Telescope to the Airborne Science Fleet. The NASA Hyperwall, a video wall used for visual-forward science storytelling, will host approximately 50 Hyperwall stories and presentations throughout the meeting, including presentations delivered by the 2024 winners of the NASA-funded AGU Michael H. Freilich Student Visualization Competition. The exhibit will also feature roughly 40 tech demonstrations throughout the week, covering a wide range of hands-on introductions to everything from the capabilities of the OpenSpace data visualization software to the scientific applications of augmented reality. Please be sure to stop by the NASA exhibit when you are at AGU.
Steve Platnick
EOS Senior Project Scientist
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Last Updated Nov 14, 2024 Related Terms
Earth Science View the full article
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By European Space Agency
Today, the European Space Agency signed six contracts that will help position Greece as a key player in the field of Earth observation.
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