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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 European Space Agency
As Arctic temperatures rise, marine-terminating glaciers—especially in places like Svalbard—are undergoing rapid retreat and intensified calving.
The ESA-funded Space for Shore project utilises radar data from the Copernicus Sentinel-1 mission to provide precise, year-over-year insights into glacier retreat and calving intensity, particularly in areas like Kongsfjorden, where notable glaciers are experiencing significant retreat.
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By NASA
Peru’s Vice Minister of Defense Policies for Ministry of Defense César Medardo Torres Vega, NASA Administrator Bill Nelson, and Director of Peru’s National Commission for Aerospace Research and Development (CONIDA) Maj. Gen. Roberto Melgar Sheen meet in Lima, Peru, Nov. 14, 2024, where the U.S. and Peru signed a memorandum of understanding agreeing to study a potential sounding rocket campaign.Credit: U.S. Embassy Peru NASA and Peru’s National Commission for Aerospace Research and Development (CONIDA) laid the groundwork for a potential multi-year scientific rocket launch campaign in the South American country.
Both countries signed a non-binding memorandum of understanding Thursday that includes safety training, a joint feasibility study for the potential campaign, and technical assistance for CONIDA on sounding rocket launches. Sounding rockets are small, low-cost rockets that provide suborbital access to space.
“We are excited to look at the possibility of once again launching sounding rockets from Peru,” said NASA Administrator Bill Nelson, who signed on behalf of the United States. “This agreement deepens our international partnership with Peru and the scientific research we conduct because of the country’s location along the magnetic equator. Together we will go farther.”
Maj. Gen. Roberto Melgar Sheen, head of CONIDA, signed on behalf of Peru. Brian Nichols, assistant secretary for Western Hemisphere Affairs for the U.S. State Department, and Stephanie Syptak-Ramnath, U.S. ambassador to Peru, also participated, among other Peruvian officials. The event took place during the week of the Asia-Pacific Economic Cooperation forum beginning Nov. 9 in Lima.
During his visit to Peru, Nelson also discussed the importance of international partnerships and collaboration in space and celebrated Peru’s signing of the Artemis Accords earlier this year.
The United States and Peru have a long history of space cooperation. NASA conducted sounding rocket campaigns at CONIDA’s Punta Lobos launch base in 1975 and 1983.
NASA uses sounding rockets to carry scientific instruments into space on suborbital flights to collect important science data and test prototype instruments. They yield invaluable data that enhance our understanding of Earth’s atmosphere and weather, our solar system, and the universe, and test equipment for deeper space travel.
Understanding our Earth’s atmosphere and how it is influenced by the Sun is crucial to protecting ground and space-based assets that we rely on every day, from the power grid to weather data and even navigation.
For more information about NASA’s international partnerships, visit:
https://www.nasa.gov/oiir
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Meira Bernstein / Elizabeth Shaw
Headquarters, Washington
202-358-1600
meira.b.bernstein@nasa.gov / elizabeth.a.shaw@nasa.gov
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Last Updated Nov 14, 2024 EditorJessica TaveauLocationNASA Headquarters Related Terms
Office of International and Interagency Relations (OIIR) Sounding Rockets View the full article
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By USH
Throughout the years, reports of alien abductions have emerged from all corners of the globe.
An alien abduction is generally described as an event in which individuals report being taken against their will by extraterrestrial beings, often undergoing various forms of physical and psychological experimentation.
Some argue that these experiences could simply reflect the subconscious mind at work or suggest that the abductees may have unknowingly been subjects of classified military experiments. Nonetheless, many abductees share accounts with such remarkable detail and consistency that some researchers feel the phenomenon deserves serious consideration.
Over time, I’ve shared numerous articles on cases of alleged alien abductions, which you can explore under the "alien abduction" tag below the article.
Here are two more intriguing cases in which abductees recount their experiences in vivid detail, prompting us to seriously consider the possibility that people may actually be taken by aliens.
The Betty Andreasson Alien Abduction: A Strange Encounter in 1967
One of the most detailed and haunting accounts of alien abduction began on January 25, 1967, in South Ashburnham, Massachusetts. That evening, Betty Andreasson’s family experienced a power outage, followed by an eerie red light outside. Peering out, Betty’s father saw five strange beings approaching who soon entered the house, seemingly passing through solid walls. They communicated telepathically and temporarily froze the family in place.
These beings had distinctive appearances, with pear-shaped heads, wide eyes, and a calm, almost friendly aura. Betty was led to a spacecraft in her backyard and taken aboard, where she underwent strange tests and experienced an otherworldly vision. Hours later, she was returned home, and the aliens left her family unharmed. Initially, Betty viewed her experience through a religious lens, but over time, she came to see it as an alien encounter.
Years later, her story caught the attention of Dr. J. Allen Hynek, a leading UFO researcher. Under hypnosis, Betty’s fragmented memories resurfaced, revealing consistent details corroborated by her daughter, who had also been briefly unfrozen by the beings. After extensive testing and interviews, investigators concluded that Betty was credible and sincerely believed in what she described. The Betty Andreasson abduction remains one of the most compelling cases in UFO lore.
The 1974 Medicine Bow National Forest Abduction: Carl Higdon's Astonishing Encounter
Carl Higdon's hunting trip to Wyoming’s Medicine Bow National Forest in October 1974 took a surreal turn when he experienced one of the most bizarre UFO abduction cases on record. Aiming at an elk, Higdon was stunned to see his bullet slow mid-air and drop, seemingly defying physics. Moments later, he noticed an unusual figure—a tall being in a black jumpsuit with rod-like appendages instead of hands—who offered him pills, claiming that one would sustain him for days.
Higdon, inexplicably compliant, swallowed a pill and suddenly found himself in a transparent structure with two more beings and five frozen elk. He was told they were traveling 163,000 light-years away to the aliens' home planet, which he described as filled with towering structures and an intensely bright sun.
Two and a half hours later, Higdon was back in Medicine Bow, disoriented and missing his elk. Later medical tests revealed inexplicably high vitamin levels and the disappearance of old lung scars. Adding credibility to his story, other witnesses reported seeing strange lights in the area. Higdon’s experience remains a mysterious case.
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