Members Can Post Anonymously On This Site
NASA's Great Observatories May Unravel 400-Year Old Supernova Mystery
-
Similar Topics
-
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.
Share
Details
Last Updated Nov 21, 2024 EditorWilliam SteigerwaldContactNancy N. Jonesnancy.n.jones@nasa.govLocationGoddard Space Flight Center Related Terms
Astrobiology Explore More
2 min read NASA-Funded Study Examines Tidal Effects on Planet and Moon Interiors
NASA-supported scientists have developed a method to compute how tides affect the interiors of planets…
Article 2 weeks ago 2 min read NASA’s New Edition of Graphic Novel Features Europa Clipper
NASA has released a new edition of Issue 4 of the Astrobiology Graphic History series.…
Article 3 weeks ago 4 min read NASA’s Perseverance Captures ‘Googly Eye’ During Solar Eclipse
Article 3 weeks ago View the full article
-
By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA’s Voyager 2 captured this image of Uranus while flying by the ice giant in 1986. New research using data from the mission shows a solar wind event took place during the flyby, leading to a mystery about the planet’s magnetosphere that now may be solved.NASA/JPL-Caltech NASA’s Voyager 2 flyby of Uranus decades ago shaped scientists’ understanding of the planet but also introduced unexplained oddities. A recent data dive has offered answers.
When NASA’s Voyager 2 spacecraft flew by Uranus in 1986, it provided scientists’ first — and, so far, only — close glimpse of this strange, sideways-rotating outer planet. Alongside the discovery of new moons and rings, baffling new mysteries confronted scientists. The energized particles around the planet defied their understanding of how magnetic fields work to trap particle radiation, and Uranus earned a reputation as an outlier in our solar system.
Now, new research analyzing the data collected during that flyby 38 years ago has found that the source of that particular mystery is a cosmic coincidence: It turns out that in the days just before Voyager 2’s flyby, the planet had been affected by an unusual kind of space weather that squashed the planet’s magnetic field, dramatically compressing Uranus’ magnetosphere.
“If Voyager 2 had arrived just a few days earlier, it would have observed a completely different magnetosphere at Uranus,” said Jamie Jasinski of NASA’s Jet Propulsion Laboratory in Southern California and lead author of the new work published in Nature Astronomy. “The spacecraft saw Uranus in conditions that only occur about 4% of the time.”
The first panel of this artist’s concept depicts how Uranus’s magnetosphere — its protective bubble — was behaving before the flyby of NASA’s Voyager 2. The second panel shows an unusual kind of solar weather was happening during the 1986 flyby, giving scientists a skewed view of the magnetosphere.NASA/JPL-Caltech Magnetospheres serve as protective bubbles around planets (including Earth) with magnetic cores and magnetic fields, shielding them from jets of ionized gas — or plasma — that stream out from the Sun in the solar wind. Learning more about how magnetospheres work is important for understanding our own planet, as well as those in seldom-visited corners of our solar system and beyond.
That’s why scientists were eager to study Uranus’ magnetosphere, and what they saw in the Voyager 2 data in 1986 flummoxed them. Inside the planet’s magnetosphere were electron radiation belts with an intensity second only to Jupiter’s notoriously brutal radiation belts. But there was apparently no source of energized particles to feed those active belts; in fact, the rest of Uranus’ magnetosphere was almost devoid of plasma.
The missing plasma also puzzled scientists because they knew that the five major Uranian moons in the magnetic bubble should have produced water ions, as icy moons around other outer planets do. They concluded that the moons must be inert with no ongoing activity.
Solving the Mystery
So why was no plasma observed, and what was happening to beef up the radiation belts? The new data analysis points to the solar wind. When plasma from the Sun pounded and compressed the magnetosphere, it likely drove plasma out of the system. The solar wind event also would have briefly intensified the dynamics of the magnetosphere, which would have fed the belts by injecting electrons into them.
The findings could be good news for those five major moons of Uranus: Some of them might be geologically active after all. With an explanation for the temporarily missing plasma, researchers say it’s plausible that the moons actually may have been spewing ions into the surrounding bubble all along.
Planetary scientists are focusing on bolstering their knowledge about the mysterious Uranus system, which the National Academies’ 2023 Planetary Science and Astrobiology Decadal Survey prioritized as a target for a future NASA mission.
JPL’s Linda Spilker was among the Voyager 2 mission scientists glued to the images and other data that flowed in during the Uranus flyby in 1986. She remembers the anticipation and excitement of the event, which changed how scientists thought about the Uranian system.
“The flyby was packed with surprises, and we were searching for an explanation of its unusual behavior. The magnetosphere Voyager 2 measured was only a snapshot in time,” said Spilker, who has returned to the iconic mission to lead its science team as project scientist. “This new work explains some of the apparent contradictions, and it will change our view of Uranus once again.”
Voyager 2, now in interstellar space, is almost 13 billion miles (21 billion kilometers) from Earth.
News Media Contacts
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-6215
gretchen.p.mccartney@jpl.nasa.gov
2024-156
Share
Details
Last Updated Nov 11, 2024 Related Terms
Voyager 2 Heliophysics Jet Propulsion Laboratory Magnetosphere Solar Wind Uranus Uranus Moons Explore More
6 min read Powerful New US-Indian Satellite Will Track Earth’s Changing Surface
Article 3 days ago 2 min read Hurricane Helene’s Gravity Waves Revealed by NASA’s AWE
On Sept. 26, 2024, Hurricane Helene slammed into the Gulf Coast of Florida, inducing storm…
Article 4 days ago 3 min read Bundling the Best of Heliophysics Education: DigiKits for Physics and Astronomy Teachers
For nearly a decade, the American Association of Physics Teachers (AAPT) has been working to…
Article 6 days ago Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Tessa Keating is a public affairs specialist in the Office of Communications at NASA’s Stennis Space Center. Keating plans onsite logistics, serves as a protocol officer, and coordinates the Space Flight Awareness Program for NASA Stennis and the NASA Shared Services Center.NASA/Danny Nowlin Every task at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, is not simply work for Tessa Keating – it is a meaningful step toward a part of something great.
“It has been a dream career. I count it an honor to share the NASA story and humbled to know our team witnesses a part of history,” said Keating, a NASA public affairs specialist in the NASA Stennis Office of Communications. “Every day is an opportunity to contribute to the NASA legacy that will last beyond today. “
Keating plans onsite logistics, serves as a protocol officer, and coordinates the Space Flight Awareness Program for NASA Stennis and the NASA Shared Services Center. In fact, she organized much of the recent Space Flight Awareness Silver Snoopy Award ceremony at NASA Stennis in August, except for one part. As the ceremony finished, NASA Stennis Director John Bailey said one more award was to be given.
No one was more surprised than the logistics coordinator herself when Keating’s family joined her on stage. The 21-year NASA Stennis employee was honored for her outstanding contributions in sharing the NASA story of exploring the secrets of the universe for the benefit of all with a diverse audience and for equipping everyone with a broader knowledge and appreciation of the center’s vital role within NASA.
“I am not sure I will ever be able to top that in my NASA career,” Keating said.
It became a full-circle moment that she described as a great honor. The Silver Snoopy is the astronauts’ personal award and is presented to less than 1 percent of the total NASA workforce. Reid Wiseman, a NASA astronaut and commander for the upcoming Artemis II mission around the Moon, presented the award to Keating, along with a lapel pin flown aboard NASA’s Artemis I mission.
As NASA returns to the Moon for scientific discovery, economic benefits, and inspiration for the Artemis Generation, Keating says it will be extra-special watching Wiseman and the Artemis II crew lay the groundwork for future milestones.
Keating helped lay the groundwork ahead of the successful Artemis I mission. She served as lead logistics for onsite guest operations in 2021 when NASA conducted the most powerful propulsion test in more than 40 years at NASA Stennis. A full-duration hot fire of the first SLS (Space Launch System) core stage and its four RS-25 engines culminated a year-long series of integrated tests. Keating coordinated the viewing of the hot fire for some 200 agency leaders and guests, despite restricted settings due to COVID-19.
“It was truly a highlight. I had grown up hearing my parents and grandparents talk about engines that were tested during the Apollo era, and I had never experienced something of that magnitude,” Keating said. “I was able to live it, feel it, and watch the next part of NASA history onsite.”
For Keating, the groundwork for a NASA career came following graduation with a bachelor’s degree in Journalism from William Carey University and a master’s degree in Communications from The University of Southern Mississippi, both schools in Hattiesburg, Mississippi. Having grown up in Pearl River County, Mississippi, for most of her life, she knew about NASA Stennis. However, she did not think she could ever work at the center because her strengths were in areas beyond math and science.
Following some additional exploration and conversations with influential people in her life, Keating discovered she, in fact, could be a part of something great at NASA Stennis.
“The possibilities are endless at NASA when you allow yourself to put your best foot forward and research the many opportunities that are available. There is always room for various types of studies,” Keating said. “I credit where I am in my career to God and to the people who have helped to guide my path. I will be forever grateful.”
Learn more about the people who work at NASA Stennis View the full article
-
By NASA
NASA, ESA, R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation), and M. Mutchler and R. Avila (STScI) This image, released on Feb. 24, 2017, shows Supernova 1987a (center) surrounded by dramatic red clouds of gas and dust within the Large Magellanic Cloud. This supernova, first discovered on Feb. 23, 1987, blazed with the power of 100 million Suns. Since that first sighting, SN 1987A has continued to fascinate astronomers with its spectacular light show. Located in the nearby Large Magellanic Cloud, it was the nearest supernova explosion observed in hundreds of years and the best opportunity yet for astronomers to study the phases before, during, and after the death of a star.
Image credit: NASA, ESA, R. Kirshner (Harvard-Smithsonian Center for Astrophysics and Gordon and Betty Moore Foundation), and M. Mutchler and R. Avila (STScI)
View the full article
-
By USH
Last Monday, paraglider Alex Lang was flying high above the Great Pyramid of Giza when he noticed unexpected movement at its peak. To his surprise, it wasn't a person, but a dog perched at the top of the ancient monument.
Image credit: Alex Lang.
Lang, who recorded the bizarre sighting, described the dog barking and chasing birds from the very summit of the pyramid.
The footage left people both fascinated and confused, wondering how the dog had managed to scale such an immense structure. Some even joked that it might be a manifestation of Anubis, god of funerary practices and care of the dead. However, the main concern was whether the dog could safely make its way back down.
Luckily, a few days later, the dog was captured on video making its way down the ancient landmark, appearing calm and unscathed, as if the climb had been no big deal.
Image credit: abcnews.
Link video dog making its way down.https://www.tiktok.com/@abcnews/video/7427042186371386654/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.