Tag Archives: Ryugu

Asteroid Ryugu Samples Indicate Possible Arrival of DNA Components from Space

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Samples retrieved from the C-type asteroid (162173) Ryugu by JAXA’s Hayabusa 2 mission reveal the presence of all five essential nucleobases: purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil). This finding suggests that fundamental aspects of life’s chemistry might have a cosmic origin.

Hayabusa2’s image of asteroid Ryugu taken from a distance of 6.9 miles, featuring a large crater at its center. Image credit: JAXA / University of Tokyo and partners.

Nucleobases are critical components of DNA and RNA, the molecules essential for life on Earth.

The detection of these compounds in pristine extraterrestrial materials enables scientists to explore how they form in non-biological contexts and how they traverse the solar system.

Prior analyses of Ryugu samples identified the nucleobase uracil. In comparison, investigations of materials from meteorites and the near-Earth asteroid Bennu have uncovered a broader spectrum of nucleobases.

“To properly evaluate the nucleobases within extraterrestrial materials, it’s crucial to examine samples minimally impacted by terrestrial factors,” explained Dr. Toshiki Koga from the Japan Agency for Marine-Earth Science and Technology and his team.

“In this scenario, raw asteroid samples that haven’t come into contact with Earth’s atmosphere hold significant scientific importance.”

Carbonate-rich particles found in the material samples from the near-Earth asteroid Ryugu. Image credit: Pilorget and colleagues, doi: 10.1038/s41550-021-01549-z.

The recent study involved analyzing two samples from Ryugu, collected by the Hayabusa 2 mission.

Both samples showed the presence of all five standard nucleobases: adenine, guanine, cytosine, thymine, and uracil.

The team compared their results with findings from the Murchison and Orgueil meteorites, as well as samples from the asteroid Bennu.

Significant differences in the relative quantities of nucleobases were observed.

Specifically, Ryugu exhibited roughly equal amounts of purine and pyrimidine nucleobases, whereas the Murchison meteorite showed a predominance of purines, while Bennu and Orgueil samples were richer in pyrimidines.

These variations reflect the distinct chemical, environmental, and evolutionary pathways of each parent body.

The identification of these nucleobases in asteroid and meteorite samples indicates their widespread presence across the solar system, despite chemical variations.

This discovery implies that carbonaceous asteroids may have played a role in shaping Earth’s early chemical landscape.

“Studying the original distribution and isotopic composition of nucleobases in other carbonaceous meteorites will yield key insights into the origins of these compounds and the astrochemical processes involving nitrogen-based molecules,” the researchers noted.

“The universal detection of all five standard nucleobases in Ryugu and Bennu samples underscores the potential for these extraterrestrial molecules to have contributed to the organic material that facilitated prebiotic molecular evolution, ultimately leading to the emergence of RNA and DNA on early Earth.”

Read the full study featured in this week’s issue of Nature Astronomy.

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Tetsuya Koga et al. A comprehensive set of standard nucleobases from the carbonaceous asteroid (162173) Ryugu. Nat Astron, published online March 16, 2026. doi: 10.1038/s41550-026-02791-z

Source: www.sci.news

Asteroid Ryugu: A Treasure Trove of Life’s Essential Building Blocks

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Hayabusa2 spacecraft captures images of the Ryugu asteroid and returns rock samples to Earth.

Ryugu: An asteroid that occasionally approaches Earth.

Credit: JAXA

Recent discoveries from samples collected from the asteroid Ryugu indicate that all five key components of DNA and RNA have been identified. This finding substantiates the theory that asteroids could have played a crucial role in delivering the fundamental building blocks of life to Earth billions of years ago.

In 2018, Japan’s Hayabusa2 spacecraft successfully visited Ryugu, employing two projectiles—one large and one small—to gather samples from the asteroid’s surface. After returning to Earth with these samples in 2020, scientific analysis has been ongoing.

Dr. Yasuhiro Ohba and a team of researchers from Hokkaido University analyzed two distinct samples from Ryugu: surface material and subsurface material obtained from the excavation caused by the projectile. The findings revealed all five major nucleobases, which are essential components that pair with sugars and phosphates to create nucleic acids, including DNA and RNA.

This isn’t the first instance of nucleobases being detected in asteroid samples; they have also been found in meteorities and samples from the asteroid Bennu. However, researchers observed variability in the abundance of nucleobases across different samples, pointing toward the potential to trace asteroids and meteorites back to their original celestial bodies, thus unraveling their evolutionary history.

The detection of nucleobases in samples from Ryugu and other asteroids highlights their potential significance in the history of life on Earth. “Their presence in Ryugu reinforces their prevalence throughout the solar system,” states Ohba. If these asteroids are indeed abundant in the precursors of DNA, they may have been instrumental in the emergence of life on our planet.

Furthermore, Ryugu and similar asteroids might harbor even more complex organic molecules, including nucleic acids. “Complex organic compounds like DNA and RNA are likely to form in asteroids,” notes Ohba, underscoring their critical role in the origin of life on Earth.

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  • Asteroid/
  • Extraterrestrial Life

Source: www.newscientist.com

Scientists Reveal That Liquid Water Once Flowed Through the Parent Body of Asteroid Ryugu

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This water flow took place on ancient asteroids over a billion years after their formation, likely due to the heat generated by melting ice, which caused rock fractures that facilitated water movement. JAXA’s Hayabusa-2 Spacecraft.

This image of the asteroid was taken on June 26, 2018, by JAXA’s Hayabusa-2 Spacecraft optical navigation camera – telescopic (ONC-T). Image credits: JAXA / University of Tokyo / Kochi University / Ricchiho University / Nagoya University / Chiba University of Technology / Nishimura University / Aizu University / AIST.

Ryugu is a CG-type asteroid close to Earth and part of the Polana family of impact asteroids.

The diamond-shaped body, also known as 1999 JU3, was identified by astronomers in May 1999 during asteroid studies near Lincoln.

Its diameter measures about 900 m (0.56 miles), and it orbits the Sun at a distance of 0.96-1.41 Astronomical Units (AU) every 474 days.

“We have a relatively good understanding of how the solar system was formed, though many gaps remain,” said Shiyoshijima, a researcher at the University of Tokyo.

“One gap in our knowledge is how Earth acquired its water.”

“It has long been known that carbonaceous asteroids, originating from ice and dust in the outer solar system, have contributed water to Earth.”

“We discovered that Ryugu preserves an unaltered record of water activity, indicating that liquid water moved through the rock much later than previously anticipated,” added Dr. Ikemoto.

“This shifts our understanding of the long-term fate of water on asteroids. The water has remained for an extended period and hasn’t been depleted as quickly as we thought.”

In this study, the authors examined the isotopes of lutetium (Lu) and hafnium (HF), with the radioactive decay from lutetium-176 to hafnium-176 serving as a sort of clock to gauge geological processes.

The expected presence of these isotopes in the studied sample was hypothesized to correlate with the asteroid’s age in a predictable manner.

However, the ratio of Hafnium-176 to Lutetium-176 was significantly unexpected.

This strongly suggests to researchers that the liquid effectively washed away lutetium from the rocks containing it.

“We anticipated that Ryugu’s chemical signatures would align with certain meteorites currently under examination on Earth,” Dr. Iizuka stated.

“However, the results were strikingly different, necessitating the careful elimination of other possible explanations, ultimately concluding that the Lu-HF system was hindered by a delayed liquid flow.”

“The most probable triggers involved the parent body of Ryugu’s larger asteroid, which disrupted the rocks, melting the embedded ice and allowing liquid water to permeate the body.”

“It was truly surprising! This impact event could be the catalyst for the parent body disruption.”

One of the crucial implications is that carbon-rich asteroids may be a significant source of water for Earth, supplying far more than previously estimated.

Ryugu’s parent body seems to have retained ice for over a billion years. This suggests that similar bodies impacting the young Earth could have delivered 2-3 times more water than standard models predict, significantly influencing the planet’s early oceans and atmosphere.

“The notion that a Ryugu-like object has preserved ice for such an extended time is remarkable,” Dr. Ikemoto remarked.

“It implies that Earth’s components were far wetter than we had imagined.”

“This prompts a reevaluation of the initial conditions for the planetary water system.”

“It’s still early to draw definitive conclusions, but my team and others may build on this research to clarify various aspects, including how our planet became habitable.”

The findings will be published in the journal Nature.

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T. Iizuka et al. Late fluid flow of primitive asteroids revealed by Lu-HF isotopes of Lu. Nature. Published online on September 10th, 2025. doi:10.1038/s41586-025-09483-0

Source: www.sci.news

The Asteroid Ryugu Once Harbored Liquid Water

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Asteroid Ryugu captured by Hayabusa 2 spacecraft

Credit: JAXA Hayabusa 2

A significant amount of water once cascaded along the surface of an asteroid, indicating that asteroids may have delivered more water to Earth than previously believed.

The source of Earth’s water remains somewhat enigmatic. Although incoming asteroids are considered potential contributors, skepticism exists regarding their ability to supply the vast quantities of water present on Earth today.

Carbonate asteroids develop from dust and ice in the outer solar system. In 2019, Japan’s Hayabusa 2 spacecraft landed on Ryugu and collected 5.4 grams of material, returning it to Earth in 2020.

Initial images of Ryugu suggested it was drier than anticipated, but further studies revealed the presence of cracks once filled with vital elements, including water.

Early dating of the samples indicated that the asteroid was among the oldest celestial objects, originating around 460 million years ago.

However, when Tsuyoshi Itsuka from the University of Tokyo and his team assessed its age using the radioactive decay of lutetium-176 in tiny asteroid samples, they found something intriguing.

“Our analysis estimates the age of the Ryugu sample at about 4.8 billion years, significantly predating the solar system,” notes Ikemoto. “This indicates the timing of Ryugu’s sample collection is critical.”

Instead, the researchers believe that roughly a billion years after its parent body was formed, Ryugu was warmed enough to convert ice into water, which in turn removed some lutetium-176, complicating dating techniques.

Solar radiation warms only the surface ice to about 40 centimeters, while the Ryugu samples were extracted from much deeper layers. Researchers suggest that collisions with other celestial objects may explain how the interior of the parent body was heated.

By estimating the volume of water required to alter the lutetium-176 levels in the Ryugu samples, the team concluded that the asteroid consists of roughly 20-30% water.

Ikemoto asserts that asteroids are believed to have delivered water to Earth in mineral form. “Our findings imply that they can actually provide water as both minerals and ice,” he adds.

The research highlights the value of sample-return missions, according to Jonti Horner from the University of South Queensland, who was not involved in this study. “By retrieving samples directly, we eliminate Earth’s interference, enhancing the validity of our findings,” Horner explains.

“This suggests that these bodies were wetter than previously thought, allowing us to better understand the origins of Earth’s oceans as we analyze early planetary formation,” he concludes.

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Source: www.newscientist.com