NASA’s Curiosity Finds Organic Molecules Never Seen Before on Mars - UNIVERSE

NASA’s Curiosity Mars rover took this selfie on Oct. 25, 2020, after drilling a rock sample from a spot nicknamed “Mary Anning.” After years of extensive analysis, the sample has revealed the greatest diversity of organic molecules ever found on Mars.

NASA/JPL-Caltech/MSSS

After years of lab work, the results are in: A rock that NASA’s Curiosity Mars rover drilled and analyzed in 2020 includes the most diverse collection of organic molecules ever found on the Red Planet. Of the 21 carbon-containing molecules identified in the sample, seven of them were detected for the first time on Mars.

Scientists have no way of knowing whether these organic molecules were created by biologic or geologic processes — either path is possible — but their discovery renewed confirmation that ancient Mars had the right chemistry to support life. What’s more, the molecules join a growing list of compounds known to be preserved in rocks even after billions of years of exposure on Mars to radiation, which can break down these molecules over time.

The findings are detailed in a new paper published Tuesday in Nature Communications.

Curiosity’s Mastcam captured this mosaic on Feb. 3, 2019, of a region on Mount Sharp with lots of clay-bearing rocks that formed when lakes and streams were present billions of years ago. The “Mary Anning 3” sample was found in this clay-enriched region.

NASA/JPL-Caltech/MSSS

The rock sample, nicknamed “Mary Anning 3” after an English fossil collector and paleontologist, was collected on a part of Mount Sharp covered by lakes and streams billions of years ago. This oasis surged and dried up multiple times in the planet’s ancient past, eventually enriching the area with clay minerals, which are especially good at preserving organic compounds — carbon-containing molecules that are the building blocks of life and are found throughout the solar system.

Among the newly identified molecules is a nitrogen heterocycle, a ring of carbon atoms that includes nitrogen. This kind of molecular structure is considered a predecessor to RNA and DNA, two nucleic acids that are key to genetic information.

“That detection is pretty profound because these structures can be chemical precursors to more complex nitrogen-bearing molecules,” said the paper’s lead author, Amy Williams of the University of Florida in Gainesville. “Nitrogen heterorcycles have never been found before on the Martian surface or confirmed in Martian meteorites.”

This is an annotated close-up of three holes NASA’s Curiosity drilled into Martian rock at a location nicknamed “Mary Anning” in October 2020. The sample where the rover found a diverse number of organic molecules came from “Mary Anning 3.” (A nearby spot nicknamed “Mary Anning 2” went unused.)

NASA/JPL-Caltech/MSSS

Another exciting discovery was benzothiophene, a carbon- and sulfur-bearing molecule that’s been found in many meteorites. These meteorites, along with the organic molecules within them, are thought by some scientists to have seeded prebiotic chemistry across the early solar system.

Martian chemistry

The new paper complements last year’s finding of the largest organic molecules ever discovered on Mars: long-chain hydrocarbons, including decane, undecane, and dodecane.

“This is Curiosity and our team at their best. It took dozens of scientists and engineers to locate this site, drill the sample, and make these discoveries with our awesome robot,” said the mission’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California. “This collection of organic molecules once again increases the prospect that Mars offered a home for life in the ancient past.”

Both sets of findings were made with a sophisticated minilab called Sample Analysis at Mars (SAM), located in Curiosity’s belly. A drill on the end of the rover’s robotic arm pulverizes a carefully selected rock sample into powder and then trickles it into SAM, where a high-temperature oven heats the material, releasing gases that instruments in the lab analyze to reveal the rock’s composition.

In addition, SAM can perform “wet chemistry,” dropping samples into a small cup of solvent. The resulting reactions can break apart larger molecules that would be difficult to detect and identify otherwise. While the instrument has several such cups, only two contain tetramethylammonium hydroxide (TMAH), a powerful solution reserved for the highest-value samples. The Mary Anning 3 sample was the first to be exposed to TMAH.

To verify TMAH’s reactions with otherworldly materials, the paper’s authors also tested the technique on Earth with a piece of the Murchison meteorite, one of the most studied meteorites of all time. More than 4 billion years old, Murchison contains organic molecules that were seeded throughout the early solar system. A Murchison sample exposed to TMAH was found to break much larger molecules into some of the ones seen in Mary Anning 3, including benzothiophene. That result verifies that the Martian molecules found in Mary Anning 3 could have been generated from the breakdown of even more complex compounds relevant to life.

Curiosity recently used its second and final TMAH cup while exploring weblike boxwork ridges, which were formed by ancient groundwater. The mission team will be analyzing those results for a future peer-reviewed paper.

Trailblazing for future missions

Built by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, SAM is based on larger, commercial-grade lab instruments. Getting such complex equipment into the rover required engineers to dramatically shrink it down and develop a way for it to run on less power. Scientists had to learn how to heat up SAM’s oven more slowly over longer periods in order to conduct some of these experiments.

“It was a feat just figuring out how to conduct this kind of chemistry for the first time on Mars,” said Charles Malespin, the instrument’s principal investigator at NASA Goddard and a study coauthor. “But now that we’ve had some practice, we’re prepared to run similar experiments on future missions.”

In fact, NASA Goddard has provided several components, including the mass spectrometer, for a next-generation version of SAM, called the Mars Organic Molecular Analyzer, for ESA’s (European Space Agency) Rosalind Franklin Mars rover. A similar instrument, the Dragonfly Mass Spectrometer, will explore Saturn’s moon Titan on NASA’s Dragonfly rotorcraft. Both instruments will be able to perform wet chemistry with the TMAH solvent.

More about Curiosity

Curiosity was built by JPL, which is managed by Caltech in Pasadena, California. JPL leads the mission on behalf of NASA’s Science Mission Directorate in Washington as part of NASA’s Mars Exploration Program portfolio.

To learn more about Curiosity, visit: https://science.nasa.gov/mission/msl-curiosity 

Source: NASA’s Curiosity Finds Organic Molecules Never Seen Before on Mars - NASA

Your Brain’s “Stop Eating” Signal Just Got a Lot More Interesting

You finish a meal, push back from the table, and feel full. Simple, right? For decades, neuroscientists assumed this sensation came straight from neurons, the brain’s primary communicators, firing signals in the hypothalamus to say enough. But a study published in the Proceedings of the National Academy of Sciences on April 6, 2026, suggests the real story is far more intricate and stars a cell type most scientists had written off as a bystander.

Meet the Understudies: Astrocytes

The brain is full of cells that aren’t neurons. Astrocytes are among the most abundant star-shaped cells (the name comes from the Greek astron, meaning star) that have long been viewed as support staff: keeping neurons healthy, clearing up chemical waste, maintaining the blood-brain barrier. Important work, sure, but nothing glamorous.

That view just changed.

A team from the University of Concepción in Chile, working with colleagues at the University of Maryland, has identified a previously unknown communication chain deep inside the hypothalamus, the brain region that governs hunger and fullness. At the center of it: astrocytes.

The Chain Reaction That Makes You Feel Full

Here’s how the newly discovered pathway works, step by step:

1.     Glucose rises. After a meal, blood sugar levels climb. Deep inside the brain, specialized cells called tanycytes, lining a fluid-filled cavity, detect this glucose as it circulates through the cerebrospinal fluid.

2.     Tanycytes release lactate. Rather than signaling neurons directly (as scientists previously assumed), tanycytes process the glucose and release a byproduct called lactate into surrounding brain tissue.

3.     Astrocytes pick up the signal. The lactate binds to a receptor on nearby astrocytes called HCAR1, activating them. Once activated, astrocytes release glutamate, a key neurotransmitter.

4.     Fullness neurons fire. That glutamate reaches appetite-suppressing neurons, triggering the sensation of fullness.

In short: tanycytes talk to astrocytes, and astrocytes talk to neurons. The previous assumption that tanycytes spoke directly to neurons missed a crucial middleman.

A Double Switch

The findings get even more elegant. The hypothalamus contains two opposing neuron populations: ones that promote hunger, and ones that suppress it. The researchers found evidence that lactate may hit both simultaneously activating the fullness neurons via astrocytes, while potentially quieting the hunger neurons through a more direct route. The brain, in other words, may be pressing the brakes from two directions at once.

In one striking experiment, scientists delivered glucose into a single tanycyte and watched what happened to surrounding astrocytes. The activity rippled outward, triggering responses in multiple neighboring cells, showing how even a tiny, localized metabolic event can cascade through the brain’s network.

Why This Matters Beyond the Lab

The study was conducted in animal models, but tanycytes and astrocytes are present in all mammals, including us. The research team’s next step is to investigate whether directly manipulating the HCAR1 receptor can change feeding behavior in animals, a necessary hurdle before any clinical applications.

But the implications are already sparking excitement. Existing weight-loss treatments like Ozempic (semaglutide) target different pathways, GLP-1 receptors, primarily. A therapy that targets HCAR1 in astrocytes could, in theory, work alongside such drugs, offering a complementary mechanism for people with obesity or eating disorders.

Nearly ten years of collaborative work between the two research groups went into these findings. The lead author, doctoral student Sergio López, carried out key experiments during an eight-month visit to the University of Maryland, a reminder that some of the most interesting science still happens through slow, careful, cross-continental collaboration.

The Bigger Picture

This discovery fits into a growing reassessment of astrocytes’ role in the brain. For years, neuroscience textbooks treated these cells as passive scaffolding. Increasingly, research is revealing them as active participants in everything from memory consolidation to disease progression.

The brain, it turns out, doesn’t just run on neurons. The support staff have been running things too, we just weren’t watching closely enough.

Source: López et al., “Tanycyte-derived lactate activates astrocytic HCAR1 to modulate glutamatergic signaling and POMC neuron excitability,” Proceedings of the National Academy of Sciences, April 6, 2026. 

Source: Your Brain’s “Stop Eating” Signal Just Got a Lot More Interesting – Scents of Science