Latest news with #Affholder
Forbes
19-04-2025
- Science
- Forbes
Alien Life On Saturn's Moon Titan May Fit Into A Small Dog, Study Says
Is there life on Saturn's giant moon, Titan? getty Is there life on Saturn's giant moon, Titan? The only world in the solar system other than Earth with weather and liquid on its surface, Titan has long been on a shortlist of places that could host some life. With NASA's exciting Dragonfly mission — which will see a drone-like craft tour of Titan — due to launch in July 2028, a new study has been published that attempts to paint a realistic picture of what it can expect. NASA's Cassini spacecraft discovered an underground ocean of water and ammonia on Titan in 2008. Although other icy moons in the solar system — notably Saturn and Jupiter — have oceans beneath their ice caps that could theoretically host life, Titan has something different. "In our study, we focus on what makes Titan unique compared to other icy moons: its plentiful organic content," said Antonin Affholder, a postdoctoral research associate at the University of Arizona's Department of Ecology and Evolutionary Biology. As well as a nitrogen-rich atmosphere, rain, lakes and oceans of liquid methane, shorelines, valleys, mountain ridges, icy boulders, mesas and dunes, Titan also hosts weird prebiotic chemistry that could be the building blocks of life itself. On Titan's surface are complex organic compounds formed from methane and nitrogen in the moon's atmosphere. That could mean food — and life. Or maybe not. Titan could harbor simple, microscopic life, according to the study, published this month in The Planetary Science Journal. However, at best, it's likely only a few pounds of biomass overall. That's because the underground ocean on Titan — where life is most likely to exist — is over 300 miles deep and doesn't interact much with the surface, where the organic compounds are. "There has been this sense that because Titan has such abundant organics, there is no shortage of food sources that could sustain life," said Affholder. "Not all of these organic molecules may constitute food sources, the ocean is really big, and there's limited exchange between the ocean and the surface, where all those organics are." However, that doesn't mean that life doesn't exist — it just changes the likely mechanism. The researchers think that fermentation is the most likely scenario for life on Titan. Familiar on Earth as the process of producing bread, wine, beer and kimchi, the breakdown of a substance, fermentation needs only organic molecules but no "oxidant" such as oxygen. That's entirely different from respiration, a chemical reaction found in every cell in living things on Earth, from plants to animals. Like on Earth could have first emerged as feeding on organic molecules left over from Earth's formation, said Affholder, adding that fermentation "does not require us to open any door into unknown or speculative mechanisms that may or may not have happened on Titan." In their research, Affholder and colleagues focused on one organic molecule, glycine, that could synthesize in Titan's atmosphere, accumulate on its surface and make its way into Titan's subsurface ocean. Could microbes in that ocean feed off glycine? It wasn't an accidental choice — glycine exists in comets, asteroids, and gas clouds from which stars and planets are formed. It was abundant in the primordial solar system. However, the team's computer simulations revealed that only a small amount of glycine would reach the ocean. "This supply may only be sufficient to sustain a very small population of microbes weighing a total of only a few kilograms at most — equivalent to the mass of a small dog," said Affholder. "Such a tiny biosphere would average less than one cell per liter of water over Titan's entire vast ocean." NASA's Dragonfly mission is set to reach Titan in 2034 and will last for two years. During the mission, a rotorcraft will fly to a new location every Titan day (16 Earth days) to take samples of the organic compounds on its surface, search for chemical biosignatures and investigate the moon's active methane cycle. Wishing you clear skies and wide eyes.
Yahoo
15-04-2025
- Science
- Yahoo
Alien life could exist on Saturn's big moon Titan — but finding it will be tough
When you buy through links on our articles, Future and its syndication partners may earn a commission. With rivers, lakes and even seas made of liquid methane and ethane, plus a hidden underground ocean of water, Saturn's moon Titan has long fascinated scientists as a place where alien life might exist. A new study backs up that idea — but with a twist. Yes, alien life could be there, researchers say, but probably not in the abundance we once hoped. "We focus on what makes Titan unique when compared to other icy moons: its plentiful organic content," study co-lead author Antonin Affholder, a postdoctoral research associate in the University of Arizona's Department of Ecology and Evolutionary Biology, said in a statement. "There has been this sense that because Titan has such abundant organics, there is no shortage of food sources that could sustain life." NASA's Cassini mission flew past Titan over 100 times, and in 2005, the European ride-along probe Huygens landed on its surface. On its way down, Huygens collected valuable data on Titan's dense atmosphere, finding a host of photochemical reactions — light-driven chemical reactions that shape the moon's chemical environment and could play a role in making it potentially habitable. This is because such reactions can create complex organic molecules, including some that could be the building blocks for life. Related: Titan: Facts about Saturn's largest moon The idea is that these organic molecules eventually settle on Titan's surface and, through a mix of material exchange and possible geochemical processes, find their way down into the moon's hidden ocean — potentially making the dark waters below a habitable environment. But "potentially" is a key word here, according to the new study. "We point out that not all of these organic molecules may constitute food sources, the ocean is really big, and there's limited exchange between the ocean and the surface, where all those organics are, so we argue for a more nuanced approach," said Affholder. Using bioenergetic modeling — a method that uses mathematical simulations to quantify the energy needed to make and break chemical bonds in a biological system — the team attempted to identify a plausible scenario in which life could emerge on Titan. They landed on a simple and familiar process: fermentation. "Fermentation probably evolved early in the history of Earth's life and does not require us to open any door into unknown or speculative mechanisms that may or may not have happened on Titan," Affholder said. Fermentation is a simple metabolic process in which microorganisms, such as bacteria, break down organic molecules like sugars or carbohydrates into simpler compounds. The key part? It all happens without oxygen, which makes it especially relevant for a world like Titan, where oxygen is scarce or absent. "We asked, could similar microbes exist on Titan?" Affholder said. "If so, what potential does Titan's subsurface ocean have for a biosphere feeding off of the seemingly vast inventory of abiotic organic molecules synthesized in Titan's atmosphere, accumulating at its surface and present in the core?" Related stories: — Titan: Facts about Saturn's largest moon — The search for alien life — Largest sea on Saturn's mysterious moon Titan could be more than 1,000 feet deep Using the simplest of all known amino acids — glycine, which is relatively abundant throughout the solar system — the team's simulations found that conditions on Titan could, in theory, support microbial life through fermentation. However, only a tiny portion of Titan's organic material might actually reach the ocean, depending on how much glycine makes its way down from the surface. "This supply may only be sufficient to sustain a very small population of microbes weighing a total of only a few kilograms at most — equivalent to the mass of a small dog," Affholder said. "Such a tiny biosphere would average less than one cell per liter of water over Titan's entire vast ocean," he added. "We conclude that Titan's uniquely rich organic inventory may not in fact be available to play the role in the moon's habitability to the extent one might intuitively think." That means that, if life does exist on Titan, it could be extremely sparse, making it especially challenging for future missions to detect — like trying to find a needle in a haystack, the team concludes. The new study was published April 7 in The Planetary Science Journal.
