Titan’s Largest Crater Could Be The Perfect Cradle For Life | Science

Saturn’s icy moon, Titan, has long puzzled scientists looking for life in the solar system. Its surface is covered with organic hydrocarbons and its icy crust covers a watery ocean. An asteroid or comet hitting the moon could theoretically mix these two ingredients, according to a new study, with the resulting impact craters providing a perfect place to start life.

The idea is “very exciting,” says Léa Bonnefoy, planetologist and Titan expert at the University of Paris. “If you have a lot of liquid water creating a temporary hot pool on the surface, then you can have conditions that would be favorable for life,” she says. And, “If you have organic material moving from the surface to the ocean, it makes the ocean a little more habitable.”

Scientists believe that an ocean has been about 100 kilometers below Titan’s crust since 2012, when NASA’s Cassini mission measured variations in the moon’s tidal view. Alvaro Penteado Crósta, a planetary geologist at the University of Campinas, knew that the moon was covered with many large impact craters. He wondered if any of the impacts were big enough to pierce the crust and push organic matter up to the surface with the water underneath. It may have produced “a primordial soup that you would need for life to develop,” says Penteado Crósta.

To find out, he and his colleagues modeled the impact of the moon’s largest crater, 425-kilometer-wide Menrva, which is believed to have formed 1 billion years ago. The model suggested that the crater was the result of a 34-kilometer-wide space rock hitting the surface at 7 kilometers per second.

The heat from the impact would have created a lake in the crater, according to the model, which the team presented this week at the Lunar and Planetary Science Conference. The lake would likely only have existed for 1 million years before freezing under the freezing temperatures of Titan. But Penteado Crósta says it may have been enough time for microbes to evolve, taking advantage of liquid water, organic molecules, and the heat of impact. “It’s pretty good for bacteria.”

Although the team’s research focused on Menrva, Penteado Crósta says it’s possible that smaller impacts were enough to pierce Titan’s ice shell, possibly even at Selk – a 90-kilometer crater. wide about 5,000 kilometers away. Selk is believed to be much younger than Menrva, perhaps a few hundred million years old, which would mean any evidence of life there would be fresher. “Selk might have a better chance of having some sort of fossilized bacteria preserved in ice,” says Penteado Crósta.

Selk is the planned landing site for NASA’s Dragonfly mission, a billion-dollar autonomous, nuclear-powered drone set to launch in 2027 and arrive on Titan 2036. If the impact shattered the crust of ice here, the mission might find out.

But Elizabeth Turtle, principal investigator for the Dragonfly mission at Johns Hopkins University’s Applied Physics Lab, isn’t so sure. “There is no strong evidence to suggest that you actually had a puncture,” she says.

Still, Dragonfly could visit other craters in an extended mission. And while Menrva may be too far away, it could be an intriguing landing site in the future, Penteado Crósta says.