Telescopes team up to predict alien storm on Titan

It was a cloudy day on Titan.

This became clear on the morning of November 5 when Sébastien Rodriguez, an astronomer at the Université Paris Cité, downloaded the first images of Saturn’s largest moon taken by NASA’s James Webb Space Telescope. He saw what appeared to be a large cloud near Kraken Mare, a 1,000-foot-deep sea in Titan’s north polar region.

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“What a wake up call this morning,” he said in an email to his team. “I think we’re seeing a cloud!”

It caused a sort of weather emergency among the Al Rokers of the cosmos, causing them to scramble for more cover.

Titan has long been a gem of astronomers’ curiosities. Less than half the size of Earth, it has its own atmosphere thick with methane and nitrogen, and even denser than the air we breathe. When it rains on Titan, it rains gasoline; when it snows, the drifts are black as coffee grounds. Its lakes and streams are full of liquid methane and ethane. Beneath its crust frozen like mud hides an ocean of water and ammonia.

Aspiring astrobiologists have long wondered whether the chemistry that prevailed during Earth’s early years is being recreated in Titan’s mud mounds. The potential precursors to life make the smog world (where the surface temperature is less than 290 degrees Fahrenheit) a long shot for the discovery of alien chemistry.

To that end, missions to Titan are being planned, including sending a nuclear-powered drone called Dragonfly to fly around Saturn’s moon in 2034, as well as more notional trips like sending a submarine to explore the its oceans

Meanwhile, however, despite observations by Voyager 1 in 1980 and by the Cassini Saturn orbiter and its Huygens lander in 2004-5, planetary scientists’ models of Titan’s atmospheric dynamics were still only tentative. But the Webb telescope, which launched nearly a year ago, has infrared eyes that can see through Titan’s haze.

So when Conor Nixon of NASA’s Goddard Space Flight Center received Rodriguez’s email, he was thrilled.

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“We had been waiting for years to use Webb’s infrared vision to study Titan’s atmosphere,” Nixon said. “Titan’s atmosphere is incredibly interesting, not only for its methane clouds and storms, but also for what it can tell us about Titan’s past and future, including whether it always had an atmosphere.”

Nixon contacted two astronomers that same day: Imke de Pater of the University of California, Berkeley, and Katherine de Kleer of the California Institute of Technology, who were affiliated with the twin 10-meter Keck telescopes on Mauna Kea in Hawaii and had they were called the Keck Titan team. He called for immediate follow-up observations to see if the clouds were changing and which way the winds were blowing.

As de Pater explained, these last-minute requests are not always possible, as telescope time is a precious commodity.

“We were very lucky,” he said.

The observer on duty that night, Carl Schmidt of Boston University, was a collaborator of his in other planetary studies.

Keck staff, de Pater added, are also eager to support the Webb telescope observations.

“They are loved by objects in the solar system,” he said, “because they are clean and always changing with time.”

Using visible light images from Keck and infrared images from the Webb telescope, Nixon and his colleagues were able to probe Titan from ground features through the different layers of its atmosphere, all that could need a long range weather forecast.

And there’s more on the way.

In an email, Nixon said his team was especially excited to see what would happen in 2025, when Titan would reach its northern autumnal equinox.

“Shortly after the last equinox, we saw a giant storm on Titan, so we’re excited to see if the same thing happens again,” he said.

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