Two views of Titan, a moon of Saturn, taken by the James Webb Space Telescope. The image on the left uses a filter sensitive to Titan’s lower atmosphere, while the image on the right is a color composite. Below is an annotated transcript showing some of the features captured in each photo. (NASA, ESA, CSA, A. Pagan (STScI), JWST Titan GTO Team via The New York Times)
It was a cloudy day on Titan.
It was light on the morning of November 5 when Sebastien Rodriguez, an astronomer at the City University of Paris, uploaded the first images of Saturn’s largest moon using NASA’s James Webb Space Telescope. He saw what appeared to be a large cloud near the Kraken Sea, a sea 300 meters deep in the northern polar region of Titan.
“What a wake up call this morning,” he emailed his team. “I think we see a cloud!”
This causes some kind of weather emergency among the rockers of the universe, forcing them to seek more cover.
Titan has long been a gem of curiosity for astronomers. Less than half the size of the Earth, it has its own atmosphere, thick with methane and nitrogen, even denser than the air we breathe. When it rains on Titan, it rains gasoline. When it snows, the mounds turn as black as coffee grounds. Its lakes and streams are full of liquid methane and ethane. Beneath the frozen, slime-like crust lies an ocean of water and ammonia.
Aspiring astrobiologists have long wondered if the chemistry that prevailed in Earth’s early years could have been recreated in Titan’s sandy mounds. Possible precursors to life make the world of smog (where the surface temperature is minus 290 degrees Fahrenheit) a long-term hope for the discovery of space chemistry.
To that end, missions to Titan are being planned, including sending a nuclear-powered drone called Dragonfly to fly around Saturn’s moon by 2034, as well as other virtual excursions such as sending a submarine to explore its oceans.
Meanwhile, despite observations by Voyager 1 in 1980 and the Cassini probe of Saturn and its Huygens probe in 2004-2005, planetary scientists’ models of Titan’s atmosphere dynamics were still preliminary. But the Webb telescope, launched nearly a year ago, has infrared eyes that can see through Titan’s haze.
So when Connor Nixon of NASA’s Goddard Space Flight Center received an email from Rodriguez, he was thrilled.
“We’ve been waiting years to use Webb’s infrared vision to study Titan’s atmosphere,” Nixon said. “Titan’s atmosphere is incredibly interesting, not only because of its methane clouds and storms, but also because it can tell us about Titan’s past and future, including whether it ever had an atmosphere.”
Nixon on the same day contacted two astronomers – Emke de Pater of the University of California at Berkeley and Katherine de Claire of the California Institute of Technology – who were connected to two 10-meter Keck telescopes on Mauna Kea, Hawaii, and called himself the Keck team . Titanium. He requested immediate follow-up observations to see if the clouds were changing and which way the wind was blowing.
As de Pater has shown, these last-minute requests are not always possible because telescopic time is a precious commodity.
“We are very lucky,” she said.
The observer on duty that night, Carl Schmidt of Boston University, was one of his collaborators on other planetary studies.
De Pater added that Keck’s team also wants to support Webb’s observations.
“They love the bodies of the solar system,” she said, “because they are ordered and always change with time.”
Using Keck’s visible light images and infrared images from the Webb Telescope, Nixon and his colleagues were able to trace Earth’s features of Titan through the various layers of its atmosphere — all a long-range meteorologist might need.
And more on the way.
In an email, Nixon said his team was particularly excited about what would happen in 2025, when the northern autumnal equinox hits Titan.
“Just after the last equinox, we saw a giant storm on Titan, so we look forward to seeing if the same thing happens again,” he said.
