Latest research is shedding light on peculiar winds swirling on Saturn’s largest moon, Titan, whose mysterious weather patterns have puzzled astronomers for a long time.
The answers may help to elucidate how Titan became the one moon within the solar system that also hosts a planet-like atmosphere, researchers say.
Astronomers have long known that seasons on Titan — each of which lasts nearly 7.5 Earth years — affect the moon’s winds. But they have not been capable of pin down the speeds of those winds; two related studies, done nearly 30 years apart, have led to contradictory findings.
Now, astronomers are revisiting this decades-old mystery with updated telescopes. The paradoxical findings from past research might need resulted from incorrect assumptions in regards to the data or instrument limitations, or it could just be that “there’s something basic that we do not understand,” Eliot Young, a principal scientist on the Southwest Research Institute in Texas, said in a statement (opens in recent tab).
Related: Titan: Facts about Saturn’s largest moon
Titan has a thick, smog-like atmosphere that reaches 370 miles (600 kilometers) into space and is 95% nitrogen with a sprinkle of organic molecules. Winds on the moon encircle it in only a day, repeatedly carrying currents of warm air from lower altitudes to the moon’s poles, as if blowing on what NASA calls a high-speed conveyor belt.
In 1989, astronomers found that Titan’s winds are slowest near its equator and fastest at midlatitudes in each the northern and southern hemispheres. This was revealed because of a likelihood alignment of a star behind Titan that allowed astronomers to review how the star’s dimming light filtered through the moon’s atmosphere, which helped them interpret wind speeds.
In 2016, a unique team used ground-based telescopes to review how the sunshine beamed by molecules within the atmosphere modified with shifting wind speeds and directions. The findings from this method revealed the other: The winds were fastest near Titan’s equator and slowest at its lower latitudes.
Because there’s an almost three-decade gap between the 2 sets of observations, astronomers think different seasons on Titan can have led to the dramatic wind changes between each studies. Also, the 1989 research studied winds circling in the center layers of the moon’s atmosphere, while the newer research focused on winds within the upper layers, which also may explain the various wind speeds, the astronomers said.
“Similar to on Earth, the winds on Titan are different at different altitudes and likewise change with seasons,” Juan Lora, an assistant professor of Earth and planetary sciences at Yale University, told Space.com in an email. “And each of those likely explain why the observations don’t agree perfectly with one another.”
To unravel this discrepancy, a gaggle of scientists has collected recent data about Titan’s winds using each methods at the identical time. Last yr, the team used eight telescopes in the US and South America to look at two likelihood alignments of Earth, Titan and faraway brilliant stars.
In September 2022, 4 telescopes in Hawaii — including NASA’s Infrared Telescope Facility and the Keck Observatory — watched because the star, 2MASS 21312124-1602427, snuck behind Titan. In November of the identical yr, a unique star called 2MASS 21292356-1611056 slid behind Titan. Data from this event was collected by 4 more telescopes in Chile, including the Very Large Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA).
The team continues to be comparing data from each observations and expects the outcomes to be ready later this yr. Up to now, ALMA observations already show evidence of speedy winds parallel to Titan’s equator, Martin Cordiner, a planetary science researcher at NASA’s Goddard Space Flight Center in Maryland whose team first identified the discrepancy in 2021, told Space.com.
The researchers behind the newest study said they were just in time to capture worthwhile data about Titan’s winds before the 2025 northern autumnal equinox, when each of the moon’s hemispheres will briefly receive equal sunlight before its northern hemisphere points more directly toward the sun. During this time, Titan’s winds will reverse directions and begin flowing from north to south — a change that has sprouted powerful dust storms (opens in recent tab) prior to now, in response to the journal Nature.
“Titan is amazingly just like Earth in some ways, nevertheless it’s also alien and sometimes surprising — teasing out which of those applies to individual phenomena as we observe them is one among the fun bits about this research for me,” Lora told Space.com.