Webb Telescope discovers new molecule on Saturn's moon Titan - What could it mean? - video Dailymotion

Nasa Space

The James Webb Space Telescope discovered a new molecule in the Saturn moon Titan’s atmosphere. It "may have implications for the future of this surprisingly Earthlike world," according to NASA.

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00:01Our solar system is home to eight planets and nearly 300 known moons,

00:06but of those many worlds, only two are shaped by an active rain cycle.

00:11Earth, and Saturn's largest moon, Titan.

00:15Now, NASA's James Webb Space Telescope has discovered a new molecule in Titan's atmosphere,

00:21one that may have implications for the future of this surprisingly Earth-like world.

00:26From space, Titan appears to be a featureless orange globe,

00:32with its lower atmosphere and its surface hidden by an organic haze.

00:36But when we look at the moon in infrared, its features emerge.

00:40Dark dune fields circling the equator, vast plains in the mid-latitudes,

00:45and in the far north, lakes and seas rivaling the Great Lakes of North America.

00:51Unlike Earth, these bodies are not made of liquid water,

00:55but of hydrocarbons like methane and ethane, chilled to cryogenic temperatures.

01:00From 2022 to 2023, my colleagues and I studied Titan with the Webb Telescope,

01:06and the Keck Observatory on Mauna Kea.

01:09Their powerful infrared vision cut through Titan's haze,

01:12to reveal its northern hemisphere during late summer.

01:15What we saw were two broad areas of methane cloud cover,

01:19around 55 degrees north, close to the largest lakes and seas.

01:23In 2004, NASA's Cassini orbiter made its first close encounter with Titan,

01:28while the southern hemisphere was in summer.

01:30Cassini witnessed rain clouds forming in the drier, south polar regions,

01:34due to seasonal heating and evaporation.

01:37Climate models predicted that as Titan's northern hemisphere entered summer,

01:41beginning in 2017, methane would evaporate from its large lakes and seas,

01:46rising into the lower atmosphere to form rain clouds.

01:50Now, our study has confirmed that when Titan's northern hemisphere warms up,

01:54it also undergoes a seasonal cycle of cloud formation.

01:59In addition to taking pictures of Titan,

02:01we used the Webb Telescope's mid-infrared instrument, or MIRI,

02:05to study the makeup of its atmosphere.

02:08MIRI is both a camera and a spectrometer.

02:10It can break apart the light from an object to determine its chemical composition.

02:15Like Earth, Titan's atmosphere is made primarily of nitrogen,

02:19but it also has a substantial amount of methane,

02:21which plays a similar role to Earth's water vapor.

02:24Trace gases are present as well, including heavier hydrocarbons, like ethane,

02:30but the details of their formation are murky.

02:33Now, Webb's MIRI instrument has shed new light on how these hydrocarbons form.

02:38When MIRI measured Titan's spectrum, it saw a previously undetected spike,

02:43indicating the presence of the methyl radical,

02:45the missing link to the heavier hydrocarbons.

02:48Here's how the process works.

02:50In Titan's upper atmosphere,

02:52UV radiation from the Sun and electrons from Saturn

02:55break apart methane into hydrogen atoms and methyl radicals.

02:59The hydrogen is lost to space,

03:01while the short-lived methyl radicals recombine into heavier molecules like ethane.

03:06Ethane and methane eventually condense into droplets

03:09and rain out of the atmosphere,

03:11replenishing lakes and seas on the surface.

03:13Rainfall on Titan has yet to be directly observed,

03:17but the discovery of methyl radicals fills a gap in our observations,

03:21and it supports our understanding of this surprisingly Earth-like world.

03:27Further discoveries will come in 2034,

03:29when NASA's Dragonfly mission touches down near the equator during northern winter.

03:34Dragonfly will drill into the icy surface to look for complex molecules

03:39made from Titan's abundant methane, nitrogen and oxygen.

03:43Of particular interest to its search are amino acids,

03:47the building blocks of proteins that make up life on Earth.

03:50As spring slowly returns to the northern hemisphere in the late 2030s,

03:55Dragonfly may also become the first mission to witness rainfall on another world.

04:02Looking ahead to the far future,

04:04our study hints at an intriguing possibility for the evolution of Titan's climate.

04:08If the methane that is being broken apart in the upper atmosphere

04:12is not replenished from the Moon's interior,

04:14it could eventually disappear from the environment.

04:17Over tens of millions of years,

04:19Titan's lakes and seas could dry up.

04:22Its shorelines could gradually give way to the encroaching desert.

04:26Its rain clouds and organic haze could vanish,

04:29leaving a dark blue sky.

04:31At last, Saturn would be visible from Titan's surface,

04:34gazing down upon a world of dry lake beds,

04:37empty river channels and endless dunes.

Webb Telescope discovers new molecule on Saturn's moon Titan - What could it mean?

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