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The epic of NASA Cassini Mission at Saturn is still generating valuable scientific data more than three years after its disappearance.
Data from one of the last overflights of the spacecraft Titan, a large moon with the precursors of the chemistry of life, reveals that a huge lake on the surface called Kraken Mare is over 300 meters deep, roughly the equivalent of the height of New York’s Chrysler Building . In fact, the lake is so deep that Cassini’s radar could not sound all the way to the bottom.
In 2014, preliminary data from this overview suggested that Kraken Mare was at least 35 meters deep but extended further; recently published results show that the lake is nearly 10 times deeper than this first estimate.
Related: Dazzling views show the surface of Saturn’s Titan moon like never before
Understanding the depth and makeup of Kraken Mare will gradually reveal more about Titan’s mysterious chemistry, dominated by the ethane and methane that collects in pools, lakes and rivers on the surface, the researchers said. The importance of the lake stems from the immense size of Kraken Mare; if placed on Earth, it would cover the five Great Lakes of North America.
“Kraken Mare… not only has a big name, but also contains around 80% of the moon’s surface liquids,” study lead author Valerio Poggiali, associate researcher at the Cornell University Center for Astrophysics and Planetary Science, said in a press release from the university.
Although Titan’s chemistry is alien to Earth’s, the moon’s geography is reminiscent of the marshy or lake-rich regions of our planet. Titan is also the only known moon in our solar system to boast a thick atmosphere – an envelope of gaseous nitrogen, compared to the predominantly nitrogen-oxygen atmosphere of the Earth.
This sets Titan apart from the many moons in our solar system with thin or atmospheric exospheres (like Earth’s moon) and the “frozen moons” potentially favorable to life where water ice covers an internal ocean – as on Jupiter’s Europe or Saturn’s Enceladus, both of which spring water through the ice into space.
The data on Kraken Mare was collected during Cassini’s 104th flyby on Titan on August 21, 2014, about three years before the engineers. deliberately threw the aging spaceship into Saturn to avoid the small chance of accidentally contaminating the surface of the moon.
Kraken Mare was just one of the lakes on the mission’s investigation list for this flyby. The researchers also wanted to look into Ligeia Mare – the site of a mysterious “magic island“which appears and disappears regularly – and a smaller estuary called Moray Sinus, which researchers estimated to be 85m deep, roughly the equivalent of the height of the Statue of Liberty. Cassini probed the surface of the moon with its radar altimeter of about 600 miles (965 kilometers).
Scientists calculated the depth of the sea by determining how long it took for the radar signal to bounce off the surface of the liquid and the seabed, comparing the difference between those depths and taking into account the composition of the liquid. lakes, which absorbs some of the energy from the radar signal.
The composition of Kraken Mare surprised scientists, as well as its depth. It contains a mixture of methane and ethane, which differed from previous models, suggesting that ethane would prevail due to the size of the lake and the more distant geographic position of the moon’s poles. The lake’s unexpected chemistry could help scientists better understand the precipitation cycle on Titan, the researchers say.
Scientists also hope to know where the liquid methane on Titan comes from. Titan receives about 100 times less energy from the sun than the Earth, given that it is about 10 times farther away.
With the weak sunlight available, Titan converts the methane in its atmosphere into ethane, but current models suggest the moon should travel through all of the methane on its surface in just 10 million years, a small fraction of its lifespan. of 4.5 billion years of our solar system.
Engineers are working on a concept for a submarine which, if funded and approved by NASA, could launch in the 2030s to probe the lakes of Titan. Poggiali said the recently analyzed data from Cassini could help engineers “better calibrate the sonar on board the ship and understand the directional flows of the sea.”
A research-based study was published in december, in the Journal of Geophysical Research: Planets.
Follow Elizabeth Howell on Twitter @howellspace. follow us on Twitter @Spacedotcom and on Facebook.
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