Moons exert a certain influence on planets. Just look at our own moon, which is responsible for the tides. Moreover, our moon is gradually moving farther away from Earth. Titan exerts a similar influence on Saturn. Decades of measurements have revealed that Titan is also moving slowly away from Saturn. But a new study suggests this is happening much faster than thought.
“Most studies have predicted that moons like Titan or Jupiter’s moon Callisto are formed at a distance similar to what we’re seeing now,” said study leader Jim Fuller. However, his new study claims something very different. Titan would have seen the light of day much closer to Saturn and moved to its current distance over the last 4.5 billion years. Titan is currently 1.2 million kilometers away from the gas giant.
In order to understand this agile process of Titan, it is best to consider our own moon. The moon actually pulls our Earth like a magnet, creating the tides. The gravitational pull of the moon is most palpable on the side of the Earth where the moon is closest. This makes the water rise (just like on the other side of the earth, by the way). The moon orbits the Earth and the high water level follows the movement of the moon. The moon’s gravitational pull on earth also slows down the Earth’s rotation. This causes the moon to move gradually farther away from the Earth. This happens at a rate of about 3.8 centimeters per year. However, you don’t have to worry about the moon dislodging from Earth at some point. The Earth will not ‘lose’ the moon until both the Earth and the moon will be swallowed by the sun in about six billion years.
Back to Titan. Titan exerts a similar attraction to Saturn. For a long time, however, it was thought that the friction processes within Saturn were weaker than those within the Earth because Saturn consists largely of gas. Theories predicted that Titan will move away from the gas giant at a steady rate of 0.1 centimeters per year. But the new results completely contradict this prediction.
In the study, two teams of researchers each used a different method to determine Titan’s orbit over a 10-year period. The first method includes accurate measurements of Titan’s position relative to background stars (also called astrometry). To do this, the team analyzed images collected by the Cassini spacecraft. The second research team measured Cassini’s speed because it was influenced by titan’s gravitational pull. “By using two completely independent datasets and applying two very different methods of analysis, we have obtained the most accurate results,” said researcher Valéry Lainey. And the results appear to be completely consistent.
The research reveals that Titan is moving away from Saturn 100 times faster than previously thought. How is that possible? Compare it to rocking. If you swing your legs the other way at just the right time, you can get higher and higher. The same principle may be going on between Titan and Saturn. Titan, as it were, compresses Saturn’s gravity with a certain frequency that allows the planet to oscillate strongly. It means titan migrates away from the gas giant at a rate of 11 centimeters per year. This phenomenon could also apply to other systems,” says Fuller. “I am now studying whether the same physics can occur in double star systems or on exoplanets.”
Titan continues to amaze scientists. For example, the moon is the only moon in the solar system with a thick atmosphere that reaches up to about 600 kilometers away into space. This atmosphere consists mainly of nitrogen and methane. While in the atmosphere of everything happens, the surface of the moon is anything but boring. There are rivers and lakes filled with liquid methane and ethane. Underneath is a thick crust of water ice. And that again may include an ocean made up of liquid water that could harbor life. All in all, there is still plenty to discover on Titan. And so becomes a mission to reality the unique and richly organic world. The dragonfly drone will be launched in 2026 and will not arrive at Titan until eight years later. The idea is that Dragonfly will use different locations to take samples to investigate whether life on the moon is possible. The instruments onboard Dragonfly will then study how far the prebiotic processes have progressed in all affected areas.
Source and Reference:
” Titan is Migrating Away from Saturn 100 Times Faster than Previously Predicted ” – Caltech
Image at the top of this article: NASA / JPL-Caltech / Space Science Institute