Titan is moving away from Saturn at a rate 100 times greater than predicted

One of the most interesting objects in our solar system is Saturn's moon, Titan. It's the only moon in the solar system to have an atmosphere and is larger than the planet Mercury. The surface of the moon is covered in rivers and seas of liquid hydrocarbons such as methane and ethane.

Underneath the crust of water ice on the surface of the moon, Titan could harbor a liquid water ocean that might host life. Decades of measurements and calculations have shown that Titan's orbit around Saturn is expanding. That means that Titan is getting further and further from Saturn. Scientists say that Titan was born much closer to the planet it orbits and migrated to its current distance of 1.2 million km over 4.5 billion years.

Caltech scientist Jim Fuller says that prior work had predicted moons like Titan were formed at an orbital distance similar to where we see them today. Titan exerts a similar pull on Saturn as the Moon does on Earth. The Moon migrates about 3.8 cm further from the Earth each year. Predictions are that Titan should be moving away from Saturn at a rate of at most 0.1 cm per year, but new results contradict the prediction.

Two research teams, each using a different technique to measure Titan's orbit over a decade, are detailed in the new study. One technique called astrometry produces precise measurements of Titan's position relative to background stars in images taken by the Cassini spacecraft. The other technique used was radiometry, was measured Cassini's velocity as it was affected by the gravitational influence of Titan.

Scientists were able to attain results that are in full agreement using two completely independent datasets. What the data sets suggest is that the migration rate of Titan is much faster than standard theories estimated. Titan is moving away from Saturn at a speed of 11 cm per year, which is more than 100 times faster than past theories predicted.