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- Titan is Saturn\u2019s largest moon.<\/strong> And Saturn\u2019s ring system is the largest in the solar system. A new hypothesis could explain the formation of both.<\/li>\n
- The collision and merger of two old moons<\/strong> might have formed what we now call Titan. The impact could have destabilized smaller moons closer to Titan.<\/li>\n
- Those small moons and other scattered debris<\/strong> then later formed Saturn\u2019s rings about 100 million years ago.<\/li>\n<\/ul>\n
EarthSky\u2019s 2026 lunar calendar is available now. Get yours today! Makes a great gift.<\/p>\n
How did Saturn\u2019s moon Titan form?<\/h3>\n
Titan is Saturn\u2019s largest moon, and the 2nd-largest moon in the solar system. How did this fascinating world of liquid methane rivers, lakes and seas form? A team of researchers in the U.S. and France, led by the SETI Institute, said on February 11, 2026, that Titan likely formed from a collision between two former moons. In addition, the new study suggests the same collision eventually led to the formation of Saturn\u2019s majestic rings.<\/p>\n
Simulations suggest a former large moon collided with what we today know as Titan. This created additional material from other smaller, inner moons that destabilized and also collided together.<\/p>\n
The researchers published their not-yet peer-reviewed draft paper on arXiv on February 11, 2026. It has been accepted for publication in the Planetary Science Journal<\/em>.<\/p>\n
![\"A](\"https:\/\/earthsky.org\/upl\/2025\/04\/Titan-NASA-JPL-UofA-U-of-Idaho.jpg\")
NASA\u2019s Cassini spacecraft captured this composite infrared image of Saturn\u2019s moon Titan in 2015. Image via NASA\/ JPL\/ University of Arizona\/ University of Idaho.<\/figcaption><\/figure>\n Did a huge collision create Titan?<\/h3>\n
According to the new study, Titan formed from the collision and merger of two moons. The researchers call the objects a Proto-Titan<\/em>, nearly as large as Titan itself, and a smaller Proto-Hyperion<\/em>. Proto-Titan might have resembled Jupiter\u2019s moon Callisto. It likely had no atmosphere and was covered in craters.<\/p>\n
This merger could explain some mysteries about Titan, such as its few impact craters and Titan\u2019s eccentric orbit. That orbit is now becoming rounder over time. Also, Proto-Hyperion might have tilted the orbit of another Saturn moon, Iapetus.<\/p>\n
![\"Irregular](\"https:\/\/earthsky.org\/upl\/2015\/05\/hyperion-false-color-9-26-2005-Cassini-800x450.jpg\")
This false-color view of Hyperion was obtained during Cassini\u2019s closest flyby of Saturn\u2019s odd, tumbling moon on September 26, 2005. Image via NASA\/ JPL-Caltech\/ SSI.<\/figcaption><\/figure>\n Hyperion provides clues<\/h3>\n
Some of the best clues come from another of Saturn\u2019s current small moons, Hyperion. It is tiny and misshapen, and constantly tumbling in its orbit. Scientist Matija Cuk at the SETI Institute explained:<\/p>\n
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Hyperion, the smallest among Saturn\u2019s major moons, provided us the most important clue about the history of the system. In simulations where the extra moon became unstable, Hyperion was often lost and survived only in rare cases. We recognized that the Titan-Hyperion lock is relatively young, only a few hundred million years old. This dates to about the same period when the extra moon disappeared. Perhaps Hyperion did not survive this upheaval but resulted from it. If the extra moon merged with Titan, it would likely produce fragments near Titan\u2019s orbit. That is exactly where Hyperion would have formed.<\/p>\n<\/blockquote>\n
![\"Smiling](\"https:\/\/earthsky.org\/upl\/2026\/02\/Matija-Cuk-SETI-Institute.png\")
Matija Cuk at the SETI Institute led the new research about Titan and Saturn\u2019s rings. Image via SETI Institute.<\/figcaption><\/figure>\n Saturn\u2019s rings<\/h3>\n
The collision that formed today\u2019s Titan might also have created Saturn\u2019s rings, the study suggests. The researchers had first proposed more than 10 years ago that the rings formed from collisions of smaller moons closer to Saturn.<\/p>\n
Titan\u2019s eccentric orbit could have destabilized some of those moons. The formation of the rings would have occurred some time after the collision that created Titan, however. The researchers say that this is consistent of the estimated age of the rings, which is about 100 million years.<\/p>\n
NASA\u2019s Dragonfly mission is scheduled to arrive at Titan in 2034. It might reveal further evidence to support the hypothesis of Titan forming from the collision and merger of two former moons. What else will it find on this intriguing world?<\/p>\n
![\"Planet](\"https:\/\/earthsky.org\/upl\/2022\/10\/Saturn-rings-sun-backlit-Cassini-July-19-2013.jpeg\")
View larger. | Here we see Saturn\u2019s rings backlit by the sun. Cassini took this iconic image on July 19, 2013. Cassini looked through Saturn\u2019s rings toward the sun, and the particles in the rings created occultations. Image via NASA\/ JPL-Caltech\/ SSI.<\/figcaption><\/figure>\n Bottom line: How did Saturn\u2019s moon Titan and Saturn\u2019s iconic rings form? A new study suggests a huge collision between two former moons was responsible for both.<\/p>\n
Source: Origin of Hyperion and Saturn\u2019s Rings in A Two-Stage Saturnian System Instability<\/p>\n
Via SETI Institute<\/p>\n
Read more: No ocean on Titan? New research reveals slushy ice world<\/p>\n
Read more: Saturn\u2019s rings much younger than Saturn itself<\/p>\n<\/div>\n
\n - The collision and merger of two old moons<\/strong> might have formed what we now call Titan. The impact could have destabilized smaller moons closer to Titan.<\/li>\n