Astronomers normally deal in time frames expressed in billions of years.
But when it comes to Saturn’s rings and some of its moons, tens of millions might suffice; they might even be younger than the dinosaurs, according to a new study.
Researchers from the Search for Extraterrestrial Intelligence Institute (SETI) used data collected by NASA’s Cassini mission and computer modeling to analyze the orbits of Saturn’s moons in order to figure out when the satellites were born.
The findings were published in the Astrophysical Journal on Thursday.
The planet was first discovered in the 1600s, and it was initially believed that Saturn’s rings existed for as long as the planet.
But in 2012, French astronomers discovered that tidal effects, the gravitational response moons have on Saturn’s fluid interior, are causing the rings, possibly made of frozen water and other liquids, to spiral quickly around the planet’s orbit.
Those findings suggested that the inner moons, and possibly the rings, formed much more recently than Saturn did.
Now SETI researchers are backing up that hypothesis with newly analyzed data that suggests the planet’s distinctive rings and inner moons were formed a mere 100 million years ago — most dinosaurs inhabited our planet 230 to 66 million years ago.
For context, the sixth planet from the Sun, along with other celestial bodies in our Solar System, formed 4.5 billion years ago.
“We find that [the inner moons] were most likely born during the most recent two percent of the planet’s history,” Matija Cuk, principal investigator at the SETI Institute, said in statement.
About 62 known moons whizzing around the gas giant. They are influenced not only by Saturn’s gravity but — because they are so closely clustered — each other’s.
Researchers observed the orbital data collected by NASA’s Cassini-Huygens spacecraft, which reached Saturn and its moons in 2004, and deduced that Saturn’s moons Tethys, Dione, and Rhea are really young moons because there isn’t evidence of changes in their orbital tilt that is typical of older moons.
They also came to the conclusion that the inner moons may have formed during the Cretaceous Period, the last era of the so-called Age of Dinosaurs.
However, distant moons like Titan and Iapetus would have not formed at the same time as these younger moons. One of the biggest questions that arises is what caused the formation of these inner moons?
“Our best guess is that Saturn had a similar collection of moons before, but their orbits were disturbed,” Cuk said. “Eventually, the orbits of neighboring moons crossed, and these objects collided. From this rubble, the present set of moons and rings formed.”