Over the past several decades, planetary scientists have continually added to the list of moons in our solar system that may contain interior oceans now or at some point in the past. Many of these moons (such as Europa or Enceladus) were gravitationally bound to the gas giants Jupiter or Saturn.

But recently planetary scientists have turned their attention to the ice giant Uranus, the coldest planet in the Solar System. And now, a new study based on images taken by the Voyager 2 spacecraft suggests that Uranus’ small icy moon Miranda may once have had a deep ocean of liquid water beneath its surface.

Moreover, remnants of this ocean may exist in Miranda today. The Voyager 2 spacecraft took photographs of the southern hemisphere as it passed by Miranda in 1986. The resulting images showed a number of different geological features on its surface, including rugged terrain, jagged cliffs and cratered areas.

Researchers like Tom Nordheim, a planetary scientist at the Johns Hopkins Applied Physics Laboratory (APL), wanted to explain Miranda’s strange geology by reverse engineering its surface features and determine what kinds of internal structures might best explain what the moon looks like. It is the same today.

The team mapped various features on the lunar surface seen by Voyager 2, such as cracks and ridges, before developing a computer model to test a range of possible compositions that could best explain the stress structure visible in the moon’s interior. surface of the moon.

The computer model found that the internal composition that provided the closest match between surface tension models and the actual geology of the Moon’s surface was the presence of a deep ocean beneath Miranda’s surface that existed between 100 and 500 million years ago. According to their models, the ocean may have once been 62 miles (100 kilometers) deep and buried under 19 miles (30 kilometers) of surface ice.

Miranda’s radius is only 146 miles (235 kilometers); This means that an ocean would cover almost half of the entire body of the moon. This also means that finding such an ocean is unlikely. “Finding evidence of an ocean inside an object as small as Miranda is incredibly surprising,” Nordheim said in a statement about the new study.

“It helps build on the story that some of these moons of Uranus could be really interesting, that there could be multiple ocean worlds around one of the most distant planets in our solar system, and that’s both exciting and surprising,” he continued.

The researchers suggest that the tidal focus between Miranda and other nearby moons is crucial to ensuring that Miranda has enough heat inside to support a liquid ocean. Miranda’s gravitational pull and compression, amplified by orbital resonances with other moons in the past, could produce enough frictional energy to keep it warm enough to freeze.

Similarly, Jupiter’s moons Io and Europa have a 2:1 resonance (for every two orbits Io makes around Jupiter, Europa makes one), creating enough tidal forces to support an ocean beneath Europa’s surface.

Miranda eventually lost synchronization with one of Uranus’ other moons, defeating the mechanism that kept the heat in. Researchers don’t believe Miranda is completely frozen yet because it should have expanded and a visible crack has formed on its surface.

“We won’t know for sure that there’s even an ocean there until we go back and collect more data,” Nordheim says. “We are extracting the latest scientific information from Voyager 2 images.” “For now, we are excited about the opportunities and look forward to returning to a deeper study of Uranus and its potential ocean moons.”