Imagine discovering that a moon once thought to be just a frozen block of ice actually had a massive hidden ocean inside. That’s exactly what scientists now believe about Miranda, one of Uranus’ 28 moons. This tiny, cratered moon, famous for its strange surface features, may have harbored an enormous ocean beneath its icy crust millions of years ago.
Strange Surface Hints at Hidden Depths
When you look at Miranda, its surface is filled with deep cracks, ridges, and odd trapezoidal shapes, called coronae. These unique patterns have long fascinated scientists, who wondered what could have created such dramatic features on a moon so small. Using a computer model, researchers decided to dig deeper, so to speak. They mapped out Miranda’s surface details and tested different possible setups for the moon’s interior to see which configuration could match those distinctive patterns on its surface.
To their surprise, the setup that best matched Miranda’s actual surface features required the existence of a large ocean beneath its icy crust. The model suggests that this ancient ocean was at least 62 miles (100 kilometers) deep, lying under an icy shell about 19 miles (30 kilometers) thick. With Miranda being only about 146 miles (235 kilometers) in radius, that means this ocean would have filled almost half of its interior—a stunning discovery for a moon that was once expected to be little more than a frozen, rocky shell.
Tidal Forces and a Surprise Ocean
So, how could Miranda, a small, cold moon, have maintained such a massive ocean? That’s where the fascinating force of tidal heating comes in. Scientists now think that gravitational interactions, or “tides,” between Miranda and Uranus’ other moons could have generated enough internal heat to keep an ocean from freezing completely. Picture Miranda tugging back and forth with its neighboring moons, generating friction and heat beneath its surface—enough warmth to keep a hidden ocean in liquid form.
This process, known as tidal heating, isn’t unique to Miranda. It’s actually the same kind of effect we see with other ocean-bearing moons in the solar system, like Jupiter’s Europa and Saturn’s Enceladus. But Miranda, due to its smaller size and age, wasn’t really expected to have this feature, which made the findings all the more surprising.
A Moon That Defied Expectations
The discovery of a potential ancient ocean on Miranda has flipped the assumptions scientists had about this little moon. Because of its small size, any heat from Miranda’s formation was expected to have dissipated long ago. Instead, it seems that the moon may have experienced a surprisingly active history, with the gravitational push-and-pull from nearby moons providing enough warmth for an internal ocean.
For now, scientists can only imagine what Miranda’s interior might have looked like in its ancient past. But as we learn more about moons like Miranda, it opens up new possibilities about where we might one day find evidence of life beyond Earth. And who knows—maybe one day we’ll get a close-up look at what lies beneath the surface of Uranus’ most intriguing little moon.
