One of our very oldest ideas, a species, is that we’re living in a bubble surrounded on all sides by vast amounts of dark water. The idea dates back to second millennium BCE Sumerian cosmology and can most famously be found in the Bible, but you’ll find the basic idea all over the place. Hinduism, for example, teaches that Earth is suspended in a vast ocean called the Garbhodaka. The general idea of a cosmic ocean can be found in precolonial oral traditions on every continent, and was almost certainly a near-universal human belief at one time.
And the idea of a cosmic ocean isn’t just an unfalsifiably mystical concept or a pre-scientific way of imagining the universe around us; Carl Sagan famously described Earth as “the shores of the cosmic ocean” three minutes into the first episode of Cosmos, and one well-substantiated recent theory of quantum gravity suggests that spacetime itself functions like a superfluid. In the event that the Apollo 11 astronauts were unable to return from the Moon, NASA had planned to treat the stranded astronauts as if they had been lost at sea.
Now, a group of Spanish cosmologists studying dark matter—the mysterious stuff that makes up about 85% of the matter in the universe—have found one more reason to believe we’re (somewhat literally) in the soup. By looking at various models of galaxy formation, they’ve found a particle that would explain the shape of the cosmic web. If dark matter were made up of infinitesimally small low-energy bosons rather than the larger fermions scientists have traditionally looked for, we’d end up with a universe that looks an awful lot like the one we inherited. And the dark matter in that universe would, in the worlds of Space.com’s Charles Q. Choi, "behave more like wavy fluids than solid particles.” The 15% of matter that isn’t dark—the matter we can see, the matter we can manipulate, the matter that comprises us—would just be bubbles in an incomprehensibly vast sea of invisible low-energy particles.
It’s one of our newest ideas; it’s also one of our oldest. “Dear God, be good to me,” as the traditional Breton fisherman’s prayer puts it. “Thy sea is so great, and my boat is so small."