If you give your eyes a little while to get adjusted to the night sky, there soon starts to be more than just great sprays of lights. Here and there, when conditions are right — meaning when the sky is free of scud that gets in the way and of moonlight that washes out star and planet light, and when your gaze is aimed in the right direction — you can detect faint clouds of light too.

Just a handful of them are visible without binoculars, and they were noticed and cataloged by ancient astronomers, of course, who called them, in Latin, “nebulae,” meaning clouds. But it wasn’t until well into the 1600s that people really started to puzzle over them because with the invention of telescopes, many more were spotted. What were they?

Those early modern astronomers knew they did not know what they were seeing. But as the instruments got better, the clouds came into better focus. Some astronomers speculated that the nebulae were clouds of gas forming into planets like ours. Others, like the eminent philosopher Immanuel Kant in the 1700s, thought they were island universes of stars, or in other words, galaxies.

Well, by the 20th century huge amounts of light-data were accumulated and analyzed, and the unknown clouds were described in several basic categories. Some were groups of stars (clusters, globular clusters and galaxies). Some were shells of gas around dying stars (called, in the original 18th century phrase, planetary nebulae, even though it turned out they were nothing to do with planets). And some were floating clouds of gas and dust, now generally spoken of in three different categories: reflection nebulae (clouds which reflect nearby starlight); absorption nebulae (clouds which are seen in silhouette against other brightnesses); and emission nebulae (clouds which glow in the presence of ultraviolet radiation). Some very distant ones were determined to be the remnants of exploded stars.

As with all serious human inquiry — scientific, philosophic, religious — it took centuries of hyper-careful observation and intellectual energy to get these descriptions into focus. The physical picture of the cosmos is a lot clearer now than it was 200 years ago, but in some ways the clouds of scientific unknowing are greater than ever. By the 1990s it was evident to cosmologists that upwards of 90 percent of all that apparently exists in the universe as science imagines it has not been seen or even detected. In fact there are some very bright people toiling away over minute data distilled from far-distant starlight who are pretty sure the universe we see is only one among what could be an infinity of universes.

And that’s just the physical cosmos out there that science has a shot at accounting for. There are whole other activities inside the mind that are as real and awe-inspiring as washes of light on the sky darkness, and more elusive than those sky nebulae were to the first astronomers. Dreams like clouds reflecting light from some unknown elsewhere. An insight silhouetted against the surface of your mind. A memory suddenly glowing up bright in your consciousness. Powerful emotions like affection or enmity appearing like radiation in the everyday scud. What are they?

As medical instruments get better, more information in more and more minute detail is compiled describing what happens in nerve and muscle tissue during these experiences. But the experiences themselves, the starlit energies of your own consciousness and the worlds it exists in, are not accounted for in biochemical statisticry. There are telescopes in philosophy and deep inside the great religions that bring these clouds of unknowing into focus. Somehow we have collectively stopped looking through them, even though many of us, maybe most of us, have the unsettling feeling that the universe we see is only one among what could be an infinity of such nebulae.

Dana Wilde’s collection of Amateur Naturalist and other writings, “The Other End of the Driveway,” is available electronically and in paperback from Booklocker.com. A second collection, “Nebulae: A Backyard Cosmography,” is expected to be published this summer. For more information about it visit Kickstarter.