Because the surface of Mercury is as hot as molten lead, its inhabitants live underground. It has an atmosphere, though, and properly suited up one can live on the surface for brief periods of time.
The planet is heavily cratered, much like Earth’s moon. It has cliffs the color of ochre that extend as much as a mile into the sky. Evidence of ancient lava flows are everywhere. There are numerous shallow basins and ringed craters. A good percentage of Mercury’s surface is covered by plains.
Mercury has its oddities, as well. And they are quite bizarre! I observe that the Sun sets in the west, a small red disk. And then — almost immediately — it rises and increases in size as it reverses course. At its zenith it stops and changes direction, growing smaller until it disappears from view. The stars come out and speed across the sky at three times their normal rate. I see Earth from the surface of Mercury. A small, pale-blue disk about the size of my thumb. I feel sad that it is no longer my home, this gentle third planet from the Sun.
Eventually, I find what I am looking for: one of the many entrance holes that lead underground. This one is nearly four feet wide. It is built into the side of a cliff fronted by windswept blue-grey boulders. I noticed it only because I thought I saw something moving amongst the rocks.
The entrance is surrounded by yellow vegetation and tall stalks made of a material that looks like petrified wood. I see a swift-moving stream of boiling water that flows beyond the entrance, and I watch in fascination as steam rises, condenses against the cliff wall, and trickles to the ground.
From out of nowhere the brown body of a Mercurian rat shoots across my path and disappears into the entrance hole. I jump back, startled. I thought Mercury was too hot for anything to live on the surface. Or was this animal but an illusion?
I find myself in a maze of tunnels. Everywhere I look there are veins of gold, diamond, sapphire. A miner’s paradise!
The tunnel I am in is suffused with a pale light which glows red like the embers of a dying fire. Try as I might I cannot discern the source.
I walk on through damp serpentine passages. I hear the drip, drip of water falling over polished rocks. More than once I slip, scattering stones in all directions. The tunnel opens and I am walking along a ridge, the escarpment of an underground cliff. I must watch my step lest I plunge to what surely would be a gruesome death. (I imagine myself as a bloodied corpse, a prisoner down here forever.) Eventually, the path levels, the tunnel walls close in once again, and I breath a sigh of relief.
An hour later I find myself a mile below the planet’s surface. The passage ends and I find myself facing a melancholy landscape with no sign of life. The soil has a bluish hue and is compact like hardened clay. The air is cool and still. It is deathly silent. If I lived down here I surely would go mad!
I see a half-dozen passageways that continue in various directions. I pick one at random. I walk for another mile or so, but encounter nothing. The passage descends, narrows, and I am conscious of thick musky air pressing down upon me. My lungs feel as if they are about to burst. My heart pounds. I am sweating about my neck and forehead. And then everything goes black.
I must have fainted, for the next thing I know my eyes are opening and I find myself on my back. The pressure on my chest is overwhelming. I gasp for breath.
Perhaps I’ve miscalculated and am closer to Mercury’s core than I’d imagined? To be honest, it’s possible I’ve been walking for days, not hours, which would surely make it so. I’ve lost all sense of time.
It is with a Herculean effort that I rise and start off once again. How to describe what I see?—or more precisely, what I think I see, for the light in the tunnel is virtually nonexistent.
I detect amorphous shapes which hover before me with appendages like the talons of a hawk. They wish to claw out my eyes, I know. There are ghosts down here. I see shadows of forms that once were, grinning, toothless faces. I feel a fiery breath. I raise my arms—a pathetic shield—and scream in terror. Yet they, too, must be afraid for they scurry into the shadows.
No, I will not find an inhabitant of Mercury today and probably never will. It is far more likely that I have descended into the underworld and now am walking among the skeletons of the damned.