The Crystal Spheres

One Solution to the Great Silence

Are we alone? It’s a question that has been pondered by mankind since antiquity. It may seem like a fairly modern idea, but as far back as 600 BC the possibility of many worlds inhabited by intelligent life has been debated. The scientific search has been in full swing since the 1960s, yet we’ve still detected no signs of ET after more than half a century.

As we discover more and more planets around alien suns—some rather nearby—a growing body of evidence tells us that the galaxy should be teeming with life. We’re learning that Earth may not be so unique after all, that life is resilient and finds a way to thrive, and that the universe is a far vaster place than we ever imagined. Despite this, our attempts to detect direct signs of intelligent life have failed.

A Universe On Mute

“The Great Silence” it is often called, a situation also known as the Fermi Paradox in which we find no signs of life when we know that we should. For decades now humans have been listening to the stars, searching for radio transmissions that originate from other advanced civilizations; but there are none.

Why is it that in a universe so vast, with so many stars capable of supporting life, there appears to be no other intelligence. A number of hypotheses have been presented over the years, but perhaps none more interesting than that described in David Brin's short story "The Crystal Spheres," winner of the 1985 Hugo Award for Short Stories. Of course, Brin's suggestion is only fiction, but just for a moment let's imagine what it would be like.

The Premise

In the 22nd Century, humans discover a hospitable world orbiting the star Tau Ceti. From their base on the Plutonion moon Charon, they gather together colonists and board a ship that will take them to their new home. On the way out of the Sol system they pass through the Oort Cloud, home of the comets. It is around this area that their ship suddenly plows into an unseen barrier. The barrier bows outward, slowing the ship, and then shatters into billions of pieces, causing comets to rain down on the inner planets. The ship has just broken our solar system's "crystal sphere."

It appears that the galaxy has opened up to us. As humans discover other "good stars" and habitable worlds, they expand out into the galaxy to colonize them, only to have their ships destroyed as they approach these star systems. The ships encounter barriers like the one that had been shattered around our own system, but on these occasions the barriers do not shatter and the ships are lost. Like our sun, these good stars are also surrounded by crystal spheres.

Interestingly, humans discover that "bad stars"—stars without habitable worlds or incapable of supporting such worlds—are not surrounded by crystal spheres. Only stars around which habitable water worlds orbit are locked in by these barriers, preventing mankind from exploring the worlds or making contact with life that may be detected there. The narrator of the story, Joshua, refers to the spheres as "the joke of the gods."

"We are the ones who have pressed our faces against the glass of the candy store, staring in at what we could not have. We are the ones who understand the depth of our depravation, and the joke the universe has played on us."

Coming to Terms with Fate

It is a depressing thought—that we may be the only intelligent life in the universe, condemned to an existence of eternal isolation—but one that the humans of Brin’s story had increasingly come to accept.

But as the story unfolds, humans once again set out to investigate a report from a probe that a good star with a shattered crystal sphere had been discovered in a nearby galaxy. They send a team of explorers to the system. Along the way they pass more than 200 good stars, many with water worlds, some with detectable life, all locked away within crystal spheres, forever inaccessible to humans. The spheres allow radio signals to escape, but block all signals coming in. It is therefore a relief when they arrive and discover that the reports from the probe are true.

Disappointment soon sets in, however, when they discover that the technologically advanced race that had once inhabited the system left millions of years earlier. But the records that they left behind clear up many things for mankind. The natives of this world shattered their own crystal sphere eons ago and journeyed out to the stars only to discover what humans had—that other “good” worlds were inaccessible. But they did eventually happen across five other shattered spheres that contained abandoned worlds.

From these records, humans learn that the crystal spheres can only be broken from the inside, and that the purpose of the spheres is akin to an egg—they exist to protect young, evolving intelligence from more advanced species who would otherwise conquer and colonize.

“If the crystal spheres had not existed, then there would come to each galaxy a first race of star treaders. Even if most intelligences were stay-at-homes, the coming of an aggressive, colonizing species was inevitable sooner or later. If the crystal spheres had not existed, the first star treaders would have gone out and taken all the worlds they found. They would have settled all the water worlds and civilized all the small bodies around every single good star.”

It then also becomes clear to humans that we exist in the early days of galactic development and that there are many worlds ripe for intelligent life to evolve; but few on which it has done so. We are in essence an elder race, doomed to live and die ages before the universe blooms and the rich intergalactic traffic and interaction of our science fiction becomes reality.

Solving the Puzzle

What David Brin so cleverly addresses is the puzzle of the Great Silence. We look up at the sky, point our radio telescopes at the heavens, and find nothing. The absence of life contradicts what common sense tells us should be true.

We have no evidence that Earth has ever been visited or colonized, yet a race that sets out into the galaxy to begin colonizing worlds should fill the entire galaxy within a few million years—but a blink of an eye on the galactic timescale. Surely a race should have already achieved this. Where is everyone?

Could it be that there are other races out there zipping between the stars, sharing culture and communications, but our crystal sphere is blocking evidence of their existence? Could the universe be sheltering us until the time is right for us to spread our wings and leave the nest?

Crystal spheres are no doubt of the realm of the imagination. But is it possible that some other natural phenomenon might prevent us from detecting the very signals we seek until our technology reaches a certain level?

In reality it is far more likely that either:

  1. there is other intelligent life out there, but it is rare and the vast distances of the space prevent races from ever detecting one another
  2. there is never more than one race in existence at one time because of the vast time scales we are dealing with. Civilizations have risen and fallen many times in the past and will again, but they exist in temporal isolation.

It is a fascinating subject and David Brin offers a interesting if not fantastical solution. What do you believe?