The black cloud - A plausible gaseous lifeform?

In an article I published yesterday, I expressed why I think the idea of “gaseous lifeforms” is silly. It’s not that I want to discourage writers from portraying unusual and creative types of alien life in their fiction, it’s just that I find the notion of a creature made of gas to be implausible, and I’d like to encourage science fiction writers to think logically about the aliens they create before blindly walking into the valley of tropes.

Just because Star Trek did it, doesn’t mean it makes any kind of logical sense. And I think science fiction writers really should strive towards some kind of sense making. I’m not saying that our creativity should be bound by logic, rather that the genre compels us to use logic for creative ends.

But not all depictions of so-called “gaseous lifeforms” are ridiculous, just the ones composed entirely of gas. Any space-dwelling lifeform is likely to have an interesting and important relationship with interstellar gas, whether it uses gas as an environmental medium, internalizes it, or even externalizes it. And while I’ve stated my doubts about lifeforms which exist only in a gaseous form, my previous article also hinted at the possibility of lifeforms which comprise of both solid and gaseous components.

But what the hell do I know? Writers much smarter and more scientifically-minded than myself have attempted to devise solutions to the problem of “gaseous lifeforms”, presenting them in well considered works of science fiction dating back over half a century. In the interest of providing balance, I’d like to share one of these with you now.


In 1957, Fred Hoyle published a clever novel titled “The Black Cloud” in which the Earth is threatened by the arrival of an immense gas cloud. The cloud is not just a random concentration of interstellar gasses, it’s alive!

I haven’t read Fred Hoyle’s novel, but I came across a description of his Black Cloud creature in Barlowe’s Guide to Extraterrestrials (written by Ian Summers).

The Black Cloud is a vast, intelligent cloud of interstellar hydrogen, about 150 million kilometers in diameter. At its center is a complex neurological system made up of massive molecular chains.

“Black Clouds travel through space, making occasional stops in the vicinity of a star in order to use the energy to produce food and the chemicals that make up their bodies. When the Cloud reaches the vicinity of a sun, it assumes a disk-like shape that enables it to absorb energy more efficiently. By condensing hydrogen in a small area of the cloud, producing a fusion reaction, the Cloud creates an explosive jet of gasses that acts like a rocket, enabling the Cloud to accelerate, decelerate, and change direction.”

– Ian Summers, writing in Barlowe’s Guide to Extraterrestrials

Fascinating. This sounds fairly plausible, right? It’s certainly very clever. The cloud’s fusion engines would technically be plasma, so its not 100% gas, but lets not dwell on that.

But how does this thing keep itself from drifting apart? And where does its intelligence reside?

Of the Cloud’s intelligence, Summers wrote this:

The brain is made up of many small units, each consisting of a piece of rock that has layers of molecular chains carefully arranged on it. These units function much like a memory bank in a computer. The units are surrounded and interconnected by the electromagnetic flow of the cloud and circulating gasses that provide energy for the units and remove wastes.

– Ian Summers, writing in Barlowe’s Guide to Extraterrestrials

Aha! So there is a solid component to the creature, small though it may be. This begs the question is the gas actually part of the creature or just a store of fuel? I guess it’s a matter of perspective, but is your fuel supply (fat) a part of you? And what about your blood? Where does “you” begin and end?

It looks like we’re dealing with a creature composed of more than 90% gas, which is enough to class it as a “gaseous lifeform” in my opinion. And while some of you may find the science here a little lacking, there’s enough to satisfy my own need for a a scientific justification. (Remember this is only a paraphrased description. We should look to Fred Hoyle’s novel for a full explanation.)

Continuing his profile of the Black Cloud, Summers writes of the creature’s reproduction:

When a Black Cloud discovers a nebula of dense hydrogen gas that does not have an intelligence, it may stop and reproduce. The Cloud begins to grow a few simple brain units inside itself, organizing the magnetic flows and energy storage systems neccessary to support intelligence. It then plants these units in the cloud, along with extra food energy and molecule chains, which become the nucleus of a new individual.

– Ian Summers, writing in Barlowe’s Guide to Extraterrestrials


There are thousands, possibly millions, of intelligent hydrogen clouds wandering through our universe. Their very nature makes it impossible for a Cloud to remain in one area for very long; if a Cloud stays in interstellar space, it will soon run out of energy and die. If it tries to remain in the area of a sun, vast gravitational forces will cause the Cloud to begin to condense into a solid body.

Although individuals live solitary existences, they do communicate with eachother by means of radio transmissions on the one centimetre bandwidth. These long-distance conversations are generally about methematics, philosophy, and the nature of the universe.

– Ian Summers, writing in Barlowe’s Guide to Extraterrestrials


What do think of this description of a gaseous lifeform? Perhaps you’ve read the book and can illuminate us all on the details of Fred Hoyle’s creation. As always, the comments are open!

Article written by Mark Ball.

With extracts from Barlowe’s Guide to Extraterrestrials by Wayne Douglas Barlowe and Ian Summers.