Seeing The Solar System As an Ecosystem

New discoveries and our own increasing presence in space mean the idea isn’t as far-fetched as it sounds

By Craig Axford | United States



noun, plural: ecosystems

A system that includes all living organisms (biotic factors) in an area as well as its physical environment (abiotic factors) functioning together as a unit. Source: Biology-Online Dictionary

Some strange things have been found in our solar system recently. Late in 2017, a long cigar-shaped object flew in from interstellar space. According to NASA, scientists figured that something from outside the neighborhood would be paying us a visit sooner or later. They just thought it would likely be a comet instead of an asteroid.

Astronomers were also surprised by the odd elongated shape this particular visitor had. “Scientists have never seen an asteroid as elongated as 1I/2017 U1 in our solar system — not even half this elongated,” NASA’s page on the object states. 1I/2017 U1 is the alpha-numeric identifier assigned to the odd rock which paid us a quick visit and is now well on its way back into the darkness from which it came. It’s since been given the name of Oumuamua, the Polynesian word for “scout.”

 Since Oumuamua’s visit, some astronomers have announced that they have found an asteroid out near Jupiter that they think arrived from interstellar space not long after the solar system’s birth. With literally only a few dozen exceptions, all the known objects orbiting our sun follow counter-clockwise orbits. According to a May 2018 National Geographic article regarding the possible discovery, “of the more than 779,000 known asteroids, at least 95 drive against our solar system’s flow of traffic.” Of the fewer than 100 known objects orbiting clockwise, at least one — BZ509 — is now thought to owe its contrary motion to its immigration status.

. . .

In April, The American Institute of Physics reported that researchers had been able to create glycine, a necessary ingredient for life, by exposing the “basic molecules of methane, ammonia and carbon dioxide” to the conditions likely to be found in space. The online science news service ScienceDaily quotes the paper’s author Michael Huels as saying “You just need the right combination of ingredients. These molecules can combine, they can chemically react, under the right conditions, to form larger molecules which then give rise to the bigger biomolecules we see in cells like components of proteins, RNA or DNA, or phospholipids.”

That the basic building blocks for life on earth may have originated in outer space isn’t exactly a new idea. But with water spurting out of Jupiter’s moon Europa, the earth can no longer reasonably be considered the only place in the solar system where their delivery via a meteor, asteroid, or comet might have resulted in life.

  NASA, as well as other national and international space agencies, recognize missions to other worlds have the potential both to contaminate them with bacteria or other substances from the earth and to bring back materials that might impact our own biosphere. According to NASA’s Office of Planetary Protection, “In general, if the target body has the potential to provide clues about life or prebiotic chemical evolution, a spacecraft going there must meet a higher level of cleanliness, and some operating restrictions will be imposed.”

Implicit in our space policy, then, is the understanding that our relationship with the universe beyond our atmosphere is at least potentially a two-way street. Planetary protection isn’t just about protecting systems that may contain life from being negatively impacted by visitors from earth, but safeguarding earth from contamination our spacecraft or astronauts may bring back with them.

There are a number of parallels between our policy toward other bodies in our solar system and our own environmental policies here at home. America’s wilderness system is perhaps where these similarities are most explicit. Though it may at first seem a stretch, the Wilderness Act of 1964 and the Outer Space Treaty adopted three years later both contain a recognition of humanity’s capacity to cause harm. In each case, proactively limiting human impact by severely restricting human activity is central to preserving the resource the law is striving to protect.

A wilderness, in contrast with those areas where man and his works dominate the landscape, is hereby recognized as an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain. ~ Section 2(c) of The Wilderness Act of 1964 (emphasis in bold added)

“State Parties to the Treaty shall pursue studies of outer space, including the moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination and also adverse changes in the environment of the Earth resulting from the introduction of extraterrestrial matter and, where necessary, shall adopt appropriate measures for this purpose. ~ Article IX of the Outer Space Treaty of 1967 (emphasis in bold added)

It’s understandable that our definition of an ecosystem, to say nothing of a wilderness, has so far been limited to regions here on our own planet. The air we breathe and water we drink are certainly more immediate concerns than anything happening on a moon orbiting Jupiter or the proteins that might exist on an asteroid shooting like a bullet through our solar system.

But the boundaries of what constitutes an ecosystem or wilderness have always been fluid. They have also always involved more than a little human social construction. There is no part of the planet that is completely cut off from all the rest. There are no environmental processes going on on our planet that are operating in complete isolation.

Likewise, though Earth may be an island in a sea of space, it does not function free of influences or visitors arriving from that sea upon its shores. The mass extinction that took out the dinosaurs and facilitated the rise of mammals is a reminder those influences do not always arrive in the form of subtle gravitational tugs or water and glycine molecules raining relatively gently down from the heavens on small rocks.

Just as forces beyond our planet have and continue to shape the development of life here in ways we are only just beginning to truly understand, NASA and other space agencies clearly recognize we now have the capacity to shape life’s development out there. At some point, if we do not destroy ourselves first, it seems likely that we will undertake at least some limited colonization of our moon, Mars, and perhaps even a few large asteroids. What will words like “wilderness” mean in an environment where literally everything we do represents a departure from its original “pristine” condition?

In his book The Song of the Dodo, David Quammen reminds us that “Isolation plus time yields divergence.” Assuming they can at least briefly survive the harsh environments of their new home, the bacteria and other organisms that we either intentionally or unintentionally introduce to other worlds will attempt to adapt. If successful, speciation will have begun. What happens over the eons that follow is anybody’s guess.

Once this process gets underway we will be moving beyond the challenges to the conventional notions of our place in the universe that have been a regular feature of our culture over the past few centuries. As life takes hold and begins going its own way on other worlds we will be confronting our traditional definition of nature itself.

Historically natural has been synonymous with “not manmade” or without significant human interference. In my view, this definition has wrongly placed humanity outside of nature rather than within it. Space exploration and potential settlement will force us to answer some questions that we’ve largely avoided on Earth. Could an environment that has begun evolving on its own because of a change humans introduced ever be considered natural? What about wild? If not initially, given sufficient isolation and time might it eventually qualify as an ecosystem worthy of some degree of protection? If it shows the potential of becoming such a system, is that potential itself something worth protecting?

Island biogeography provides a model for the introduction of life to other worlds. Earth is dotted with examples of volcanic islands that emerged sterile from the sea: the Hawaiian Island chain, the Galapagos Islands, and Iceland to name just a few. Life on these islands was initially a product of the seeds, insects, birds, and other animals that were able to make their way to their remote shores on mats of debris or that blew in on the wind. As humans arrived rats, pigs, and other species came with them as intentional and unintentional introductions to these emergent island ecosystems.

Assuming martian soils aren’t hiding some simple lifeforms already, Mars is a sterile planetary island waiting for something to wash up on its shores. So is every other rocky environment that can humans can safely pay at least a short visit to. That so far glycine and other proteins arriving from space don’t appear to have gotten things started doesn’t preclude the possibility that a visit from us and our the microbiomes we support can’t do the trick.

Distance and time had, until the 20th century, made such an event a very remote possibility. But now life has begun launching itself on rafts into space, suddenly making the possibility that it will spread very real, the efforts of NASA’s Office of Planetary Protection notwithstanding. It makes no difference whether life gets going on Mars or elsewhere accidentally or intentionally. The first stirrings of life on Hawaii, the Galapagos Islands, and Iceland were accidental arrivals. The initial chemical stirrings of life on Earth may very well have occurred on an asteroid or comet that later paid us a random visit. Now, whether it means to or not, life on Earth may be poised to return the favor.

Featured Photo by Nate Rayfield on Unsplash

  1. I think you’re right on the mark. Other stars approach the sun close enough on the order of once every 10^5 years, so we should assume interstellar mixing is the rule and not the exception. We’ve found these things repeatedly without evern looking for them. (see: )


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