It’s the middle of spring, which is gardening season at my house. Not that I’m a gardener, mind you. My hobby is woodworking—apparently I find it easier to create things from dead plants than to keep plants alive. But my wife, Amy, loves to garden. This time of year almost always finds her outside digging, planting, weeding, or watering. In years past it’s been a vegetable garden, herbs, and flowers. This year it’s been landscaping, with more perennials than usual. The point is, she has a green thumb and likes to make things grow. While my mind is off wandering among the stars, hers, at least in the spring, is firmly on the ground. I’m sure there’s a metaphor for our marriage in there somewhere.

Because of her hobby, Amy is much more attuned to the various relationships among living things than I am. She knows which species like to be planted close to each other and which will compete for the same nutrients and should be kept farther apart. She understands and takes time to learn about what does well in shade and what needs more sun; how much water is too much or not enough; what the deer will eat and what they’ll leave alone. She’s transforming our front and back yard into a place where various plants will not only look pleasing together, but will flourish as individual organisms.

Reflecting on Amy’s talents for gardening has me thinking about what our relationship with other organisms means for humanity’s future—or rather, what humanity’s future might mean for those other organisms. I often imagine a future where humans are an interplanetary species, inhabiting the Moon and Mars and maybe other worlds in addition to Earth. Such a future excites me, even though it’s far off and I probably won’t live to witness it. Nonetheless, it’s my passion to help Christians take this long view and understand what it means for our faith, and explore how our faith can draw us forward into this future confident in God’s grace and presence.

What I forget, though, and what Amy’s love of gardening helps me remember, is that we won’t go into this future alone. Humankind will never be the sole earth-originating interplanetary species. Other species will come along with us. We simply can’t survive apart from other organisms; we’re part of an ecosystem, as much as modern life and culture might push us to forget it. When (if) some of us leave Earth, we won’t just become an interplanetary species; we’ll initiate and shape an interplanetary ecosystem, a community of creatures that succeeds or fails with the flourishing (or not) of each species that’s a part of it.

Humans depend on other organisms for food. We can probably start on another planet with preserved food that’s transported from Earth, but that’s an impractical solution in the long term. Better to raise crops in lunar or Martian soil—which will require identifying and perfecting crops that not only will thrive in their own right, but will provide us with what we need in terms of nutrients and energy.

Even discounting the food we eat, we can’t get away from the microbiome in our own guts. The moment we take up residence on another world, the various bacteria in our stomachs become interplanetary species as well. When Neil Armstrong took one giant leap for mankind, he also made that same leap for certain kinds of microbial life that hitched a ride with him to the Moon.

That is to say nothing of the many other ways we depend on plants and animals, fungi and bacteria. They are our companions; test subjects; providers of clothing and shelter; sources of healing; givers of color, aroma, texture, and taste. The list could go on. The other organisms with which we share our world actually enable us both to live and to thrive. We can’t go somewhere else without them. We would be incredibly foolish even to try.

This means that humanity’s decisions, ventures, and journeys don’t affect only us. Our decisions about whether or not to explore and colonize space and other planets make those same decisions on behalf of many of Earth’s other species too, because we’re the only species powerful and intelligent enough to have the choice available to us and because our fates are intricately linked to theirs. We can decide to a certain extent which of Earth’s species to take with us and which to leave behind. We can decide, either intentionally or by default, that humanity and all other species will remain Earth-bound. Recognizing this increases our responsibility—it’s not just about us, it’s about the rest of our fellow creatures on Earth too.

This is one area where the excitement and trepidation surrounding interplanetary exploration converges with our humanity (though it’s surely not the only one). We have been created in God’s image with a purpose, and in Genesis 1 that purpose is to “have dominion over the fish of the sea, and over the birds of the air, and over the cattle, and over all the wild animals of the earth, and over every creeping thing that creeps upon the earth” (Genesis 1:26 NRSV). This means we have the authority, the ability, and the responsibility to exercise dominion over all the other creatures in our world—that is, to lead and direct all of creation in responding in love to our creator. In doing so we will enable all of our fellow creatures to flourish, and direct all their energies as well as ours toward the love of God and love for one another.

It’s a responsibility we can’t lay aside as we look to the stars, because to do so is to turn away from the very thing that makes us human, the very honor and power that comes to us as the creatures made in God’s image.