A couple of years ago, I was a guest on a comedy and science panel discussion — a combination that works well because when you laugh your mouth opens, allowing information to float freely in to your head. We were talking about the possibility of travel to Mars. The conversation had turned to how moving to Mars would be useful if and when we wreck our own planet.

James L. Green, a physicist who has since become the chief scientist at NASA, said the reason he wants to send humans to Mars is to colonize it: “As explorers, as Americans, this is what we do.” The audience cheered, the atmosphere was jubilant, and that’s when something inside me flinched a little.

I’ve been trying to work out why. Obviously, there’s the whole colonialism thing, which has historically been not that great for many of us. Also, there’s the enormous resources we’d need to get to Mars. So far, only Matt Damon has made it safely there. Mainly though, I balked at the thought of us marauding around the solar system instead of simply getting a hold of ourselves back here on Earth and working to prevent our own extinction.

Ghosting, in modern dating parlance, is when your beloved vanishes without explanation, having taken what he or she needed. Rhiana Gunn-Wright, whose expertise helped shape the Green New Deal, says that humans are ghosting the planet. The joke is a perfect analogy: We’re in this fabulous life-giving relationship with Earth, this ideal planet, but we’re messing her around. We’re using her and we’re not answering her calls, and planning on leaving her for a cooler planet as soon as we figure out how.