Buzzkill.

Astronomers confirmed the existence of an exoplanet, Proxima b, only 4.2 light-years from Earth, Christopher Crockett reported in "Planet orbits sun's nearest neighbor" (SN: 9/17/16, p. 6).

Some readers thought there was too much excitement over the new potentially habitable planet.

Christina Gullion believes keeping Earth habitable in the face of a changing climate is more important than searching for other planets. "Off-planet exploration seems to me to be a counterproductive diversion of funds and scientific knowledge," she wrote. "I think it is self-indulgently romantic to invest scarce resources in curiosity about life out there in the universe when we could be protecting and enhancing life here on Earth." Although Proxima b is relatively close to Earth, Gullion correctly noted that it is still too far away to reach anytime soon.

Even if humans could travel to Proxima b, reader Steve Moore pointed out, scientists don't know much about the planet. It could be tidally locked with its star and vulnerable to solar flares, he said, which would make it hard, if not impossible, for humans to live on.

Crockett agrees that enthusiasm for Proxima b should be tempered by the little we know about the planet--so far, only its minimum mass, orbit and a few details about its star. Tidal locking is possible, Crockett says, "though there's an active debate about whether that would be OK for habitability or not." And though solar flares also pose a threat to habitability, "a denser atmosphere might be able to withstand Proxima's flares," he says. "We just won't know until we get better data on the planet."

Despite all of the unknowns, Crockett still thinks it's an exciting discovery. "The proximity of the planet means it's probably going to come under a lot of scrutiny in the years and decades to come," he says. "And knowing that there's a planet right next door is pretty neat. I can't wait to see what we learn about it."

Caption: SEPTEMBER 17, 2016

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