Three Earth-size planets orbit a small, dim star. Are they Earthlike? It’s not clear yet. (ESO/M. Kornmesser)
Earlier this week, a string of somewhat breathless news stories reported that three Earthlike exoplanets could be the most likely hosts for life outside the solar system. But that’s not exactly true. There’s a lot we don’t know about these newly revealed planets, and a vast ocean of data that needs gathering before an Earth-size world can make the leap to truly Earthlike. Already, a new study has suggested that two of these planets could be desiccated, parched, and decidedly un-Earthy.
Yet even if the trio aren’t as Earthlike as advertised, they’re still interesting and notable—even without trumped up reports of habitability.
“All of the stuff about habitability, surface environments, etc., is merely idle speculation and conjecture,” says Greg Laughlin of the University of California, Santa Cruz. “Even with our own solar system, there’s been zero success in predicting what surface environments for a large moon or planet look like until the body is viewed up close.”
The journey from Earth-size to Earthlike depends on which definition is at the destination. How much of an Earth twin does a planet need to ...