Lipps says many scientists thought the solar radiation is "too fierce for life to exist on the surface... we'd last about 2 minutes." This is because scientists thought "Europa is like a cue ball: smooth. But it's not." Europa is covered in cracks and crevices, caverns and boulders and overhangs. "It's geologically extremely variable," says Lipps, providing life with plenty of places protected from the extreme radiation. "It only takes a meter and a half of ice to damp out that radiation." So life could potentially live just a meter and a half below the icy skin of Europa--essentially on the surface. And this, says Lipps, "freaks [people] out."