We don't need to land to find life on Europa

[Nipuna]

"All these worlds are yours. Except Europa. Attempt no landing there." So warned the protectors of life on Jupiter's icy moon in 2010: Odyssey Two, by Arthur C. Clarke.

The novel's omnipotent aliens are adamant that the life forms inhabiting Europa's oceans should be left to evolve without interference.

The prospect of finding extraterrestrial life on Europa has inspired real scientists to plan ambitious – and expensive – missions. But they, too, are cautious about landing. The risk of contamination is very real: no one wants to introduce earthly bugs to a pristine environment.

Now the discovery that Europa is emitting plumes that could be checked for biomarkers offers a tantalising alternative (see "Water plumes spark a race to Jupiter moon Europa"). Perhaps we can detect life without attempting a landing at all.

This article appeared in print under the headline "ET: off limits but within reach"