In search of alien worlds

In order to hunt a key component for planets like our own, astronomer Francesco Pepe will use the fiber to feed star light into a new detector-the High Accuracy Radial velocity Planet Searcher-North (HARPS-N), an ultraprecise spectrograph that is being assembled nearby, not far from a field of grazing horses. In the coming months, Pepe, an astronomer, and his colleagues will take apart the go-cart-size instrument, box up the pieces, and put them together again in a room near Italy's Telescopio Nazionale Galileo on La Palma, one of the Canary Islands. When HARPS-N begins observations in April, astronomers expect it will be the most precise planet hunter in the northern hemisphere. They also reckon it will be particularly well placed to help bag the most coveted extrasolar quarry of all-planets small enough to have rocky surfaces and cool enough to have liquid water.