The inventor of the DNA sequencing technique embarks on the next big challenge.

Profile: Leroy Hood, inventor of the DNA sequencing technology, embarks on the next big challenge.

In some ways, cells are a lot like cities. Maps of a cell’s innards depict thoroughfares linking factories that build large molecules to post offices where those molecules are packaged up and shipped out, for example. The cell’s denizens — proteins and other molecules — shuttle around busy cellular byways like people on the street, meeting up, interacting and keeping the whole enterprise going.But anyone who has ever been delayed on the way to an important meeting knows something about cities that biochemists are just beginning to learn about cells: Maps don’t capture a lot of detail... (p. 22)

Inspired by a classic particle physics experiment, researchers get water droplets to condense by shooting a light beam skyward.

Laser physicists have set their sights on new types of waves — manufacturing beams of sound, creating plasma swells and looking for ripples in spacetime. (p. 28)

Tropical asphalt lake could be analog for extraterrestrial microbial habitat.

The famous fragment of Mars, once proposed to hold signs of extraterrestrial life, is still pretty old. But the rock appears to have formed about 400 million years later than earlier analyses indicated. (p. 10)

Reversed orbits among ‘hot Jupiters’ decreases chance of Earthlike neighbors. (p. 11)