Genes tell stories of disease, of health, of parentage, all recorded in the chemical composition of DNA. But to many biologists, one of the most exciting tales that sequences of DNA letters can tell is an evolutionary one. And since evolution on its largest scale—the shifting cast of organisms populating Earth over the past few billion years—happens over lengthy periods of time, some of the best stories may be locked in the DNA of species long buried and gone extinct. Sequencing the complete genome of a woolly mammoth that died 60,000 years ago or a Neandertal man who lived 40,000 ye... (p. 18)

Amid the liveliest stars in the cosmos lie stellar corpses. Of these dead stars, the most abundant are white dwarfs — stars that in their prime were similar to the sun. These dense corpses foreshadow what will become of most of the stars in the universe. Although white dwarfs are dead, they aren’t useless. Postmortem examination shows they have different masses and different chemical makeups. Some are strongly magnetic. Others pulsate. A few even have orbiting planets and debris disks. “Understanding why these cadavers are all different might help us understand the li... (p. 26)

With solid findings under its belt and the Martian summer waning, the Phoenix Mars lander perseveres in its study of the soil and sky of the planet’s arctic plain.

A new study finds that early dinosaurs coexisted with and were outnumbered by a competing species. Dinosaurs eventually reigned supreme anyway, but perhaps not because they were better.

Men’s brain tissue shows higher density of neuron connections than similar tissue from women. (p. 15)

Ancient DNA shows North American woolly mammoths migrated back to Asia and displaced Siberian mammoths.

Astronomers discover the heftiest, most distant galaxy cluster, suggesting evidence for dark energy’s existence.

Two space telescopes capture the titanic collision of galaxy clusters in an image that shows dark matter separating from normal matter.

Gamma-ray telescope sees first light and gets a new name.

Deep-sea vent waters harbor high numbers virus-carrying bacteria. The viruses may actually help the bacteria survive the harsh vent environments.

Black holes may not come in mid-sized versions. Astronomers expecting to find one in a galaxy cluster found a tiny black hole there instead.

New suggestions for defining a planet would put Pluto back on the list. Scientists discuss the International Astronomical Union’s definition during the Great Planet Debate Conference.

Successful heart transplant experiment in infants draws attention to debate on defining death of organ donors.