Ancient climate change made plants shift range. Read more about the research with Jonathan Bloch of the University of Florida Museum of Natural History.

Dusty disks around young stars in infrared images provide a way to directly study these star-forming disks. Read more about how astronomers are studying them.

Consider three requirements for a sustainable world. Everyone on the planet would have their human needs met. Hunger and poverty would be substantially reduced. And, the natural systems that support life on the planet would be preserved.

Nobel Laureate Kenneth Arrow, a prominent economic theorist of the 20th century, talks about how to measure the impact of the anthropogenic causes of change.

There is no consensus on desirable levels of consumption, or even what "sustainable consumption" looks like. Read more with Alex de Sherbinin.

On July 2, 2006, asteroid 2004 XP14 passed not much farther than the moon's average distance from Earth. There is no danger of this asteroid striking Earth in the foreseeable future. But astronomers - like Judit Ries of the University of Texas - now know and study hundreds of other Near-Earth Objects like 2004 XP14.