Ethno-botanist Darron Collins talks about rainforest logging. It may be more sustainable, but it'll take much more to save the rainforests. Read more.

Most stars reside in a galaxy. In 2006, astronomers used the Hubble Space Telescope to study over 5,000 stars found in the space between galaxies in the Virgo cluster. The lack of iron in these stars indicated that they may have come from small galaxies that got ripped apart when they passed too close to larger galaxies.

Older dwarf stars, such as Proxima Centauri, have fewer flares and starspots (the stellar equivalent of sunspots). Read more about older dwarf stars here.

Double centaurs are a centaur plus a compaion. Centaurs are icy planetoids orbiting the sun between the outer planets Jupiter and Neptune. Read more.

Scientists are now speaking of what they call the "coupled human-environment system." It's a new way of thinking about the relationship between nature and human beings.

Kai Lee said, "I think one of the great dilemmas we face is acknowledging this interdependence in a way which also enables us to live our lives. We don't want to be encumbered all the time with thinking about all the indirect consequences of what we're doing in the world. And I think that's a dilemma that we don't even recognize is a dilemma yet ... "

Urbanites soon to outnumber country dwellers

Don't count on forests to keep us cool. Learn more about how trees in the far northern forests have been growing more slowly in the summertime.

B.L. Turner is a professor at Arizona State University. He talks about the history of the biophysical system and the social system as one of a coupled system.

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