An expert panel asked by President Obama to make recommendations about the future of human spaceflight has said the goal of returning to the moon by 2020 isn’t feasible if NASA’s budget continues at its current level. The panel is scheduled to the brief the White House on Friday.

The past decade has been the most intense period of hurricane activity since the medieval ages. The new study, using data from the earth and oceans, found that conditions were ideal for hurricanes about 1,000 years ago.

Carbon dioxide isn’t just affecting our climate, it is also increasing the acidity of our seas. Scientists worry that corrosive conditions will harm marine life, and could change our oceans in ways they’re just now starting to understand.

Hundreds of utilities around the U.S. — and a growing number of companies — are offering customers a chance to buy green power. Businesses use them to promote their environmental consciousness. But where does the power come from?

NASA’s new program prepares young Earth scientists to tackle tough environmental issues. In an airplane laboratory, students study everything from the growth of unusual algae blooms to the methane from a dairy cow’s burp.

The world could lose all its coral reefs within the next century. As the Earth heats up, warming ocean waters could be deadly to these fragile ecosystems. On the Caribbean island of Bonaire, scientists are trying to figure out how to help coral reefs become more resilient.

Coral reefs are the rain forests of the oceans — teeming with diverse and postcard-perfect fish, towering sponges and multicolored coral. In these photos, Dr. Mark Vermeij, scientific director of the Caribbean Institute for Research and Management of Biodiversity (CARMABI), documents the diversity of life in this magnificent — yet fragile — underwater world.

Both the federal government and the state of Massachusetts are making plans to zone the oceans, much like planners zone our cities. The goal is to balance the needs of fishermen, wind farmers, aquaculture developers, freighters, and the rich sea life that depends on this space for survival.

Does exercise really melt pounds, or just rev your appetite? Pass the donuts.

A very old house in Boston’s Roxbury neighborhood is getting an extreme green makeover. The house uses super-insulating materials so that it won’t need a furnace in the winter.