Jonathan Jiang of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and colleagues used sensors from multiple satellites in the Afternoon Constellation, more commonly called the A-Train, to find that South American clouds infused with airborne pollution – classified as "polluted clouds" – tend to produce less rain than their "clean" counterparts during the region's dry season. Details of the findings are presented today at the American Geophysical Union's 2008 Joint Assembly in Fort Lauderdale, Fla.

A new NASA-led study helps answer decades-old questions about the role of smoke and human-caused air pollution on clouds and rainfall. Looking specifically at deep convective clouds -- tall clouds like thunderclouds, formed by warm air rising -- the study shows that smoky air makes it harder for these clouds to grow. Pollution, on the other hand, energizes their growth, but only if the pollution isn't heavy. Extreme pollution is likely to shut down cloud growth.

The study of exoplanets -- planets that lie outside our solar system -- could help scientists answer big questions about our place in the universe, and whether life exists beyond Earth. But, these distant worlds are extremely faint and difficult to image directly. A new study uses Earth as a stand-in for an exoplanet, and shows that even with very little light -- as little as one pixel -- it is still possible to measure key characteristics of distant worlds.

A study by scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, and Duke University in Durham, North Carolina, shows, in detail, the reason why global temperatures remain stable in the long run unless they are pushed by outside forces, such as increased greenhouse gases due to human impacts.

The 16-year-old Zhai, who will be a senior this fall at La Cañada High School near JPL in southern California, and JPL research scientist Jonathan Jiang built on Zhai's science fair project, a statistical model of economic losses from hurricanes. They found that the common practice of using only wind speed to represent hurricanes in economic hurricane damage models is inadequate for large storms, such as 2012's Hurricane Sandy. Zhai and Jiang are the first to quantify the economic impacts of increasing hurricane size.