Physics Buzz

Once in a rare while, the moon turns red—because the sky is blue. That might sound like nonsense, but it's the simplest accurate way to explain what happened early this morning, when the moon disappeared from view before returning with an eerie, rusty cast to it.

The sun is an hour over the horizon. It's the first week of October in Maryland, and there's something uniquely enchanting in how the light catches the tips of the trees. What is it that makes this morning sunlight so spectacularly yellow-gold? As with most things, the answer—at some level—comes down to physics.

Stratocumulus clouds over the Pacific Ocean on January 4, 2013 / Image Credit: NASA NASA scientists and engineers are devising new ways to study how low-lying clouds and aerosols influence the climate. For climatologists, the role of clouds on the climate remains one of the highest remaining  uncertainties . Aerosols affect the climate by altering reflectivity of the earth's atmosphere and nucleating clouds. For the next three weeks, scientists will test fly new sensor devices that NASA mission leader David Starr says "will dramatically change what we can do from space to learn about clouds and aerosols."

Reproducibility forms one of the cornerstones of physics; independent scientists need to corroborate a finding before it's widely accepted in the scientific community. But sometimes the window of observation only lasts for several hours twice every hundred years or so. That makes reproducibility fairly difficult. Earlier this summer, Venus passed in front of — or transited — the sun for the last time this century. While the astronomical event amazed viewers across the world, a group of physicists were re-creating an observation from over 250 years ago: the discovery of Venus' atmosphere. At the same time, they've stoked the fire in a debate over who first made this discovery. The entire Venus transit of 2012 in one image. Image courtesy of NASA.