Lab plays role in striking view of Mercury transit

Around 13 times per century, Mercury passes between Earth and the sun in a rare astronomical event known as a planetary transit. The 2016 Mercury transit occurred on May 9 between roughly 4:12 a.m. and 11:42 p.m. PDT.

NASA's stunning video of the transit of Mercury across the sun was made possible in part by work done by Lawrence Livermore scientists. Regina Soufli, a member of the Physics Division, led her LLNL team, including Jeff Robinson, Eberhard Spiller, Sherry Baker and Jay Ayers, and collaborated with Eric Gullikson of Lawrence Berkeley National Laboratory's Center for X-Ray Optics, Reflective X-ray Optics, LLC and other institutions, on the design, development, fabrication and calibration of the multilayer mirrors used in the extreme ultraviolet (EUV) telescopes of NASA's Solar Dynamics Observatory (SDO) mission.

The SDO multilayer mirrors act as reflective lenses and are responsible for capturing the images and movies of the sun produced by SDO at seven extreme ultraviolet (EUV) wavelengths, including those shown in NASA’s video of the Mercury transit.

The SDO EUV multilayer mirrors were calibrated and tested by Soufli at Lawrence Berkeley's Advanced Light Source Beamline 6.3.2 before being launched into space in 2010. Since then, SDO telescopes have been recording solar activity in exquisite spatial, spectral and temporal resolution 24 hours a day, 365 days a year, including Monday's transit. 

Launched in 2010, SDO is NASA's most advanced solar mission to date. It observes the sun's surface, called the photosphere, and its atmosphere, called the corona. Scientists use SDO data to study and elucidate the sun's extremely complex and dynamic magnetic field, and its plasma and related phenomena, including intense solar activity such as solar flares and coronal mass ejections. These phenomena directly impact Earth's upper atmosphere and nearby space environments.

This project was sponsored at LLNL by the Smithsonian Astrophysical Observatory and by Lockheed Martin Corporation, for NASA.