Astronomers Prepare for 2017 Solar Eclipse Spectacle
Eeriness creeps in. Colors change and shadows sharpen. The last minutes before a total solar eclipse trigger a primal reaction in the human psyche, says astronomer Jay Pasachoff.
"You don't know what's going on," says Pasachoff, of Williams College in Williamstown, Mass. "But you know something is wrong."
Millions of people will know something is wrong on August 21, 2017, when a total eclipse of the sun sweeps across the country, the first to grace the continental United States since 1979 (and the first to go coast-to-coast since 1918). The roughly 120-kilometer-wide path of totality created by the moon’s shadow will travel through 12 states, from Oregon to South Carolina.
Eclipse enthusiasts will travel from all over the world to experience up to nearly three minutes of midday twilight and glimpse the seldom-seen solar corona, a halo of light from plasma that will frame the blacked-out sun.
For researchers, the 2017 eclipse is another chance to connect what they see on the surface of the sun to what's happening in the outer reaches of the corona.
One enduring mystery is why the corona is millions of degrees hotter than the surface of the sun, which is a relatively balmy 5,500° Celsius. "The consensus is that the sun’s magnetic field is responsible," says Paul Bryans, a solar physicist at the National Center for Atmospheric Research in Boulder, Colo. "But it's not clear how."
The magnetic field in the corona is too tenuous to study directly. Instead, researchers want to look at the effect of magnetism on certain wavelengths of infrared light emitted by the corona. Bryans is leading a team that will point a spectrometer at the sun during the eclipse to detect that light. "The plan is to put us in the back of a trailer, drive north to Wyoming and just sit and stare at the sun," says Bryans, for whom the 2017 eclipse will be his first.
Another option is to point an infrared spectrometer out the window of a Gulfstream V jet and cruise at an altitude of about 15 kilometers along the path of the eclipse. That is what Jenna Samra, a Harvard University applied physics graduate student, will be doing. Aside from getting away from weather intrusions, the flying telescope will soar above much of Earth"s water vapor, which absorbs a lot of infrared light.
Read more at Science News.