Dark, Cameras, Action: Scientists and Amateurs Prepare for Solar Eclipse
Astronomers say a total eclipse of the sun later this month, the first to be visible across the continental U.S. in almost a century, will be an experiment in solar physics conducted on a national scale, as citizen scientists join researchers in scrutinizing the star that helps make life on earth possible.
The total solar eclipse on Aug. 21 will fall across 14 states, each of which will experience more than two minutes of daytime darkness. Those in the U.S. outside the 70-mile-wide zone that stretches from Oregon to South Carolina will see at least a partial eclipse.
Although an eclipse lasts mere minutes, the event offers scientists a rare opportunity to study the sun and its properties, including the corona, the wispy fringe of outer atmosphere normally obscured by the star’s blinding brightness.
Researchers say understanding the sun is key to unlocking many mysteries of space. “It is the Rosetta Stone of all stars,” says astrophysicist Thomas Zurbuchen, NASA’s associate administrator for science, who plans to watch the eclipse aboard an agency jet off the coast of Oregon.
At NASA and the National Oceanic and Atmospheric Administration, scientists plan to marshal an armada of 50 high-altitude balloons, 11 orbiting satellites, the international space station and thousands of ground-based telescopes. Scientists from the Southwest Research Institute in Boulder will fly two converted tactical bombers at an altitude of 50,000 feet, where they expected to get the clearest pictures yet of the sun’s outer atmosphere.
Researchers will be joined by scores of student astronomers and volunteer sky watchers using telescopes, other high-altitude balloons and smartphone cameras to capture data and images, creating a continuous panorama of the event.
In fact, so many people are volunteering to conduct observations that scientists anticipate a record harvest of solar data. “We are expecting that millions of people will get involved,” says Carrie Black, who oversees solar research at the National Science Foundation. “Images and data collected from this will be analyzed for years to come.”
Cameras aboard high-altitude balloons launched from 25 sites around the country by students participating in NASA’s Eclipse Ballooning Project will transmit live video and images, which will be available for streaming, as onboard sensors collect data on temperatures and other effects.
As part of a project called the Citizen Continental-America Telescopic Eclipse Experiment, volunteers will use 68 telescopes along the 2,400-mile path of the eclipse to collect images of the sun’s corona, which astronomer Matt Penn and his colleagues at the National Solar Observatory in Tucson will then splice together into an uninterrupted, 90-minute video that will, at least initially, be used purely for research.
Over 1,000 photographers and amateur astronomers, meanwhile, have signed up for the Eclipse Megamovie Project, led by the University of California at Berkeley’s Space Sciences Laboratory and Google’s Making & Science initiative. Organizers plan to stitch together the images, uploaded to a special site, to capture how the sun’s corona changes over time. The data will be made available to scientists and the public.
Amateur scientists and astronomers involved in the Do-It-Yourself Relativity Project hope to duplicate and confirm an original test of Einstein’s relativity theory, which was conducted during a 1919 solar eclipse, by measuring how the sun’s gravitational pull bends the light of nearby stars.
And volunteers with the International Occultation Timing Association, an international group of researchers who specialize in the study of astronomical events like the eclipse, plan to measure the width of the shadow cast by the eclipse near Minden, Neb., helping them gauge the sun’s diameter. In the past, such measurements appeared to reveal that the star pulsates.
The sheer volume of observations from the eclipse may help resolve key questions about the brightest object in the sky: Is the sun growing or shrinking? Why is its outer atmosphere so much hotter than its surface? What role does its flickering corona play in the powerful electromagnetic storms that can disrupt electronics, power grids, radio and communications on earth?
The corona “places our technologically dependent society in peril almost every day,” says Scott McIntosh, director of the High Altitude Observatory at the National Center for Atmospheric Research in Boulder, Colo. “It is vitally important to understand the connection between the sun and the earth.”
One such connection researchers are eager to study is how the drop in solar radiation during an eclipse affects the ionosphere, a layer of atmosphere that influences radio signals. A team at George Mason University in Virginia has been recruiting volunteers for its EclipseMob project, which it believes will be the largest crowdsourced ionosphere experiment in history.
During the eclipse, volunteers around the country will monitor two transmissions: a precise, continuous time signal broadcast by the National Institute of Standards and Technology radio station WWVB in Fort Collins, Colo., which is normally used to synchronize radio-controlled clocks and watches, and the signal from a U.S. Navy transmitter in central California. They’ll measure and compare reception at the different receiving stations as the sun’s radiation is blocked by the moon, which should alter the ionosphere.
“It takes an entire continent to really gather all the information of various kinds to fully understand how intimately we are connected to our star,” says Madhulika Guhathakurta, NASA’s lead eclipse scientist.