All is not calm on the sun. New images released Wednesday, which the National Science Foundation says are the star's most detailed close-ups, show turbulent solar plasma: Charged particles that rise to the surface of the star, forming convection cells the area of Texas, which cool and descend back into the sun's depths.
The images, from the nearly complete Daniel K. Inouye Solar Telescope, are the most zoomed-in examinations of that turbulence. They reveal structures as small as 30 kilometers (18.6 miles) on the surface of the sun. Those details are five times smaller than any solar image had captured before, Thomas Rimmele, the telescope's director, told reporters Friday. (The sun is 1.4 million kilometers, or 870,000 miles, in diameter.)
The Inouye Solar Telescope, a $344-million tool built on the peak of Haleakala on Maui, took these images on its first day of operation in December. This is the "largest, most powerful solar telescope in the world," Rimmele said. The telescope will help astronomers understand the sun's magnetic field and its atmosphere, known as its corona, more fully.
From its violent atmosphere, the sun belches energetic particles that move so swiftly that they are able to hit Earth in minutes. Such solar storms are capable of overwhelming electric grids and disturbing radio communications.
"We still do not understand how the corona is heated to millions of degrees when the surface of the sun is only 6,000 degrees," Rimmele said. (If that phenomenon sounds counterintuitive, well, it is. Solar experts often describe the effect like this: Imagine pulling your hand away from a hot plate, only for your palm to heat up even more.)
"The Inouye telescope has the unique resolution and sensitivity required to perform the most precise measurements of the sun's magnetic field, especially in the corona," he said.
The telescope is a marvel of engineering. A mirror within the telescope adjusts 2,000 times per second, to compensate for distortions introduced by Earth's atmosphere. As the telescope focuses on the sun, it generates heat — in the manner of a magnifying glass, except it gets hot enough to melt metal, Rimmele said. Coolant fed through 7.5 miles of pipe keeps the telescope chill. "We make the equivalent of a swimming pool full of ice every night to provide cooling for the optics and structures during the day," he said.
The construction at Haleakala was the target of protesters, who said the telescope was on sacred land. Twenty people were arrested there while attempting to block trucks from the summit in the summer of 2015. Protests have continued at another Hawaiian mountain, Mauna Kea, where construction of the Thirty Meter Telescope was put on hold in December.
At Haleakala, after "semiannual meetings with a native Hawaiian working group," telescope officials were "able to smooth over a lot of that contention," said David Boboltz, program director for the NSF's astronomy division. Under an agreement, 2 percent of the telescope time will be allocated to native Hawaiian scientists.
A new wave of solar astronomy is forming, which include observation platforms in space. The Parker Solar Probe, which launched in August 2018, has been skimming by the sun to collect temperature and other data. The European Space Agency plans to launch its solar orbiter in February. The Inouye telescope will be finished in June, while the astronomers prep to catch the next hotspot cycle on the sun.
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