Different elements in the sun, like hydrogen and helium, emit different colors of light. By examining the spectra of sunlight from the corona using a device called a spectroscope , scientists can identify the spectral lines from different elements. The brightness of various lines in the sun's spectrum tells astronomers how hot the gas is in the sun's corona. The total solar eclipse allows scientists to measure the temperature of the corona by itself. Many scientists around the world were examining spectrum and checking colors in the corona during this eclipse.
Some scientists think that solar flares heat the corona.
Solar flares are gigantic explosions on the sun. However, it may not be the biggest flares that do the heating, because there aren't enough of them. Instead, some scientists believe that many, many tiny solar flares, called microflares, do the job. One group of English sun scientists traveled to the Black Sea Coast in Bulgaria. They took speedy digital cameras that they hoped would be fast enough to catch the microflares.