New Images of Sun Could Help Solve Mystery of Its Warmth

Nuclear Spectroscopic Telescope Array, meaning Nuclear Spectroscopic Telescope Array, is a NASA satellite launched in June 2012 on a mission to search for massive black holes. Recently, images created by the satellite were used by scientists to solve one of the biggest mysteries about the Sun: why is its outer atmosphere – the corona – at least 100 times hotter than its surface?

Since the heat of our star starts from its core and radiates outward, it is difficult to explain why the solar corona rises above one million degrees Celsius while the Sun’s outer layer does not exceed 6,000°C. “It’s like the air around the fire is 100 times hotter than the flames,” says a statement released last week by NASA’s Jet Propulsion Laboratory.

To solve the problem, the scientists decided to do a kind of “radiography” by overlaying images of high-energy X-rays emitted by the hottest substance in the sun’s atmosphere, seen in blue in the images below, with those from two other observatories. . Green is from the Japanese agency JAXA’s X-ray Telescope (XRT) and red from NASA’s Solar Dynamics Observatory (SDO).

What did the images from the three telescopes show?

Comparing the three sets of images, the scientists realized that the solar corona’s heat source could be attributed to tiny explosions called nanoflares (something like nanoflares) in the Sun’s atmosphere. These events are so named to distinguish them from so-called flashes, massive bursts of heat, light, and widely visible particles. However, regardless of size, both phenomena produce material that is hotter than the corona average.

While flashes alone cannot explain the high temperatures of the solar corona, NuSTAR has shown: nanoblasts could happen more often than previously thought, even in the midst of the star’s scorching light, as they go undetected by other methods of observation. As a result, physicists began to observe the formation of nanoflares and evaluate the energy they released.

These observations are comparable, as they will coincide with the 12th approach to the Sun (perihelion) of NASA’s Parker Solar Probe, which flies “close” to the star.