The Sun has been very active so far this month, with powerful sympathetic solar flares dazzling scientists and viewers alike and recent X-class flares making many wonder about communications network integrity. NASA’s Solar Dynamics Observatory (SDO) constantly monitors the Sun and captures the recent powerful solar flares in exquisite detail across multiple wavelengths.
In a new video, NASA shows how recent flare events on February 21st and 22nd appeared in several wavelengths of extreme ultraviolet light. Throughout the video, viewers are treated to blends of 131 and 171, 171 and 304, and 171 and 1,600-angstrom-light images.
An angstrom, named for Swedish physicist Anders Jonas Ångström, is a unit of length equal to 10-10 meters, or 0.1 nanometers. The unit is primarily used to measure wavelengths of light. For reference, visible light ranges from 4,000 to 7,000 angstroms, so the SDO works far below the light that human eyes can see. 131 angstroms is 13.1 nanometers, far below even what the James Webb Space Telescope can see (600 to 28,500 nanometers).
Each of the various wavelengths highlights different plasma temperatures, showcasing numerous layers and features of the Sun. For example, the extreme ultraviolet wavelength of 131 angstroms shows scorching plasma (six to 10 million Kelvin) and cooler plasma (400,000 Kelvin), per NASA. (https://svs.gsfc.nasa.gov/14536) For reference, 10 million Kelvin is nearly 18 million degrees Fahrenheit.
Solar flares are immense explosions of electromagnetic radiation emitting from the Sun and appear as intense bright regions on the star’s surface that last a few minutes to several hours. They result from the Sun’s intense magnetic fields becoming too tangled and stretching so far that they snap like a rubber band stressed beyond its physical limits.
Solar flares often occur alongside coronal mass ejections (CMEs), which are closely related to auroral displays in Earth’s atmosphere, although the relationship between flares and CMEs is not fully understood.
A crucial part of the SDO’s mission is to help scientists better understand solar activity and the Sun’s impact on Earth, including how it creates space weather phenomena. The SDO is the first mission launched within NASA’s Living With a Star (LWS) program.
NASA’s SDO includes numerous imagers, each with specialized filters to help study specific parts of the Sun’s activity. On the Atmospheric Imaging Assembly (AIA), four telescopes help the SDO get very close to the Sun’s surface. The AIA can see details as small as 725 kilometers (450 miles) across, which is equivalent to looking at a human hair held 10 meters (33 feet) away.
Credits: NASA’s Goddard Space Flight Center/SDO Scott Wiessinger (KBR Wyle Services, LLC), A. J. Christensen (AVL NCSA/University of Illinois)