By Dr. Gary L Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
It rises and sets every day, providing the energy necessary for us to exist on Earth. It has been the inspiration of stories, poems, songs, and even religions. We welcome it as a source of warmth and comfort each day.
But the Sun is also a potentially very dangerous entity in our solar system. While its energy makes life possible, that same energy could also easily eradicate it. A tragically timed ejection of plasma could destroy the Earth or make it entirely uninhabitable.
And yet, we still have a lot to learn about the giant ball of nuclear fusion at the center of our solar system. It is absolutely critical that we seek to understand our Sun better than we do now so that we can predict its often-erratic behavior.
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NASA Has Launched Three Key Missions Aimed at Solar Research
In pursuit of that goal, NASA has launched a series of key missions over the past few decades aimed at solar research.
The Solar TErrestrial RElations Observatory (STEREO) consists of two identical spacecraft which NASA launched in 2006 into two different heliocentric orbits, one trailing behind the Earth in its orbit and one leading ahead of Earth. The mission of STEREO is to capture stereoscopic images of the Sun from angles that the Earth cannot see. That will permit scientists to study coronal mass ejections without having to infer what is happening from angles to the Sun that we cannot observe from our reference point.
Each of the two STEREO spacecraft has four instruments onboard: the Sun-Earth Connection Coronal and Heliospheric Investigation (SECCHI), the STEREO/WAVES tracker, the In-situ Measurements of Particles and CME Transients (IMPACT), and the PLAsma and SupraThermal Ion Composition (PLASTIC).
STEREO’s data has already helped experts understand the 3D structures of coronal mass ejections so that we now better understand why they happen. Additionally, STEREO serves as a kind of early weather alert system for such events, warning ground stations of a major coronal mass ejection that might threaten the Earth. Mission controllers lost contact with one of the two STEREO spacecraft in 2014, but the other one is still operational today.
The Solar Dynamics Observatory (SDO) is a probe launched by NASA in 2011 to understand the cause and effect dynamics between the Sun and the Earth. Specifically, the task is to measure the solar atmosphere and magnetic field to better understand how magnetic energy in the Sun is released into the heliosphere through solar wind and solar irradiance.
There are three instruments on board the SDO, which is still in operation today: The Extreme Ultraviolet Variability Experiment (EVE), the Helioseismic and Magnetic Imager (HMI), and the Atmospheric Imaging Assembly (AIA). The SDO has used its sensitive instruments to observe solar flares, coronal mass ejections, sunspots, and even solar tornadoes in exquisite, never-before-seen detail, so astronomers can study the dynamics of the Sun’s magnetic energy.
IRIS Was Designed to Investigate the Chromosphere of the Sun
NASA launched the Interface Region Imaging Spectrograph (IRIS) in 2013 and it is still in operation today. IRIS was designed to investigate the chromosphere of the Sun. The spacecraft consists of a telescope and a high-frame-rate ultraviolet spectrometer that studies the boundaries between the chromosphere and other layers of the Sun’s mass. Among other things, data from IRIS has revealed fascinating phenomena at work on the Sun, including heat bombs, plasma jets, flares, and tornadoes.
Finally, the Parker Solar Probe (PSP) was launched in 2018 to observe the outer corona of the Sun. The PSP is making repeated passes near the Sun, and will continue to do so through 2025. At its closest approach, the PSP will be less than five million miles from our host star. The probe travels at several hundred thousand miles an hour, which makes it the fastest man-made object ever created.
The PSP is equipped with four main instruments. The FIELDS suite of sensors collects data on the Sun’s magnetic field dynamics. The Wide-Field Imager for the Parker Solar Probe (WISPR) will photograph coronal mass ejections and other ejecta. The Solar Wind Electrons Alphas and Protons (SWEAP) array will measure the dynamics of the solar wind. And the Integrated Science Investigation of the Sun (ISOIS) will measure the way that particles move in their lifecycle through the Sun’s layers and out into space.
Obviously we still have much to learn about the Sun. But these three missions — STEREO, the SDO, and the PSP — are helping to move the needle forward in terms of our understanding of solar behavior. Still more missions in various stages of development will continue the work in specialized areas of study.
Through this research, we hope to be able to better predict the kinds of solar events that might threaten Earth, so it is vital that these kinds of missions continue to be funded and supported well into the future. The Sun is far too important not to give it the attention that it deserves.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.