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All eyes on the Sun by Jason Jackiewicz and James McAteer

(Published in the Las Cruces Sun News on May 3, 2020 – link)

On August 21 2017, the sun put on an astronomical showcase. The moon blocked out the sun’s disk, day turned into night, stars appeared during lunchtime, and the sun’s corona became visible for that brief moment we know as a solar eclipse. Indeed it is the shape of that corona that provides the name, formed from the latin (corona in latin is ‘crown’) that we use for the sun’s atmosphere, the well-known beer, and now the virus.

Understanding the solar corona is the motivation behind three major astronomical facilities that have opened up their eyes to stare at the sun since that day.  First, in late 2018 NASA’s Parker Solar Probe launched into orbit. This spacecraft will measure the sun’s outflowing particles and get closer to the star than any other spacecraft. If the sun-Earth distance were a football field, the spacecraft will get 4 yards from the endzone – effectively inside the sun’s corona. In January, the NSF’s Daniel K. Inouye Solar Telescope, the world’s largest, took its first images of the sun’s surface from atop a mountain on Maui. The highest-resolution images ever revealed the “caramel corn” features called granules that blanket the surface. Then, in February, the European Space Agency’s Solar Orbiter was launched. Among other things, it will study the poles of the sun as never before from a high vantage point. All together, the international price tag for these three efforts is over $2 billion.

Why do we continue to invest big bucks in studying our nearest star? There are four main motivating factors, three scientific and one purely emotional.

The first of these is space weather. That is, the sun is the main source of intense radiation, high-speed charged particles and magnetic fields in the solar system. When large explosive events such as solar flares and coronal mass ejections are Earth-directed, they become detrimental to our technological assets both on the ground (e.g., power grids, oil lines) and in space (e.g., communications satellites, astronauts). Trying to better understand and forecast these space-weather events is a major effort by solar astrophysicists, and timely as the sun will enter a period of high activity in a few years.

The second reason is that the sun is a model for many areas of astrophysics. Knowing the sun well allows us to understand other stars that are not so nearby. While stars about the same mass and size as the sun make up only a few percent of all the stars in our Milky Way galaxy (most stars are much smaller), that still amounts to a few billion stars! Furthermore, when studying other stars, astronomers try to measure their properties relative to the sun. So, in not knowing the sun well enough, we cannot know those stars either.

The third reason is that the sun is a giant physics laboratory, free to use, where conditions exist that cannot be replicated on Earth. This allows for the direct study of complex plasma phenomena, from the nuclear fusion processes occuring in the 15 million degree core, to magnetic field reconnection during flares.

The fourth, and perhaps the most important reason, is beauty and wonder. Our human thirst for understanding nature, means the sun has, and will always be, an object of fascination. Our state symbol of New Mexico, from the Zia Pueblo, dates back to at least the early 1800’s and probably much earlier. Tracking the Sun at Chaco Canyon dates back to around 1000AD. The ancient Egyptians worshiped a powerful sun god, Ra, 4000 years ago.  Beyond providing the Earth its welcome light and heat, the sun has clearly played a role in aspects of every civilization, invoking mystery, fear and ultimately, respect.  We are a curious species that continually observes and interprets our surroundings. If you missed the 2017 eclipse, you missed a life-changing emotional moment. But don’t worry – you have another chance to see a solar eclipse in mainland USA during your lifetime. On April 8, 2024 a solar eclipse will be visible from Durango, Mexico, up through Austin, Dallas and onto Little Rock, Cleveland and Niagara Falls. Go to any of those places and see the beauty for yourself. Don’t miss this one –the next shot after that is 2045.

Closer to here and now, southern New Mexico has been at the forefront of solar astrophysics research for decades. The Sunspot Solar Observatory in Otero County in the Sacramento Mountains hosts one of the world’s most powerful solar telescopes. It has been visited and used by almost all solar astronomers worldwide in its 50 years of service. Operated by NMSU, the telescope is open to the public, and there is a fantastic visitor center on site to educate us about the sun and the history of Sunspot. It will reopen as soon as the (other corona) pandemic is over.

Jason Jackiewicz and James McAteer are associate professors of astronomy at NMSU.