Our Sun’s 5 Biggest Remaining Mysteries

Science Our Sun’s 5 Biggest Remaining Mysteries Bruce Dorminey Contributor Opinions expressed by Forbes Contributors are their own. I cover aerospace, astronomy and host The Cosmic Controversy Podcast. New! Follow this author to improve your content experience.

Got it! Jul 2, 2022, 01:30am EDT | Share to Facebook Share to Twitter Share to Linkedin A Solar and Heliospheric Observatory image shows Region 486 that unleashed a record flare last week . . .

[+] (lower left) November 18, 2003 on the sun. The spot itself cannot yet be seen but large, hot, gas-filled loops above this region are visible. These post-flare loops are still active.

(Photo by NASA via Getty Images) Getty Images As we revel in the Northern hemisphere’s long days of summer, few realize that there’s still much that we don’t understand about the Sun. For billions of years, our star has offered the kind of steady energy output that not only allowed for the evolution of life as we know it, but also the evolution of civilization as we know it. Yet the fine points of the astrophysics controlling our deceptively simple yellow dwarf star remains a puzzle.

We know the basics of how the Sun’s energy comes from its fusion of hydrogen into helium and that the Sun’s complex chemical composition largely originates from previous generations of stars that seeded its elemental makeup. But there are significant gaps in our understanding of the Sun’s internal mechanics and chemical composition. To learn more about what we don’t know about the Sun’s physics, I reached out to astronomer and solar physicist Jason Jackiewicz, at New Mexico State University in Las Cruces, for his take on five of the most important solar mysteries below.

—- The mystery of why the Sun’s outermost atmosphere (or corona) is so much hotter than its surface. The corona lies above the surface of the Sun, therefore above the heat source, yet is 1000 times hotter, Jackiewicz told me. The Sun’s surface provides enough energy flowing away from it to keep the corona hot, he says.

Yet that sort of heating would require that the energy be deposited there somehow. But because this outer corona is so tenuous, Jackiewicz and colleagues can’t figure out why this energy doesn’t simply pass on into outer space. Solar physicists are still puzzled over how the corona hangs onto this amount of heat.

MORE FOR YOU New Research Finds A Connection Between Domestic Violence And These Two Personality Disorders This Scientist Helps Andean Forests And Ecuador’s Women In STEM Exceptional Fossil Preservation Suggests That Discovering Dinosaur DNA May Not Be Impossible The sun’s coronal loops are shown in this photo, released September 26, 2000, taken by special . . .

[+] instruments on board NASA’s Transition Region and Coronal Explorer (TRACE) spacecraft. Fountains of multimillion-degree, electrified gas in the atmosphere of the sun have revealed the location where the solar atmosphere is heated to temperatures 1000-times greater than the sun’s visible surface. (Photo by NASA/Newsmakers) Getty Images —- How and where the Sun generates its magnetic fields Magnetic fields are observed at the surface (as sunspots) and in the solar atmosphere (as coronal loops), but they are likely generated in the interior, says Jackiewicz.

Such processes require plasma (charged gas) and motion (likely rotation), he says. Many researchers think this most strongly occurs at about 70 percent of the solar radius, which could be where the fields are “wound up” and strengthened, says Jackiewicz. And since magnetic fields are buoyant, they then rise up to the surface and pop out as sunspots, he says.

But because the Sun is a gaseous body, it doesn’t rotate at the same fixed speed, like a terrestrial mass body. For instance, at the surface, its poles rotate more slowly than its equator. The equator rotates once in about 25 days, and the polar regions about 30-32 days, says Jackiewicz.

This certainly doesn’t happen on Earth, or the planet would shear itself into pieces, he notes. Different layers beneath the Sun also rotate at different speeds. So, if you go into the Sun from the surface about 50,000 km, you’d be in a region that rotates faster than the surface, says Jackiewicz.

Then if you go a little deeper than that, it slows down again, he says. At a depth of about 200 million km, we find that the Sun rotates as a solid body, more like Earth, says Jackiewicz, and we know all this from studying sunquakes that probe the interior. —- What sets and regulates our Sun’s 11-year solar cycles? Sunspots and magnetism in general waxes and wanes in the Sun over 11 years, says Jackiewicz.

Sunspots manifest as darker areas on the solar surface due to strong magnetic fields that emerge through the solar surface. This causes a slight area cooling which causes what looks like dark spots when juxtaposed with the Sun’s surrounding very bright photosphere (or surface). At the beginning of the solar cycle, sunspots tend to be at mid-latitudes, around plus or minus 30 degrees latitude in each hemisphere, says Jackiewicz.

As the cycle continues, they emerge closer and closer to the equator, he says. When the next cycle begins, they are then back to emerging at mid-latitudes, although the polarity has flipped in the Northern and Southern hemisphere from the previous cycle, says Jackiewicz. As for the 11-year cycle? Surface features on the Sun come and go every day or so, says Jackiewicz; this is a strange timescale.

—- What generates the Sun’s super eruptions and superflares? They are connected to magnetic fields, which occur when magnetic energy needs to be released due to twisting and stretching of the fields, says Jackiewicz. The main difference between flares and coronal mass ejections (CMEs) is that flares mainly emit x-rays and Ultraviolet radiation, but CMEs actually lift mass off the Sun, he says. Large solar events cause billions in damage annually, via power outages, communications disruptions, and electrical systems damage, says Jackiewicz.

If we return to a more human-centered space exploration program, with humans on the Moon or Mars, then the consequences of such space weather will become even more important, he says. Sunrise over the West Indies, as seen from the space shuttle Discovery during NASA’s STS-70 mission, . .

. [+] July 1995. (Photo by Space Frontiers/Getty Images) Getty Images —- The mystery of the Sun’s chemical composition In the beginning there was only hydrogen and helium, says Jackiewicz, with all the other elements on the periodic table synthesized in the cores of stars.

Our Sun was formed when the universe was about two-thirds or its current age and is thus more enriched in these other elements than those early stars, he says. “The Sun is the reference star for all the hundreds of billions of other stars in our galaxy, and the trillions and trillions of stars in other galaxies,” said Jackiewicz. We know all the elements that make up the Sun, but we don’t know their relative abundances, says Jackiewicz.

So, the chemical composition of the Sun is still under debate, he says. It’s a difficult thing to measure, even for our nearest star, says Jackiewicz. Observations and models must work together to give consistent results, and they don’t always do so, he says.

What puzzles you most about the Sun? It’s fair to say that we understand the Sun’s mass, age, size and total irradiance quite well, says Jackiewicz. We know how it has evolved, and how it will evolve billions of years into the future, in a general kind of way, he says. But it’s the higher-order things that are so puzzling; its deep interior structure, magnetic fields, solar cycle variations, and eruptive events, says Jackiewicz.

As for his own personal quest in understanding the Sun? I want to know what the interior looks like, says Jackiewicz. Like sonograms that show a fetus inside the mother, we try to make images of the Sun’s subsurface, but can only probe a bit of the way in, he says. Follow me on Twitter or LinkedIn .

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