She was contributing writer for (opens in new tab) for 10 years before that, since 2012. This is helpful to understanding solar physics because the funnels may be where fast particles of the solar wind originate.Įlizabeth Howell, Ph.D., is a staff writer in the spaceflight channel since 2022. Scientists also found that the patches line up with magnetic funnels coming from the photosphere, called supergranules. Now fresh findings, from the mission's sixth solar flyby, suggest that switchbacks "occur in patches and have a higher percentage of helium" than other elements, NASA said. While scientists at first assumed the switchbacks were confined to solar regions, Parker found the switchbacks were quite common in the solar wind in 2019. The switchbacks have been known for some time and were first discovered by the NASA-European Space Agency mission Ulysses, which orbited the sun's poles in the 1990s. Parker's work on this aspect of solar physics, now in press at the Astrophysical Journal, suggests that switchbacks originate at the visible surface of the sun, known as the photosphere.
(Image credit: NASA Goddard/CIL/Adriana Manrique Gutierrez) On future flybys, Parker is expected to creep even closer to the sun, coming as low as 8.86 solar radii (3.83 million miles or 6.16 million km) from the sun's photosphere, its visible surface.įarther away from the sun, the spacecraft has been exploring the physics of " switchbacks," or zig-zag-shaped structures in the solar wind.Īn artist's depiction of magnetic switchbacks in the solar wind. "Passing through the pseudostreamer was like flying into the eye of a storm," NASA said in the same statement, noting that Parker saw changes such as quieter conditions and fewer particles. In that zone, it found a "pseudostreamer," one of the huge structures you can see from Earth during total solar eclipses.
Parker could only spend a few hours in the corona due to the intense conditions there, but it did manage to go as low as 15 solar radii from the sun's surface. (Image credit: NASA Goddard Space Flight Center/ Ryan Fitzgibbons, Walt Feimer, Chris Meaney, Swarupa Nune, and Merav Opher)) Where the sphere ends, harsh cosmic rays butt up against our solar system. This illustration shows our solar system suspended in the "bubble" of protective solar wind known as the heliosphere. "Discovering where these protrusions line up with solar activity coming from the surface can help scientists learn how events on the sun affect the atmosphere and solar wind," NASA officials wrote in the statement. The surface also likely varies with solar wind activity, which in turn depends on the sun's 11-year solar cycle. More importantly, Parker found the critical surface is not uniform, and there are "spikes and valleys" (as NASA termed it) in which the surface protrudes higher or lower from the center of the sun. Parker's data suggests it crossed the critical surface at 18.8 solar radii, or 8.1 million miles (13 million km) above the sun's surface. As it turns out, these estimates were not too far off. Previously, faraway pictures of the corona suggested that the critical surface was somewhere between 4.3 to 8.6 million miles (6.9 to 13.8 million kilometers) from the surface of the sun, or in relative terms, the equivalent of 10 to 20 times the radius of the sun. The point of no return is called the Alfvén critical surface and scientists had not been able to measure exactly where it was, before Parker reached it. It's from that point where the solar wind flows away from the sun, never to return. The sun isn't a solid sphere like our Earth, but it does have a zone in which the immense gravity of the star keeps in the solar material it spews through fusion.Īt a particular distance from the sun, however, gravity and magnetic fields are no longer able to keep that material close. An annular eclipse captured by the Hinode satellite on Jan.
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