Amazing stuff! What a human achievement! Kudos!
The coronavirus is named after the sun's corona!
Why is Global Warming a hoax and Climate Change a religion? We do not even understand the sun very well. The propaganda and demagoguery will have us believe that the sun is a constant and invariant source of energy etc., which is false!
"A NASA spacecraft has entered a previously unexplored region of the Solar System — the Sun’s outer atmosphere, or corona. The long-awaited milestone, which was reached in April but announced on 14 December, is a major accomplishment for the Parker Solar Probe, a craft that is flying closer to the Sun than any mission in history. ...
But it took the US$1.5-billion Parker Solar Probe to finally get there. Since its launch in 2018, it has been orbiting the Sun: with each pass, it loops ever closer to the solar surface. A carbon-composite heat shield protects its instruments from temperatures that will eventually soar to 1,370 °C. ...
Some researchers had speculated that the boundary would be rather ‘fuzzy’ — but, instead, it was sharp and wrinkly. The spacecraft’s trajectory took it into the corona for nearly five hours and then back out; and it might have briefly crossed into the corona twice more. Inside the corona, the solar wind speed and plasma densities dropped, suggesting the boundary had indeed been crossed. ...
As it crossed the Alfvén surface, the Parker probe flew through a ‘pseudostreamer’ of electrically charged material, inside which conditions were quieter than the roiling environment outside of it. While inside the corona, the spacecraft also studied unusual kinks in the magnetic field of the solar wind, known as switchbacks. Scientists already knew about switchbacks, but the probe’s data have enabled the researchers to trace where the switchbacks come from, all the way down to the solar surface ...
The Parker Solar Probe ultimately aims to make 24 close passes of the Sun. It crossed the Alfvén surface on the eighth of those fly-bys, and might have done so again during its ninth pass in November — a manoeuvre for which the data have not yet been fully downloaded and analysed. The mission’s closest approach is scheduled for 2025, when it will be only 6.2 million kilometres from the solar surface, well within the orbit of Mercury. ..."
But it took the US$1.5-billion Parker Solar Probe to finally get there. Since its launch in 2018, it has been orbiting the Sun: with each pass, it loops ever closer to the solar surface. A carbon-composite heat shield protects its instruments from temperatures that will eventually soar to 1,370 °C. ...
Some researchers had speculated that the boundary would be rather ‘fuzzy’ — but, instead, it was sharp and wrinkly. The spacecraft’s trajectory took it into the corona for nearly five hours and then back out; and it might have briefly crossed into the corona twice more. Inside the corona, the solar wind speed and plasma densities dropped, suggesting the boundary had indeed been crossed. ...
As it crossed the Alfvén surface, the Parker probe flew through a ‘pseudostreamer’ of electrically charged material, inside which conditions were quieter than the roiling environment outside of it. While inside the corona, the spacecraft also studied unusual kinks in the magnetic field of the solar wind, known as switchbacks. Scientists already knew about switchbacks, but the probe’s data have enabled the researchers to trace where the switchbacks come from, all the way down to the solar surface ...
The Parker Solar Probe ultimately aims to make 24 close passes of the Sun. It crossed the Alfvén surface on the eighth of those fly-bys, and might have done so again during its ninth pass in November — a manoeuvre for which the data have not yet been fully downloaded and analysed. The mission’s closest approach is scheduled for 2025, when it will be only 6.2 million kilometres from the solar surface, well within the orbit of Mercury. ..."
From the abstract:
"The high temperatures and strong magnetic fields of the solar corona form streams of solar wind that expand through the Solar System into interstellar space. At 09:33 UT on 28 April 2021 Parker Solar Probe entered the magnetized atmosphere of the Sun 13 million km above the photosphere, crossing below the Alfvén critical surface for five hours into plasma in casual contact with the Sun with an Alfvén Mach number of 0.79 and magnetic pressure dominating both ion and electron pressure. The spectrum of turbulence below the Alfvén critical surface is reported. Magnetic mapping suggests the region was a steady flow emerging on rapidly expanding coronal magnetic field lines lying above a pseudostreamer. The sub-Alfvénic nature of the flow may be due to suppressed magnetic reconnection at the base of the pseudostreamer, as evidenced by unusually low densities in this region and the magnetic mapping."
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