SCIENCE: For the first time humans have come to the sun.

For the first time, a human space­craft has lit­er­al­ly touched the sun. Sci­en­tists made the announce­ment at the Amer­i­can Geo­phys­i­cal Union meet­ing in New Orleans. They said the Park­er solar probe flew over the sun’s upper atmos­phere, its vaporous coro­na, on April 28, 2021. The coro­na is that fiery out­er lay­er of the sun that appears around the sil­hou­ette of the moon dur­ing total solar eclipses. Park­er Solar Probe sam­pled the par­ti­cles and mag­net­ic fields of the coro­na. He’s made dis­cov­er­ies that more dis­tant space­ships can’t. For exam­ple, the solar wind is a flow of charged par­ti­cles released by the solar coro­na. Park­er Solar Probe has dis­cov­ered zigzag struc­tures in the solar wind that sci­en­tists call switch­backs. Cool!

On the same day, the peer-reviewed Phys­i­cal Review Let­ters pub­lished the results of Park­er Solar Probe’s first for­ay into the sun’s upper atmos­phere. The Astro­phys­i­cal Jour­nal also accept­ed the results for publication.

Thomas Zur­buchen, Asso­ciate Admin­is­tra­tor of the Sci­en­tif­ic Mis­sions Direc­torate at NASA Head­quar­ters in Wash­ing­ton, said:

Touch­ing the sun is a mon­u­men­tal moment for solar sci­ence and a tru­ly remark­able achieve­ment. Not only does this step pro­vide us with more in-depth infor­ma­tion about how our sun has evolved and its impacts on our solar sys­tem, but every­thing we learn about our own star also tells us more about stars in the rest of the universe. .

In addi­tion, Nour Raouafi of the Johns Hop­kins Applied Physics Lab­o­ra­to­ry said:

Fly­ing so close to the sun, Park­er Solar Probe is now detect­ing con­di­tions in the mag­net­i­cal­ly dom­i­nat­ed lay­er of the solar atmos­phere — the coro­na — that we have nev­er been able to before. We see evi­dence of being in the coro­na in mag­net­ic field data, solar wind data, and visu­al­ly in images. We can actu­al­ly see the space­craft fly­ing through coro­nal struc­tures that can be seen dur­ing a total solar eclipse.

On the one hand, when Park­er Solar Probe passed through our sun’s coro­na, or vaporous out­er atmos­phere, it flew over struc­tures called coro­nal stream­ers. These struc­tures are the light fea­tures mov­ing upward in the upper images above and slant­i­ng down­ward in the low­er row. These are the stream­ers vis­i­ble around the sil­hou­ette of the black moon dur­ing total solar eclipses. And now our robot emis­sary — Park­er Solar Probe — has touched these stream­ers and mea­sured them for the first time.

As Park­er cir­cled clos­er and clos­er dur­ing sev­er­al over­flights, sci­en­tists looked for indi­ca­tions that he had reached the crit­i­cal sur­face of Alfvén. Alfvén’s crit­i­cal sur­face is the point that marks the end of the solar atmos­phere and the start of the solar wind. Although the sun does not have a sol­id sur­face, it does have a bound­ary. The bound­ary is the point at which solar mat­ter bound to the sun by grav­i­ty and mag­net­ic forces ends.Zone con­tenant les pièces jointes