Privileged Planet: built in cosmic ray protections (Introduction)

by David Turell , Thursday, October 07, 2021, 19:44 (926 days ago) @ David Turell

The latest solar research:

https://nautil.us/issue/107/the-edge/the-safety-belt-of-our-solar-system

"What might count as our solar system’s boundary? There is no definite point at which light from our sun completely fades, or where its gravity stops being felt, so neither of those could mark it. But the heliosphere can. It “moves through the galaxy, keeping our home safe,” McComas says. The sun’s solar wind, an outflow of ionized gas, or plasma, pushes out against the galactic material between stars, also called the “interstellar medium.” The interstellar medium in our very local region is a mixture of plasma, helium, and neutral hydrogen. It is formed by warm, partially ionized clouds found in the Local Bubble, a large cavity filled with plasma that was likely produced by multiple supernova explosions, along with interstellar dust and other stellar winds. The barrier separating us from this occupies a region far beyond the orbit of Pluto, one you can define and measure.

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"These particles, coming toward us from all directions, some of them bouncing off of the inside of the heliosphere, clue scientists in on how the sun’s solar wind interacts with interstellar space as our solar system drifts around the galaxy. Weighing a little more than the average American, IBEX has been orbiting Earth for more than a decade, observing the solar system’s edge with enough success to have earned McComas the chance to probe the barrier further, with IMAP.

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"Early results from IBEX made the cover of Science in 2009. The satellite captured a mysterious ribbon structure projected over an “all-sky” map flattened to two dimensions. “The IBEX results are truly remarkable, with emissions not resembling any of the current theories or models of this never-before-seen region,” McComas said at the time. “We expected to see small, gradual spatial variations at the interstellar boundary, some 10 billion miles away. However, IBEX is showing us a very narrow ribbon that is two to three times brighter than anything else in the sky.” The neutral atoms IBEX was collecting, in other words, were not coming from all directions in more or less equal amounts. It’s a big hint to scientists that the way our sun’s magnetic fields interact with the galaxy’s magnetic field is much more complicated than they supposed.

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"What seems to be happening, McComas explained, is that a fraction of the charged particles that were part of the solar wind, and are now neutralized, are propagating radially out, past the heliopause into the local interstellar medium. They become trapped and gyrate around the magnetic field draped across the heliosphere. Eventually, the energetic neutral atoms reneutralize and radiate back in, toward the heliosphere. This series of charge exchanges could explain the ribbon, which originates a few hundred astronomical units beyond the heliopause. (One astronomical unit, the distance between Earth and the sun, is 93 million miles.)"

Comment: Our sun's particle atmosphere appears to protect us from all the wild rays in the universe as we/the Milky Way moves through the universe's interstellar space.