In Interstellar Space, There Is Likely 40% More Hydrogen Than We Thought: New Data From New Horizons

The "Pluto and Beyond" mission continues to pay new dividends, in the form of space science. And this is a jammin' gif animation below right, too! So. . . "What's not to like," I ask?

I was smitten, as many remember, with New Horizons' whizzing-flyby of Pluto, offering us a heart-shaped topographical feature, nearly the size of one quarter of the orb, one no human eye had ever seen to that moment, as not even then mighty Hubble could resolve tightly enough to show us the surface in such detail -- see at left. Now, Goddard / NASA reports that ionization data from the craft, well out in the Kuiper Belt now, pretty much confirms that past the bow-shock of interstellar space, we are in fact flying through a much more dense cold hydrogen fog than we earlier thought, based on the pair of Voyager's more rudimentary instruments and data.

Do go read it all -- it is helpfully all told in fifth grade (or so) science level prose:

. . .Just as Earth moves around the Sun, so our entire solar system hurtles through the Milky Way, at speeds exceeding 50,000 miles per hour. As we cruise through a fog of interstellar particles, we’re shielded by the magnetic bubble around our Sun known as the heliosphere. Many interstellar gases flow around this bubble, but not all.

Our heliosphere repels charged particles, which are guided by magnetic fields. But more than half of local interstellar gases are neutral, meaning they have a balanced number of protons and electrons. As we plow into them the interstellar neutrals seep right through, adding bulk to the solar wind.

“It's like you're running through a heavy mist, picking up water,” said Eric Christian, space physicist at NASA’s Goddard Space Flight Center in Greenbelt, MD. “As you run, you’re getting your clothes all soggy and it’s slowing you down.”

Soon after those interstellar atoms drift into our heliosphere, they are zapped by sunlight and slammed by solar wind particles. Many lose their electrons in the tumult, becoming positively-charged “pickup ions.” This new population of particles, though changed, carry with them secrets of the fog beyond.

“We don’t have direct observations of interstellar atoms from New Horizons, but we can observe these pickup ions,” said Pawel Swaczyna, postdoctoral researcher at Princeton University and lead author of the study. “They are stripped of an electron, but we know they came to us as neutrals atoms from outside the heliosphere. . . .”

NASA’s New Horizons spacecraft, launched in January 2006, is the one best suited to measure them. Now five years past its rendezvous with Pluto, where it captured the first up-close images of the dwarf planet, today it ventures through the Kuiper belt at the edge of our solar system where pickup ions are the freshest. The spacecraft’s Solar Wind Around Pluto, or SWAP instrument, can detect these pickup ions, distinguishing them from the normal solar wind by their much higher energy. . . .

Out there, it is all. . . "powdered with stars" -- and Milton was so much more right, than he then knew. . . making all the difference, here 346 years from the day Milton passed, to the out there -- into the powder -- into the Infinite.

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