Kawasaki Concours Forum
Mish mash => Open Forum => Topic started by: Conrad on June 14, 2011, 02:30:36 PM
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http://science.nasa.gov/science-news/science-at-nasa/2011/09jun_bigsurprise/ (http://science.nasa.gov/science-news/science-at-nasa/2011/09jun_bigsurprise/)
June 9, 2011: NASA's Voyager probes are truly going where no one has gone before. Gliding silently toward the stars, 9 billion miles from Earth, they are beaming back news from the most distant, unexplored reaches of the solar system.
Mission scientists say the probes have just sent back some very big news indeed.
It's bubbly out there.
"The Voyager probes appear to have entered a strange realm of frothy magnetic bubbles," says astronomer Merav Opher of Boston University. "This is very surprising."
ScienceCasts: Big Surprise (http://www.youtube.com/watch?v=yUt6mRDV5hY#ws)
According to computer models, the bubbles are large, about 100 million miles wide, so it would take the speedy probes weeks to cross just one of them. Voyager 1 entered the "foam-zone" around 2007, and Voyager 2 followed about a year later. At first researchers didn't understand what the Voyagers were sensing--but now they have a good idea.
"The sun's magnetic field extends all the way to the edge of the solar system," explains Opher. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are now, the folds of the skirt bunch up."
When a magnetic field gets severely folded like this, interesting things can happen. Lines of magnetic force criss-cross and "reconnect". (Magnetic reconnection is the same energetic process underlying solar flares.) The crowded folds of the skirt reorganize themselves, sometimes explosively, into foamy magnetic bubbles.
"We never expected to find such a foam at the edge of the solar system, but there it is!" says Opher's colleague, University of Maryland physicist Jim Drake.
Theories dating back to the 1950s had predicted a very different scenario: The distant magnetic field of the sun was supposed to curve around in relatively graceful arcs, eventually folding back to rejoin the sun. The actual bubbles appear to be self-contained and substantially disconnected from the broader solar magnetic field.
Energetic particle sensor readings suggest that the Voyagers are occasionally dipping in and out of the foam—so there might be regions where the old ideas still hold. But there is no question that old models alone cannot explain what the Voyagers have found.
Says Drake: "We are still trying to wrap our minds around the implications of these findings."
The structure of the sun's distant magnetic field—foam vs. no-foam—is of acute scientific importance because it defines how we interact with the rest of the galaxy. Researchers call the region where the Voyagers are now "the heliosheath." It is essentially the border crossing between the Solar System and the rest of the Milky Way. Lots of things try to get across—interstellar clouds, knots of galactic magnetism, cosmic rays and so on. Will these intruders encounter a riot of bubbly magnetism (the new view) or graceful lines of magnetic force leading back to the sun (the old view)?
The case of cosmic rays is illustrative. Galactic cosmic rays are subatomic particles accelerated to near-light speed by distant black holes and supernova explosions. When these microscopic cannonballs try to enter the solar system, they have to fight through the sun's magnetic field to reach the inner planets.
"The magnetic bubbles could be our first line of defense against cosmic rays," points out Opher. "We haven't figured out yet if this is a good thing or not."
On one hand, the bubbles would seem to be a very porous shield, allowing many cosmic rays through the gaps. On the other hand, cosmic rays could get trapped inside the bubbles, which would make the froth a very good shield indeed.
"We'll probably discover which is correct as the Voyagers proceed deeper into the froth and learn more about its organization1," says Opher. "This is just the beginning, and I predict more surprises ahead."
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Go 33+ year old probes! I've said it before - they don't build 'em like they used to.
Another shining example of the benefits of nuclear power!
;D
Quite the interesting discovery! I'm hoping they reach the Heliopause Boundary before the reactor output degrades too much for operations:
Both Voyagers are headed towards the outer boundary of the solar system in search of the heliopause, the region where the Sun's influence wanes and the beginning of interstellar space can be sensed. The heliopause has never been reached by any spacecraft; the Voyagers may be the first to pass through this region, which is thought to exist somewhere from 8 to 14 billion miles from the Sun. This is where the million-mile-per-hour solar winds slows to about 250,000 miles per hour—the first indication that the wind is nearing the heliopause. The Voyagers should cross the heliopause 10 to 20 years after reaching the termination shock. The Voyagers have enough electrical power and thruster fuel to operate at least until 2020. By that time, Voyager 1 will be 12.4 billion miles (19.9 billion KM) from the Sun and Voyager 2 will be 10.5 billion miles (16.9 billion KM) away.
All this is possible due to over-engineering! I'm sure the designers/builders could only dream that their probes would still be operational and still collecting data 3 decades after launch!
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Can anyone say "V ### GER". Live long and prosper.
And, ride safe.
Greg
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Way cool! Love this stuff, even the parts I can't quite wrap my brain around so it makes sense.
I love pure science . . . and love it even more when scientists bump up against something they never expected.
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They need to get the guys who designed and worked on the Voyager probes out of retirement and put them back to work. Those guys knew how to build something that lasts!
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...and God is laughing his a** off at us puny humans trying to understand! I just hope we're not finding that we're in the middle of God's Beer Glass. ;D
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They need to get the guys who designed and worked on the Voyager probes out of retirement and put them back to work. Those guys knew how to build something that lasts!
Did they design the C-10? :o
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A great book for the pure science lover is "a briefer history of time" by Leonard Mlodinow. Great great book that explains all the stuff you wish you understands. I feel that it also takes into account God and how he plays into the scientific understanding. It's not overt, rather very subtle, and it's interesting to see in a science book.
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No conflict between God and Science to me. My dear economist wife says "Science tells us how and when, God tells us who and why."
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Just a quick followup on Voyager 1. Rather than start a new thread, and since this seems to be related to the previous discovery, I felt it was best to post it here.
http://voyager.jpl.nasa.gov/news/new_region.html (http://voyager.jpl.nasa.gov/news/new_region.html)
Of course, both probes are still nominal, and at this point it takes over a day for transmissions to make a round trip to either probe.
http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm (http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm)
The webmaster that posts the weekly reports takes his/her sweet time getting them up. This has been true for several years now, so the fact that the most recent report is from November 25th isn't unusual.
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...and God is laughing his a** off at us puny humans trying to understand! I just hope we're not finding that we're in the middle of God's Beer Glass. ;D
The probes will bump into the side of the test tube next..
Thanks Conrad, again! Now I can start off today by say'in that I've already learned something new!
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Is this the 'Barrier'? Ooooops, wrong thread....
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I am just a dreamer, but you are just a dream...