Family Portrait done by Voyager 1 in February 1990
Posted on 12/23/2009 8:42:00 PM PST by PeaceBeWithYou
December 23, 2009: The solar system is passing through an interstellar cloud that physics says should not exist. In the Dec. 24th issue of Nature, a team of scientists reveal how NASA's Voyager spacecraft have solved the mystery.To read the original research, look in the Dec. 24, 2009, issue of Nature for Opher et al's article, "A strong, highly-tilted interstellar magnetic field near the Solar System.""Using data from Voyager, we have discovered a strong magnetic field just outside the solar system," explains lead author Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. "This magnetic field holds the interstellar cloud together and solves the long-standing puzzle of how it can exist at all."
The discovery has implications for the future when the solar system will eventually bump into other, similar clouds in our arm of the Milky Way galaxy.
Astronomers call the cloud we're running into now the Local Interstellar Cloud or "Local Fluff" for short. It's about 30 light years wide and contains a wispy mixture of hydrogen and helium atoms at a temperature of 6000 C. The existential mystery of the Fluff has to do with its surroundings. About 10 million years ago, a cluster of supernovas exploded nearby, creating a giant bubble of million-degree gas. The Fluff is completely surrounded by this high-pressure supernova exhaust and should be crushed or dispersed by it.
"The observed temperature and density of the local cloud do not provide enough pressure to resist the 'crushing action' of the hot gas around it," says Opher.
So how does the Fluff survive? The Voyagers have found an answer.
"Voyager data show that the Fluff is much more strongly magnetized than anyone had previously suspected—between 4 and 5 microgauss*," says Opher. "This magnetic field can provide the extra pressure required to resist destruction."
NASA's two Voyager probes have been racing out of the solar system for more than 30 years. They are now beyond the orbit of Pluto and on the verge of entering interstellar space—but they are not there yet.
"The Voyagers are not actually inside the Local Fluff," says Opher. "But they are getting close and can sense what the cloud is like as they approach it."
The Fluff is held at bay just beyond the edge of the solar system by the sun's magnetic field, which is inflated by solar wind into a magnetic bubble more than 10 billion km wide. Called the "heliosphere," this bubble acts as a shield that helps protect the inner solar system from galactic cosmic rays and interstellar clouds. The two Voyagers are located in the outermost layer of the heliosphere, or "heliosheath," where the solar wind is slowed by the pressure of interstellar gas.
Voyager 1 entered the heliosheath in Dec. 2004; Voyager 2 followed almost 3 years later in Aug. 2007. These crossings were key to Opher et al's discovery.
The size of the heliosphere is determined by a balance of forces: Solar wind inflates the bubble from the inside while the Local Fluff compresses it from the outside. Voyager's crossings into the heliosheath revealed the approximate size of the heliosphere and, thus, how much pressure the Local Fluff exerts. A portion of that pressure is magnetic and corresponds to the ~5 microgauss Opher's team has reported in Nature.
The fact that the Fluff is strongly magnetized means that other clouds in the galactic neighborhood could be, too. Eventually, the solar system will run into some of them, and their strong magnetic fields could compress the heliosphere even more than it is compressed now. Additional compression could allow more cosmic rays to reach the inner solar system, possibly affecting terrestrial climate and the ability of astronauts to travel safely through space. On the other hand, astronauts wouldn't have to travel so far because interstellar space would be closer than ever. These events would play out on time scales of tens to hundreds of thousands of years, which is how long it takes for the solar system to move from one cloud to the next.
"There could be interesting times ahead!" says Opher.
It really was. I remember his showing me the plutonium canisters being destructively tested to make sure they wouldn’t crack open upon launch. Some amazing engineering feats in that project!
Just amazing! There are a lot of guys who are retiring now, who cut their professional teeth on the Voyager program, and the spacecraft are still out there doing meaningful science./
Wow. Just wow!!
6000c = 10832f
Cool. How long will Voyager last in that?
I ran across a book, a few years back, called “The Big Bang Never Happened.” It’s premise was that cosmologists assumptions that only gravity mattered on a cosmic scale, because positive and negative electromagnetic forces canceled each other out, was unfounded. And that the observations were consistent with a universe filled with massive electromagnetic flux.
Interesting that we should have found some.
Of course, the consequence of having electromagnetism matter is that the past and the future of the universe is no longer predictable. If gravity is everything, we can know the end state. If it is not, we cannot.
http://bigbangneverhappened.org/
Voyager is still sending data.It probably has enough power until another decade
NASA’s two Voyager probes have been racing out of the solar system for more than 30 years.
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The spacecraft are moving at approximately 12 miles per second......And they still haven’t left the solar system...lol..
Where does the Solar System “end” or where interstellar space “begin”?
bump
Voyager will most likely be OK, as the density of the cloud is much less than the Heliosphere and Heliosheath. (See link in post 29)
Hey Hey, You You get off of my cloud...
Milky Way is center just below the top with Fluff to its left:
Cheers!
Pretty sure only climatologists know everything.
Cheers!
Well, there is no sign or solar system border line, but it's generally thought to be beyond the orbit of Pluto...It's up for debate...lol
That being said, the gravitational influence of the sun is estimated to reach approximately two light years out. Give or take.
That’s cool. I’m amazed the Voyagers are still cruising some thirty years later.
No, it just means that we just enter and exit the system through the sun’s ‘wake’ or come up with a subspace drive that bypasses it entirely. Same reason you don’t jump off the front of a moving boat when diving.
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