The Voyager probes have found that the gas surrounding our solar system is held together by surprisingly strong magnetism. Space.com article.
Established Member
The Voyager probes have found that the gas surrounding our solar system is held together by surprisingly strong magnetism. Space.com article.
Administrator
Thanks marsbug! Interesting story. I hope the Voyagers survive long enough to tell us more details, and that New Horizons can tell us something similar a decade or two from now.
Forming opinions as we speak
Order of Kilopi
Thank you marsbug. Interesting article indeed, echoing antoniseb...
The accompanying artist's rendition seems like a beautiful Cosmic Eye.
Happy Christmas ye all!
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The fluff itself is ionised?
Administrator
Figured I'd make use of an old thread for an old spacecraft...
From NASA.gov
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."
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.
Established Member
There is enough tantalising data to justify, in my mind, a dedicated mission out to the heliosheath / heliopause region. The technical challenge of getting a probe out there in a reasonable time is itself compelling, but with the right instrument suite the potential for science out on the edge of the solar system is greater than anticipated.
Order of Kilopi
New Horizons will be out that way a few years after it passes Pluto. In general, that seems like a pretty good ongoing plan: any flyby mission eventually makes it out that far, so rather than building a dedicated outer heliosphere mission, just make sure we build flyby missions with enough longevity that we can expect them to make it that far. We don't have to wait 20 or 30 years before we reach the main mission objective, but we still get to explore the outer reaches of the solar system.Originally Posted by marsbug
Conserve energy. Commute with the Hamiltonian.
Established Member
I don't disagree with doing it that way but it makes the heliosheath investigation a secondary objective, so the instruments are ging to be picked much more for the primary mission. I think the solar systems far edge is interesting enough to get the kind of investigation that comes with being a primary mission target.....though with existing propulsion it may be too long a wait for science return I admit.
Administrator
Given all that, maybe the best bet would be to add heliosheath investigations, and instruments dedicated to that mission (or instruments that at least are designed for dual use) to any other missions heading to the outer system.
The other way might be mini-probes dedicated for heliosheath missions. Given the small size, it might be easier to get them out there faster. I'm just not sure if a mini-probe would be able to transmit with decent power back to Earth from that far out.
Order of Kilopi
Let's look at it in the other direction--if we wanted probes with a primary mission of heliosheath investigation, what might their secondary objectives be?
For a primary mission of heliosheath investigation, speed is good. And the way to get speed is an Oberth effect thrust near the Sun.
We start off doing several Venus flyby maneuvers to get a close solar approach. Then, each probe uses a solar thermal thruster at perihelion to kick itself into a fast solar escape trajectory. A 5km/s burn provides a V_inf of 45km/s. It starts off at 220km/s. At 1AU, it's still screaming along at 78km/s. As it passes the orbit of Pluto it's still hustling at 66km/s. That's FAST!!!
The primary objective is to study the heliosheath, but in the meantime the probes can study the Sun, the magnetic field in the inner system, and Venus.
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Nature is always reliably far more exotic than anything we can dream up.
Order of Kilopi
Yay!!I read the article at spaceweather.com yesterday. GO VOYAGERS!!
Order of Kilopi
An update on Voyager 1 from physorg. http://www.physorg.com/news/2011-12-...olar-edge.html
From that article:
"NASA's Voyager 1 spacecraft has entered a new region between our solar system and interstellar space. Data obtained from Voyager over the last year reveal this new region to be a kind of cosmic purgatory. In it, the wind of charged particles streaming out from our sun has calmed, our solar system's magnetic field has piled up, and higher-energy particles from inside our solar system appear to be leaking out into interstellar space.
"Voyager tells us now that we're in a stagnation region in the outermost layer of the bubble around our solar system," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. "Voyager is showing that what is outside is pushing back. We shouldn't have long to wait to find out what the space between stars is really like.""
Moderator
At 66km/s, it would take almost a year to go 100 million miles, but the Voyagers do it in weeks? How fast are they going?
Administrator
Heavens-above.com has a page for "Spacecraft escaping the Solar System" with various data (the spacecraft are Pioneer 10 and 11, Voyager 1 and 2, and New Horizons). According to that, the speed relative to the sun for V1 is 17.05 km/s (3.6 AU/year) and V2 is 15.45 km/s (3.3 AU/year); NH is going 15.55 km/s at the moment.
Order of Kilopi
Just out of curiosity, if we sent a mission to upward or downward rather than outward along the elliptic plane, would it encounter the heliopause sooner? If so, it would be a potential mission.
As above, so below
Administrator
Actually, neither Voyager is in the elliptic plane. V1 is 35 degrees above and V2 is 34 degrees below. But your question as to the shape of the heliopause is interesting.
Moderator
OK, what is NASA talking about?100 million miles is more than an AU, right?
Member
What do you mean?
By a bit. 100,000,000 miles is 1.076 AU.
Moderator
First off, I must've dropped a decimal place in my other post, so I was thinking it would take years, not weeks. But now it looks like months?
Member
Yes, those probes are traveling at truly remarkable speeds.
What functions can still be performed by Voyager 1 besides telling us how far away it is?
Order of Kilopi
Voyager 1 can do anything Phobos Grunt can do, and more. Well, except for falling to earth.
Seriously though, I don't know what information Voyager 1 sends exactly, but I'll google it for you as I'm interested as well.
Order of Kilopi
The wiki site gives a good overview of all instruments on the spacecraft and which ones are still being used. Further down, they describe how these instruments are used now to study Voyager's surroundings.
http://en.wikipedia.org/wiki/Voyager_1
These are truly remarkable craft. Launched in 1977, flying in the harsh environment of space for 3 decades, and still happily doing science, sending back data, recording data (a digital tape recorder working for 3 decades without a finger touching it!), and receiving commands.
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