Voyager 2 Detects Peculiar Solar System Edge

ClickOnThis writes "CNN reports that Voyager 2 has detected evidence of the magnetic edge of the solar system (aka the heliopause) at 76 AU (1 AU = 93 million miles), much closer to the Sun than the location of 85 AU found by Voyager 1. From the article: 'This implies that the heliosphere, a spherical bubble of charged low-energy particles created by our Sun's solar wind, is irregularly shaped, bulging in the northern hemisphere and pressed inward in the south. [...] The researchers think that the heliosphere's asymmetry might be due to a weak interstellar magnetic field pressing inward on the southern hemisphere.'"

Comments

I knew it

[sidfaiwu]

I have been living in a bubble all my life.

Er. Wait.

[Roody Blashes]

That's two data points, and "bulging" implies a highly irregular shape, or at least an even shape that couldn't be accurately modeled by two data points.

Wouldn't it be equally as logical to say that it's just expanding/contracting? How can they know with only two points?

Re:Er. Wait.

[rockhome]

The 2 data points aren't informing the size or shape, but are observations related to a theory.

The theoretical belief is that it should be relatively uniform, but it does not appear to be. Are 2 observations sufficient? No, but a difference in 9 AU in the 2 observations is significant in that it is far off the scall were it less than 1, or maybe only slightly different, that would better confirm the theory. If the physics say that it ought to be uniform, and observations shows that it isn't, th theory needs to be adjusted.

Correct me if i'm wrong...

[Tibor the Hun]

...but all that mumbo-jumbo about weak this and that seems really complicated.

Couldn't the inward bulge on the south be because the turtle shell is pushing in on it?

Re:Variable size?

[sidfaiwu]

Could it not be both changing sizes and be irregularly shaped and off center?

Re:oh great

[Trails]

North and south also refer to magnetic poles. North is generally assumed to be the positive pole, and south the negative, though when poles flip, as happens on earth (every one million years I think), and the sun (every 11 years or so, sometimes refered to as a period of solar maxima), common usage north and south probably won't switch. Wikipedia has a bit more info.

There's also galactic north and south, which are imaginary axes perpendicular to the the plane of the galaxy. Again, wikipedia has more info.

I'd hazard that what this article refers to as north is probably some assumed "solar north" roughly parallel to Earth's north.

En1arge your heli0sphere

[mikeeg555]

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Some corrections and clarifications...

[jnik]

I should learn to not read slashdot during AGU.

I forgot whose talk I heard yesterday (they changed the speaking order; session was SH22A) but basically: V1 passed the termination shock (NOT the heliopause; summary is wrong) at the end of 2004; this was the big announcement at last spring AGU meeting. Before that, they were seeing foreshock signatures (plasma and magnetic). V2 is now seeing those signatures, but seeing them a fair bit closer in than V1 was observing them. So, V2 has not passed the heliopause, nor even the termination shock, but appears to be nearing the TS closer to the Sun than V1 did. This is a surprising/interesting result, but not huge overturning of theory or anything. Learning the structure of the outer regions of the Solar System is the whole point of these exercises (and the upcoming IBEX mission).