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First Images of Solar System's Invisible Frontier
Posted by
ScuttleMonkey
on Wed Jul 02, 2008 05:11 PM
from the champagne-method-to-science dept.
from the champagne-method-to-science dept.
FiReaNGeL writes an unexpected side-effect from NASA's STEREO spacecraft has allowed scientists to see a much more well-defined picture of the boundary of our solar system. "The twin STEREO spacecraft were launched in 2006 into Earth's orbit about the sun to obtain stereo pictures of the sun's surface and to measure magnetic fields and ion fluxes associated with solar explosions. Between June and October 2007, however, the suprathermal electron sensor in the IMPACT (In-situ Measurements of Particles and CME Transients) suite of instruments on board each STEREO spacecraft detected neutral atoms originating from the same spot in the sky: the shock front and the heliosheath beyond, where the sun plunges through the interstellar medium."
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Acronym in an Acronym? (Score:5, Funny)
IMPACT (In-situ Measurements of Particles and CME Transient)
Dear God, an acronym inside another acronym! I think the space geeks have beat us computer geeks yet again.
Re:Acronym in an Acronym? (Score:5, Insightful)
Parent
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Just wait 'til they come up with something like GNW's Not WINE.
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And apparently XINU Is Not Unix, either.
But "The TTP Project" is, of course, the best.
Re:Acronym in an Acronym? (Score:4, Funny)
And apparently XINU Is Not Unix, either.
Of course not, Evil Galactic Overlords always use Windows.
Parent
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He sad 'recursive', not 'accursed'.
[ I played with HURD some years back: there are compelling reasons to stick with Linux or any working, open source kernel. ]
Re:Acronym in an Acronym? (Score:5, Funny)
It's acronyms all the way down...
Parent
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SSE
Re: (Score:3, Informative)
Technically, it's an abbreviation inside of an acronym. Acronyms are words formed from abbreviations, and so are a subset of abbreviations.
Simple rule: If it's generally pronounced as a word, it is an acronym. If the letters are generally spelled out, it's not an acronym.
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When you abbreviate all the words in a phrase to their first letters and combine them into something that isn't a word, I think the term for it is 'initialism'
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When you abbreviate all the words in a phrase to their first letters and combine them into something that isn't a word, I think the term for it is 'initialism'
I thought the word was "Elitism". Or maybe just "malarkey".
Re:Acronym in an Acronym? (Score:4, Funny)
Can't think of something that uses GTK or I'd continue the fun!
Parent
And a sign that reads... (Score:5, Funny)
Last chance for gas, 20,000,000,000 km. We have lotto tickets and cold beer!
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We have lotto tickets and cold beer!
But you need a towel. A towel will insulate the beer for a few minutes. You want cold beer, but not beer at -273C.
And a towel will absorb your tears when you discover that you lost the intergalactic lottery. Again.
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Pfft, Pluto's doing fine, it's got a whole category named after it now! All it needs is a leaked sex tape and it'll be the Verne Troyer [stuff.co.nz] of the Milky Way.
Images of an invisible frontier? (Score:5, Funny)
Re:Images of an invisible frontier? (Score:5, Funny)
The sound of one hand clapping.
Parent
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I can actually clap with one hand, learned the trick while figuring out how to pack a can of skoal. It's hell on your knuckles, though.
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Don't make me slap you.
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Re:Images of an invisible frontier? (Score:5, Informative)
Also from TFA "The termination shock is the region of the heliosphere where the supersonic solar wind slows to subsonic speed"
Last I checked wasn't sonic speed something only relative to earth? Wouldn't that make this point completly arbitrary in a cosmic sense?
This was covered in the Slashdot post a while back about Voyager 2 crossing the termination shock. It boils down to the fact that the plasma from the solar wind does conduct waves, although due to the density of the particles and the nature of a plasma, the waves are much faster than the speed of sound through earth's atmosphere. So sonic speed does have a point (and related phenomena in this context. See this article [space.irfu.se], or google "super sonic speed heliopause".
Parent
Woooooosh (Score:2, Insightful)
Not the sound the Solar system makes as it travels through the galaxy, but the sound of this article going over my head.
So this boundry is what exactly? The limit to which the solar winds reach out from the Sun and the interaction that they have when they hit the expansive nothing out there?
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It, grasshopper, is the sound of one star clapping.
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Re:Woooooosh (Score:5, Insightful)
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Re:Woooooosh (Score:5, Informative)
In our neighbourhood it's a a lot less dense [berkeley.edu] than average.
Even taking the average of about 1 hydrogen atom per cc, if you had a tube 1 cm in diameter that stretched from here to Alpha Centauri, the total mass inside the tube would be 3e-12 grams.
So yes theres stuff out there, but it wouldn't ruffle your hair if you put the convertible top down on your spaceship.
Parent
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You have nebula and lots of (hundreds of billions?) stars
Ah yes, the approximation of the universe if Carl Sagan had been British.
Re:Woooooosh (Score:4, Interesting)
Parent
Sloar system's velocity (Score:5, Interesting)
Possibly, using this information, couldn't an orbital pattern of our solar system be extrapolated against the center of the galaxy as a reference point?
Re:Sloar system's velocity (Score:5, Informative)
Parent
Re:Sloar system's velocity (Score:5, Funny)
I'm sure it's possible, but pointless. Decades ago, astronomers mapped proper motion and showed that all the stars were streaming away from a single point in the constellation Hercules. Presumably, that's where we're headed.
Makes you think, doesn't it? Everyone is getting the hell out of there and we're headed straight for it. Someone ought to do something about this... :)
Parent
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Why? I'm sure with them getting the hell away it's a buyer's market, we could triple or quadruple the size of our solar system, buy a few more planets, maybe even add another star to really brighten things up.
Re:Solar system's velocity (Score:5, Informative)
However, the Sun's motion relative to the Galactic center is reasonably well known. It is based on looking at the velocities of stars in the local neighborhood (which should be in the same general orbit around Galactic center), and assuming that the average of these would be zero IF the Sun had no velocity except that required for its orbit around Galactic center. The average isn't, so the Sun has an extra velocity component, which is just the negative of this average. (The technical terms used for these quantities are the "solar motion" and the "Local Standard of Rest".) It turns out to be around 16.5 km/sec diagonally inward and slightly upward from its rotation.
Parent
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[...]assuming that the average of these would be zero IF the Sun had no velocity except that required for its orbit
around Galactic center. The average isn't, so the Sun has an extra velocity component, which is just the negative of this average. It turns out to be around 16.5 km/sec diagonally inward and slightly upward from its rotation.
It must be funny getting lost in your neighborhood and asking you for directions.
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Have a look at this:
http://adsabs.harvard.edu/abs/1998MNRAS.298..387D
A Terry Gilliam fan writes (Score:4, Funny)
"Ah, so *that's* what an invisible frontier looks like!"
the question is.. (Score:3, Funny)
Call me when they have pictures... (Score:2, Funny)
of the universes invisible frontier ; )
Invisible? (Score:2)
I wanna see!
Math Quiz (Score:5, Funny)
TFA: The termination shock is the region of the heliosphere where the supersonic solar wind slows to subsonic speed as it merges with the interstellar medium.
Okay boys and girls. Quick, grab your calculator and calculate the speed of sound in space...
Re:Math Quiz (Score:5, Insightful)
c = (k p / Ï)^1/2
Put in the numbers and get your answer. The speed of sound in space works out to around 300 m/s in these parts.
Or were you under the impression that sound isn't transmitted in space? Sound we can hear isn't, but the ambient gas in space certainly does transmit disturbances, and will let you know if something passing through it exceeds the speed of sound by forming a shock wave.
Parent
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but you see, (Score:2)
since it's invisible, there's nothing to see...
nice picture... (Score:5, Funny)
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Re:Hot, that's really hot! (Score:5, Funny)
Parent
Moar Sloar (Score:2)
Gozer the Traveler. He will come in one of the pre-chosen forms. During the rectification of the Vuldrini, the traveler came as a large and moving Torg! Then, during the third reconciliation of the last of the McKetrick supplicants, they chose a new form for him: that of a giant Slor! Many Shuvs and Zuuls knew what it was to be roasted in the depths of the Slor that day, I can tell you!