First Images of Solar System's Invisible Frontier

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."

Re:

[uberphear]

Where's the "-1 *Groan*" mod when you need it?

Re:Hot, that's really hot!

[Jerome H]

http://www.thebestpageintheuniverse.net/c.cgi?u=puns [thebestpag...iverse.net]

Re:

[Starayo]

I came here fully expecting to see nothing but a huge, transparent .png...

Acronym in an Acronym?

[RManning]

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?

[bunratty]

Meh. It doesn't even recurse like GNU's Not Unix.

Re:

[HTH NE1]

Just wait 'til they come up with something like GNW's Not WINE.

Re:

[sconeu]

And apparently XINU Is Not Unix, either.

But "The TTP Project" is, of course, the best.

Re:Acronym in an Acronym?

[corbettw]

And apparently XINU Is Not Unix, either.

Of course not, Evil Galactic Overlords always use Windows.

Re:

[MadnessASAP]

Man, if that was true they would NEED a hero to MAKE the Death Ray work.

Re:

[c_forq]

I'm sure if you let the GNU guys know they will make a recursive acronym inside of another recursive acronym.

Re:

[Jesus_666]

They did, HURD. We all know how that played out.

Re:

[Antique Geekmeister]

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?

[Taibhsear]

It's acronyms all the way down...

Re:

[florescent_beige]

SSE

Re:

[Martin Blank]

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.

Re:

[Anti_Climax]

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'

Re:

[street struttin']

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:

[gstoddart]

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.

Well, I guess you've lost the battle on that front, since TLA [wikipedia.org] is used by an awful lot of people.

I think to most people by now (grammar nazi's notwithstanding) no longer really differentiate based on if you pronounce it or not. (Oh, sure, it's not technically correct in a grammatical sense -- but, who is nowadays? ;-)

Cheers

Re:Acronym in an Acronym?

[GXTi]

((GNU's Not Unix) Image Manipulation Program) Tool Kit

Can't think of something that uses GTK or I'd continue the fun!

Re:

[Sodki]

gtkmm, gtk#...

And a sign that reads...

[chill]

Last chance for gas, 20,000,000,000 km. We have lotto tickets and cold beer!

On a more serious note,

[Anonymous Coward]

I wonder if they found any more plutoids [newscientist.com] out there... Poor Pluto! [mathiaspedersen.com]

Re:

[glittalogik]

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.

Re:

[stefanlasiewski]

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.

Re:

[zapakh]

But you need a towel. A towel will insulate the beer for a few minutes. You want cold beer, but not beer at -273C.

Insulate it from what? Heat loss from conduction and convection is not much of an issue in the local environment, and radiation certainly takes longer than a few minutes. Besides, a towel won't help you keep your beer liquid.

Images of an invisible frontier?

[DigitalReverend]

Would that be like recordings of silence or the smell of nothing?

Re:Images of an invisible frontier?

[neokushan]

The sound of one hand clapping.

Re:

[Khyber]

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.

Re:

[PakProtector]

The sound of one hand clapping

Don't make me slap you.

Re:

[indi0144]

More like: If one hand claps in the middle of the forest...

Re:

[felipekk]

Ask your wife if she gained some pounds and you shall see what an invisible frontier looks like.

Re:

[gregbot9000]

If you go by this article it would be more like a crudely drawn diagram of silence.

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?

Re:Images of an invisible frontier?

[tchuladdiass]

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".

Woooooosh

[halsver]

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?

Re:

[lazyDog86]

It, grasshopper, is the sound of one star clapping.

Re:

[lazyDog86]

Arrrrgghhh! One should refresh before posting if one does not wish to repeat someone else's joke. Go ahead mod me down, I can take it.

Re:

[Prosthetic_Lips]

What do you mean, repeat? You took the joke everyone had seen, and EXPECTED (one hand clapping), and made it into something else completely (star).

That, my good sir, is sheer (comedic) genius. You could be the next George Carlin (that's pronounced, "dead comedian").

Re:Woooooosh

[khallow]

Interstellar space isn't empty. You have nebula and lots of (hundreds of billions?) stars spewing particles just like the Sun does, etc. So there is something for the solar wind to run into.

Re:Woooooosh

[florescent_beige]

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.

Re:

[dintech]

if you had a tube 1 cm in diameter that stretched from here to Alpha Centauri

Interesting. Let 'Big Oil' know when you get that to 60cm. :)

Re:

[khallow]

But let's say your afro is a couple hundred AU [wikipedia.org] across and no more dense than the interstellar medium.

Re:

[Rich0]

At a substantial portion of the speed of light the blue-shifted background radiation would bake you in an instant - most of the mass/energy of the universe is tied up in very-low-energy photons floating around in the interstellar medium - if you speed up they suddenly aren't low-energy any longer.

Re:

[corbettw]

You have nebula and lots of (hundreds of billions?) stars

Ah yes, the approximation of the universe if Carl Sagan had been British.

Re:

[street struttin']

Whenever life gets you down, Mrs.Brown And things seem hard or tough And people are stupid, obnoxious or daft And you feel that you've had quite enough Just remember that you're standing on a planet that's evolving And revolving at nine hundred miles an hour That's orbiting at nineteen miles a second, so it's reckoned A sun that is the source of all our power The sun and you and me and all the stars that we can see Are moving at a million miles a day In an outer spiral arm, at forty thousand miles an hour

Re:

[RabidMoose]

Was your "Preview" button broken?

Re:

[Eth1csGrad1ent]

Yep. The slashdot summary was like listening to the techno-babble
between Abby and McGee on NCIS... lots of cool words strung together,
but I didn't understand any of it...

Re:Woooooosh

[jd]

It's the boundary where the charged particles that make up the solar wind get blasted by the galactic wind. Somewhere on the perimeter of the galaxy, there will be a similar shock boundary where the galactic winds become too faint and get ripped sway by the intergalactic winds. The solar winds are supposed to offer considerable protection from the galactic winds and I seem to recall hearing that probes that go outside of the heliopause will need far more extensive shielding from radiation to handle the conditions they will meet.

Re:

[kalirion]

Wait a second, if within the solar system the solar winds are more powerful than the galactic winds, wouldn't they also be more damaging?

Re:

[jd]

You should know by now I hate to admit the limits of my knowledge. :) I don't know the answer, but I can take a guess at what the answer presumably addresses.

I would imagine it depends on the composition of the winds and the relative strengths. In the case of strengths, that will fall off with the square of the distance. The distances are very large, but so are both the individual sources and the number of those sources. However, it is likely the composition that is the key. The winds are comprised of cha

Sloar system's velocity

[em0te]

Wouldn't it be possible, using the sun as a center point, to measure the distance to the termnation shock vs the boundaries of the heliosphere to determine how fast and in what vector our solar system is moving through space relative to the center of our galaxy? Or has this already been done, 'cause I can't find the info.
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:

[HJED]

one with mod points der..............

Re:

[4D6963]

It's become clear that meta moderation does not work. Moderation does not become better over time scales of months, or even years, at it, in theory, should, if unfair moderations tossed morons out of the pool.

There's a solution to it, give more points to more people more often with a much much decreased weight. It's simple as statistics, the more people you make moderate a comment the closer the moderation will be to the comment's true value. More people -> reduced distribution -> increased significance. The notion of "wisdom of the crowds" is often misused but it's a very appropriate solution in that sort of case. Much simpler than weeding out the noise-increasing elements out there, as the noise decrease

Re:Sloar system's velocity

[techno-vampire]

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.

Re:Sloar system's velocity

[Dunbal]

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... :)

Re:

[servognome]

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... :)

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

[Bemopolis]

Well, the gas into which the Sun is driving the termination shock could also have a mean motion relative to the Keplerian velocity at its distance from Galactic center so...no.

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.

Re:

[Thanshin]

[...]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.

Re:

[Antique Geekmeister]

Would you prefer if he pointed out the Sun's path by the Starbucks we're passing?

Re:

[Anonymous Coward]

Have a look at this:
http://adsabs.harvard.edu/abs/1998MNRAS.298..387D

Re:

[em0te]

Awesome, thanks guys!

A Terry Gilliam fan writes

[metamatic]

"Ah, so *that's* what an invisible frontier looks like!"

the question is..

[owlnation]

...what does god need with a Twin Stereo Starship?

the answer is...

[RabidMoose]

...the ability to throw awesome parties, duh.

Call me when they have pictures...

[MRe_nl]

of the universes invisible frontier ; )

Invisible?

[Kingrames]

I wanna see!

Next they'll be telling us

[Mesa MIke]

.. that invisible unicorns are pink.

Math Quiz

[Pedrito]

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

[ceoyoyo]

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.

Re:

[buttwidget]

So what's this about passing gas? There's a shockwave, and thereby a sound?

Re:

[Antique Geekmeister]

No, that's an "I'm shocked!" wave, and it happens _after_ a sound occurs.

Re:

[SimonGhent]

Okay boys and girls. Quick, grab your calculator and calculate the speed of sound in space...

c = (k p / Ï)^1/2

OK, next question, calculate the speed of light in the dark.

(hint: will be easier with an LED calculator than an LCD one)

Re:

[kalirion]

Wait a second, so the speed of sound in space is the same as the speed of sound in our air?

Re:

[cuby]

No. The speed of sound at sea level is 340.29 m/s.

Re:

[ceoyoyo]

Within a factor of 1000 or so, yes. ;)

Re:

[Cypher04]

So if a tree falls on a bear in space and nobody is around, does it make a sound?

Re:

[ceoyoyo]

Yup. Only if someone were around he'd need ears 10 km across to hear it.

Re:

[4D6963]

Put in the numbers and get your answer

Yeah.. you know that would help a bunch if you'd mentioned what your variables represent. I can't even find the same equation on wikipedia [wikipedia.org] so I have no idea what your equation is supposed to do.

Re:

[ceoyoyo]

Ah, sorry. I didn't think anyone would actually want to work it out. The equation is the same as the equation for the speed of sound in an ideal gas here. [wikipedia.org]

The speed of sound equals the square root of the adiabatic index times the pressure over the density. I think the variables were the same as the wikipedia formula except that Slashdot screwed up the greek letters.

Those particular variables might be somewhat hard to measure for space, but there are lots of different ways of calculating the speed of sound

Geeks honor :

[ZarathustraDK]

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."

Admit it, you don't know what it means.

but you see,

[serbanp]

since it's invisible, there's nothing to see...

nice picture...

[Ogive17]

I was expecting a picture that didn't look like something I drew today at work using MS Excel and autoshapes.

Re:

[chord.wav]

They are the "First IMAGES of Solar System's INVISIBLE Frontier" I was glad it wasn't any goatse or April's fools kind of thing.

Images of invisible stuff, neat!

[coffeemugger]

Images of invisible stuff, neat! What will NASA do next?

Re:

[kalirion]

Look for a Pink Unicorn of course.

Pictures?!!!

[Enrique1218]

If there is an article that says there is image of some astronomical phenomenon, then damnit I want some pictures! My taxpayer dollars go to pay for the equipment and I want something back. I don't care if it is invisible! Color it in, spruce it up, and post it. Coloring is the first thing anyone learns in Kindergarten. If you forgot, hire my niece. With a pack of Crayola, she will make invisible look interesting.

Helioshock?

[thebryce]

From 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.

Why is anything relating to the sound-barrier even mentioned in this article? I was under the impression that there was no sound in the vacuum of space.

Re:

[pohl]

I'm going to go out on a limb and guess that they're putting the velocities into a frame of reference that more people can appreciate.

Re:

[Tim C]

The interstellar medium is essentially a gas. An extremely thin gas, but a gas all the same. As such, it does indeed transmit sound and so objects can be said to be moving supersonically and subsonically through it.

Supersonic and subsonic are used to denote the speed relative to the speed of sound in the medium in question, just as they are in any fluid.

Did they photograph the sign that says...

[master_p]

..."Hi. Can I take your order?" ???

But doesn't it look just like...

[Illbay]

...the The Galactic Barrier [memory-alpha.org]?

Only, you know, smaller?

Moar Sloar

[slyborg]

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!