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Voyager 2 Set to Reach Termination Shock

CmdrTaco posted more than 6 years ago | from the cool-stuff-you've-never-heard-of dept.

Space 308

Invisible Pink Unicorn writes "A computer model simulation developed at UC Riverside has predicted that in late 2007 to early 2008, the interplanetary spacecraft Voyager 2 will cross the termination shock, the spherical shell around the solar system that marks where the solar wind slows down to subsonic speed. At the termination shock, located at 7-8.5 billion miles from the sun, the solar wind is decelerated to less than the speed of sound. The boundary of the termination shock is not fixed, however, but wobbly, fluctuating in both time and distance from the sun, depending on solar activity. Because of this fluctuation, the spacecraft is also predicted to cross the boundary again in middle 2008. The article abstract is available from The Astrophysical Journal."

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Zzzzzzz (-1, Troll)

HomeLights (1097581) | more than 6 years ago | (#21506773)

Zzzzzz..Huh? What I am awake. Why do I care about this? Will I ever be able to travel that far? What does it meant to me? Will my pizza get to ne any slower?

And then what? (0, Redundant)

stratjakt (596332) | more than 6 years ago | (#21506795)

Other than "we sent something outside the solar system again", does this mean anything? Will we get any new data about "termination shock" or whatnot?

Re:And then what? (5, Insightful)

mabhatter654 (561290) | more than 6 years ago | (#21506897)

this is the kind of thing scientists predict all the time and observe in lab experiments... but this device is actually GOING to the edge of a solar system... it's someplace human made instruments haven't been. Science at it's very purest form, simply going and observing something nobody has actually seen before.

Why do you go on vacation to foreign places.. aren't postcards and Discovery channel good enough? It's a whole lot different to say "we were there" than guessing what it would be like from a long distance.

Re:And then what? (3, Funny)

mustafap (452510) | more than 6 years ago | (#21507003)

>Why do you go on vacation to foreign places..

I think you will find he is an american, and therefore that doesn't apply.

Re:And then what? (2, Informative)

FirstTimeCaller (521493) | more than 6 years ago | (#21507139)

this device is actually GOING to the edge of a solar system... it's someplace human made instruments haven't been.
From the Wikipedia article:

In May 2005, it was announced that Voyager 1 had crossed the termination shock...
Don't get me wrong, I think the prospect that our reach is expanding past our solar system is indeed exciting news...

Re:And then what? (5, Funny)

GodfatherofSoul (174979) | more than 6 years ago | (#21507225)

Why do you go on vacation to foreign places...

OMG, underage Taiwanese hookers...in space?

Why don't we do this more often? (1)

Crazy Taco (1083423) | more than 6 years ago | (#21507633)

Science at it's very purest form, simply going and observing something nobody has actually seen before.

I agree that this is a very pure and useful form of science. However, what I don't understand is why we don't do this more often. Why haven't we been sending out a probe every year, or at least every five years, upgraded with the best propulsion systems and scientific instruments we can put on it? These two probes were launched 30 years ago, and while they still work, technology improved a lot over the decades. If it takes 30 years to get to the termination shock, it seems like they took an awfully big risk sending just two probes and then sitting tight. If something went wrong or failed, you have just one probe left, or maybe none if it was an issue common to the two of them. And then you have to wait 30 years to get back to where you were. In addition, science usually likes many repeated observations of phenomena more than just a few, and repeatedly launching probes in different directions would have helped establish even more reliablity for all data returned.

I just don't understand why we don't do this more often. I would have to think we could build a better, sturdier probe with a faster propulsion system, longer lasting power sources and far more powerful scientific devices. Unless perhaps we have launched another probe that will eventually have this mission (but maybe is doing something else on the way for now), I just don't understand why we don't do this again.

Re:And then what? (5, Funny)

niceone (992278) | more than 6 years ago | (#21506933)

It means Janeway's going to have to pretend to be thrown all over the place while bits of the ship fall off.

Re:And then what? (2, Funny)

Anonymous Coward | more than 6 years ago | (#21506969)

Speaking as someone working on the project, posting anonymously for obvious reasons, I can give a little info. When the spacecraft reaches termination shock, it is quite likely that all the transistors will fall off the pcb's that make up the electronics. Chances are this isn't so bad, as their are lots of backup resistors, but if theres a leak in the spacecraft's petrol tank then it might be ignited by some arcing currents, which would probably throw it off course a bit.

Re:And then what? (0)

Anonymous Coward | more than 6 years ago | (#21507113)

Maybe you do work on the project. But you sound like the janitor for the project.

Why is it relevant that there are 'backup resistors' if 'all the transistors' fall off? Even if resistors were the same as transistors, all would include the backups.

Re:And then what? (0)

hyperstation (185147) | more than 6 years ago | (#21507125)

hey all you armchair rocket scientists! you're feeding an AC troll. petrol tank? hahaha!

Re:And then what? (0)

Anonymous Coward | more than 6 years ago | (#21507241)

But what about the Delta Mark IV Hasselhoff-Dusseldorf-Kruller Flanges? Surely those should help compensate for the lack of vacuum tubes in the Minolta/Konica spinny thing-a-mabob.

Re:And then what? (1)

jav1231 (539129) | more than 6 years ago | (#21507567)

Should've gone diesel...I'm just sayin'... :P

Re:And then what? (5, Informative)

DeepBlueDiver (166057) | more than 6 years ago | (#21507247)

Other than "we sent something outside the solar system again", does this mean anything?
Again? The only man made objects travelling beyond Pluto's orbit are Pioneer 10 & 11, and Voyager 1 & 2.
Four, just four small space probes.

Sorry dude, all the space ships you see on TV are just FX. We are not (yet) exploring the galaxy.

Will we get any new data about "termination shock" or whatnot?
Yeah! We may confirm that there exists this termination shock we expect to find there, or we may find our theories are wrong and there is not such "thing".

Unless I'm mistaken (3, Informative)

porkchop_d_clown (39923) | more than 6 years ago | (#21507711)

The Pioneers were dead when the left the solar system. The Voyagers are still sending data.

Re:And then what? (4, Insightful)

theStorminMormon (883615) | more than 6 years ago | (#21507387)

Other than "we sent something outside the solar system again", does this mean anything? Will we get any new data about "termination shock" or whatnot?
Also, and stop me if I'm wrong, but if the probe is going outwards and the boundary isn't perpetually expanding it can't really cross the boundary twice, can it? It has to be once or thrice.

Once to get outside the boundary, twice if the boundary expands and catches back up with it, and thrice to once again get outside the boundary.

Just a thought.

Re:And then what? (1)

camperdave (969942) | more than 6 years ago | (#21507741)

Once for Voyager 1, then once again for Voyager 2, making twice.

Some but not much (1)

WindBourne (631190) | more than 6 years ago | (#21507635)

The nukes are way down on power, so most of the instrumentation is not running. We will get some though.

It would be interesting to see a new voyager sent out. In particular, obtain bigger nukes, use bigger rockets (perhaps the ares IV/V), and finally, add ION drives. I do not know how long it would take to reach the edge again, but if done right, it could reach there in a fraction of the time and obtain more useful data. If nothing else, this would be the kind of science that Russia or China should consider doing. For some odd reason USSR/Russia really does not do that much with long term Science missions. They have never sent anything real deep. For the most part, they appear to be only interested in places that we can send mankind to.

butt wobbly (-1, Troll)

Anonymous Coward | more than 6 years ago | (#21506809)

word up

Re:butt wobbly (3, Funny)

Facetious (710885) | more than 6 years ago | (#21507087)

Sir Mix-a-lot? Is that you?

speed of sound (2, Interesting)

AndyST (910890) | more than 6 years ago | (#21506827)

speed of sound... wait a minute? In which medium? I don't think there is much atmosphere up there...

Re:speed of sound (1)

qbwiz (87077) | more than 6 years ago | (#21506941)

The medium is, in fact, the solar wind.

No (4, Informative)

InvisblePinkUnicorn (1126837) | more than 6 years ago | (#21506993)

No, it is not. It is the interstellar medium. Read: termination shock [wikipedia.org] .

Re:speed of sound (3, Interesting)

InvisblePinkUnicorn (1126837) | more than 6 years ago | (#21506951)

The speed of sound in the interstellar medium is much higher than it is on earth. In case you didn't know, space is not empty. Vacuum is, but space isn't.

That's Garbage (3, Insightful)

Crazy Taco (1083423) | more than 6 years ago | (#21507505)

The speed of sound in the interstellar medium is much higher than it is on earth. In case you didn't know, space is not empty. Vacuum is, but space isn't.

That's garbage. Space is not a total vacuum, it's true. However, the density of particles of matter in space is, for the most part, so low that space can be treated as a vacuum. It's like rounding 0.1xE-25 to just 0.

And as for the whole thing about sound travelling faster in space, you just made that up. Light (and other electromagnetic phenomena) do travel faster in a vacuum like space (perhaps you've confused the two). Sound, however, is caused waves of physical compression. In other words, one particle bumps into the next, which bumps into the next, and so on. Sound travels faster and farther through more solid materials. It has a certain speed and a certain distance it will travel in air, a faster speed and greater distance in water, and an even faster speed and greater distance through concrete. It has no speed or distance at all in space, because what little matter there is isn't close enough to touch the next peice of matter, and you can't set up the compression wave.

Re:That's Garbage (1)

AHumbleOpinion (546848) | more than 6 years ago | (#21507637)

0.1xE-25

I apologize but the nerd in me has to ask, why not 1.0E-26? Is it some kind of psychological thing that makes the number look significantly smaller, like pricing at (x-1).99 rather than x.00?

To other readers, yes I know that (x-1).99 != x.00. Notice the word "significantly" and note the context of psychology of pricing.

Remind me again (2)

tompaulco (629533) | more than 6 years ago | (#21506829)

What exactly is the speed of sound in a vacuum?

Re:Remind me again (1)

locster (1140121) | more than 6 years ago | (#21506903)

Exactly zero.

Re:Remind me again (1)

Orange Crush (934731) | more than 6 years ago | (#21507255)

IANAP, but I think "undefined" would be a better answer. Sound is just vibrations travelling through matter. True vacuum, being the absence of matter has nothing for the sound to travel through so there is nothing to measure--zero is a measurable value, after all.

Re:Remind me again (1)

drachenstern (160456) | more than 6 years ago | (#21507717)

IalsoANAP, but wouldn't that imply that light cannot travel through a vacuum? since light is predominantly viewed as electro-magnetic waves, not purely particles. And if you have light in a vacuum (since we don't speak of singular lights, "light" would imply vastly many "light(singular)"), then don't you now have a mechanism that allows for vacuum to transmit vibration?

It seems like the current definition of physicists is flawed, as you and I understand it (presumably we understand the same thing).** If vacuum cannot transmit vibration, then how does light pass through it? If vacuum is the absence of matter, then how does a light particle travel through it? These are two questions that pre-suppose the other question has been answered with the subject of the question. In other words, the general retorts are as follows:
If vacuum cannot transmit vibration, then how does light pass through it? - Light is a particle, and can therefore move through where vibrations cannot.
If vacuum is the absence of matter, then how does a light particle travel through it? - The absence of particles does not imply the inability to transmit vibration.

Yet current physics theories (as I understand them) don't tackle both of these questions at the same time.

The other thing I'm a little hazy on, how do you measure speed when there is no friction coefficient to measure against? Isn't that rather how speed is measured in the conventional sense? I realize that speed is a simple mathematical quantification of the amount of energy a unit has expended to move in a given direction, while overcoming friction (or not, if speed = 0).

Ah well, that's just me $.02

**Now, given that I am playing Devils Advocate doesn't mean that we understand two different things.

Re:Remind me again (1)

mabhatter654 (561290) | more than 6 years ago | (#21506963)

There's still solar particles out there, however sparse.. normally they move too fast for devices on earth to measure... at this point the device will be going faster than solar particles... kind of cool that the device has "outrun" it's home star.

Re:Remind me again (1)

inviolet (797804) | more than 6 years ago | (#21507233)

There's still solar particles out there, however sparse.. normally they move too fast for devices on earth to measure... at this point the device will be going faster than solar particles... kind of cool that the device has "outrun" it's home star.

If that is true, then the device will begin slowing down, ever so gradually, as it runs into random interstellar particles, and as it runs over the slower particles of the solar wind.

Re:Remind me again (1)

lstellar (1047264) | more than 6 years ago | (#21507011)

Zero. But space is not a true vacuum. The fact that you can travel from one entity to the other creates relevance for the speed of sound. If space was infinite and truly *empty* then the limit would be negligible.

Re:Remind me again (5, Informative)

Veinor (871770) | more than 6 years ago | (#21507017)

Space is not a vacuum. The speed of sound in space is about 100 km/s, according to Wikipedia. [wikipedia.org]

Re:Remind me again (5, Funny)

Nos. (179609) | more than 6 years ago | (#21507111)

So, in space, they can hear you scream?

Re:Remind me again (4, Funny)

AragornSonOfArathorn (454526) | more than 6 years ago | (#21507183)

So, in space, they can hear you scream?
Yes, but they have to take off their helmets to hear you. And then they scream.

100km/s? Bloody unlikely (1)

Viol8 (599362) | more than 6 years ago | (#21507235)

The speed of sound goes DOWN with reducing density , not up. Theres no way the speed in an almost vacuum could be hundreds of times higher than at sea level. Even in rock it only manages a few km/s. Perhaps the author meant 100m/s but even then I'd be suspicious since in intersteller space the gas molecules rarely touch each other so theres no physical way for sound to propagate anyway.

Re:100km/s? Bloody unlikely (3, Informative)

imsabbel (611519) | more than 6 years ago | (#21507673)

Plasma, meet speed of sound.
"Why are you so high, for my low density?"
"Because you are plasma, and no stupid ideal gas, slowpoke!"

Re:Remind me again (4, Informative)

kimvette (919543) | more than 6 years ago | (#21507027)

That's what I was wondering. How can there be a speed of sound in a "medium" which does not have enough mass to transmit sound waves? I mean, I know there are sparsely-distributed particles even in "empty" interstellar space, but is the medium thick enough that there can even be a "speed of sound" associated with it? Can sound transmission in such a medium ever even be measured? I was curious and googled on desity of matter in space and found this:

http://library.thinkquest.org/C0126626/fate/fate%20of%20universe.fate%20of%20universe.mass%20density%20of%20the%20universe.htm [thinkquest.org]

The most obvious technique for discriminating between an open and a closed universe is to measure the average density of matter. The Friedmann equation describes the competition between the attractive gravitational force and the expansion of the universe. The gravitational attraction exerted at the center of an arbitrary sphere cut out of the universe is proportional to the average density of matter. The measured value of the Hubble constant (H) yields the kinetic energy of the expansion of the sphere. If the present density is below the critical value at which the expansion and gravitational attraction balance, gravity cannot halt the expansion, and the universe must be open. The critical density for closure of the universe is



d critical = 3H2/8G = 5×10-30 gram cm-3



[sorry the equation got munched! -Kim]

where G is Newton's constant of gravitation. Another way to express this critical density is in the number density of atoms, which amounts to 3 x 10-6 atoms per cubic centimeter (cm-3), or only 3 atoms per cubic meter.





3 atoms per cubic meter is actually higher than I expected it would be given the immense (infinite? It certainly can't be definitively measured by any means we have, only theorised and later disproven) size of the Universe. Is 3 atoms per cubic meter enough to even have a "speed of sound" associated with it?

Re:Remind me again (4, Informative)

cnettel (836611) | more than 6 years ago | (#21507105)

That number of 3 atoms per cubic meter is the average density of the complete universe, inluding stars, planets and black holes, but also including the vast void between galaxies. Any place in the Milky Way, and especially in the relative vicinity of the Sun, is "much" denser.

Re:Remind me again / Jango Fett (0)

Anonymous Coward | more than 6 years ago | (#21507373)

He proved that sound is possible in that episode whateverthefuxit when he attacked Obi-Wan in the mini spacecraft piloted by R4. Jesus! I know too much(or don't if you know what I mean), LOL!

Re:Remind me again (1)

Sockatume (732728) | more than 6 years ago | (#21507411)

The difference between our atmosphere and the "vacuum" of space is quantitative, not qualitative. Solids, liquids, and gases (even very, very low pressure gases) can all transmit mechanical vibrations (what we call sound) to some degree.

A Few Things (3, Informative)

BlackGriffen (521856) | more than 6 years ago | (#21507557)

As another reply already noted, this is the interstellar medium, which should be a good deal dense than the space between galaxies and galaxy clusters.

Next, how does sound transmit? Well, sound is a density/pressure wave, right? All I need is for the free particles to be interacting somehow to set one up. Turns out, the interstellar medium isn't a gas like you're used to thinking of, it's a plasma. The important point here being that because the electrons are not bound to the atoms, the effective "size" of the atoms goes up (that is, the disntance over which they interact with neighboring atoms). Thus you should be able to get sound waves more easily than you would suspect from a regular gas that is that sparse.

I'll take a crack at it. (1)

Khyber (864651) | more than 6 years ago | (#21507705)

While it's not as DENSE, since sound is just energy, the atoms carry the energy (and the vacuum between transmits the energy) but there's not enough atoms to really stimulate your eardrum. That is, provided you could take your helmet off in the relative vacuum of space and survive, there's just simply not enough mass present to allow stimulation of our aural system.

Re:Remind me again (1)

jbeaupre (752124) | more than 6 years ago | (#21507749)

I got to wondering myself and did a bit of searching. Turns out that the speed of sound in space is not due to particle collisions as much as it due to magnetic interactions of the ionized atoms. It's the magnetic fields bouncing off one another. If you're curious to learn more, the place I started was http://www-istp.gsfc.nasa.gov/Education/wtermin.html [nasa.gov] . From that clue I came across http://en.wikipedia.org/wiki/Alfv%C3%A9n_wave [wikipedia.org] , but I'm not about to do the math to confirm the speed of sound in space.

Re:Remind me again (1)

gclef (96311) | more than 6 years ago | (#21507029)

These guys [sciencedirect.com] seem to think it's 100km/sec.

Re:Remind me again (2, Informative)

InvisblePinkUnicorn (1126837) | more than 6 years ago | (#21507031)

In space, it is much higher than the speed of sound on earth. Tens of kilometers per second, a couple orders of magnitude faster than on earth. See, space is not empty.

Re:Remind me again (4, Funny)

magarity (164372) | more than 6 years ago | (#21507327)

See, space is not empty
 
It's full of stars...

Re:Remind me again (3, Informative)

Sockatume (732728) | more than 6 years ago | (#21507145)

Neither the interstellar medium nor the stellar medium is a true vacuum though. The solar wind comes out of the sun faster than the speed of sound in the interstellar medium, in the same way that the expanding sphere of gases from an explosion moves faster than the speed of sound in the air around it. The breakneck expansion of the solar wind and the pressure of the interstellar medium (such as there is) eventually come into equilibrium once you get far enough from the sun. This boundary is your shock front, or in this specific case, the termination shock. What's interesting to me is that changes in the pressure of the solar wind should set up shock waves in the interstellar medium. Please note IANAAstronomer, just an interested postgrad with Google at hand.

cool (3, Interesting)

wwmedia (950346) | more than 6 years ago | (#21506833)

but can someone describe in layman's term what will that mean for the probe (if anything), will it change course/direction? can this negatively affect the mission/spacecraft itself?

Re:cool (1)

calebt3 (1098475) | more than 6 years ago | (#21507149)

Yes [slashdot.org]

Re:cool (4, Insightful)

zippthorne (748122) | more than 6 years ago | (#21507531)

No. It will have very little effect on the actual spacecraft itself. However it will provide invaluable data (being only the second instrument ever to make in situ measurements there) to confirm and help update our models.

No matter what happens, it can't negatively affect the mission, because it is the mission. (well part of the mission, anyway) As a useless analogy, if Space Aliens came down and ray-gunned all of SETI's equipment, you wouldn't say that SETI's mission would be negatively impacted, would you?

so it's wibbly wobbly timey whimey then? (0)

Anonymous Coward | more than 6 years ago | (#21506849)

(sorry, a little Doctor Who humour there...)

Surfin' Safari (1)

locster (1140121) | more than 6 years ago | (#21506853)

Perhaps a better subject line would've been "Voyager 2 Surfin' the termination shock wave!"

Re:Surfin' Safari (1)

sconeu (64226) | more than 6 years ago | (#21507371)

Maybe that means the Voyager will come up with a new Theory of Everything?

back to the future (1)

192939495969798999 (58312) | more than 6 years ago | (#21506857)

Does it travel back in time/come out the other side/anything else cool, or is it just like hitting a bug on the windshield? News at 11.

Re:back to the future (1)

HTH NE1 (675604) | more than 6 years ago | (#21507015)

Maybe it receives super ESP powers, creation of matter, exertion of force at a distance, every mental god-like power except for being able to correctly guess someone's middle initial.

The Sky is Falling! (0, Interesting)

Anonymous Coward | more than 6 years ago | (#21506859)

Interesting that the sun can have variation 8 billion miles away, with its power "fluctuating in both time and distance" but Global Warming Alarmists will deny that it has any varying influence a mere 93 million miles away on the Earth. Never mind, buy some carbon credits, and we'll all be safe until the next crisis!

Haven't you heard? (0, Redundant)

ebolaZaireRules (987875) | more than 6 years ago | (#21506873)

In space, no one can hear you scream? ... because the speed of sound in space is zero (well, undefined would probably be better)

So apart from it being a long way away, its where space (where there is no sound) is slower than sound (on earth)

?

Completely WRONG (1)

InvisblePinkUnicorn (1126837) | more than 6 years ago | (#21507083)

The speed of sound on earth is about 0.3 km/s. In the interstellar medium, it is tens of km/s.

Re:Completely WRONG (1)

calebt3 (1098475) | more than 6 years ago | (#21507199)

Other posters are saying 100km/s at the termination shock.

It varies (1)

InvisblePinkUnicorn (1126837) | more than 6 years ago | (#21507245)

"Other posters are saying..."

That's only because it's what Wikipedia says. The speed of sound in the interstellar medium depends on the density of the medium, which varies, so it's different everywhere.

Re:Haven't you heard? (1, Informative)

Anonymous Coward | more than 6 years ago | (#21507323)

Uh. That is wrong. The solar wind is a gas plasma, and as such has a defined (though somewhat complicated to work out) speed of sound*. It also fills the space surrounding Sol. It is in effect the "atmosphere" of the Sol star system, however one that itself travels at supersonic speed outward from Sol. The termination shock is where it goes subsonic and becomes pretty much indistinguishable from the interstellar medium, the "atmosphere" of the galaxy. (There is an intergalactic medium too, which is really not dense at all).

* Speed of sound in a material is the speed at which information propagates through collisions between constituent particles. In a supersonic flow, no information can propagate upstream through collisions, the flow just changes weirdly and suddenly at "shocks" (the math works out, honest) - a "sonic boom" is a travelling shock attached to a supersonic aeroplane in a generally subsonic medium sweeping past you.

Will its speed change? (2, Interesting)

schwit1 (797399) | more than 6 years ago | (#21506905)

Now that the tailwind has slowed down.

Re:Will its speed change? (1)

ksalter (1009029) | more than 6 years ago | (#21507021)

Why would that happen? What force is acting against it?

Re:Will its speed change? (0)

Anonymous Coward | more than 6 years ago | (#21507325)

Friction. Space is not a complete vacuum.

Re:Will its speed change? (1)

e4g4 (533831) | more than 6 years ago | (#21507569)

The force of solar wind [wikipedia.org] . It probably has had a negligible impact on the speed of Voyager 2, but its effects are certainly non-zero.

Re:Will its speed change? (0)

Anonymous Coward | more than 6 years ago | (#21507571)

The speed shouldn't change at all. Since the spacecraft is going X kph in some direction anyway, the only thing that crossing a boundary is going to do is slow down the acceleration of the craft, so it will go faster at a slower rate.

Then again, is Voyager riding the solar winds at all? Maybe just a little boost to its speed, but I thought that Voyager set out with an inital push from Earth and then got speed boosts looping around planets and such.

Voyager 2... (5, Funny)

jez9999 (618189) | more than 6 years ago | (#21506915)

There's a Voyager 2?! Oh God no; come back Enterprise, all is forgiven...

Worst. Write up. Ever. (2, Insightful)

Anonymous Coward | more than 6 years ago | (#21506931)

"The boundary of the termination shock is [...] wobbly, fluctuating in both time and distance from the sun"

Are you SURE that it fluctuates in time from the sun, or do you actually mean that it fluctuates (only) in distance from the sun? Then there's this beautiful piece of prose:

"... Voyager 2 will cross the termination shock, the spherical shell around the solar system that marks where the solar wind slows down to subsonic speed. At the termination shock [...] the solar wind is decelerated to less than the speed of sound."

And finally:

"Because of this fluctuation, the spacecraft is also predicted to cross the boundary again in middle 2008."

Ignoring the poor English, care to explain the logic behind this? Surely, going from inside to outside, Voyager 2 will have to cross the boundary an odd number of times? Ladies and gentlemen, I suggest that this is worst article EVAR on slashdot. I rest my case.

Re:Worst. Write up. Ever. (1)

DigitalReverend (901909) | more than 6 years ago | (#21507219)

I don't understand how this was moderated a troll. You are absolutely correct on every point. I wish my moderator points were active today, I'd at least try to get you back to 0.

Re:Worst. Write up. Ever. (1)

Kohath (38547) | more than 6 years ago | (#21507345)

Surely, going from inside to outside, Voyager 2 will have to cross the boundary an odd number of times?

I was going to ask this same question.

I wonder what's wrong with the mods who moderated you down?

Re:Worst. Write up. Ever. (1)

ChinggisK (1133009) | more than 6 years ago | (#21507399)

Ladies and gentlemen, I suggest that this is worst article EVAR on slashdot.
Obviously you didn't see the article earlier today about how the House of Reps has declared the internet to be a terrorist threat. [slashdot.org]

Maybe... (4, Interesting)

Dan East (318230) | more than 6 years ago | (#21506957)

Anyone else notice the related stories on the news site?
Nov. 6, 2003: Voyager Spacecraft Approaches Solar System's Final Frontier
Dec. 19, 2000: Most Distant Spacecraft May Reach Shock Zone Soon
May 25, 2005: Voyager Spacecraft Enters Solar System's Final Frontier

Besides the speculation, will we even know when the boundary is crossed? Do they expect data to indicate a transition, or do we even know if the instruments can detect such a thing?

Dan East

Re:Maybe... (5, Funny)

Galaga88 (148206) | more than 6 years ago | (#21507059)

Much like killing Rasputin, leaving the Solar System is apparently an ongoing process marked by significant milestones.

Re:Maybe... (1)

igotmybfg (525391) | more than 6 years ago | (#21507159)

I didn't look up those articles, but it's plausible that some of them may be talking about Voyager I, which apparently passed termination shock in 2004. In any case, the termination shock's distance from the sun varies from 75 to 90 AU, depending on solar activity, which is why some are predicting that Voyager II will re-encounter the boundary in 2008 (and possibly beyond).

My solar system, let me show it to you... (4, Interesting)

rucs_hack (784150) | more than 6 years ago | (#21507297)

Want to see the actual orbital trajectories of the Voyager probes for yourself in 3d type of thing? Because you can, if you use my nBody modeling software.

If you go here:

http://code.google.com/p/nmod/downloads/list [google.com]

and get the windows installer or linux source for my nbody modeling kit, and then download this:

http://www.politespider.com/nbo/time_series.zip [politespider.com]

And unzip it to save you the bother of having to actually generate your own time series (3d time series model of the solar system), which can take a while. You can then watch both Voyager probes follow their orbits (with 24th august 2006 as their starting date), for 20,000 days of travel time.

This isn't a program with a scrummy easy interface I'm afraid, the viewer is console opengl. But there are instructions here:

http://code.google.com/p/nmod/wiki/nbview [google.com]

And it's not too hard once you get the hang of it.

The orbits do not take termination shock into account, this is pure Newtonian motion. The dataset for the solar system has taken months to put together. It's incomplete, It only has our moon (zoom in for ages with Earth centred and you'll see it), the others have been tricky to get right.

Re:Maybe... (1)

Ruie (30480) | more than 6 years ago | (#21507329)

Besides the speculation, will we even know when the boundary is crossed? Do they expect data to indicate a transition, or do we even know if the instruments can detect such a thing?

Yes. They are still receiving telemetry from both spacecraft (Voyagers I and II) indicating plasma density, strength of magnetic fields and some other data that I forget.

We already are quite accurate (4, Informative)

junglee_iitk (651040) | more than 6 years ago | (#21507443)

What you are refering to is Voyager 1. TFA is about Voyager 2. They are two different vehicles.

<wikipedia href="Heliosphere">
Evidence presented at a meeting of the American Geophysical Union in May 2005 by Dr. Ed Stone suggests that the Voyager 1 spacecraft passed termination shock in December 2004, when it was about 94 AU from the sun, by virtue of the change in magnetic readings taken from the craft. In contrast, Voyager 2 began detecting returning particles when it was only 76 AU from the sun, in May 2006. This implies that the heliosphere may be irregularly shaped, bulging outwards in the sun's northern hemisphere and pushed inward in the south.
</wikipedia>

Re:Maybe... (4, Funny)

ghostlibrary (450718) | more than 6 years ago | (#21507449)

Yep, Voyager has approached the theoretical location of the termination shock often-- and each time, we get to revise our theories and have a better understanding of just how interesting our sun is. The joke among solar physicists is: "Where is the termination shock?" 'Just past Voyager.'

Re:Maybe... (2, Informative)

imnojezus (783734) | more than 6 years ago | (#21507651)

Those articles all refer to Voyager 1. This one is about Voyager 2

Re:Maybe... (1)

januth (1000892) | more than 6 years ago | (#21507659)

If you look closely you'll see that those items refer to Voyager 1 not Voyager 2. Voyager 2 is on a different trajectory and will encounter the termination shock under a different set of circumstances.

And what effect will this have? (1)

FirstTimeCaller (521493) | more than 6 years ago | (#21507071)

I would expect that something called "Termination Shock" would have some dramatic effect on an object crossing it. Is this the case? It doesn't sound like it based on what I read. Sounds like a more appropriate name would be "Subsonic Solar Wind Boundary". But what fun is that?

Re:And what effect will this have? (1)

Dr. Eggman (932300) | more than 6 years ago | (#21507579)

The mechanics definition of a shock is a sudden acceleration/deceleration. It's the sudden stop that kills you in the end of a fall; it's the pressure in the nuclear explosion that bowls over everything. As for termination, I suppose substituting 'Solar wind' would make it a bit clearer. But, termination tends to indicate an end to things, and placed with 'shock' sounds to indicate a boundary of sudden deceleration, where as 'solar wind shock' sounds more ambiguous, in an ironic sort of way.

finally a use for for seti telescopes: (2, Funny)

andreyvul (1176115) | more than 6 years ago | (#21507091)

they will be used to get data from voyager 2 on conditions at the edge of the solar system

however, a wobbly spacetime continuum means that voyager 2 must be running linux
because the wobbly spacetime is an infinite loop, only linux can escape it in 5 seconds
but time at the termination shock is slow enough that 5 seconds will be 2 years

Over The Horizon Stuff (1)

blueZhift (652272) | more than 6 years ago | (#21507151)

This is pure, over the horizon, is the earth round or flat, kind of stuff. While no one is expecting anything extraordinary, you never really know until you go and look.

avoid repetitive redundancy (0)

Anonymous Coward | more than 6 years ago | (#21507277)

...will cross the termination shock, the spherical shell
    around the solar system that marks where the solar wind
    slows down to subsonic speed. At the termination shock,
    located at 7-8.5 billion miles from the sun, the solar
    wind is decelerated to less than the speed of sound.

repeat repeat after after me me

There's nothing there... (1)

Myria (562655) | more than 6 years ago | (#21507321)

Once it gets there and crossing is a non-event, we will see that there is nothing of interest out there. Voyager 2 is just crossing into vast, bleak nothingness.

Re:There's nothing there... (1)

gstoddart (321705) | more than 6 years ago | (#21507521)

Once it gets there and crossing is a non-event, we will see that there is nothing of interest out there. Voyager 2 is just crossing into vast, bleak nothingness.

Even if nothing cool or dramatic happens, this isn't a non-event.

This will be the furthest we've ever flung an object from our planet. The milestone may be more symbolic than anything, but this is actually rather impressive.

Cheers

Re:There's nothing there... (0)

Anonymous Coward | more than 6 years ago | (#21507581)

Wow.
I thought about this statement for a while and had this brief but intense sadness for that little twist of metal. Some David Bowie lyrics came to mind as I pictured that inky void, that abyss approaching. Bleak, indeed.

 

hrm... (2, Funny)

spottedkangaroo (451692) | more than 6 years ago | (#21507391)

What is the speed of sound in a vacuum? Kinda existential...

The edge of... (4, Funny)

infodude (48434) | more than 6 years ago | (#21507395)

It's going to reach the edge of the simulation, where it'll get rendered in lower resolution.

next step: interstellar probe (1)

ceroklis (1083863) | more than 6 years ago | (#21507423)

I am looking forward to the interstellar probe [nasa.gov] mission, which is specifically designed to explore the interstellar medium.

Unfortunately it will probably not happen in my lifetime, unless we stop putting in charge of the budget people who think that a talk between a teacher in LEO and school-children on earth is more "inspiring" than fundamental research.

...and then... (2, Funny)

Sebastopol (189276) | more than 6 years ago | (#21507541)

...it will land with a "kerPLUNK!" into a half full goblet of mead at the foot of Zeus.

The speed of sound (0, Redundant)

SCHecklerX (229973) | more than 6 years ago | (#21507587)

what?

The speed of sound is different depending on the medium. The speed of sound where? (I didn't RTFA, just pointing out the lameness of the summary). Usually, when you talk about the speed of sound, it is relative to the density where you are observing your speed. So in space, having the solar wind be less than that (~0), does it then bounce back? :-)

Obvious question... (0, Redundant)

pottymouth (61296) | more than 6 years ago | (#21507609)



Ehhhh, how fast does sound travel in space again.....?

Congrats to Humanity (1)

Jtheletter (686279) | more than 6 years ago | (#21507723)

We will soon be intergalactic litterbugs.
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