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Mystery Force Affecting Probes

michael posted more than 13 years ago | from the VGER-awakening? dept.

Space 296

imipak writes: "The BBC reports that after exchaustive investigations, NASA scientists have run out of possible explanations for the mysterious tiny course deflections experienced by the Pioneer and Voyager spacecraft as they head out of the solar system towards the heliopause. Could it be that there's something wrong with our theory of gravity? (Well, yes, we already know that...) or could it be Oort Cloud objects? The tenth planet? Informed comment, please!"

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Informed Comment (5)

Anonymous Coward | more than 13 years ago | (#220988)

So, let me get this straight. NASA has given up trying to explain this, they have no idea. So for informed comments, now we turn to ...

Slashdot Readers

Hurrah! Please explain it for me, guys. I have a friend at NASA who would really like to know.

Re:Another Possibility (1)

Proteus (1926) | more than 13 years ago | (#220998)

There exists the possibility that, if alien intelligence exists, they may not be able to do the things you describe.

Also, establishing direct contact with a race (humans) who have a long history of violent reactions to the unknown would be unwise. Perhaps "they" are testing the waters? Or testing our level of sophistication?

--

Another Possibility (2)

Proteus (1926) | more than 13 years ago | (#220999)

Though I'm on the fence about the probability, there is, I suppose, the possibility of intelligent influence as well. Since NASA has no explanation, it might very well be worth considering that an extraterrestrial entity could be responsible.


After all, what better way to make contact than to cause an unexplainable error? We'd be sure to notice it!

--

+1 Funny? (1)

waldoj (8229) | more than 13 years ago | (#221006)

A slap with a wet salmon to whatever fool modded this up as "Funny."

-Waldo

Springfield Effect (2)

mattkime (8466) | more than 13 years ago | (#221007)

Clearly, this is due to the Springfield Effect [flat-earth.org] . They have simply passed through new, undiscovered Springfield locations.

Mr. Teapot [flat-earth.org] can answer all your questions.

Re:Invasion of The Mind Snatchers (2)

ansible (9585) | more than 13 years ago | (#221008)

There is a cult within the spacetime physics community led by a small but influential cadre of nerd physicists and mathematicians whose credo is "physics is math" and who think they are free to create physics simply by manipulating spacetime equations using what-if scenarios.

LOL! That reminds me of Logopolis episode of Dr. Who. This was where the Doctor and the Master visited this city where these people run "block transfer computations" which control reality.

Probably not an unseen body's gravity. (2)

Wayfarer (10793) | more than 13 years ago | (#221011)

As the article states, both Pioneer 11 and Pioneer 10, on opposite sides of the Solar System, are experiencing the same effect, which rules out local gravitational effects.

Oddly enough, it also seems that this deviation is not evident in the orbits of the planets.

Me? I just think that they've been slowed by local debris--though I'd like to believe in a gravitational constant.

-W-

"Is it all journey, or is there landfall?"

Re:Just shows how much more there is than we know (2)

SteveM (11242) | more than 13 years ago | (#221013)

A few comments above we have, "So, let me get this straight. NASA has given up trying to explain this, they have no idea. So for informed comments, now we turn to ... Slashdot Readers Hurrah! Please explain it for me, guys. I have a friend at NASA who would really like to know.

I thought it was funny (so did several moderators).

And now we get this obvious troll, and it is moderated as insightful.

Not so funny anymore.

Steve M

Funny? (2)

SteveM (11242) | more than 13 years ago | (#221014)

Its funny (or sad) not flamebait!

Well it sure ain't funny. It may be a sad attempt at humor.

But I'm going with flamebait.

Steve M

Probe instrumentation is adequate. (2)

Christopher Thomas (11717) | more than 13 years ago | (#221018)

Sorry but I don't think the instrumentation on these probes really is advanced enough to gather what is needed to make an accurate or informed decision.

How so?

To start with, the main data of interest (probe positions and trajectories) doesn't require additional instruments to measure. They're looking at the timing and doppler-shifting of the probes' radio signals, and getting a very good estimate of their positions and velocities.

The record of the probes' trajectories over long periods of time is what suggests the effect and places limits on how it acts.

Secondly, there isn't anything *out* there to look at. At least a few of these probes have micrometeorite detectors and dust analyzers and radiation analyzers. That covers just about everything you'll run into. What extra instrumentation do you propose to add?

What kinds of instruments do you think would give us a better idea of what's going on than we already have?

Re:Could this be the "missing mass" explanation? (5)

Christopher Thomas (11717) | more than 13 years ago | (#221021)

If they're slowing as they get very far from the Sun, that seems to imply that the force of gravity is not dropping of quite as fast as 1/r^2.

The problem is, as the article points out, we would have seen the effects of this on the orbits of the planets if this was the case.

I'm personally wondering about drift in the probes' radio sources throwing off the doppler measurements, but if this was happening they should have caught it already (you can directly measure the probes' positions by measuring the round-trip signal times to them at a few different imes during the year).

Duh.. (2)

RAruler (11862) | more than 13 years ago | (#221022)

Informed comment, please!

Bullshit, informed? how do you know it's not a bunch of flying winged monkeys. Theories are only slightly better than guesses. Besides, Slashdot isn't exactly the best place to go for people knowledagable in the physics of bodies moving through uncharted portions of space. If you really want informed opinions, try and berate the people at NASA and JPL. Slashdot is more of a jack-of-all-trades thing, theres probably someone with the background similar to Stephen Hawking on here. But the only thing they can offer you is, their opinions and theories. Again, not necessarily better than my theory of tiny space going simians.

---

Re:Just shows how much more there is than we know (3)

nyet (19118) | more than 13 years ago | (#221035)

I am extremely offended at your attitude. My father spent the last years of his life _skeptically_ examining all the evidence gathered throughout the THIRTY years the pioneer probes were operational.

The fact that you can sit in your armchair and question his objectivity, wonder, and *passion* for the mysteries of life makes me physically ill.

Any failing of science is OUR fault. OUR faliere to educate. OUR faliure to recognize our biases. OUR faliures to drag concieted shits like you out of the dark ages.

Re:The Paper is here (5)

nyet (19118) | more than 13 years ago | (#221036)

My (recently deceased) dad is on that paper.. he believed that it was most probably (b) (outgassing of some sort, possibly a malfunction/weakness common to both pioneer probes). No real evidence of that of course, and a "mysterious" force is more publishable ;) Still it is very spooky.

(g) and (h) were (in his opinion) the least likely.

Note that the paper was actually first released in April, and just revised today.

Stellar gas? (5)

KFury (19522) | more than 13 years ago | (#221038)

Could it be that there's just more mass in the solar system than we think? Wait, hear me out. I'm not talking about Planet X or a bloated G, I'm talking about ambient stellar gas.

Here's the deal: On the Earth, the gravitatinal forces acting on you at the surface all sum out to equal to the forces that would be exerted by a point source with the Earth's mass and a distance r, the diameter of the Earth. Though that ocean to your left and that continent to your right pull you in opposite directions, and the ground under your feet is pulling harder than the ground in China (um, unless you're in China, in which case, 'hi'), but it all sums out exactly right to a point mass at radius r.

Now, take that example and pose it to the solar system. Forget about the forc of solar wind blowing, and realize that all that wind has mass, and exists everywhere. It's pretty thin, but it's a lot thicker than the four hydrogen atoms per cubic meter in deep interstellar space. All that stuff, wispy as it is, has mass, and even though most of it is so godawful far away, the net gravitational effect of all of it is as if there were an additional point source inside the sun, with the mass of all the stray gasses and particles inside the huge sphere that has the sun as the center and the space probe on the outer surface.

What makes the math even more wonky is that, assuming a roughly even distribution of gas as inversely proportional (or inverse square, or even constant, doesn't matter in this case as long as it's uniform by uniform radius) to the distance form the sun, then the farther out the probe goes, the more mass there is behind it, and the farther back the point source goes.

If the density were uniform (it's not) then the effect of this force would actually increase as the probe got further away. As it is, it may be a constant force. For conceptualization's sake, if you had a well to the center of the earth and went to the bottom (forget magma, use the moon if it makes you feel better) you'd be weightless. Go halfway up, and you'd have a force of one-half g. Go to the surface and you are being pulled with a stronger force than you were when you were closer to the center.

Anyhow, HTML's bad for math, but I just wanted to get the idea out there. I don't have enough info on particulate density over the scope of the solar system and beyond to make any educated numbers anyhow. Hopefully someone out there does.

Kevin Fox
--

Re:Another Possibility (1)

SEWilco (27983) | more than 13 years ago | (#221041)

If spacefaring aliens wanted to contact us, they could put Pioneer 10 on The Mall outside the National Air & Space Museum, with the gold-coated greeting record in a suitable player.

But that would spoil the fun, wouldn't it?

Interstellar Medium Density? (3)

SEWilco (27983) | more than 13 years ago | (#221044)

As the article says, four probes in different directions are showing this behavior so this is probably not due to an unknown planet.

The interstellar medium (interstellar gas & dust) is much less dense than normal around our solar system due to the Scorpius-Centaurus Association superbubble [uchicago.edu] and the Geminga supernova bubble [lanl.gov] . Perhaps we're seeing a slight increase in the ISM density -- of course these researchers should know all about this, so it's still a puzzle...

Approximations (2)

spectecjr (31235) | more than 13 years ago | (#221046)

A hundred years ago, an unexplained force seemed to be affecting the orbit of Mercury, causing a wobble in its orbit that should not have existed in a Newtonian framework. Then in 1915, Albert Einstein developed the theory of General Relativity, describing the complex curvatures of our universe that could explain Mercury's path around the Sun.

You know... a lot of these problems occur when you take an approximation instead of the real thing.

Eg. Newton's laws are a 1st order approximation to the real thing.

Relativity gets closer.

Now, I can't remember the specifics, but the general equations we use when utilizing relativistic motion are actually still only approximations -- it's just that the third, fourth, etc. order terms of the equation are so small that you can ignore them.

The thing is - what happens over large distances? Well, the smaller terms will start to become very important. I've got to wonder if they forgot that the equations they'll typically use ARE approximations which are simplified for ease of use in calculations?

Simon

Re:Could this be the "missing mass" explanation? (1)

Mike Van Pelt (32582) | more than 13 years ago | (#221048)

But if the effect doesn't show up until somewhere past Pluto's orbit... (I know the probes aren't yet beyond Pluto's apehelion... but there's still an unexplained anomaly in Pluto's orbit, isn't there? And we haven't observed Pluto for a full orbit yet.)

Could this be the "missing mass" explanation? (3)

Mike Van Pelt (32582) | more than 13 years ago | (#221049)

If they're slowing as they get very far from the Sun, that seems to imply that the force of gravity is not dropping of quite as fast as 1/r^2. If the strength of gravity is higher than inverse square and great distances, perhaps that effect would explain the "missing mass" problem? There isn't really any missing mass. This effect makes it look like the galaxies are more massive than they really are.

An Explanation (5)

Mignon (34109) | more than 13 years ago | (#221052)

I have found a truly marvelous explanation, which this input field is too small to contain.

--Fermat

Re:The Paper is here (1)

legoboy (39651) | more than 13 years ago | (#221055)

Wind, on a galactic scale, is my loony guess.

--

Magnetism? (1)

ender- (42944) | more than 13 years ago | (#221057)

Ok, I know nothing about this sort of thing, but...

Could it be a long term affect of magnetism? If the metal of the probes are reacting to the solar systems magnetic fields, wouldn't it possibly show up with the same symptoms[slowing down]? I'd think it would show this over long periods if the probe was being magnetically pulled back towards the solar system. But I'm not sure how far out the sun's magnetic field goes, or if there is a larger [if fainter] magnetic field based around the entire solar system.

Just a thought...

Ender

Informed Comment (2)

Sogol (43574) | more than 13 years ago | (#221060)

NASA scientists have run out of explanations, but we're going to figure it out. Right here on Slashdot.

Re:As every fan of McElwaine knows... (1)

Owen Lynn (46218) | more than 13 years ago | (#221061)

Heh heh heh,

But your obscure reference to the glory days of Usenet just whizzed over the heads of 95% of the Slashdot crowd - most of them aren't old enough to remember those times.

Gravity doesn't exist (1)

darkonc (47285) | more than 13 years ago | (#221063)

The universe just sucks.
(sorry)
--

Niven readers have understood this for decades (3)

devphil (51341) | more than 13 years ago | (#221065)


It's Protector Brennan, making slight alternations to make certain that the probes don't eventually travel to planets with possibly-hostile alien species, thereby alerting them to the existence of humans.

Re:They need better instruments, then they might b (2)

QuoteMstr (55051) | more than 13 years ago | (#221067)

The probles don't *need* to be sophisticated. It's sufficient to use the doppler effect of the radio signals from the spacecraft to determine the speed of the craft, and the position can be determined by simple position in the sky. Distance can be determinedby delay between send and receive, which can be measured.

Re:Niven readers have understood this for decades (2)

Evil Pete (73279) | more than 13 years ago | (#221082)

And wasn't it Niven who asserted that humans didn't discover FTL because they did all their experiments in a gravity well and so didn't realise that the laws of physics were slightly different outside the solar system .... so they had to buy the technology from the Outsiders. He he he.

Peter

Re:The Paper is here (3)

selectspec (74651) | more than 13 years ago | (#221083)

New Physics Theory Highlights:

Due to the fact that the size of the anomalous acceleration is of order cH, whereH is the Hubble
constant (see Eq. (56)), the Pioneer results have stimulated a number of new physics suggestions.
For example, Rosales and S anchez-Gomez [136] propose that aP is due to a local curvature in
light geodesics in the expanding spacetime universe. They argue that the Pioneer eect represents
a new cosmological Foucault experiment, since the solar system coordinates are not true inertial
coordinates with respect to the expansion of the universe. Therefore, the Pioneers are mimicking
the role that the rotating Earth plays in Foucault's experiment. Therefore, in this picture the
eect is not a \true physical eect" and a coordinate transformation to the co-moving cosmological
coordinate frame would entirely remove the Pioneer eect.
From a similar viewpoint, Guruprasad [137] nds accommodation for the constant term while
trying to explain the annual term as a tidal eect on the physical structure of the spacecraft
itself. In particular, he suggests that the deformations of the physical structure of the spacecraft
(due to external factors such as the eective solar and galactic tidal forces) combined with the
spin of the spacecraft are directly responsible for the detected annual anomaly. Moreover, he
proposes a hypothesis of the planetary Hubble's ow and suggests that Pioneer's anomaly does
not contradict the existing planetary data, but supports his new theory of relativistically elastic
space-time.
stvang [138] further exploits the fact that the gravitational eld of the solar system is
not static with respect to the cosmic expansion. He does note, however, that in order to be
acceptable, any non-standard explanation of the eect should follow from a general theoretical
framework. Even so, stvang still presents quite a radical model. This model advocates the use
of an expanded PPN-framework that includes a direct eect on local scales due to the cosmic
space-time expansion.
Belayev [139] considers a Kaluza-Klein model in 5 dimensions with a time-varying scale factor
for the compactied fth dimension. His comprehensive analysis led to the conclusion that a
variation of the physical constants on a cosmic time scale is responsible for the appearance of the
anomalous acceleration observed in the Pioneer 10/11 tracking data.
Modanese [140] considers the eect of a scale-dependent cosmological term in the gravitational
action. It turns out that, even in the case of a static spherically-symmetric source, the external
solution of his modied gravitational eld equations contains a non-Schwartzschild-like component
that depends on the size of the test particles. He argues that this additional term may be relevant
to the observed anomaly.
A proposal to modify the theory of gravity in order to provide an explanation of the Pioneer
anomaly has also appeared. Capozzielo et al. [141] discuss the possibility of determining the
stability and characteristic geometrical and kinematical properties of galaxies strictly based on a
minimal action whose value is on the order of the Plank constant.

Due to the fact that the size of the anomalous acceleration is of order cH, whereH is the Hubble
constant (see Eq. (56)), the Pioneer results have stimulated a number of new physics suggestions.
For example, Rosales and S anchez-Gomez [136] propose that aP is due to a local curvature in
light geodesics in the expanding spacetime universe. They argue that the Pioneer eect represents
a new cosmological Foucault experiment, since the solar system coordinates are not true inertial
coordinates with respect to the expansion of the universe. Therefore, the Pioneers are mimicking
the role that the rotating Earth plays in Foucault's experiment. Therefore, in this picture the
eect is not a \true physical eect" and a coordinate transformation to the co-moving cosmological
coordinate frame would entirely remove the Pioneer eect.
From a similar viewpoint, Guruprasad [137] nds accommodation for the constant term while
trying to explain the annual term as a tidal eect on the physical structure of the spacecraft
itself. In particular, he suggests that the deformations of the physical structure of the spacecraft
(due to external factors such as the eective solar and galactic tidal forces) combined with the
spin of the spacecraft are directly responsible for the detected annual anomaly. Moreover, he
proposes a hypothesis of the planetary Hubble's ow and suggests that Pioneer's anomaly does
not contradict the existing planetary data, but supports his new theory of relativistically elastic
space-time.
stvang [138] further exploits the fact that the gravitational eld of the solar system is
not static with respect to the cosmic expansion. He does note, however, that in order to be
acceptable, any non-standard explanation of the eect should follow from a general theoretical
framework. Even so, stvang still presents quite a radical model. This model advocates the use
of an expanded PPN-framework that includes a direct eect on local scales due to the cosmic
space-time expansion.
Belayev [139] considers a Kaluza-Klein model in 5 dimensions with a time-varying scale factor
for the compactied fth dimension. His comprehensive analysis led to the conclusion that a
variation of the physical constants on a cosmic time scale is responsible for the appearance of the
anomalous acceleration observed in the Pioneer 10/11 tracking data.
Modanese [140] considers the eect of a scale-dependent cosmological term in the gravitational
action. It turns out that, even in the case of a static spherically-symmetric source, the external
solution of his modied gravitational eld equations contains a non-Schwartzschild-like component
that depends on the size of the test particles. He argues that this additional term may be relevant
to the observed anomaly.
A proposal to modify the theory of gravity in order to provide an explanation of the Pioneer
anomaly has also appeared. Capozzielo et al. [141] discuss the possibility of determining the
stability and characteristic geometrical and kinematical properties of galaxies strictly based on a
minimal action whose value is on the order of the Plank constant.

Re:Informed Comment (5)

selectspec (74651) | more than 13 years ago | (#221084)

Bill Gates dark life force is clearly sucking the energy out of these scientific projects. We must remember that these spacecraft have been an endevour of science and that the scientific process has often been linked as an inspiration for Open Source. Need to paint a picture people? Of course, the Gates-Effect doesnt bother the planets. I'm still trying to figure out the Intel angle, but I suspect they might be involved too.

maybe the probe is going straight (1)

chinakow (83588) | more than 13 years ago | (#221086)

Is it possible that the whole solar system is moving away from a fixed point and the probe is actually traveling a straight line which makes it appear to be moving off course?





Jon

Mystery forces ... (1)

JoeGee (85189) | more than 13 years ago | (#221087)

All we need to do is look the way the universe is expanding to realize that something is amiss in our understanding of the forces that interact with gravity.

It's not a major shock to see that we do not have a perfect grasp of our outer solar system. For all of our cleverness the past century we are still a young species, and there are quite a lot of things that we just don't know. Something in the outer solar system has to be disturbing the Oort cloud every once in a while or we would exhausted our supply of new comets a few billion years ago.

Perhaps negative energy somehow interacts with gravity wells to clump matter, like drops of water on an oil slick? Maybe if the politicians ever get their heads out of their rear ends and start investing in further development of space we can scrape together enough money to send a probe to find out what's going on.

We might even learn something in the process.

Re:Just shows how much more there is than we know (2)

nublord (88026) | more than 13 years ago | (#221093)

though science destroys wonder by replacing it with understanding

Naah. Sounds like you simply lost your ability to let your imagination run free.

Science Baffled by extraterrestrial intelligence (2)

BierGuzzl (92635) | more than 13 years ago | (#221096)

The problem with NASA's calculations is that they all involve objects in space that are either drifting or in some sort of orbit,etc -- but they haven't taken into account other space craft that would be wizzing by along the way. In fact, if one of our little probes were to pass close enough to a large transport, it may well get slingshotted not just out of it's course path, but to places completely unfathomed by our dear NASA engineers.

My 2 bit informed comment. (2)

BierGuzzl (92635) | more than 13 years ago | (#221097)

I was visited by a little green man last night who promised to tell me all the secrets of the universe for a buck and a quarter. I told him all I had was two bits, to which he replied that he'd only be able to tell me why our space probes aren't sticking to their projected paths. I took note of his advice, but can't say that I believed much of what he told me. I was just about to shred the notes that I took, lest they be discovered in my posession and I be taken for a lunatic, possibly even a danger to our society as we know it. I will have to weigh further what to do with this transcripts, .... damn, I spilled coffee all over them! ..nevermind.

Re:Just shows how much more there is than we know (5)

SIGFPE (97527) | more than 13 years ago | (#221104)

Let us spread this failing of science everywhere, so that we can regain our childhood sense of wonder and expose the necessary failing of science.
A failure to explain a phenomenon isn't a failure of science. It's the opposite. It's what every scientist dreams of. Finding a disagreement between observed reality and theory is what the most exciting science is about.

I'm not sure what planet you're on because you seem to be trying to write an anti-science diatribe and yet much of what you say is no different from the view of a scientist.

--

The map is not the territory (2)

Jart (100459) | more than 13 years ago | (#221108)

Pardon my doofyness but a certain piece of obviousness is just begging to be laid out. Theories are like lossy data compression: You never get a perfect rendition. In fact, if "reality" could be said to contain an infinite amount of information everywhere (I mean, what sets the resolution of a definition, some mythical objective reality or simple satisfaction? How many words are enough?) then any theory made about it must always be infinitely deranged. So mysteries, while easily ignored-to-forgetting from the comfort of your livingroom/office/customary-groove (in fact one might say that an act of intentional ignorance is the bedrock underlying any useful theory. Ignoring the irrelavent.), should be considered the norm to a degree proportional to your elsewhereness.

Tractor beams (1)

SmokeSerpent (106200) | more than 13 years ago | (#221109)

But seriously, I want to see an actual point-by-point calculation accounting for radiation pressure, gas leaks, and all that before I'll imagine something affecting our space probes that doesn't affect the planets.

What about all the photons (radio waves) we've been sending back and forth between the Earth and the probes, that's got to add up at least a tiny bit.

Re:Oh no... (1)

KingAdrock (115014) | more than 13 years ago | (#221115)

A quick search of google produces 0 results for "Elquibre drive"

Re:The Paper is here (2)

StevenMaurer (115071) | more than 13 years ago | (#221116)

Funny, they didn't include my first thought on what might be causing it: (i) our understanding of the heleopause is incorrect.

It may be that the heleosheath is not a hard boundary, but rather has a mix of both solar winds and interstellar gasses for a much wider region than is presently thought. In other words, it could be that there is no true heleopause at all. If that was the case, our little space probes could have been heading "upwind" against largely stagnant gasses for some time now, slowing them.

Of course I have absolutely no evidence for this, but it is a missing hypothesis.

assumptions about gravity (4)

Argylengineotis (118734) | more than 13 years ago | (#221121)

There is no reason to suppose gravity gradients are even across large distances (>20 A.U.) If you pour over your references, you'll see that at no point, from the General Theory on up, does any theorist take into account the possibility that between strong influences (astral bodies), spacetime must be smooth. in fact, it is perfectly reasonable to suppose that there are variations large enough to account for these variances in trajectory. The universe is not beholden to your 'rubber sheets and marbles' analogy for gravity.

Oort Cloud Object most likely (1)

Code Archeologist (128429) | more than 13 years ago | (#221128)

Something that must be taken into account with these phenomena is that the pull of gravity from the sun and the planets is negligible out where these two probes are. And since neither of these probes are all that massive themselves small 1-2 ton objects massing within 10,000 km of the probe would cause its course to alter slightly. The closer it comes to one of these objects the larger the deflection of its course. And the probes probably do not have the instrumentation sensitive enough to be able to detect these 1-2 ton masses that it passes near.

I think: (1)

ssimpson (133662) | more than 13 years ago | (#221130)

For god sake Jim, I DON'T HAVE THE POWER!

Re:The Paper is here (1)

efuseekay (138418) | more than 13 years ago | (#221133)

(e) is my favourite. Not that it works of course. I just happen to be working on funny gravity stuff.

Sigh.Where are the troll-bashers when you need 'em (1)

efuseekay (138418) | more than 13 years ago | (#221134)

nuff said.

Re:Some possibilities... (3)

efuseekay (138418) | more than 13 years ago | (#221135)

(1) What you described is called "vacuum energy", and is actually one of the suspects. However, current physics has a problem : the predicted vacuum energy is 10^(120) (that's 1 followed by 120 zeroes) larger than the actual measured vacuum energy (called the cosmological constant by some people). With respect to the Pioneer 10 acceleration, the predicted VE will be too big, the measured VE will be too small.

(2) Not likely. Small things can theoretical deflect the probe. However you run into two showstoppers (i) things are too small to make any difference (ii) the things will deflect the probe, averaged out, in an "isotropic" way (what this means is that, on average, there will be no net deflection).

(3) Possible. But this uneven distribution will be detected long before. It's discussed in the paper that I listed in another post here. The punchline is that such things will also cost deflection of the planets, and we don't see that.

Hope this helps.

The Paper is here (5)

efuseekay (138418) | more than 13 years ago | (#221136)

Check out the JPL final paper [lanl.gov] on this.

Possibles are :
(a) Heat Ejection (b) Gas Leak (c) Clock Drift (d) Anomalous objects (pretty dead, despite BBC giving prominence) (e) modifications to gravity (f) solar radiation pressure (g) systematics of observations (h) antenna radiation pressure

Let the armchair speculation begin. (But remember to read the paper to check your answers!) Have Fun!

You forgot about cancer. (2)

MongooseCN (139203) | more than 13 years ago | (#221137)

Screw what's affecting space probes that NASA can't figure out, how about some informed comments on a cure for cancer? Clearly there's a slashdotter somewhere just waiting to spill out the answer to that if you just ask.

Re:Another Possibility (1)

seaker (141236) | more than 13 years ago | (#221140)

what better way to make contact than to cause an unexplainable error

I would have said a better way was to send a direct signal or even turn up in person. Certainly something better than an ambiguous hard to measure, might not be there, drift in probe position.

-----------------------------

Re:They need better instruments, then they might b (2)

seaker (141236) | more than 13 years ago | (#221141)

The measurements are not being made via the instruments on the probes, but rather from measuring the dopper shift of signals from the probes.



-----------------------------

Well maybe... (2)

Salsaman (141471) | more than 13 years ago | (#221142)

Maybe all their calculations were in feet and inches, and all their measurements are in centimeters.

Shape of the universe (5)

rmcgehee (142010) | more than 13 years ago | (#221143)

A hundred years ago, an unexplained force seemed to be affecting the orbit of Mercury, causing a wobble in its orbit that should not have existed in a Newtonian framework. Then in 1915, Albert Einstein developed the theory of General Relativity, describing the complex curvatures of our universe that could explain Mercury's path around the Sun.

While this news report is very likely just a measurement error, we must be reminded that the last time we discovered an error in a celestial body's trajectory we reinvented the notion of the universe.

One of the big open questions of the day is: What is the shape of the universe? Euclidean, hyperbolic, a torus--we aren't sure. It is thought that each of these geometries would profoundly affect an object moving across the universe in a different way. These NASA probes could in a sense be the moving laboratory that we need to understand what exactly our universe looks like.

Robert

http://wso.williams.edu/~rmcgehee [williams.edu]

yeah, right. (1)

lgas (143053) | more than 13 years ago | (#221145)

"Informed comment, please!"

Yeah, right. Ahahahahahahahahahahahahaha

Re:They need better instruments, then they might b (2)

Eloquence (144160) | more than 13 years ago | (#221146)

I don't think the instrumentation on these probes really is advanced enough

Voyager is more advanced than anything that NASA has produced lately. Pathfinder was a joke, not to talk about the failures that followed. It is doubtful whether with "faster, better, cheaper" Goldin in power, NASA would manage to build another Voyager, let alone a more advanced probe. I'm happy that they keep listening to it at all.

But if we get something decent built in the next decades, we might as well send a probe to 550 AU and use the sun as a gravitational lens for SETI. Talk about alien TV stations ..

--

Re:They need better instruments, then they might b (1)

bob_jenkins (144606) | more than 13 years ago | (#221147)

Oh jeesh.

I remember a science fiction story in some anthology that placed a futuristic Disneyworld on Pluto. A reborn finance minister was growing up his new body there, he had temporary gills and it was all oceans and desert islands. It got bombed and the fake sky fell. Nothing vaguely comical about the story.

But you're right. Disneyworld. Pluto. World. Mickey's dog. Bah, I didn't get that for YEARS. Ack what an awful pun.

My Kingdom for some Mod points! (1)

PingXao (153057) | more than 13 years ago | (#221150)

ROTFLMAO! Those damn pussy gnomes. Could this be the same force that has caused my underpants to expand over the last few years?

Ummm, Not Exactly... (1)

PingXao (153057) | more than 13 years ago | (#221151)

Spacetime curvature, in Einstein's theory, is not described as being the cause or the effect of gravity. Rather, the theory postulates that spacetime curvature IS gravity!

You are the weakest link.

Old News (2)

PingXao (153057) | more than 13 years ago | (#221152)

This Bible prophecy [philologos.org] site reported the same thing in 1998. They referenced a Washington Times report. This Space.com story [space.com] reported the same thing in November last year.

Well, I guess the final JPL report is newsworthy.

Note: I don't frequent the online Bible sites, but I knew I had heard this years ago and the referenced site turned up near the top of my Google search!

no, that's not it! (1)

rneches (160120) | more than 13 years ago | (#221153)

That new nothing-but-pork-rines diet is really working for Rosane Bar, so the mass of the Earth-Moon-Rosane system is considerably less than the NASA estimates took into account.

I'm sorry - that was cheap.

--

Re:here's a reason.... (1)

rneches (160120) | more than 13 years ago | (#221154)

No that couldn't be it. The course would be way off course -- the headline would be "Voyager 2 probe crashes into ranch in Texas, kills 3 head of steer." They probably went to the dealership to get the steering aligned, and now they're surprised that the damn thing won't go streight anymore.

--

Gravity is perhaps the least understood force (3)

proxima (165692) | more than 13 years ago | (#221159)

For each of the other 3 forces (weak, strong, electromagnetic), we have discovered a "carrier" particle for that force.

The strong force is carried by particles called "gluons" while the weak force is carried by "weak bosons". The electromagnetic force is carried by "photons". These have been detected in particle accelerators. Scientists have a name for the carrier particle of gravity - "graviton", but it has never been detected - yet.

The strong and weak force have a relatively (no pun intended) limited range. The strong force has a range of only about 1x10^-15 meters. On the other hand, gravity and the electromagnetic force have infinite ranges. Perhaps we're wrong about the gravity force, considering we don't even have a carrier particle. Maybe its strength isn't an inverse squared relationship for infinitely long distances - or it's simply an approximation.

Too bad I don't know nearly enough about experiments testing the gravitational constant and how well we've applied it to extrasolar objects.

Electric Universe (1)

alexgp (173035) | more than 13 years ago | (#221164)

These folks reckon we've got gravity all wrong and that electric fields are dominant.

http://www.holoscience.com [holoscience.com]

Re:Niven readers have understood this for decades (1)

maetenloch (181291) | more than 13 years ago | (#221169)

Using the gravity polarizer, no doubt.

Re:Just shows how much more there is than we know (1)

SgtAaron (181674) | more than 13 years ago | (#221171)

"Lovers Arrival, The" is indeed one of the most highly-rated trolls I've known as a /. reader. Try not to be too offended, it's just that he/she/it is quite good at socially-engineering moderators to give him/her/it points. Truth be told, the post should have been below my threshold, don't know about yours.

Anyway, just remember the guy/gal/thing next time you have moderator points :-)

Informed comment? (3)

Sodium Attack (194559) | more than 13 years ago | (#221177)

Informed comment? On slashdot? Methinks you're looking in the wrong place.

You'll see lots of speculation by people who have no idea what they're talking about, but at least that won't get modded up. You'll also see lots of speculation by people who have a very slight idea of what they're talking about, and even though that speculation is little better, it will get modded up by other people who have a slight idea of what they're talking about, because it sounds plausible.

Maybe a legitimate space scientist or two will post with something that might actually be useful. Maybe--possibly--that will get modded up. More likely it won't, because it will be over most people's heads, or because he came too late to the conversation (say, two days from now) when no one's going to use mod points on the story.

Assuming your characterization of the BBC story is accurate (/.ed, can't get to it right now), and assuming that the BBC story itself is accurate--both of which are nontrivial assumptions--why wouldn't the quoted "NASA scientists" be the informed comment you're looking for? Is anyone here going to give you a better answer than the "we don't know" you got from the NASA scientists?

(Don't mind my ranting, I'm just in an anti-/. mood today.)

Doppler, eh? explain this then.. (1)

The Akond of Swat (205939) | more than 13 years ago | (#221180)

One of the things that cries out in this story is an explanation from the NASA scientists: why their apparent "mystery force" which can be detected on spacecraft a few billion kilometres away is not noticed in Doppler and gravity observations of bodies billions of light-years apart, on the galactic scale.. a new type of force, one that doesn't work on the micrososmic or macrocosmic scale, but sort of "in the middle"? Doppler observations led to the discovery of the expansion of the universe, and since then a very accurate figure for that expansion. Why have no astronomers ever reported such findings? Sorry, but lately whenever I see "NASA scientists" being quoted my heart sinks. They are becoming well known for launching half-baked ideas into the mediasphere (life on Mars, etc.)This looks like another.

hrm... (1)

ageitgey (216346) | more than 13 years ago | (#221187)

Maybe it's that Cadre of Stealth Chickens that keeps forcing me to read this page. They don't call them stealth chickens for nothing.

here's a reason.... (2)

unformed (225214) | more than 13 years ago | (#221192)

"Aye, ye know...it's all due to them damn metric system. Dammit, we used the english system again"
-Daniel S. Goldin, Head of NASA, two weeks later

gravity like magnet (1)

mholt108 (229701) | more than 13 years ago | (#221196)

Lets make no bones about it i am a complete idiot. Having said that maybe there is an effect when an object with mass moves away from a gravity field similar to a conductor moving through a magnetic field. Might be interesting to ....say.....weigh... the space probes to see if they are any heavier. Momentum must be conserved (I think) so maybe with decreased velocity mass has incresed in some way thus messing up calculations.

damn them! (1)

megadodo (236208) | more than 13 years ago | (#221198)

it's those damn british scientists and their tractor beams!

either that or the whole universe is leaning slightly to one side, like a bad pool table

--
Barnaby Mannerings (heh) http://www.wasd.co.uk [wasd.co.uk]

?? Moderation gone haywire ?? (1)

MaxQuordlepleen (236397) | more than 13 years ago | (#221199)

Uh, how is this off-topic? Somewhat funny on-topic humour, posted early on in the thread. +1 funny or at worst +0 ignore...

If I was the guy who moderated this down I'd fear metamod...

The probes are (1)

Bimkins (242641) | more than 13 years ago | (#221201)

being shot at by the Klingons, and they keep missing! (See Star Trek V for details)

They need better instruments, then they might be (2)

Shivetya (243324) | more than 13 years ago | (#221204)

Sorry but I don't think the instrumentation on these probes really is advanced enough to gather what is needed to make an accurate or informed decision.

I would not mind seeing a mission equiped so they could determine what really is out there. In other words, ditch the hardware needed for planetary observations, use the slingshot effects of gravity and get a probe out there pronto.

It would probably be a better use to understand what goes on out there than visit the disney planet.

As every fan of McElwaine knows... (2)

RareHeintz (244414) | more than 13 years ago | (#221205)

It's the Russian COSMOSPHERES! The Russians have had CONTROL OVER GRAVITY since 1965! Even if the NA$A scientists have been kept in the dark by their FA$CI$T MA$TER$, the Russians are sending a clear signal that they have SPACE-BASED GRAVITY WEAPONS that they will turn on the UNITED $TATE$ at the SLIGHTEST PROVOCATION.

This IMPORANT INFORMATION should be DISSEMINATED etc etc...

With apologies to Robert McElwaine, and everyone else.

OK,
- B
--

Maybe it's "The" Force (3)

the real jeezus (246969) | more than 13 years ago | (#221207)

Jedi:"You will alter your course."
Probe:[ continues course ]
Jedi:(under breath) "Oops."
[ Jedi waves hand in front of probe ]
Jedi:"You will alter your course."
[ back on earth... ]
BBC News:"Mystery force tugs distant probes" [bbc.co.uk]


Ewige Blumenkraft!

Re:Informed comment? (2)

imipak (254310) | more than 13 years ago | (#221210)

> Maybe a legitimate space scientist or two will
> post with something that might actually be useful.

Curiously enough, that was exactly what I was hoping . Now that I've finally lain the karma-whore ghost, I'm reading at -1, and, well, it's embarrassing to admit but I've been laughing my arse off.
--

Re:Interstellar Medium Density? (2)

imipak (254310) | more than 13 years ago | (#221211)

IIRC, some ground-breaking automated surveys going on at present are producing three dimensional maps of our local galactic environment (the SMC and LMC, local group etc), and that they're finding 'stuff' (objects, phenomena) that weren't previously known. Could any such things produce a systematic error in the observations that set currently accepted values for physical constants?
--

Re:The Paper is here (4)

imipak (254310) | more than 13 years ago | (#221213)

Right. Thans for the link.

Sod's law suggests that it's 99% likely to be one of (a|b|c|d|g|h). However, astronomers and physicists are generally rather good at methodically excluding likely explanations, starting with the least unlikely, until all that's left, however unlikely,..

We know that, at some level, the standard model is inconsistent - quantum physics and relativity are mutually incompatible. One tantalising observation for which there's no generally accepted explanation is that gravity is many, many orders of magnitude less powerful than the other fundamental forces.

I'd love ot believe that this phenomena, which has been bobbing around for a few years now, is a pointer to some Theory of Everything. But, after 25 years in space, the tiniest force acting on the probes which is not accounted for, can stack up to an observable difference of position from prediction.
--

My gravitational theory (1)

hypergreatthing (254983) | more than 13 years ago | (#221214)

Muahahahaha, here it goes

gravity is a byproduct of matter moving through space and as such the biggest concentration of matter is located at the sun, and it is moving fast through the galaxy, and the galaxy is moving through the universe. This will be called theorem 1.

Theorem 2 - Matter is actually an influx of dimentions. We take the substring theory to a new level and say instead of having dimentions rolled up inside of matter (quarks), they are constantly interacting in one another. The universe which we percieve to live in is just another dimention which these multidimentions exist inside of. The main idea is that the interactions of dimentions with this universe is a benign one, but when moving, it causes an.. interaction with this dimention thus causing "matter" to be in "existance". Thus matter is just a byproduct of the interactions, but the interactions of this universe and the others cause gravity.

Theorem 3 - Time is also a byproduct of the dimentional interaction with this universe. There can be no time with no space and vice versa. But that really isn't part of the theorem. The theorem goes as follows. Each rotating force in this universe has "fields" of force around it, or a certanty field in which it is the main driving force. Each galaxy has a center (massive black hole) in which everything rotates around it. Each solar system has a sun (red dwarf or whatnot) that is the main gravitational force. Each atom has a nucleous, ect. Once outside the main force, it will ahere to the rules of the greater force outside of it.

Hense, out of all my theorems, theorem 3 is the cause for the deflection. After getting too far away from the sun (ordos clouds or whatever they're called), it will be under the influence of the galactic center. The problem with this is the incredible distance, the relative speed of the probe to the center (remember that solar systems rotate around this center, if the probe is leaving the solar system, it is either traveling faster or slower than the solar system in relative speed.

So basically think of it like... Lauching something from a satelite in orbit horizontally (not to or away from the planet). The increased speed will make it change orbit, or fall to the earth. That or dark matter :P

Maybe gravity is more powerful than before thought (1)

mikethegeek (257172) | more than 13 years ago | (#221216)

Could be that scientists have underestimated the power of gravity, and as such, the planets, and Sol have stronger influence than thought, and thus, the probes may be closer to the limit of Solar gravity escape velocity than originally calculated.

Could even be that their paths are actually a parabola... That once they reach their apogee, may actually fall back into a very distant Solar orbit...

Re:Another Possibility (2)

mikethegeek (257172) | more than 13 years ago | (#221217)

Why would an intelligent species want to slow down our probes, but not stop them, or capture them?

About the only theroy I've got is maybe there is a dark "brown dwarf" star companion of Sol orbiting out there. Could that explain it?

Don't know, but I suspect that small mass pseudo-stars like Brown Dwarfs will be found to be among the most common objects in the universe (as it's known that the sim, low mass, long lived Red Dwarf stars are by FAR the most common stars).

A brown dwarf in the Oort Cloud may be dark enough to be obscured by the comet-like matter there, yet have enough influence to affect the outer solar system (like sending the odd new comet towards the Sun every now and then).

But then, I'm only a curious amateur in Astronomy ;)

Re:Could this be the "missing mass" explanation? (2)

mikethegeek (257172) | more than 13 years ago | (#221218)

The coolest thing about Astronomy, is that we "KNOW" very little. What we have are mostly very brilliantly reasoned "guesses" that presumably get more accurate as more minds refine and build on the therories pioneered by Copernicus, Galileo, and Newton.

Just in my own lifetime, the picture of our Solar System has changed drastically, with the information the Pioneers and the Voyagers returned and still return (Pioneer 10 was launched close to the very day I was born!)

In fact, with the recent confirmation of the existance of other solar systems with planets, our theroies on what is "normal" for solar systems are already in question...

Is there any doubt that those four little spacecraft, of our WHOLE space program, delivered the MOST bang for the buck? And that we should be sending more advanced versions of them out?

Is it the probe or is it us? (2)

jamesmartinluther (267743) | more than 13 years ago | (#221222)

Why do we assume that an "apparent anomalous acceleration is acting on Pioneer 10 and 11"?

Perhaps this observed acceleration is actually us "decelerating". Could our close proximity to a large source of gravitation (the sun) lead to such an observation?

We need to, er, Think Different(TM) about stuff like this.

Today's earlier story (1)

cavemanf16 (303184) | more than 13 years ago | (#221223)

Didn't today's earlier story regarding anti-matter/matter creation answer this question. The existence of anti-matter is quite obvious to the naked eye.

Re:Could this be the "missing mass" explanation? (1)

Ayende Rahien (309542) | more than 13 years ago | (#221225)

I think that this would be noticable to observations in the solar system if it was so.

Re:Oh no... (1)

Ayende Rahien (309542) | more than 13 years ago | (#221226)

My spelling is not to be trusted :-)
Alcubierre's warp drive

And here is the link to NASA's research:
http://www.grc.nasa.gov/WWW/PAO/html/warp/

Go to Ideas based on what we'd like to achieve to read about it.

informed content? (1)

capoccia (312092) | more than 13 years ago | (#221231)

informed content? do you mean like super-string theory or oort cloud objects?
before you guys get too carried away, try reading this:
Notorious Spacetime Crackpots [gte.net] .


Bored with your projects?
Try Einsteinium [redbearnet.com]

Sub-surface Global Conspiracy (2)

RevDobbs (313888) | more than 13 years ago | (#221232)

It's those damn elves again...

  1. Deflect space probe courses.
  2. Profit.


God bless those Albino Ninjas...

Re:The Paper is here (1)

Faust7 (314817) | more than 13 years ago | (#221238)

modifications to gravity

Like from an inverse-square to an inverse-cube law? That would rock. -bounces away-

Re:Just shows how much more there is than we know (2)

Canonymous Howard (325660) | more than 13 years ago | (#221240)

You know, most scientists do look at the world with eyes of wonder. It's the wonder that arouses their curiosity and leads them to be explorers.

I think the arrogant assumption that we know it all frequently comes from non-scientists who have an axe to grind. The average scientist has far too much experience with failed hypothesis to think that they know it all. (And, of course, it's only the non-scientists who think that a failed hypothesis indicates a failure. I'll bet there are folks at NASA who are beside themselves with delight over this puzzle.)

Sorry, Arrival, if you stopped gazing at the stars with wonder. I seriously doubt that anyone at NASA ever did.


Shame on me for responding to such an obvious troll, but the contrast was hard to resist.

Re:Informed comment? (2)

Waffle Iron (339739) | more than 13 years ago | (#221241)

You'll see lots of speculation by people who have no idea what they're talking about, but at least that won't get modded up. You'll also see lots of speculation by people who have a very slight idea of what they're talking about, and even though that speculation is little better, it will get modded up by other people who have a slight idea of what they're talking about, because it sounds plausible.

OK, folks, mod this guy up. His post speculating about the /. mod system qualifies under these terms :-).

Dark Matter (1)

downeym1 (401104) | more than 13 years ago | (#221242)

I remeber reading that the majority of the universe is made of "Dark matter" or things like black holes that we can not obverve directly because they are not emissive. If this is the case, then the changes in course could be small cumulitive effects from lot of dark matter gravitational interactions... Or maybe they just forgot to convert from pounds to kilograms again.

Re:Informed Comment (2)

Guppy06 (410832) | more than 13 years ago | (#221243)

Simple: The folks at NASA (other than the astronauts) took their job because they couldn't get a better-paying job with their degree (we're talking government wages here, people). At least here they have a chance of finding somebody that might know. :)

It's gonna fall of the edge. (1)

Dutchmaan (442553) | more than 13 years ago | (#221245)

Isn't it obvious... The universe is flat, and these probes are just heading over the giant matterfalls at the edge of our solar system. I've heard stories of creatures from "out there" as well...

Re:Oh no... (1)

4444444 (444444) | more than 13 years ago | (#221247)

after reading through your past comments I have concluded you are a troll http://slashdot.org/users.pl?op=userinfo&nick=Ayen de%20Rahien

Re:Oh no... (1)

Spektre_ii (451320) | more than 13 years ago | (#221254)

There are some flaws in your theories...

First and foremost are the laws of physics, specifically the speed of light. It can not be exceeded by a physical object and still maintain atomic integrity. This plainly makes travel over any significant distance impossible.
Ok, so because the speed of light has not yet been achieved by the human race, aliens cannot exsist? Did I miss something here or are you telling me that the human race has to be "the most intelegent" life ever? Maybe, we are slower than (alien) life form and they are moving at many times the speed of light.

"Well, what about our own solar system?" you may ask. Please. Do you really think there are little green men coming down to abduct farmers in the midwest? This is reality, people, not the X-Files. Quit dreaming.
What does this have to do with the article?

"You can believe in a higher power - as a matter of fact you should " Why should I? I can believe anything that I want. And im sorry, but people that attempt to force this theory that I should believe in a higher power upon me are the reason that I cannot believe in a higher power.

Points to consider in favor of extra terrestrial life:

1. We would have to be very conceeded if we believe that we are the only ones that can be alive in this huge expanse of our universe.

2. Elements that we say are required to sustain life here on earth are in huge abundance in various other planets that we know of, let alone in pockets of gassesous clouds through out space.

3. The human race and varous other animal and plant life here on earth have proven that we can adapt to and overcome any obsticles to our survival.

Just because we havent seen aliens doesnt mean that they are not there. Just because I havent seen God, doesnt mean he isnt there.

Maybe it's just NASA... (2)

Freija Crescent (452135) | more than 13 years ago | (#221261)

You know they have a problem with math sometimes. I'd check to see that everything was in metric this time and that no units are getting confused. Probably something silly like that, silly until the probes come crashing back to earth.. wait!! that's it.. they are using the probes as new weapo ... thud..

You forget something !! (1)

SirLestat (452396) | more than 13 years ago | (#221262)

What about CowboyNeal did it?

Microsoft's Fault (1)

WankersRevenge (452399) | more than 13 years ago | (#221263)

Its probably running Windows CE Outer Limits Edition. If you think about it, it makes total sense. My computer runs Windows 98 and it does some of the strangest things, yet nobody raises an eyebrow.
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