More Spacecraft Velocity Anomalies

ZonkerWilliam recommends a bulletin from the American Institute of Physics, which discusses a study noting that recent spacecraft, such as NEAR, appear to display velocity anomalies much like those seen in Pioneer 10 (which were observed beginning ten years ago). The anomalies amount to up to 13 mm/sec., with a measurement accuracy of 0.1 mm/sec. Quoting: "A new look at the trajectories for various spacecraft as they fly past the Earth finds in each case a tiny amount of surplus velocity. For craft that pursue a path mostly symmetrical with respect to the equator, the effect is minimal. For craft that pursue a more unsymmetrical path, the effect is larger."

spooky

[superdana (1211758)]

Does anyone else feel like they just read the first console in an old Bungie game? We should probably be arming ourselves.

Recheck that gague

[yotto (590067)]

It's actually 13 inches per hogshead, which is what they expected.

No problems here.

Awesome precision

[DancesWithBlowTorch (809750)]

I'm amazed that they can apparently measure the speed of spacecraft that's millions of kilometers away, to a precision of 10e-4 m/s. How do they do this? I imagine it must be some sort of interferometry. Still, awesome. If only cruise control (with automatic distance control) was this accurate. :-)

Re:

[pnewhook (788591)]

Even if you had hyperaccurate cruise control, you'll still get some jackass yammering on a cellphone cutting you off or slamming into you.

Re:Awesome precision

[Detritus (11846)]

The range isn't an issue, it's how accurately they can measure doppler. The standard technique is to transmit a special signal to the spacecraft, which retransmits it to the Earth, like an RF mirror. This allows them to use extremely stable ground-based oscillators, like Hydrogen masers. This signal can also be modulated with a PN code to allow precise range measurements.

Global gravity, my shiny metal ass!

[frankie (91710)]

Come on already! How many fatal flaws have to be revealed before "scientists" will admit that the Theory of Gravity is invalid?

Intelligent Pushing [google.com] describes this behavior quite easily. It's obvious that GSM would apply more appendage force to non-equatorial motion. Things going in odd directions are simply more fun to play with. Duh!

I'm surprised the electric universe otaku [slashdot.org] haven't jumped in to claim credit for this yet.

Re:Global gravity, my shiny metal ass!

[Walt Dismal (534799)]

Phooey. This clearly proves existence of the ether, a theory I've supported since I was a child in grade school, 108 years ago. Michelson-Morley my ass. And Xenu particles can travel faster than light, too. Modern physics is all invalid. I shall prove you all wrong with my free energy machine, controlled by Windows Vista, Crackpot Edition.

I'm sure it's the hamsters..

[splutty (43475)]

They're getting sick and tired of these slow things and finally got out and started pushing.

Must be it.

Or possibly dark matter... ;)

Re:I'm sure it's the hamsters..

[sm62704 (957197)]

Hamsters? What hamsters? It's the mice and the dolphins.

Re:I'm sure it's the hamsters..

[MBGMorden (803437)]

You're very clever, young man, very clever, but it's turtles all the way down!

Hmmm.....

[TripMaster Monkey (862126)]

Could this anomaly possibly be explained by dark matter [blogspot.com]?

Re:

[Yetihehe (971185)]

Or maybe by time running out of universe [slashdot.org]. If there is time running out, then everything would speed up (like expansion of universe and satellites).

Re:Hmmm.....

[Leperous (773048)]

Unlikely. If "everything [were to] speed up" that would presumably include us, and hence we wouldn't be able to observe any difference. Plus, if this was happening, it should be more apparent faster moving objects, such as particles whizzing around particle accelerators at relativistic speeds - but it's not.

Re:Hmmm.....

[kestasjk (933987)]

Lets postulate an entirely new field/form of matter/universe to explain this phenomenon!

Re:Hmmm.....

[macslas'hole (1173441)]

The Earth does indeed gain mass continuously from in-falling space dust, captured solar wind, etc., and as a consequence of GR, our clocks should be getting slower over time relative to distant satellites. However, I would think that the effect is not sufficient to account for the observed velocity discrepancy. I am just a lowly programmer, but I would be very surprised if those physicists have not taken this into account or discounted this accordingly.

Re:Hmmm.....

[sm62704 (957197)]

Could this anomaly possibly be explained by dark matter [blogspot.com]?

Maybe, but I think it's more easily explained by dork matter [slashdot.org].

There is no dork side of the moon. As a matter of fact it's all dork.

Re:

[drooling-dog (189103)]

Or, there could be some more conventional gravitational source in the vicinity, one that hasn't yet been detected by other means. It doesn't take a hell of a lot to create an anomaly of that magnitude, and if an object were fairly massive it could still be quite far away.

Re:

[DerekLyons (302214)]

If such a source did exist, and was in fact the cause of the Pioneer anomaly - it wouldn't be be the Pioneer anomaly as we'd have seen it's effects on the outer planets decades ago. This goes 1x10^10 for NEAR which has barely left the inner solar system.

Re:

[macslas'hole (1173441)]

we'd have seen it's effects on the outer planets decades ago

Perhaps not. According to the summary and the article, the effect dies down the closer you get to the ecliptic plane (i.e. where the planets are).

One could imagine that the local dark matter field (or whatever) has been swept up, in the ecliptic, by the sun and the planets.</handwave>

Re:Hmmm.....

[Teancum (67324)]

One thing you must remember is that this is being published in scientific journals, not just some back page of your local newspaper. If there is one thing scientists do like to perform, is showing that somebody else missed a basic calculation on their raw data like you are suggesting. This is called "peer review", and very common in scientific journals... even if it is more informal than an organized panel. That is in fact why results like this are published in journals like this, so these kind of mistakes can be vetted.

Or more to the point, if you want to make a name for yourself, look through the raw data, perform the calculations yourself, and show what mistake somebody with a PhD did with this sort of data. Many graduate students have indeed gained notice when they have performed exactly these sort of calculations.

Have fun! Seriously, I mean it!

Re:Hmmm.....

[florescent_beige (608235)]

According to this [aip.org], the acceleration anomaly can't be accounted for by dark matter.

Link: Explanation with physics equations included

[ergon (1248558)]

Here is an interesting explanation for it by a PhD. with the following credentials:

Beginning in 1979 he worked for Sandia National Laboratories (New Mexico) in nuclear physics, geophysics, pulsed-power research, and theoretical atomic and nuclear physics. In 1985, he began working with Sandia's 'Particle Beam Fusion Project', and was co-inventor of special laser-triggered 'Rimfire' high-voltage switches, now coming into wider use.

The last few years at Sandia had seen greater emphasis on theoretical nu

Re:Link: Explanation with physics equations includ

[rthille (8526)]

I think it is more of the human ability to interpret vagueness into anything. The genesis description of the origin of the universe lends itself to analogy, which he uses in that paper. Now his physics may be accurate in that the Universe may extend much further than the matter we can detect, and that may explain the velocity anomaly. But to extend that to say that a very vague story from 3000 years ago is a true an accurate description of the universe's origins and that therefore the bible is literally true is just fantasy.

I've never been a believer. Recently, after reading The Selfish Gene and seeing just how much real evidence there is for evolution and seeing that science really _is_ an accurate and true explanation for how we came to be on the earth. It really does explain away any "need" for any sort of "personal god" as an alternate explanation. So, to give equal time to "the other side", I tried to read the bible. I got thru Genesis, but realized that there really is "nothing there" as far as explanatory power. And certainly to try to extract morals from the old testament would be a mistake. So then I got "Skeptics Answered" and again, there really isn't anything to the arguments of the believers.

While I'm interested in why people believe, and how we can change that going forward, I've really lost interest in _what_ they believe. It really holds no value as near as I can tell.

Re:Link: Explanation with physics equations includ

[ergon (1248558)]

Here is the summary from the article:

If a large volume of empty space surrounds the matter of the cosmos, so that the cosmos can have a centre of mass, then the matter is in a deep gravitational potential 'well'. If space is expanding and spreading the matter outward, then the depth of the well is decreasing. According to general relativity, especially a new solution of Einstein's equations derived in the Appendix (which also deals with Birkhoff's theorem), the decreasing depth continuously shortens 'radar' distances within the well, causing the observed apparent acceleration. The magnitude of the anomalous acceleration implies the bottom of the potential well has not yet risen very far above the critical depth for gravitational time dilation. Thus the Pioneer effect supports the essentials of several creationist cosmologies: a centre of mass, expansion of space and recent time dilation. Big bang theorists, whose cosmology does not have a centre of mass, cannot use this explanation.

The specialization of knowledge...

[Kagura (843695)]

Sadly, none of us can probably make a useful suggestion on this topic (one that would have eluded all the physicists that have been working on this). Unless the next Einstein is reading Slashdot,we can only make narrow conjectures. How many of us have the knowledge and data required? We might as well try to diagnose a medical condition based on a cursory discussion. It's fun to talk about, though.

Re:Hmmm.....

[CheshireCatCO (185193)]

I can't speak to this specific case, but someone did a study several years ago of the Voyager anomaly and whether it could be a gravitational effect. The gist of the analysis was the if it were gravitational, it would also affect the distribution of long-period comets, especially the "new" ones from the Oort cloud. They calculated the effect you'd expect and it's much too large relative to what we see in the comets, so whatever is affecting Voyager pretty much cannot be gravitational in nature.

It's also worth noting that even in the mega-analysis by Anderson et al. concluded that although they couldn't determine a source for the anomaly, they still generally felt that it was more likely to be endogenic than exogenic.

Good excuse

[Anne_Nonymous (313852)]

I'm sorry officer; I was experiencing a velocity anomaly.

Re:Good excuse

[sm62704 (957197)]

I'm sorry officer; I was experiencing a velocity anomaly.

That's too bad, son, I'm still writing you a ticket. From now on keep it under 299,792,458 meters per second. The law is the law!

An appropos quote

[jandrese (485)]

Someone once said: The most profound scientific discoveries never begin with EUREKA! Usually they start with the words "now that's odd..."

Re:An appropos quote

[AndroidCat (229562)]

I thought it was "Here, hold my beer."

Re:An appropos quote

[ZaMoose (24734)]

No, no, that's the way we get Darwin Award nominees.

Re:

[orclevegam (940336)]

i thought that was "that would be a cool thing to do..."

No, it's "Hey, watch this!"

Re:An appropos quote

[MBGMorden (803437)]

There's an old redneck joke in there somewhere. Something like 50% of deaths by rednecks are immediately preceded by "Hey ya'll, watch this!".

Having grown up around (and most people would probably say as) rednecks, there's some weird level of truth to that. Who else can say that they know a guy paralyzed from the neck down from trying to steal a riding lawn mower from Wal-mart by using an extension cord to tie it to the back of his buddies pickup, and then trying to drive/be towed on the lawnmower down the road at 60+ mph. Lets just say he lost control a few miles down the road . . .

Re:An appropos quote

[camperdave (969942)]

Some would say he lost control long before he ever got on the lawnmower.

Re:An appropos quote

[tppublic (899574)]

I believe you're referring to: "The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but rather, 'That's funny...'"-Isaac Asimov

Occasionally this is also quoted as ending with 'Hmm, that's funny'.

Re:

[jandrese (485)]

That's probably right. I only vaguely remembered the quote and did a Google search for it, but only turned up the version I posted.

well duh

[circletimessquare (444983)]

gravitons display a bias for polar rather than equatorial output. this was the basis for the graviton engine that first bought man...

oh shit, forgot what time line was in, you guys aren't supposed to discover this until 2039. dang it, screwed up again. i'll have to shut this time line down...

That's quite enough, Titor

[dreamchaser (49529)]

John, yet ANOTHER Slashdot ID??? We told you to stop trolling here!

Message from your gods

[rbarreira (836272)]

We're sorry about the bugs you've been observing lately. The latest anomalies are due to bug #14310, a hardware glitch much like those present in your own Pentium processors.

We're trying as hard as we can to mitigate this issue, primarily by avoiding the use of floating point calculations in our physics engine. In the meantime, we're manually changing your physics books so that you'll be able to calculate the ship's movement correctly. In one day, you'll have no memory that this incident ever happened, so do not worry.

And...

[djupedal (584558)]

Number 857 #2, February 28, 2008 by Phil Schewe

More Spacecraft Velocity Anomalies

        A new look at the trajectories for various spacecraft as they fly past the Earth finds in each case a tiny amount of surplus velocity. For craft that pursue a path mostly symmetrical with respect to the equator, the effect is minimal. For craft that pursue a more unsymmetrical path, the effect is larger. In the case of the NEAR asteroid rendevous craft (), for instance, the velocity anomaly amounts to 13 mm/sec. Although this is only one-millionth of the total velocity, the precision of the velocity measurements, carried out by looking at the Doppler shift in radio waves bounced off the craft, is 0.1 mm/sec, and this suggests that the anomaly represents a real effect, one needing an explanation.

        Some ten years ago another anomaly was identified for the Pioneer 10 spacecraft (see http://www.aip.org/pnu/1998/split/pnu391-1.htm [aip.org]) and a certain amount of controversy has clung to the subject since then. One of the researchers on that earlier measurement is part of the new study, conducted by Jet Propulsion Lab scientists. John D. Anderson ([e-mail], 626-449-0102) says that the JPL scientists are now working with German colleagues to search for possible velocity anomalies in the recent flyby of the Rosetta spacecraft. (Anderson et al., Physical Review Letters, upcoming article; designated as an editor's suggested articlePhysical Review Letters)

I know what it is!

[kiick (102190)]

Once you leave Earth for a while, particularly if you travel far, you realize that it doesn't suck quite as much as you thought.

A similar phenomenon occurs when traveling outside of the U.S.

precision, not accuracy

[rangek (16645)]

The precision of the measurements is 0.1 mm/sec, not the accuracy. Those are different things.

I'm thinking solar wind

[glenmark (446320)]

The solar wind output from the sun is anisotropic, and can certainly account for variations in a space probe's velocity. I'm wondering if that was taken into account in their calculations.

Simpler explanation?

[ChrisMaple (607946)]

The article has little information about what types of trajectories are affected, so this is just wild guessing. If the orientation of solar panels or dish antennas are markedly different for different trajectories, drag from particles or acceleration from absorbing/reflecting solar radiation can also differ. There's more garbage in the plantary plane, so there's more drag and more blocking of solar radiation.

correction on Pioneer anomalies chronology

[harvey the nerd (582806)]

The Pioneer 10 and 11 speed-position anomalies, unaccounted drift, were noticed by the late 70's. NASA and the peole involved just didn't discuss it with the public until much later, after many potential sources of error and theoretical possiblities had been analyzed. That is when I first heard it mentioned, in Houston, ca 1977-78.

mm/sec ! wha...!

[uss (1151577)]

We've seen this Metric-hogwash replay innumerable times, when dealing with stuff flying around in the heavens.

If those europeans and europeans-wanna-be stopped using fancy units of measurements, and just plainly used the well-worn all-American "Inches/just-a-sec" for measurements, there would be no anomolies.

The only mm/sec I know, is the # of m&ms I can pop into my mouth per second.

Re:

[Deadstick (535032)]

...but those variations have been quantified with exquisite precision by half a century of satellite tracking. I'm guessing it has something to do with motion of molten metal in the earth's core, only now beginning to show up because it's a long-term effect.

rj

Re:I mean...

[reverseengineer (580922)]

Both "asymmetric" and "unsymmetric" are in accepted use, though "a" is a lot more common than "un," particularly in math and physics (so yes, "asymmetric" would probably be more common to describe a spacecraft trajectory).

Chemists use "un" to describe non-symmetric molecules pretty often- consider the rocket fuel UDMH: unsymmetrical dimethylhydrazine, though chemical reactions lacking symmetry are more often called "asymmetric," like the Sharpless asymmetric epoxidation. Asymmetric reactions can sometimes produce unsymmetrical products. Yes, it is unpossibly confusing. Just make sure to not confuse either "asymmetric" or "unsymmetric" with "antisymmetric."

Re:I mean...

[Oktober Sunset (838224)]

Antisymmetric is when you hate Jews right?

Re:

[zippthorne (748122)]

no. That is wrong. The "particle" part of "wave-particle duality" does not refer to a separate state. Further, it doesn't have mass, either.