NASA Baffled by Unexplained Force Acting on Space Probes

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Everything I need to know I learned through Googling.

Yay! Of all the mysteries of space, I thought the Pioneer anomaly, (no need for quotes) was going to be significant because its so close to home. And now the flybys are showing it. I'd really like to see a good solution to this. I wonder if it has anything to do with gravity and space topograghy ala the rubber sheet theory.


Thank you Toseek!

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Gimme a minute to read through Jay's latest observations...

It is certainly something if it happens to five different spaceprobes, I am very curious what this could be.

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We've got a lot of unmapped and undetected mass, dust, and gas out there. No surprise that not everything goes as smoothly as equations and simulations predict.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
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Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

If each of them had a similar or the exact same effect (all faster or all slower) I wouldn't be at all hesitant to say that it was an unknown force, possibly.

And while it still might be an unknown force, it seems far more likely that noclevername has the idea down, small anomalies a new theory for gravity do not make.

For instance, the NEAR mission approached Earth at about latitude 20 south and receded from the planet at about latitude 72 south. The spacecraft then seemed to fly 13 millimeters per second faster than expected. While this is just one-millionth of that probe's total velocity, the precision of the velocity measurements was 0.1 millimeters per second, carried out as they were using radio waves bounced off the craft. This suggests the anomaly seen is real — and one needing an explanation.

The fact this effect seems most evident with flybys most asymmetrical with respect to Earth's equator "suggests that the anomaly is related to Earth's rotation," Anderson said.

Hmm. Lot of variables there. Not a very big anomaly.

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Everyone is entitled to his own opinion, but not his own facts.

There was a recent article/post that I read, and I wish I could remember where, that attributed the anomalies to GR induced electromagnetic radiation. The effect had been overlooked in the calculations. It sounded plausible.

Richard?

Mr. Cougar,

I know you are a person who takes his physics seriously, but isn't it said that most great discoveries aren't discovered with "Eureka!" but with, "Hmmm, that's funny."

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Gimme a minute to read through Jay's latest observations...

I don't really buy that the close-Earth-approach data is anomalous. From a geodesy standpoint, the "calculated" orbits of GPS satellites have to be constantly tweaked or they'll drift so far from reality to become useless in a matter of days. Our best gravity maps of the Earth just aren't that precise. With spacecraft - as opposed to satellites - you get one pass to figure out how well your a priori orbit matches reality. I'd expect a little more error to pop up than what they are assuming.

- J

Perhaps you are thinking of this:

NASA's astonishing evidence that c is not constant: The pioneer anomaly.
http://arxiv.org/abs/physics/0701130

Or this:

January 20th, 2008
A Possible Answer to Flyby Anomalies.
Written by Ian O'Neill
"Strange things are happening to our robotic space explorers. Also
known as the "Pioneer effect" (the unexpected and sudden alterations
to Pioneer 10 and Pioneer 11 trajectories measured as they continue
their journey into the outer solar system), similar anomalies are
being seen in flybys by modern space probes. Earth flybys by Galileo,
Rosetta, NEAR and Cassini have all experienced a sudden boost in
speed. After cancelling out all possible explanations, including
leakage of fuel and velocity measurement error, a new study suggests
the answer may lie in a bizarre characteristic of universal physics..."
http://www.universetoday.com/2008/01...yby-anomolies/



Bob Clark

If it was really a single unexplained force, there would be some consistency. Instead some are too fast, some are too slow, and all are moving in different directions.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

Clev,

The post above your's says all were faster. As if all were "uphill" upon returning from beyond Earth's orbit. The slow one I heard of elsewhere was coming from "downhill"

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Gimme a minute to read through Jay's latest observations...

What I'd like to know is, how do they know the theoretical uncertainties? When everything comes out an "anomaly", it looks to me like there are simply more variables than they are tracking-- no new physics.

"What could be causing a tiny but constant acceleration toward the sun?" NASA's scientists asked themselves.

Finally, after much brilliant research, they hit upon a novel idea:

Maybe the sun exerts gravity!



<ducking and running>

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The truth, as always, is more complicated than that.

That post wasn't above mine when I posted my post!

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort

If I was living in a movie, it would start with me reading this thread, and the creepy music would start playing...

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"If you think the LHC will create black holes, you might as well believe Hobbits are at the bottom of your garden."- Dr. Mike Inglis
Rovers forever! - ToSeek
"Carl Sagan sent a message to ET,
Neil Armstrong walked in the Sea of Tranquility
Steve Squyers built Spirit and Opportunity
Dan Haylen upchucked in zero gravity." -Brent Simon, The Space Camp Song

You, you mean you can't hear the MUSIC!
dun dun dun

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009

I wasn't aware of that until I saw RGClark's posts. Thanks RGC.

The first paper, in physics-general, about a variable speed of light depending on the total energy density of space, including the gravitational energy density(which idea is not very well defined in GR), is well, not too serious. It's an idea, but one that doesn't fit too well with known physics.

The second one, and this is probably the effect you were thinking about is *Unruh* radiation. This is heavy duty QFT stuff and is related to Hawking radiation -- heck they are the same thing, which brings up this vexxing question I have about coordinate vs real radiation. My gut says that only real curvature should produce "real" Hawking-Unruh, and the rest is some sort of coordinate effect.

Anyway, an accelerating observer should see himself in a "bath" of thermal radiation (very small). This is a coordinate effect that shifts the quantum vacuum as seen by the non-inertial observer in some complex way I don't begin to understand. The upshot is the "vacuum" is a frame dependent thing. There's something there to do with Killing vectors and preserving the metric. Classes of observers with the same metric see the same vacuum. Different metrics see different vacuua. That is, all that quantum field crap operators that tell what the various field values will be resolve differently in different metrics.

So Inertial observers in flat space-time with a Minkowski metric see the vacuum in it's zero state, say. No radiation. However, go to the curved coordinates of the accelerating observer, and that vacuum looks filled with excited states. You can see that as Hawking radiation coming from the Rindler horizon, actually!

All this is well beyond me, mind you, so don't take my ramblings here as gospel, just my vague attempts to paint a picture.

The idea that the Unruh effect would be large enough to cause the Pioneer anomaly is sort of hard for me to believe. I figured it would be so vanishly small for anything short of millions and billions of g's worth of acceleration.

-Richard

Could it be that the probes were doing what they were expected to be doing and something affected the radio waves that provided evidence of the velocity deltas?

Meanwhile I'm surprised there hasn't been a somewhat reluctant cosmological post in this thread.

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