"Mysterious Pioneer Anomaly may finally be solved"

This gravitational anomaly has been bothering me for years. The Pioneer spacecraft have been mysteriously slowing or experiencing some kind of drag which was first noticed in 1980. Seems the mystery has more than likely been solved....

I did a search on this and found so many threads speculating about possible reasons for it I decided to just start a thread about it....my first thread.




news.discovery.com...

May I encourage you to seize the moment when creating a thread. This is a good article with lot's of info, and it's okay to bring a paragraph or 2 over. Maybe tell us a little about what this info means to you, or perhaps how you feel about it. If you need any help with the functions, shoot me a message.

With the best intentions,
spec

ETA: This discovery was originated by a 1970's computer model of the Pioneer.
I thought this was intersting:

After their respective flybys, they continued on escape trajectories out of the Solar System, both decelerating under the force of the Sun's gravity. But careful measuremenrs show that the spacecraft are slowing faster than they ought to, as if being pulled by an extra unseen force towards the Sun.

This deceleration is tiny: just (8.74±1.33)×10^−10 ms^−2. The big question is where does it come from.

Phong shading was dreamt up in the 1970s and is now widely used in many rendering packages to model reflections in three dimensions. It was originally developed to handle the reflections of visible light from 3D objects but it works just as well for infrared light, say Francisco and co.

In particular, Phong shading has allowed the Portuguese team to include for the first time the effect of heat emitted from a part of the spacecraft called the main equipment compartment. It turns out that heat from the back wall of this compartment is reflected from the back of the spacecraft's antenna. Since the antenna points Sunward, towards Earth, reflections off its back would tend to decelerate the spacecraft. "The radiation from this wall will, in a first iteration, reflect off the antenna and add a contribution to the force in the direction of the sun."

www.technologyreview.com...
Interesting also during their studies, they determined gravity was not any stronger at those distances.

Okay. So the anomoly is caused by heat.
From where, that is what my pea brain is asking.

reply to post by speculativeoptimist

Since the antenna points Sunward, towards Earth, reflections off its back would tend to decelerate the spacecraft. "The radiation from this wall will, in a first iteration, reflect off the antenna and add a contribution to the force in the direction of the sun."

Do they mean the rays hitting the dish is bouncing back towards the spacecraft, and slowing it down? Because there was a spaceship that was designed with an umbrella in front to capture solar rays in order for it to push the spacecraft. It was only theories, but would it also have lost a bit of its speed by what was speeding it?!?

Thanks.

Originally posted by billxam
Okay. So the anomoly is caused by heat.
From where, that is what my pea brain is asking.

From the Plutonium power source on voyager....

ahah comon guys, its something that starts with brown

Originally posted by speculativeoptimist
May I encourage you to seize the moment when creating a thread. This is a good article with lot's of info, and it's okay to bring a paragraph or 2 over. Maybe tell us a little about what this info means to you, or perhaps how you feel about it. If you need any help with the functions, shoot me a message.

With the best intentions,
spec

ETA: I thought this was intersting:

After their respective flybys, they continued on escape trajectories out of the Solar System, both decelerating under the force of the Sun's gravity. But careful measuremenrs show that the spacecraft are slowing faster than they ought to, as if being pulled by an extra unseen force towards the Sun.

This deceleration is tiny: just (8.74±1.33)×10^−10 ms^−2. The big question is where does it come from.

Phong shading was dreamt up in the 1970s and is now widely used in many rendering packages to model reflections in three dimensions. It was originally developed to handle the reflections of visible light from 3D objects but it works just as well for infrared light, say Francisco and co.

In particular, Phong shading has allowed the Portuguese team to include for the first time the effect of heat emitted from a part of the spacecraft called the main equipment compartment. It turns out that heat from the back wall of this compartment is reflected from the back of the spacecraft's antenna. Since the antenna points Sunward, towards Earth, reflections off its back would tend to decelerate the spacecraft. "The radiation from this wall will, in a first iteration, reflect off the antenna and add a contribution to the force in the direction of the sun."

www.technologyreview.com...
Interesting also during their studies, they determined gravity was not any stronger at those distances.

edit on 14-4-2011 by speculativeoptimist because: (no reason given)

Thank you for helping me with my first thread here, You brought over info from the article which I should have if following the posting rules....My computer skills are limited and I appreciate your offer of assistance....

PS. I looked at the link you posted but did not see anything about "gravity was not any stronger at these distances". Please elucidate as I thought gravity was constrained by the "square of the distance" law.

Originally posted by csgt428
Seems the mystery has more than likely been solved....

Excellent first thread!

The semantics of "may be solved" versus "has more than likely been solved" is a minor point but I'd have to agree with the former, until this is independently confirmed.

But I think the heat theory has been a leading contender to explain it for some time so we won't be surprised if it's confirmed.

The amount of attention paid to this exceedingly tiny anomaly is fascinating to me. It just goes to show how picky scientists are. But if there had been new physics involved as some had speculated, I can understand their interest in it.

Great first thread.

I have wondered about this since I first heard about it years ago but this seems to definately provide an answer to the "slowdown" in the probes travel.

Thank you for sharing it.

- I had hoped for a MOND answer because then we could have built "impulse" drives but it doesn't look like there are any weird loopholes for us to exploit.

Originally posted by Arbitrageur

Originally posted by csgt428
Seems the mystery has more than likely been solved....

Excellent first thread!

The semantics of "may be solved" versus "has more than likely been solved" is a minor point but I'd have to agree with the former, until this is independently confirmed.

But I think the heat theory has been a leading contender to explain it for some time so we won't be surprised if it's confirmed.

The amount of attention paid to this exceedingly tiny anomaly is fascinating to me. It just goes to show how picky scientists are. But if there had been new physics involved as some had speculated, I can understand their interest in it.

Thanx for the kudoo ( 1'st thread thing) People in general like a good mystery.....they are fascinating. Point taken on the "more than likely" part.... the math just made sense. I wanted it to be something more as well...perhaps a step foreward in our understanding of gravity.......Leading to a revolution in physics which would show us a way past the speed of light thing....It is so depressing thinking of the time it would take us to get even to the closest star! Of course we have only just begun down the road to discovering and understanding the laws of Physics so I still have hope that we will be able to continue our explorations of our surrounds, out there.....

Originally posted by csgt428
I wanted it to be something more as well...

I can't say I wanted it to be something more. Per my signature that would constitute an extraordinary claim and Occam's razor says to eliminate the mundane before concluding the extraordinary. So the heat explanation fits my expectations just fine. And the heat explanation was pretty mundane.

But we do have more unanswered questions like dark matter and dark energy, so there definitely is something more to discover for us to understand those observations.

Regarding interstellar travel, some people think it's just a matter of time before we break light speed, but I'm not so sure that will happen. The Fermi Paradox suggests that even advanced technologies in extraterrestrial civilizations haven't mastered interstellar travel to any great extent. I think it will probably take a generational ship with a breeding population to travel to other stars with earth-like worlds, but I think that's doable, even if it is at sub-light speeds.

reply to post by Arbitrageur



Heh, sorry about the ASSumption. As soon as I wrote it I knew I was possibly ascribing something to you...an attitude which you did not have but.....I was to lazy to ....well, This Fermi paradox you mention sounds like another conclusion based on an ASSumption. Correct me if I digress, but this sounds like it is based on our present day knowlege of physics?? As you mentioned, Dark Matter and Energy theories indicate (to me) just how little we actually know about the Universe and how it works.

reply to post by csgt428
Hey it's your thread so if you want to ask about the Fermi Paradox that's your right. It doesn't assume much, only that our technology will advance modestly to the "slow" kind of interstellar travel, and that we're probably not alone in the universe:

The Fermi paradox can be asked in two ways. The first is, "Why are no aliens or their artifacts physically here?" If interstellar travel is possible, even the "slow" kind nearly within the reach of Earth technology, then it would only take from 5 million to 50 million years to colonize the galaxy. This is a relatively small amount of time on a geological scale, let alone a cosmological one. Since there are many stars older than the Sun, or since intelligent life might have evolved earlier elsewhere, the question then becomes why the galaxy has not been colonized already.

That link then offers quite a few possible explanations to the paradox, but of course they are all just possibilities, not really assumptions.

Nobody knows the real answer, though I suspect it may be a combination of those explanations. But my whole point in bringing it up, is the paradox is based on "slow" interstellar travel, and if the faster type of interstellar travel you alluded to was possible, the paradox gets much worse, since some civilization a million years more advanced than us probably would have discovered it, and then colonization of space would spread even faster, going further in a shorter period of time.

But bringing the discussion back to the Pioneer anomaly, just because the source of the anomaly didn't turn out to provide new physics doesn't mean interstellar travel is impossible, just very very difficult. We may be on the threshold of being able to send robots into deep space with this technology within a few decades:

en.wikipedia.org...

As of February 2011, NASA has 100 personnel assigned to the project to work with Ad Astra to integrate the VF-200 onto the space station.

Potential future applications:...
ultra fast deep space robotic missions

reply to post by Arbitrageur


This theory is my personal belief.... Well, the first part, not the resource depletion part, though many of the others at the link you provided make sense as well....


"Civilizations only broadcast detectable radio signals for a brief period of timeIt may be that alien civilizations are detectable through their radio emissions for only a short time, reducing the likelihood of spotting them. There are two possibilities in this regard: civilizations outgrow radio through technological advance or, conversely, resource depletion cuts short the time in which a species broadcasts.

The first idea, that civilizations advance beyond radio, is based in part on the "fiber optic objection": the use of high power radio with low-to-medium gain (i.e., non-directional) antennas for long-distance transmission is wasteful of spectrum, yet this "waste" is precisely what makes these systems conspicuous at interstellar distances. Humans are moving to directional or guided transmission channels such as electrical cables, optical fibers, narrow-beam microwave and lasers, and conventional radio with non-directional antennas is increasingly reserved for low-power, short-range applications such as cell phones and Wi-Fi networks. These signals are far less detectable from space. Analog television, developed in the mid-twentieth century, contains strong carriers to aid reception and demodulation. Carriers are spectral lines that are very easily detected yet do not convey any information beyond their highly artificial nature. Nearly every SETI project is looking for carriers for just this reason, and UHF TV carriers are the most conspicuous and artificial signals from Earth that could be detected at interstellar distances. But advances in technology are replacing analog TV with digital television which uses spectrum more efficiently precisely by eliminating or reducing components such as carriers that make them so conspicuous. Using our own experience as an example, we could set the date of radio-visibility for Earth as December 12, 1901, when Guglielmo Marconi sent radio signals from Cornwall, England, to Newfoundland, Canada.[63] Visibility is now ending, or at least becoming orders of magnitude more difficult, as analog TV is being phased out. And so, if our experience is typical, a civilization remains radio-visible for approximately a hundred years. So a civilization may have been very visible from 1325 to 1483, but we were just not listening at that time. This is essentially the solution, "Everyone is listening, no one is sending."

More hypothetically, advanced alien civilizations evolve beyond broadcasting at all in the electromagnetic spectrum and communicate by principles of physics we don't yet understand. Some scientists have hypothesized that advanced civilizations may send neutrino signals.[64] If such signals exist they could be detectable by neutrino detectors that are now under construction.[65] If stable wormholes could be created and used for communications then interstellar broadcasts would become largely redundant. Thus it may be that other civilizations would only be detectable for a relatively short period of time between the discovery of radio and the switch to more efficient technologies.

A different argument is that resource depletion will soon result in a decline in technological capability. Human civilization has been capable of interstellar radio communication for only a few decades and is already rapidly depleting fossil fuels and confronting possible problems such as peak oil. It may only be a few more decades before energy becomes too expensive, and the necessary electronics and computers too difficult to manufacture, for us to continue the search. If the same conditions regarding energy supplies hold true for other civilizations, then radio technology may be a short-lived phenomenon. Unless two civilizations happen to be near each other and develop the ability to communicate at the same time it would be virtually impossible for any one civilization to "talk" to another.

Critics of the resource depletion argument point out that alternate energy sources exist, such as solar power, which are renewable and have enormous potential relative to technical barriers.[66] For depletion of fossil fuels to end the "technological phase" of a civilization, some form of technological regression would have to invariably occur, preventing the exploitation of renewable energy sources."
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Well, I'm still doing something wrong while posting as the "Off site content" bars didn't come up...

Originally posted by csgt428
Well, I'm still doing something wrong while posting as the "Off site content" bars didn't come up...

Just type [ex] in front of and [/ex] after the external content, except use square brackets instead and it will work.

Click "quote" on someone's post with external content and you can see the tags as they are typed in rather than how they are displayed.

Yes, that's a possibility but like just about everything else, it constitutes an anthropocentric view. But we don't really have any alien views to consider so in the absence of that we're stuck with anthropocentrism. That may be part of the problem as stated elsewhere in that source. Some alien civilizations may skip the broadcasting completely and go straight to fiber optic delivery.

OK, Thanx, I'll try that next time.

Anthropocentric.....hmmm. My conclusions (for now anyway) are a work in progress. Aside from tech progressing to other than radio wave communications is the problem of energy consumed in communications. Any society with limited resources would attempt to use as little energy as possible to communicate. In other words, efficiently and economically, not blasting it all over the Galaxie as that would be extremely wastefull of the energy needed to ensure it got to where it needed to go. This is not neccesarily an Anthropocentric thing, it is something any life form with limited resources would have to deal with...

reply to post by csgt428
Some resources may be extremely limited, like certain rare metals for example.

But energy is an abundant resource. The Earth receives more energy from the sun in one hour than mankind can use in a year.

And if you count the total output from the sun, energy is even more abundant. The sun puts out more energy in 10 milliseconds than the total supply of all fossil fuel reserves on the Earth including coal, oil, natural gas, etc.

I think someday we'll figure out how to harness this energy much more efficiently than with the extremely primitive solar technologies we have today. Someday may almost be here: www.sciencedaily.com...

And we don't have to be limited to harnessing just the energy that strikes the Earth, as Dyson envisioned when he speculated about a "Dyson Sphere", look up the Wiki. My point is I'm not sure how valid the argument is about energy being such a limited resource.

However, you may be right about not broadcasting, for other reasons.

Originally posted by csgt428

Originally posted by billxam
Okay. So the anomoly is caused by heat.
From where, that is what my pea brain is asking.

From the Plutonium power source on voyager....

We're talking about Pioneer, not Voyager mate.

reply to post by csgt428


electrostatic attraction.

the sun is emitting charged particles and so must have a net attractive charge relative to the probe and thus acting as a attractive force.

Q1Q2/euR SQUARED.