Solving NASA's Great Gravity Mystery

[Startraveler]

It's been known for a while that something seems to be accelerating the first two objects to leave the solar system back toward the Sun.

space.com:

NEW YORK – It’s been years since NASA last heard from either of its two Pioneer probes hurtling out of the solar system, but scientists are still debating the source of an odd force pushing against the outbound spacecraft.

Dubbed the Pioneer Anomaly, the unexplained force appears to be acting against NASA’s identical Pioneer 10 and 11 probes, holding them back as they head away from the Sun.

Whether that force stems from the probes themselves, something exotic like dark matter, or some new facet of physics or gravity, remains in doubt.

But a wealth of newly recovered data and telemetry, spanning decades of observations by both Pioneer 10 and 11, may yield the final answer to whether conventional physics or perhaps something new is at work on the two spacecraft. An answer could arise from the new data after about a year of analysis by an international team of researchers.

“I would like to see this story reach its finality,” said Slava Turyshev, an astrophysicist with NASA’s Jet Propulsion Laboratory (JPL) who has spent the last 14 years—some of it on his own time—studying the Pioneer Anomaly. "So if it’s conventional physics, that’s fine and we can all go about our daily business. But if it’s something else, there may be another page.” . . .

Just to throw in something to the tune of the "new facet of gravity" approach, the acceleration the Pioneers seem to be experiencing is, oddly enough, pretty close to the acceleration scale introduced in Modified Newtonian Dynamics, the idea that suggests changes to Newton's laws are required (instead of dark matter) to explain the dynamics of galaxies. There's a tiny bit on that in this thread.

[Jjbreen]

Good read - it actually caused me to IM some friends of mine and we had a great dialog over this article.

The theory we all came up w/and some of these guys hold Phd's in Astro Physics was the possiblity that:

Just like we see Solar Loops shoot out of from the Sun and then fall back in - what if some of the "Push/Pull" continues a lot further out? The "solar particles" (for lack of better term) are so + and - charged, they are do PUSH and the PULL back. The Ort Cloud could be the "breaking point" where the limits of this begin to seariously break down.

Now the above is a 'break down' of about two hours of dialog... but it was a fun dialog and some of these guys are going to take this back to "work" w/them. One is even going to give it as an assignment in his Astro-Physics class.

Good post!

[magnetar]

A few cheap satellites, a little Cassini-style signalling, a little trigonometry...

[magnetar]

Ignore L2...sorry. It's from WMAP.

[Waspie_Dwarf]

A few cheap satellites, a little Cassini-style signalling, a little trigonometry...

I'm not sure how putting satellites in Lagrangian points is going to help. Orbital perturbations by the sun and planets is likely to mask the effects.

The effects have been noticed on spacecraft at the edge of the solarsystem, Pioneer 10 & 11 and Voyager 1 & 2, far away from the sun and planets. New Horizons and the Interstellar Boundary Explorer (IBEX), currently being constructed and due for launch in June 2008, will reach the required distances and help explore this phenomenon.

[magnetar]

At first glance, true, Waspie. But, that did not stop them from testing Newton versus Einstein with Cassini. I was merely suggesting a small constellation at Lagrangians. Perhaps they should be configured in a special arranged moving orbit, instead.

General Relativity Test Using the Sun

Of course, the complexity and telemetry is perhaps better suited to other missions, as you said.

Thanks

[Startraveler]

Just like we see Solar Loops shoot out of from the Sun and then fall back in - what if some of the "Push/Pull" continues a lot further out? The "solar particles" (for lack of better term) are so + and - charged, they are do PUSH and the PULL back.

The Pioneer anomaly has been studied pretty extensively by a guy from JPL named John Anderson (and others). You might be interesting in skimming through part of one of their papers on it: this one. They spend a few pages (starting with "Sources of systematic error external to the spacecraft" on pg. 27) looking at possible sources like that: radiation pressure, the solar wind, some sort of accumulated charge on the Pioneers interacting with a magnetic field, gravitation from the Kuiper belt, etc. It's interesting stuff but they haven't been able to pin the anomaly on that stuff. Not yet, anyway.

A few cheap satellites, a little Cassini-style signalling, a little trigonometry...

You might find this thread interesting, though the connection between your idea and that experimental suggestion might be tough to forge (for all I know). Still if, as some suggest, some sort of modification of inertia is responsible for the Pioneer anomaly then it'd be very interesting to study these kinds of effects locally.

[poleshift]

Wondering if they are in a place (or a parallel world) over there the time system slows down.

[IamsSon]

Almost seems as if there was some sort of magnetic instead of gravitic attraction at work, doesn't it?

[Leonardo]

I must admit, I haven't followed this very much but I have a question that may be rather stupid.

Has anyone calculated the velocity of Pioneer 10 and 11 relative to anything other than the Earth/Sun? The reason I ask this is because I am wondering if the anomalous acceleration observed is only apparently in the direction of the sun but could be actually be towards another object (Galactic Centre etc.).

[Startraveler]

The Piioneers are on opposite sides of the solar system and both are accelerating back toward the sun.

[Leonardo]

Okay, thanks for that Startraveler. I'll try to think up another useless idea

[Waspie_Dwarf]

The Pioneers are on opposite sides of the solar system and both are accelerating back toward the sun.

It is more true to say that they are experiencing an accelerating force in the direction of the sun.

The above quote may give the impression that they are going to head back towards the sun. They are not, they still have enough velocity to continue out of the solar system and into interstellar space, however they are decelerating at a rate faster than gravity can account for.

[Startraveler]

That's a fair point. To clarify, the sunward acceleration the Pioneers are experiencing is around 10 billion times smaller than the one we experience at the earth's surface. It's detected only as a slight blueshift in the signals the Pioneers relay back to earth, not as any real appreciable change in the speed of the spacecraft.

[Roj47]

Once again demonstrating my lack of knowledge on physics and such....

If these objects are struggling to escape the solar system, and are indeed decellerating..... What is different about Halley's comet that allows it to escape freely and return in cycles? Purely the speed or composition?

What is the gravitational pull of the Sun? It obviously extends to Pluto (and beyond reading another thread 1Ly? ouch!).... Is this force significant enough to decellerate?

Have the probes been caught into the gravity of an asteroid or similar that has not yet been discovered?

Regards

Edited April 18, 2007 by Roj47

[poleshift]

Unaccountable interstellar wind?

[Waspie_Dwarf]

Unaccountable interstellar wind?

This occured whilst the craft were still inside the heliopause, so the effect from solar wind would be greater than that from intestellar space. If there was any effect form this at all (and that is highly unlikely as the solar and interstellar winds are highly tenuous) it would be an acceleration in the opposite direction to that actually observed.

[Startraveler]

If these objects are struggling to escape the solar system, and are indeed decellerating..... What is different about Halley's comet that allows it to escape freely and return in cycles? Purely the speed or composition?

Halley's comet is in a bound orbit, meaning it actually has less energy and can't escape the solar system. The Pioneers, on the other hand, won't be turning around, even if the anomalous acceleration is taken into account. The total energy is what determines whether the orbit is bounded or unbounded.

What is the gravitational pull of the Sun? It obviously extends to Pluto (and beyond reading another thread 1Ly? ouch!).... Is this force significant enough to decellerate?

The anomalous acceleration is an extra one on top of all other factors.

Have the probes been caught into the gravity of an asteroid or similar that has not yet been discovered?

That seems unlikely. It's rare to encounter a body in space by accident and both Pioneers (which are on opposite ends of the solar system) seem to be experiencing an acceleration of roughly the same magnitude, which would be quite a coincidence.

[poleshift]

Thanks Waspie.

[Leonardo]

Here's another silly idea to be shot down in flames.

Could this be the result of a reflection of energy from the heliopause?

I know the solar wind slows down dramatically as the heliopause is approached, eventually to sub-sonic speeds. Well, I know sound doesn't travel in vacuum but it's not technically a vacuum and it could be possible some kind of weak wave energy is being reflected back from the sonic barrier/heliopause and this is having a small effect on these craft?

*waits for Waspie and Startraveler to show him how stupid the idea is*

Edited April 21, 2007 by Leonardo

[Startraveler]

Ignoring any physics, just the timing makes an idea like that suspect. The effect has been known since about 1980 when Pioneer 10 was 20 AU (a little more than a fifth of the way to the heliopause).

[wtwt5237]

Is there data available of how much deviation is there? If this deviation is not that much, we needn't pay too much attention. Anything can cause such deviation. Floating particles in space, gravity pull of small unknown celestial bodies or some kind of problems related to observation methods. If not, revolution in physics or astronomy is waiting for us, surely.

[Legatus Legionis]

Is there data available of how much deviation is there? If this deviation is not that much, we needn't pay too much attention. Anything can cause such deviation. Floating particles in space, gravity pull of small unknown celestial bodies or some kind of problems related to observation methods. If not, revolution in physics or astronomy is waiting for us, surely.

First of all. Unknown Celestial Objects in the solar system are quite very rare as Startraveler said

That seems unlikely. It's rare to encounter a body in space by accident and both Pioneers (which are on opposite ends of the solar system) seem to be experiencing an acceleration of roughly the same magnitude, which would be quite a coincidence.

and small particles in space would not affect the speed of the "Pioneers" in their current speed.