Mysterious force holds back Nasa probe in deep space

[APODman]

"Researchers say Pioneer 10, which took the first close-up pictures of Jupiter before leaving our solar system in 1983, is being pulled back to the sun by an unknown force. The effect shows no sign of getting weaker as the spacecraft travels deeper into space, and scientists are considering the possibility that the probe has revealed a new force of nature.

Dr Philip Laing, a member of the research team tracking the craft, said: "We have examined every mechanism and theory we can think of and so far nothing works.

"If the effect is real, it will have a big impact on cosmology and spacecraft navigation," said Dr Laing, of the Aerospace Corporation of California.

Pioneer 10 was launched by Nasa on March 2 1972, and with Pioneer 11, its twin, revolutionised astronomy with detailed images of Jupiter and Saturn. In June 1983, Pioneer 10 passed Pluto, the most distant planet in our solar system.

Both probes are now travelling at 27,000mph towards stars that they will encounter several million years from now. Scientists are continuing to monitor signals from Pioneer 10, which is more than seven billion miles from Earth.

Research to be published shortly in The Physical Review, a leading physics journal, will show that the speed of the two probes is being changed by about 6 mph per century - a barely-perceptible effect about 10 billion times weaker than gravity.

Scientists initially suspected that gas escaping from tiny rocket motors aboard the probes, or heat leaking from their nuclear power plants might be responsible. Both have now been ruled out. The team says no current theories explain why the force stays constant: all the most plausible forces, from gravity to the effect of solar radiation, decrease rapidly with distance.

The bizarre behaviour has also eliminated the possibility that the two probes are being affected by the gravitational pull of unknown planets beyond the solar system.

Assertions by some scientists that the force is due to a quirk in the Pioneer probes have also been discounted by the discovery that the effect seems to be affecting Galileo and Ulysses, two other space probes still in the solar system. Data from these two probes suggests the force is of the same strength as that found for the Pioneers."

The complete text in: http://www.telegraph.co.uk/science/space/1384420/Mysterious-force-holds-back-Nasa-probe-in-deep-space.html

More about the Pionner Anomaly in:
"Study of the anomalous acceleration of Pioneer 10 and 11"
John D. Anderson1,*, Philip A. Laing2,†, Eunice L. Lau1,‡, Anthony S. Liu3,§, Michael Martin Nieto4,**, and Slava G. Turyshev1,††  
- http://arxiv.org/abs/gr-qc/0104064v5

[ ]´s

[Naru523]

In June 1983, Pioneer 10 passed Pluto, the most distant planet in our solar system.

Haha. This proves Pluto is still a planet! Joking...

But it's really weird. I wonder what kind of force it is, and how does it works. Maybe the gravity of the planets pull the probes too?... Hm. Oh well, NASA will have to take care of this force.

The universe is really weird.

EDIT: So this also eliminates the possibilities of another unknown planet beyond? Looks like the Nemesis theory was fail... Or... something.

[atomic7732]

The article says "slowing down" but all that I have heard about was mysterious ACCELERATION. Maybe negative acceleration? (deceleration?)

[deoxy99]

Looks like the Nemesis theory was fail... Or... something.

Wrong? Is that the word you were looking for?

[atomic7732]

Hmmm... was Pioneer 10 a member of the Universe Sandbox Forum, Dan?

(Darvince )

[Darvince]

Hmmm... was Pioneer 10 a member of the Universe Sandbox Forum, Dan?

(Darvince )

. I'm a human being. You need to pass the fuzzy word test for the chat and Pioneer 10 can't do that because it is a computer.

[Laura]

The article says "slowing down" but all that I have heard about was mysterious ACCELERATION. Maybe negative acceleration? (deceleration?)

In physics any force acting to influence the motion of a body is called acceleration. There is no deceleration - just acceleration opposite to the current vector of the body.

As for what's really going on.... good question!
It could be that gravity isn't subject to inverse square falloff all the way, but is close enough to having made it seem that way so far. Probably not, but it must be considered.
Or it could be more friction in the outer solar system than previously thought possible.
Or maybe dark matter within the solar system itself?

We know that something weird is going on with galaxies, as they shouldn't behave as they do given the laws we know. Perhaps this is evidence of that same kind of behavior on a much smaller scale?

[atomic7732]

You didn't get it Darvince?

You said "A strange force is bringing old people from the forum back".

So, was Pioneer 10 a member of the forum?

Actually, I was thinking about black holes, and I was thinking how they get started sucking in. Since Pioneer is outside all objects within the Kuiper Belt, every object there is acting like the sun, maybe pulling it back in? It could also be a miscalculation of the escape velocity to reach outside our solar system (possibly due to the same reason). Maybe there is alot of debris out in interstellar space (Laura's friction idea)... I think 3 of the 4 that were shot out of the solar system reached the heliopause, and if I am not mistaken that's the boundary of our solar system to interstellar space.

[Laura]

I was thinking, like NeutronStar, that it might be the combined mass of the Kuiper-belt objects adding a little to the gravity, but the article states that the effect is also present with newer probes that haven't yet gone that far.

[atomic7732]

Good point. I think I remember hearing Pioneer measured a 35 millisecond difference than was expected when it shot by Earth on the way out of the solar system... Something like that.

But wait, still, the combined mass of anything in an orbit where it is closer ot the sun, so the further out you get, the stronger the force is... So if it passed by Earth, all the sattellites inside it's orbit may have caused the differnece?