The PIONEER anomaly

[PacSubCom]

A recent piece on Spiegel online reminded me of that mysterious and fascinating phenomenon: The Pioneer anomaly, which I'd like to put to your attention.

http://en.wikipedia.org/wiki/Pioneer_anomaly

http://www.planetary.org/programs/pr...te_200511.html

Two space probes, Pioneer 10 and 11, launched in 1972 and 73, show some curious deviation form their flight paths as they continue to leave the solar system. This is known for quite some time now. An unknown force is pulling at the two spacecraft, as if the sun's gravitation is stronger than we know it to be. The moment has arrived when scientists have almost ruled out the systematic explanations, like measurement errors and radiation pressure from the craft's nuclear energy source. The force is acting on both craft in the same way and the same strength, so local phenomena like asteroid gravity can be ruled out too.

While explanations like these seem to become more and more unlikely, the remaining explanations start to send "shivers down the spines" of scientists everywhere, and I must admit that even I can feel a cold hand resting upon my shoulder...physics as we know it - is wrong.

Some of our natural constants are wrong. Gravity is not doing what we think it should be doing. The new force is somewhere near the product of the hubble constant and the speed of light, suggesting a connection to the expansion of the universe. Or does light (or time...) experience acceleration?

In March, a last attempt was made to contact Pioneer 10, 87 AU out, and gain one last bit. of information. It did not respond.

There already is a proposal to do a dedcated mission, ENIGMA, to explain the pioneer anomaly. It would require the enigma craft to fly out 200 AU or more. Is this one of the first measurements of the "new science" with its braneworlds, dark energies and matter?

[bdh]

There already is a proposal to do a dedcated mission, ENIGMA, to explain the pioneer anomaly. It would require the enigma craft to fly out 200 AU or more. Is this one of the first measurements of the "new science" with its braneworlds, dark energies and matter?

It could be good news. The only thing disconcerting about this affair, to me anyway, is that the force is moving BACK towards the Sun rather than away. Getting out of the solar system could be harder than we thought....

The be-all end-all. Coming soon in Southern France.

Hehe, fusion

[Invoker]

Eh, I think we've known for a while that our physics system is wrong, like all previous ones, and we need to reform it and base things off a new theory.

Gravity does work like equations show it should when it comes to galaxy rotation. So scientists proposed "dark matter" which would make up for the lack of mass which was causing the equations to be wrong. There's no evidence of dark matter's existence, and I think it's much more probable that our theories of gravity are off.

Problem being, how exactly do we figure out how gravity works? It will require a lot of money, time, and at least one revolutionary physicist on the level of Newton and Einstein.

[Amalith]

their could be something besides the suns gravitational pull. Like maybe some extrasolar body they didn't know existed.

How long would it take that ENIGMA to get out their?

[Invoker]

their could be something besides the suns gravitational pull. Like maybe some extrasolar body they didn't know existed.

How long would it take that ENIGMA to get out their?

It depends on what engines they use. If they use something that most satellites of that kind use, it'll be a long time to get out to 200 AU. Voyager 1 is the furthest satellite from earth, launched in 1977 and only in 2006 has it passed the 100 AU mark and entered the heliosphere and terminal shock. Any satellite at that distance couldn't rely on solar energy, and Voyager and its companions out in deep space are just coasting along. A nuclear powered satellite could do it a lot faster, but it'd be expensive like nothing else, and it'd still take a long time.

200 AU is 18,600,000,000 miles, or 29,933,798,400 kilometers. Take some of the fastest objects we have ever made. The space shuttle and other satellites in low earth orbit travel at about 28,000 km/hour. It'd take about 122 years at that speed. The Helios 2 space probe reached a top speed of 252,792 km/hr, which is insane in my opinion, even faster than the speed of the earth orbiting the sun, and even at that speed a journey to 200 AU would take about 13 and a half years. Light itself takes over a day to reach that distance.

What's even more amazing about the numbers I just gave is how small they are even. 200 AU is a little over a light-day (the distance light travels in a day in a vacuum). The nearest star, Alpha Centauri, is 4.3 light-years distant, well over 1500 times a light day. So, no matter how we launch something into space, it's going to take a long time to get there until we discover near light speed travel. And when it comes to traveling the stars, we had better either find a way to teleport or travel faster than light.

[PacSubCom]

The force is not strong enough to hamper anybody who wants to leave the solar system and has the means to do it.

[bdh]

The force is not strong enough to hamper anybody who wants to leave the solar system and has the means to do it.

Not nescessarilly. Over a long enough period of time, even the slightest acceleration can cause an object to stop completely. We simply don't know enough about the force to describe its properties. You would need constant propulsion to counter it, and propellant isn't readily available in deep space.

[PacSubCom]

Not nescessarilly. Over a long enough period of time, even the slightest acceleration can cause an object to stop completely. We simply don't know enough about the force to describe its properties. You would need constant propulsion to counter it, and propellant isn't readily available in deep space.

The newly found acceleration term acting on the probe is (8.74 ± 1.33) × 10−10 m/s2. The normal gravitational acceleration acting on the probe at 87 AU is 6.82 × 10-5 m/s2. Five orders of magnitude.

Edit: More clearly maybe, if your spacecraft is subject to the force for 100 years, it amounts to a speed decrease of only 2.75 m/s. You would be mere 4 million kilometers short of where you are supposed to be without the force. After 10,000 years, the deviation would be 40 billion kilometers, more than a solar system's width, but still little compared to the distances to the neigboring stars. To stop the spacecraft it would take millions of years.

And only if the force remains constant over the whole journey, and only if the target star hasn't a corresponding effect that accelerates you. You hopefully will have arrived before 10,000 years have gone by anyway. Even if the effect is constant over the whole universe, which would be very peculiar to say the least, because it would mean that we are kind of the center of the universe, the force wouldn't be a big problem for interstellar exploration.

[bdh]

And only if the force remains constant over the whole journey

All of your calculations are correct, but I still think that the potential for the force to change could be problematic. Though I must concede the point.

and only if the target star hasn't a corresponding effect that accelerates you.

That would be a good benefit and, I imagine, cancel out the effects even if the acceleration of the unknown force grew greatly.

[mysticflame]

Man, I didn't know anything about this. It's kind of spooky. Hopefully it's just an observational error. Lots of them.

A 200 AU mission? That is a hell of a long way. Voyager one was launched nearly 30 years ago and it's still only half that distance.


And also...

The be-all end-all. Coming soon in Southern France.

Nice.