Pioneer spacecraft mystery may be laid to rest

New Scientist Space ^ | 15 April 2008 | Valerie Jamieson

[AndrewC]

Pioneer spacecraft mystery may be laid to rest

14:30 15 April 2008

NewScientist.com news service

Valerie Jamieson, St Louis

What is making NASA's twin Pioneer spacecraft mysteriously drift off course, apparently defying the laws of physics? A rigorous new analysis suggests ordinary heat emission can at least partly explain the wayward probes' strange trajectories.

Pioneer 10 and 11 were launched in the early 1970s and explored the outer solar system. But in 1980, mission scientists noticed that the spacecraft have unexpectedly drifted off course.

Both spacecraft have been pulled a little harder than expected towards the sun, and since their launch, they have drifted off course by hundreds of thousands of kilometres.

...

The uneven heat emission is enough to nudge the spacecraft off course, accounting for 28% to 36% of the anomaly detected when Pioneer 11 was 3750 million kilometres, or 25 times the Earth-sun distance, away from us.

[AndrewC]

It's those heavy heat particles.

[AndrewC]

Ping

[GeorgiaDawg32]

1) Global Warming

2) Bush’s fault

[NonValueAdded]

falling under the influence of V’ger?

[RightWhale]

Dr Kaku mentioned a couple weeks ago that several papers are in preparation because of this anomaly and the slingshot anomaly. Don’t know if this is part of that work.

[GeorgiaDawg32]

ROFL..GMTA..That was my first thought..only this would be caller P’eer

[Hegemony Cricket]

P’eer pressure?

[DManA]

accounting for 28% to 36% of the anomaly

Laid to rest? After accounting for a third of the anomaly? Pretty sloppy science I'd say. Tiny fractions of a percent anomalies have lead to enormous discoveries.

[Swordmaker]

Are they saying it’s caused by “Global Warming?”

Unless they can show some kind of consistent vector for these “heat emissions” they have a problem with this theory. Such emissions would radiate with an essentially equal force in all directions in a globular pattern averaging out any thrust.

[urabus]

So much for escaping the Solar System!

[JRios1968]

All your Pioneer are belong to us!

[BitBucket]

Hitchhiking thetans from the van Allen belt?

[Enchante]

"Laid to rest? After accounting for a third of the anomaly? Pretty sloppy science I'd say"

Or perhaps a piss-poor headline and story. I didn't see any indication that the researchers themselves claim that the anomaly will be completely explained here.....

[DManA]

Science reporting is horrible and getting worse.

[RightWhale]

Yes, however math and science are declining as school subjects, so perhaps the dumbed-down approach after all is only appropriate to their audience.

[Lonesome in Massachussets]

It's those heavy heat particles.

I can't tell if you're kidding, man. Radiation pressure is real, heat causes thermal radiation.

(Einstein derived the formula E = mc2 as an addendum to his 1905 paper on relativity, actually reasoning that the mass of radiation is related to its energy, m = E/c2 from considerations of radiation pressure.)

Most of the radiation pressure on objects in space is caused by reflection of solar radiation. Reflection actually imparts twice the impulse that absorbtion does. Absorbed radiation is ultimately reradiated, but perhaps not as directionly, some component of the scattered velocity in the same direction as the incident, thereby partially cancelling the effect of absorbtion.

Radiation pressure is never more than a few millionths of the effect of gravity, but integrated over time, the effect is measurable.

[SunkenCiv]

Thanks AndrewC.

pioneer anomaly site:freerepublic.com

Google

[CougarGA7]

[SunkenCiv]

Thanks AndrewC. TVF's take on it.

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[AndrewC]

I was kidding, but I don't think that the probes have an inadvertant heat thruster pointed towards the sun. I also would guess that the thermal radiation from the sun along with whatever solar wind remains at that distance would overwhelm the contribution that chance heat would impart. (the variances of the two mentioned sources I would expect to be larger than the total directional output from heat.)

p=h/λ is rather small for "heat"