Pioneer Anomaly... Solved?

[DeltaV]

I hope they are wrong. I'd rather have it be due to "new" physics. But I'll have to accept their result if it withstands scrutiny.

http://arxiv.org/PS_cache/arxiv/pdf/110 ... 5222v1.pdf

...the acceleration arising from thermal radiation effects has a similar order of magnitude to the constant anomalous acceleration...

[TallDave]

Seems plausible. Boring, but plausible.

[Giorgio]

Neat and clean.
I don't think there is much more to be said on the issue.

[CaptainBeowulf]

I'd rather that we know the truth than fantasize about "new" physics.

That said, we still don't really know how gravity works, and I still think it's possible that we'll eventually figure out how to generate and use artificial gravity fields for propulsion etc. However, in terms of that objective, it's good to rule out "dead ends."

Anyone hear anything about Tajmar's work recently?

[chrismb]

we'll eventually figure out how to generate and use artificial gravity fields for propulsion etc.

Let's assume we could generate linear artificial gravity: If we can't use electric or magnetic forces for propulsion, why do you think it'd be any easier to use artificial gravity?

[bcglorf]

we'll eventually figure out how to generate and use artificial gravity fields for propulsion etc.

Let's assume we could generate linear artificial gravity: If we can't use electric or magnetic forces for propulsion, why do you think it'd be any easier to use artificial gravity?

We are pretty deep in a relatively large gravity well. I always figured if we could manipulate gravity fields like we can electric and magnetic ones it would help a great deal in getting mass out of Earth's well.

[Giorgio]

Anyone hear anything about Tajmar's work recently?

His last published paper was from September 2009.
Nothing new from him since then.
Maybe they are getting into some deep experimental phase or maybe they dropped the issue as noise error.

[CaptainBeowulf]

Maybe they are getting into some deep experimental phase or maybe they dropped the issue as noise error.

It looked like that was a distinct possibility (the noise error), but I'd like some confirmation yes/no from the experimenters. Oh well.

Science fiction and speculation often portrays gravity drives as extremely powerful, allowing you to make flying disks or cylinders which generate enough gravity to repel themselves away from a planet's surface rapidly. It may be that this is completely unrealistic; however, even if you generate a field which only repels weakly against the planet's gravity, or masks some of the mass of an object, you might be "effectively" reducing the weight of a launch vehicle by some percentage. Even a reduction of 10-15% would be big, as you'd get the increasing returns of then having to carry less fuel to launch the same weight, meaning even less weight, and also less LV structure to hold less fuel volume, meaning even less weight. So maybe you could build robust SSTO vehicles then, even though they would still have a ring of thrusters around the gravity field generator.

Of course, if the grav field generator ends up being really heavy, it would cancel out any benefit. We just have to wait and see.

[chrismb]

we'll eventually figure out how to generate and use artificial gravity fields for propulsion etc.

Let's assume we could generate linear artificial gravity: If we can't use electric or magnetic forces for propulsion, why do you think it'd be any easier to use artificial gravity?

We are pretty deep in a relatively large gravity well. I always figured if we could manipulate gravity fields like we can electric and magnetic ones it would help a great deal in getting mass out of Earth's well.

OK, sure, whilst in a gravity well the manipulation of an opposing field (if that is possible - this is just drilling down a bit further on this) would likely mean being able to get off of the earth's surface. But once faster than the escape velocity and a goodly distance off out of the solar system, how would artificial gravity fields then be 'propulsion'.

So an artificial gravity field might accomplish 'levitation', but I don't see how it could accomplish 'propulsion'.

[bcglorf]

Let's assume we could generate linear artificial gravity: If we can't use electric or magnetic forces for propulsion, why do you think it'd be any easier to use artificial gravity?

We are pretty deep in a relatively large gravity well. I always figured if we could manipulate gravity fields like we can electric and magnetic ones it would help a great deal in getting mass out of Earth's well.

OK, sure, whilst in a gravity well the manipulation of an opposing field (if that is possible - this is just drilling down a bit further on this) would likely mean being able to get off of the earth's surface. But once faster than the escape velocity and a goodly distance off out of the solar system, how would artificial gravity fields then be 'propulsion'.

So an artificial gravity field might accomplish 'levitation', but I don't see how it could accomplish 'propulsion'.

But your missing the smaller picture .

Getting things out of Earths gravity well right now is the most expensive and difficult part. If we can easily and safely lift mass into LEO, we can send up navy style nuke reactors linked to huge arrays of ion drives to zip around the solar system. We could do that already sure, but the cost with chemical propulsion is... prohibitive.

[chrismb]

Fair enough, but that would be written as using gravity fields to enable XYZ, rather than to propel XYZ.

[AcesHigh]

we'll eventually figure out how to generate and use artificial gravity fields for propulsion etc.

Let's assume we could generate linear artificial gravity: If we can't use electric or magnetic forces for propulsion, why do you think it'd be any easier to use artificial gravity?

Doesnt a MagLev train fits that description?

[kunkmiester]

Maglev train works against magnets in the track. Moot example.

Gravity seems to have very far reaching affects, we're even affected, although insignificantly, by the gravity of starts light years away. Within the solar system, working against the various planets, you could pretty much go anywhere in the system of interest.

Thats also assuming it doesn't work to put a black hole on the end of a big stick and do a carrot-and-mule like Alan Dean Foster's KK drive.