Friday, May 04, 2007

Good News: Perturbing the Peace

Prometheus perturbing Saturn's braided F Ring. This moon and others exist inside the "Roche Limit." It was once thought that this marked a demarcation line within which moons would be torn apart. Prometheus has one of the lowest densities of a solar system object, just 0.47 g/cm^3. That is less than 1/2 the density of liquid water. It is very odd that objects with less density than liquid should exist inside the Roche Limit, within which liquid objects are not supposed to exist.

Shepherd moons Prometheus and Pandora orbit on opposite sides of the Ring. These little moons could harbour something very dense within their cores. If Prometheus' 10^17 kg mass contained a 10^11 kg singularity, the moon would not be sucked up. Presence of a singularity would hold Prometheus together and also account for a magnetic field. The magnetic field of Prometheus has not been detected, but it will be.

Having followed this blog for nearly a year, you will be pleased to hear that a paper about GM=tc^3 has been accepted for publication by a major journal. This means a lot of work preparing illustrations and copyrights. It will lead to more publications, for other editors have been waiting for a major journal to take the lead. Publishing allows 49,000 subscribers to read a paper, far more than the audiences at conferences. Spreading a simple idea will not require so much travel.

On another subject, at the end of this month I hope to reveal a technology that will make human spaceflight safer, easier and far more comfortable.

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Blogger Kea said...

That's good news about the paper. As you say, there probably won't be 49000 conference goers at GRG18. Thanks for another great photo.

1:24 PM  
Anonymous Anonymous said...

Hi Louise,

I'm very glad to hear that your paper will get published. Let us know more as soon as you can.

As for Prometheus, I think many of the small objects of the asteroid belt have been shown to be like "piles of rubble" and their very low density is ascribed to a structure with a lot of empty space between the pieces. Does the limit you mention here apply as well to aggregate objects loosely bound ?


11:48 PM  
Blogger nige said...

Hi Louise,

Congratulations that things are going well with publishing in a journal. I hope you then can get get your paper on to, because that way you can make periodic updates to the paper if it needs expansion.

Best wishes,

4:39 AM  
Blogger L. Riofrio said...

HI all, and I hope to keep meeting people at conferences. Publishing means more work too, getting everything ready.

The Roche Limit would have appied to any liquid objects, even rubble piles. Now we know by example that small objects like Prometheus can exist inside the limit. We can't say for certain whether they contain super-dense objects in the cores, but this would be a good place to look.

Thanks, nige. Getting in major journals should force arxiv to finally publish. As you know, it has mutated into a repository of currently fashionable ideas.

6:59 AM  
Blogger L. Riofrio said...

Tommaso, a second thought on that subject:

I've asked this of Carolyn Porco, and modern theory is similiar to Lagrangian points. Earth's moon has an inner point L1 and an outer point L2 on the axis from Earth orbiting with the Moon. Between these points objects will fall toward the Moon. Outside the zone defined by these points they will drift away from the Moon due to Earth's influence.

Since Saturn is so massive, the zone of an object like Prometheus is quite narrow. Within this zone particles will drift toward Prometheus and the moon will continue to accrete.

HOWEVER, this does not explain how a moon got started. If the initial mass is zero, there is no safe zone and a moon will not accrete from small particles. A large initial mass is required, which leads one to suspect that something else could be involved.

8:24 AM  
Anonymous Anonymous said...

Congrats on the paper Louise!

Let us all know when it finally comes out (as your theory of light in slow motion is starting to make more sense than the dark energy theory that I've been hearing about.

Note: I'm not saying that dark energy can not exist, I'm just saying that it doesn't make that much sense as it implies an "ever filling energy source" which I find hard to grasp.

But I'll leave that to the scientists to debate.

6:57 AM  
Blogger CarlBrannen said...

Ewwwwweeeeee! I'm having way too much fun with my gravity simulator. I've just added a demonstration of the r=6 inner edge on the accretion disk of a black hole to the program, which now goes through a series of automatic demonstrations.

I can't do a Roche limit demonstration because it is a multi-body effect. It depends on the parts of the moon attracting each other more than the tidal forces.

Hmmm. I guess I could add some sort of cheat.


2:39 PM  
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