Sunday, September 18, 2011

Tidbits on Extrasolar Planets and Polonium Halos

I've been busy with a number of other projects of late, both work-related, and/or relevant to this blog, which has encroached on my writing time.  I may actually miss a few posts in the coming weeks as I work through these other projects.

One project near completion is my own N-body simulation (scholarpedia) code written in Python and running on modern hardware.  It can generate several types of plots and I can even generate output through the POVray ray-tracing software to make movies.  I've been testing the code with gravitational and electromagnetic problems.  This program will be used to provide a couple of visual examples for subjects discussed on this blog and I hope to start write-ups for it soon.

A side-benefit of developing the N-body code was that I also solved an algorithm issue that aided in the development of different work-related project - a small plasma simulation using PIC (Particle-in-Cell, wikipedia) methods.

Since I don't have a full regular post, I'll update on some recent news and other activities relevant to this blog.

More Exoplanets Imaged Directly
One of the YEC claims I've covered before (Another failed creationist prediction?)
suggested we would never have direct evidence of extra-solar planets.  Flying in the face of that claim are even more images of these extra-solar planets:
Wired: Exoplanet Portraits: Direct Images of Other Worlds

The discovery methods behind these extra-solar planets are also additional examples of of how astronomy knowledge grows by expanding on our existing knowledge base.   Many of these extra-solar planets were too faint to be imaged directly by technology of the day and many were first detected by their gravitational effects.  This approach has enjoyed much success throughout the history of astronomy and is currently part of the strategy in searching for Dark Matter (On Dark Matter. I: What & Why?, On Dark Matter. II: An Exotic Hack?)

Mystical Migrating Polonium...
I've already written a fair amount on Robert Gentry's claims about polonium halos (Polonium Halos as Evidence of a Young Earth? Polonium Halos). Here's an update with some new data I've uncovered.

I recently completed reading Richard Rhodes' book, "The Making of the Atomic Bomb" (Barnes & Noble).  In the chapter discussing the development of the neutron initiator for the atomic bomb (pp 579-580 in the Easton Press Collector's Edition), the author mentions an interesting problem with the polonium used in the initiator:
Thomas shipped the Po on platinum foil in sealed containers, but another nasty characteristic of polonium caused shipping troubles: for reasons never satisfactorily explained by experiment, the metal migrates from place to place and can quickly contaminate large areas.  "This isotope has been observed to migrate upstream against a current of air." notes a postwar British report on polonium, "and to translocate under conditions where it would appear to be doing so of its own accord."  Chemists at Los Alamos learned to look for it embedded in the walls of shipping containers when Thomas' foils came up short.
So even outside granites and micas, polonium has a track record of moving around on its own. 

The problem is mentioned again in  "Contribution of Chemistry in Early Day Los Alamos" by Penneman and Meade.  However, the authors of this report attribute the polonium migration to the recoil of the atom due to the alpha-particle decay.  I'm a little dubious of that claimed cause as one would probably expect to see similar behavior in other alpha-decay radioisotopes near the mass of polonium.  To my knowledge, polonium is unique in this migration characteristic in this part of the isotope table.  However, the decay channel through radon is part of the polonium decay chain.  Note in my chart below:

If your polonium sample has some trace of Po-218 (half-life approximately 3 minutes) from this decay series, some fraction of the nuclei will beta-decay (two green arrows) up to Rn-218 where transition to a gas phase can allow the isotope to move.  Later, the nuclei can alpha decay (red arrows)  back to Po-214 (half-life approximately 160 microseconds) and some may decay to Po-210 (half-life approximately 138 days).  I suspect this migrated polonium is actually from traces of Po-218 in the original sample. If you only perform chemical tests to identify polonium, researchers might not notice that the isotopic composition of the sample.  The alternate branches in this decay series suggest one could test this hypothesis looking for migration of other isotopes in the Rn-218 decay.

So we see that polonium can move around in modern times WITHOUT divine assistance!

9/20/2011 update: fixed some typos.
6/7/2014 update: fixed broken link to graphic

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