Hi everyone,
contribute today.
I was reading an article today about the next generation of
"invisibility cloak" that Duke University has created and it occurred
to me that this same metamaterial technique could be used to create a
low-mass, passive radiation shield.
Here are a couple of articles about it:
http://www.physorg.com/news151251853.html
http://www.technologyreview.com/computing/21971/?a=f
Most of the emphasis so far has been on moving the cloaked spectrum
towards the visible range. However, if the "cloak" was designed to
handle radiation more towards the x-ray portion of the electromagnetic
spectrum, whatever was in it's "shadow" would be protected.
If it was discovered that it was too hard to directly cloak the
higher-energy cosmic rays, we could possibly take advantage of the
fact that cosmic rays produce secondary, lower-energy radiation when
shielded by normal materials. We could put a thin aluminum (or some
other material) shell on the outside of the "cloak". The cloak would
then only have to handle radiation in the x-ray range.
What are your thoughts?
Jonathan Lee
I don't know, but my guess is that this kind of thing won't help with
radiation shielding. Copper is already quite effective at blocking
visible light: I think it wouldn't work if they tried it with
something that couldn't stop light to begin with.
One may be able to diffract photonic radiation (x-rays and, perhaps,
even gamma rays) with this method eventually. I think mass shielding
from accelerated particles (electrons, neutrons, protons, etc.) is still
the only known protection from this kind of radiation - especially
cosmic "rays". When cosmic "rays" strike atoms they produce a shower of
secondary accelerated particles. If charged, they might be deflected by
strong magnetic fields. The low tech approach is to have enough mass
between you and the particles to make sure they're absorbed by the
shield.
Chris
--- In spacesettlers@yahoogroups.com, "jlee72315" wrote: