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List of Unsolved Problems in Physics

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Re: List of Unsolved Problems in Physics

#3
post #2

I always find reading over this article pretty entertaining, in particular Sonoluminescence generally catches my attention: http://en.wikipedia.org/wiki/Sonoluminescence As it seems like it should be practical to replicate it on a relatively small budget.

Looks like they can reproduce it at will but they can't figure out why it happens.

Re: List of Unsolved Problems in Physics

#7
post #3
post #2

I always find reading over this article pretty entertaining, in particular Sonoluminescence generally catches my attention: http://en.wikipedia.org/wiki/Sonoluminescence As it seems like it should be practical to replicate it on a relatively small budget.

Looks like they can reproduce it at will but they can't figure out why it happens.

yep, I find it interesting that on a relatively small budget (hobbyist level) you can reproduce an experiment which exhibits unexplained physical phenomena.

It gives me some home that there's still interesting experimental physics to be done on a low budget. Potentially by hobbyists outside of a traditional industrial or academic framework.

Re: List of Unsolved Problems in Physics

#8
post #2

I always find reading over this article pretty entertaining, in particular Sonoluminescence generally catches my attention: http://en.wikipedia.org/wiki/Sonoluminescence As it seems like it should be practical to replicate it on a relatively small budget.

Its pretty hard to observe as the luminisence is ridiculously low.

Re: List of Unsolved Problems in Physics

#9
post #2

I always find reading over this article pretty entertaining, in particular Sonoluminescence generally catches my attention: http://en.wikipedia.org/wiki/Sonoluminescence As it seems like it should be practical to replicate it on a relatively small budget.

Its pretty hard to observe as the luminisence is ridiculously low.

Huh? The luminisence is for very short periods of time, but I don't believe it's particularly challenging to detect. I would imagine it's more challenging to setup the chamber. The first paragraph of the wikipedia article should tell you it's not that hard to detect:

"H. Frenzel and H. Schultes put an ultrasound transducer in a tank of photographic developer fluid. They hoped to speed up the development process. Instead, they noticed tiny dots on the film after developing and realized that the bubbles in the fluid were emitting light with the ultrasound turned on."

Other articles suggest photomultipler tubes have been used, with which you can detect single photons. PMT are relatively cheap (I've seen them for ~30USD on ebay), the motivation seems to be to get good time domain resolution. Even so other pages suggest that around 500,000 photons are produced. This should be relatively tractable.

Obviously it's not as easy as making an LED flash, but I can't see that it would be intractable for a hobbyist.

Re: List of Unsolved Problems in Physics

#10
"Ecliptic alignment of CMB anisotropy

Some large features of the microwave sky at distances of over 13 billion light years appear to be aligned with both the motion and orientation of the solar system. Is this due to systematic errors in processing, contamination of results by local effects, or an unexplained violation of the Copernican principle?"

Wait what? An unexplained violation of the Copernican principle? That's pretty crazy. What is being referred to? The article on the CMB says that it's isotropic to one part in a thousand

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