Official "Science News" Thread

[ewmayer]

Originally Posted by xilman

I am very far from being an expert and I've no idea how to resolve the BH information loss issue, but here is my take.

AIUI (meaning imperfectly) information is "lost" in classical thermodynamics when you cease to pay attention to individual particles but instead decide to work with ensemble averages. The particles themselves continue to preserve information in terms of their momenta, etc, and if you were prepared to re-record their properties all the original information will still be there. A particular "random" state taken from the large number of random states which are a close enough approximation to a distribution in thermal equilibrium is unique --- it differs from all other states taken from any distribution and requires exactly the same amount of information to specify it as any other state whether taken from a distribution near or far from equilibrium.

The problem with GR and QM, again AIUI, is that the former doesn't know how to treat what happens at a singularity. On the face of it, nothing can happen at a singularity because by definition almost everything is either infinite or zero in size. GR allows a black hole to posess abitrary values only for its mass, angular momentum and electric charge. Everything else is either uniquely determined by those quantities or can not be determined at all. Information appears to fall into the latter class.

By way of thinking aloud:

1. Such recording imposes a cost - which gets back to the 'no free lunch" aspect of the 2nd law;
2. At some point the unique original data encoded in a thermalizing ensemble inevitably get smoothed below the threshold of distinguishability set by the uncertainty principle. Beyond that there is no meaningful concept of 'uniqueness', ergo the information is irretrievably lost;
3. From my own PhD field, there are known physical phenomena which incur not merely gradual but sudden irretrievable information loss, perhaps the best-known of which is fluid flow through a shock wave. It is mathematically provable that infinitely many different initial states can give rise to the same post-shock state, i.e. there has been irreversible information loss (and hence an entropy jump) on passage through the shock. I need to think some more on reconciling that purely-classical-sounding information loss phenomenon with the above QM-based one.

It just sounds very much to me - and Ross's link supports this - that the 'paradoxists' are invoking some kind of speculative 'new physics' which is contrary bith to the classical 2nd law and the uncertainty principle as the basis for their no-quantum-information-loss claim. But not being an expert in the field, I will continue reading and mulling over the issue. In any event it is interesting stuff to think about, especially when one needs a break from one's own workaday headaches. 'Trade one kind of headache for another!'

[LaurV]

Information theory:
ewmayer: There is a horse on aisle five
xilman: my house is full of traps

[Xyzzy]

http://www.financialexpress.com/arti...-study/128816/

[kladner]

Originally Posted by Xyzzy

http://www.financialexpress.com/arti...-study/128816/

“Finding such widespread estimates of plastic in seabirds is borne out by some of the fieldwork we’ve carried out where I’ve found nearly 200 pieces of plastic in a single seabird,” Hardesty said.

http://ocean.si.edu/slideshow/laysan-albatrosses%E2%80%99-plastic-problem

[rogue]

Originally Posted by kladner

http://ocean.si.edu/slideshow/laysan-albatrosses%E2%80%99-plastic-problem

That makes me think of an idea that I suggested to my boys a few weeks back for the next Syfy monster flick. Some scientist could breed giant birds to clean up the plastic in the oceans, but the birds quickly find out that humans taste much better. The could call it "Gullzilla".

[only_human]

Originally Posted by rogue

That makes me think of an idea that I suggested to my boys a few weeks back for the next Syfy monster flick. Some scientist could breed giant birds to clean up the plastic in the oceans, but the birds quickly find out that humans taste much better. The could call it "Gullzilla".

This wins the internet for the best Sharknado blended entertainment mashup. And it even has ecology, gastronomy, and possibly even evolutionary sub-themes. I'm betting it could also be used in schools to foster discussion.

[kladner]

Originally Posted by rogue

That makes me think of an idea that I suggested to my boys a few weeks back for the next Syfy monster flick. Some scientist could breed giant birds to clean up the plastic in the oceans, but the birds quickly find out that humans taste much better. The could call it "Gullzilla".

We have it coming.

I am waiting for some entrepreneur to start harvesting plastic from the ocean gyres
for re-refining.

[Xyzzy]

http://www.latimes.com/science/scien...901-story.html

[ewmayer]

Originally Posted by kladner

I am waiting for some entrepreneur to start harvesting plastic from the ocean gyres
for re-refining.

You need wait no more (at least for the entrepreneurs and their proposal to do just that):

Researchers sample enormous oceanic trash vortex ahead of clean-up proposal | Reuters

[Uncwilly]

Originally Posted by ewmayer

You need wait no more (at least for the entrepreneurs and their proposal to do just that):

Researchers sample enormous oceanic trash vortex ahead of clean-up proposal | Reuters

And there are a couple of names that going into production:
http://www.dezeen.com/2015/07/08/adi...ocean-plastic/

[kladner]

The Dutch project seems more likely to collect significant quantities of "stuff," were it to be implemented on a large enough scale. I wonder how they might handle the extreme range of particle sizes in the refuse.

I guess the Adidas item might be called 'consciousness-raising', but 'attention-getting' is equally descriptive.