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Friday, March 13, 2015

How chameleons change their colour?

With a little help from Raman spectroscopy, Swiss scientists have found the answer to an endlessly intriguing evolutionary poser. 

It turns out that chameleons have a mobile “lattice” of#nanocrystals on the surface of their skin, which come together, change shape and disperse thereby shifting the wavelength of light reflected by the reptile.

Scientists studied the panther chameleon Furcifer pardalis from Madagascar, known for its particularly dynamic colour changing abilities — going from green to red within minutes — especially during social interactions such as courtship or male-male combat. These #nanocrystals — of different shapes, sizes and organizations — are distributed in two layers of skin cells called #iridophores (iridescent light-reflecting cells). While the upper layer of iridophores is responsible for rapid colour change achieved by a shift in spacing of nanocrystals in a triangular lattice, the deeper layer of cells broadly reflects light, especially in the near-infrared range, the scientists report in Nature Communications.

The distance between crystals is on average 30 per cent less in the resting state (blue or green skin) than it is in the excited state (yellow or white). With an increase in distance between nanocrystals in excited male panther chameleons, iridophores shift their selective reflectivity from short (blue) to long (red or infrared) wavelengths, causing the corresponding shift from green to yellow/orange skin, says the paper.

Chameleons originated in post-Gondwanan Africa around 90 million years ago. The way these iridophores are organised allows some species “to combine efficient camouflage with spectacular display,” while also potentially providing passive thermal protection.

Read more about this here:

‪‎Physics of the Impossible by Michio Kaku - ‪Review

The "impossibilities" in Physical Life have been narrated well with skirmishing incidents of the Bohr-Einstein-Schrodinger era debates that are found written in many books. But Michio Kaku takes the reader beautifully into some impossibilities predicted by Physics which could become possible in the years to come (I am yet to read his book "Physics of the Future"). Occasionally a few pages are very
interesting, nevertheless, the reader is never distracted. Quotes from Bohr, Pauli, Sagan and others are very interesting. The analysis about symmetry on which physics is now based and the nature's laws connected with predators and preys are very reasonable. The prey is always faster than the predator!
A few classifications are significant:
"Class 1 Impossibilities: These are technologies that are impossible today but that do not violate the known laws of physics. So they might be possible in this century, or perhaps the next. They include teleportation, anti-matter engines, certain forms of telepathy, psycho kinesis, and invisibility.
“Class 2 Impossibilities: These are technologies that sit at the very edge of our understanding of the physical world. If they are possible at all, they might be realized on a scale of millennia to millions of years. They include time machines, the possibility of hyperspace travel, and travel through wormholes.”
“Class 3 impossibilities: These are technologies that violate the known laws of
physics. Surprisingly, there are vary few such technologies. If they do turn
out to be possible they would represent a fundamental shift in our understanding of physics.”
And the Civilizations that would bother these:
Type 1 civilization: Those that harvest planetary power, utilizing all the sunlight that strikes their planet. They can, perhaps, harness the power of volcanoes, manipulate the weather, control earthquakes, and build cities on the oceans. All planetary power is with in their control.
Type 2 civilization: Those that can utilize the total power of their sun, making them 10 billion times more powerful then a type 1 civilization. A type 2 civilization in a sense, is immortal; nothing known to science, such as ice ages, meteor impacts, or even supernovae, can destroy it.
Type 3 civilization: Those that can utilize the power of an entire galaxy. They are 10 billion times more powerful then a type 2 civilization. The Borg in Star Trek, the Empire in Star Wars, and the galactic civilization in Asimov’s Foundation series correspond to a type 3 civilization. They have colonized entire star systems and can exploit the black hole at the center of their galaxy. They freely roam the galaxy.
This apart, his views on Ramjet, Telepathy, Force Fields,Invisibility, Energy Weapons, Teleportation, Psychokinesis, Robots, UFOs & Aliens,Space Travel (including Faster Than Light travel & Particle) Parallel & Alternate Universes, Time Travel, Perpetual Motion Machines, Precognition, Parallel Universe and perpetual motion, make the book very interesting one.
The ‪#‎Quantum‬ era incidents including the Dirac's ignorance to patent his equation on ‪#‎Relativity‬ theory, because of which gadgets exist in our hands, truly refresh our sense of inclination towards Physics, in particular and Science, in general.
That the entire Universe/Multiverse has dark energy to about 73%, with the energy by humans amounting to only about 0.03% is truly astonishing (while computing zero point energy) and shows the long way one has to cover to understand the Creator.