Author: mosqueeto

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Scientist Developed The Guitar Hero of Birds

Originally shared by Yi Yao

Scientist Developed The Guitar Hero of Birds

Bird song hero is a new, visual way to learn bird songs. With the help of spectrogram visualization, you will be able to visualize the unique qualities of each song and commit sound patterns to memory.

The game is quite popular in twitter now, why not give it a try?

http://biology.allaboutbirds.org/bird-song-hero/?_ga=1.255840136.1248268842.1402322118

 

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Searching for Sugar Man

 

Originally shared by Buddhini Samarasinghe

Searching for Sugar Man

If you watch just one documentary this year (or month, or week -depending on how often you watch them), make it this one. In the late 1960s, amidst the height of the apartheid in South Africa, a bootleg recording of an album titled ‘Cold Fact’ by a mysterious American artist known as Rodriguez suddenly became a phenomenon. But his album failed miserably in America, and there were rumours about a gruesome onstage suicide – one in which he set fire to himself. After that, he disappeared into oblivion. But two South African fans turned into musical detectives to find out more about what really happened to him. The story is incredible, with an unbelievable plot-twist. I won’t give it away, but it is a humbling, poignant story that was gripping from start to finish. 

And it goes without saying, but the soundtrack is amazing – all original music from Rodriguez. 

For those in the UK, you can watch this on BBC iPlayer: http://goo.gl/e313nI

For those outside the UK, this link should work: Sugar Man

Full album ‘Cold Fact’ on YouTube: Sixto Rodriguez- Cold Fact full album

 

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24, the Monster, and quantum gravity

Originally shared by Richard Green

24, the Monster, and quantum gravity

Think of a prime number other than 2 or 3. Multiply the number by itself and then subtract 1. The result is a multiple of 24. This observation might appear to be a curiosity, but it turns out to be the tip of an iceberg, with far-reaching connections to other areas of mathematics and physics.

This result works for more than just prime numbers. It works for any number that is relatively prime to 24. For example, 25 is relatively prime to 24, because the only positive number that is a factor of both of them is 1. (An easy way to check this is to notice that 25 is not a multiple of 2, or 3, or both.) Squaring 25 gives 625, and 624=(24×26)+1.

A mathematician might state this property of the number 24 as follows:

If m is relatively prime to 24, then m^2 is congruent to 1 modulo 24.

One might ask if any numbers other than 24 have this property. The answer is “yes”, but the only other numbers that exhibit this property are 12, 8, 6, 4, 3, 2 and 1; in other words, the factors of 24.

The mathematicians John H. Conway and Simon P. Norton used this property of 24 in their seminal 1979 paper entitled Monstrous Moonshine. In the paper, they refer to this property as “the defining property of 24”. The word “monstrous” in the title is a reference to the Monster group, which can be thought of as a collection of more than 8×10^53 symmetries; that is, 8 followed by 53 other digits. The word “moonshine” refers to the perceived craziness of the intricate relationship between the Monster group and the theory of modular functions.

The existence of the Monster group, M, was not proved until shortly after Conway and Norton wrote their paper. It turns out that the easiest way to think of M in terms of symmetries of a vector space over the complex numbers is to use a vector space of dimension 196883. This number is close to another number that is related to the Leech lattice. The Leech lattice can be thought of as a stunningly efficient way to pack unit spheres together in 24 dimensional space. In this arrangement, each sphere will touch 196560 others. The closeness of the numbers 196560 and 196883 is not a coincidence and can be explained using the theory of monstrous moonshine.

It is now known that lying behind monstrous moonshine is a certain conformal field theory having the Monster group as symmetries. In 2007, the physicist Edward Witten proposed a connection between monstrous moonshine and quantum gravity. Witten concluded that pure gravity with maximally negative cosmological constant is dual to the Monster conformal field theory. This theory predicts a value for the semiclassical entropy estimate for a given black hole mass, in the large mass limit. Witten’s theory estimates the value of this quantity as the natural logarithm of 196883, which works out at about 12.19. As a comparison, the work of Jacob Bekenstein and Stephen Hawking gives an estimate of 4π, which is about 12.57.

Relevant links

Wikipedia on the Monster group: http://en.wikipedia.org/wiki/Monster_group

Wikipedia on the Leech lattice: http://en.wikipedia.org/wiki/Leech_lattice

Wikipedia on Monstrous Moonshine: http://en.wikipedia.org/wiki/Monstrous_moonshine

A 2004 survey paper about Monstrous Moonshine by Terry Gannon: http://arxiv.org/abs/math/0402345