Arthur and the eclipse

by @ulaulaman about #ArthurEddington #AlbertEinstein #GeneralRelativity
On the 17th November 1922, Albert Einstein, accompanied by his wife, arrived in Kobe (see the report of the visit published on the AAPPS Bulletin - pdf). Here he was surrounded by journalists and fans: while the first asked him questions, the latter were on the hunt for an autograph from one of the most famous physicists and scientists of the time. Einstein, as written by Naoki Urasawa on the initial pages of Billy Bat #9, to a specific question on why he won the Nobel Prize for the photoelectric effect and not for the theory of special and general relativity, replied:
Because, that can't be verified.
But the mangaka committed a chronological mistake, probably caused by the Urasawa's need to focus on the innovation represented by the Einstein's theories: the point, in fact, is that just three years earlier, on the 6th November, 1919, during a meeting of the Royal Society and Royal Astronomical Society, Arthur Eddington presented the results of the celestial observations made ​​in mid-spring of that year. The interest and the importance of the discovery was such that the next day, the Times headlined:
Revolution in Science: New Theory of the Universe: Newton's Ideas Overthrown, by Joseph John Thomson:
Our conceptions about the structure of the universe must be changed in a fundamental way
So, when Einstein went to Japan, the evidence of the correctness of his theory had already been around.

The hobbit, the dragon, and the green knight

by @ulaulaman about #TheHobbit #JRRTolkien #Smaug #mathematics

Gandalf and Bilbo by David Wenzel
The Peter Jackson's Hobbit movie trilogy is arrived to a conclusion, so it could be a good point to write a little, funny curious post about the science and the Tolkien's novel. We start with a paper published last year(1) (2013) in which the researchers find the cause of the triumph of good over evil:
Bilbo Baggins, a hobbit, lives in a hole in the ground but with windows, and when he is first encountered he is smoking his pipe in the sun overlooking his garden (it is worth noting [parenthetically] that smoking is itself associated with skeletal muscle dysfunction6). Dwarves and wizards smoke too, and the production of smoke rings is unfortunately glamourised. The hobbit diet is clearly varied as he is able to offer cake, tea, seed cake, ale, porter, red wine, raspberry jam, mince pies, cheese, pork pie, salad, cold chicken, pickles and apple tart to the dwarves who visit to engage him in the business of burglary. The dwarves also show evidence of a mixed diet and, importantly, although they “like the dark, the dark for dark business”, they do spend much time above ground and have plenty of sun exposure during the initial pony ride in June that begins their trip to the Lonely Mountain.
Gollum, himself "as dark as darkness" lives in the dark, deep in the Misty Mountains. He does, however, eat fish, although the text describes these only as "blind" and it is not clear whether they are of an oily kind and thus a potential source of vitamin D. He sometimes eats goblins, but they rarely come down to his lake, suggesting that fish play little part in the goblin diet. Interestingly, these occasional trips to catch fish are undertaken at the behest of the Great Goblin, leading one to speculate that his enhanced diet may have helped him to achieve his pre-eminent position within goblin society. In due course, the Great Goblin is replaced by the Son of the Great Goblin. While simple nepotism is a likely explanation, we are unable to exclude an epigenetic process whereby the son’s fitness to rule has been influenced by parental vitamin D exposure.(1)
So the secret is in the diet!
Another great character from The Hobbit is Smaug, the dragon. Its physiology is really peculiar (read also Disco Blog):

When and why the coffee spills the #physics of spilling and walking with #coffee
How do we spill coffee?
(a) Either by accelerating too much for a given coffee level (fluid statics)
(b) Or, through more complicated dynamical phenomena:
  • Initial acceleration sets an initial sloshing amplitude, which is analogous to the main antisymmetric mode of sloshing.
  • This initial perturbation is amplified by the back-and-forth and pitching excitations since their frequency is close to the natural one because of the choice of normal mug dimensions.
  • Vertical motion also does not lead to resonance as it is a subharmonic excitation (Faraday phenomena).
  • Noise has higher frequency, which makes the antisymmetric mode unstable thus generating a swirl.
  • Time to spill depends on "focused"/"unfocused" regime and increases with decreasing maximum acceleration (walking speed).
How can we prevent spilling?
Lessons learned from sloshing dynamics may suggest strategies to control spilling, e.g. via using
  • a flexible container to act as a sloshing absorber in suppressing liquid oscillations.
  • a series of concentric rings (baffles) arranged around the inner wall of a container.

Text via Walking with coffee: when and why coffee spills (pdf)
More information on physics buzz blog
Paper: Mayer H.C. & Krechetnikov R. (2012). Walking with coffee: Why does it spill?, Physical Review E, 85 (4) DOI: (pdf)