Beauty in Physics
prof. dr. E.A. (Eric) Bergshoeff
What makes equations correct? Are we looking for one super equation which describes the world around us, or is it not that simple? Why are we so hung on the fact that the laws of nature must have some sort of elegance and what are the criteria for this? During this talk about physics the aforementioned, and other, questions will be reviewed.
Beautiful optics on the wing: birds, butterflies and beetles
prof. dr. D.G. (Doekele) Stavenga
The wings of many birds, butterflies and beetles are strikingly patterned by colorful
feathers and scales. Structural coloration occurs through the application of thin films,
multilayers, or 3D-photonic crystals, sometimes in complex combinations and together
with pigments. Thin films are widely applied in animal coloration. They are combined
with pigmented multilayers in the breast feathers of the bird of paradise Lawes's Parotia
(Parotia lawesii), allowing sudden changes from blue to green to golden colors. The
silvery color of the nape feathers is due to regularly arranged melanin rodlets that
create a reflective multilayer. The cortex of the feather barbs of the Common Kingfisher
(Alcedo atthis) also acts as a thin film. In the orange breast feather barbs the cortex
envelopes pigmented cells, but in the blue back feathers and the cyan tail feathers the
cortex envelopes spongy cells, which act as quasi-ordered photonic crystals. Many
butterflies use brightly reflecting multilayers, e.g. the famous Morphos and the common
blues, but others employ gyroid photonic crystals, the optics of which is now well
understood. The Diamond Weevil, Entimus imperialis, has large mono-crystalline
photonic crystal domains in the single scales of diamond-type structure with distinct
orientations in the scales cuticle. By applying microspectrophotometry, electron
microscopy, imaging scatterometry, and finite-difference time-domain (FDTD) methods,
the photonic response of the photonic crystals in the extremely colourful feathers
and scales of birds, butterflies and beetles can now be understood in great detail. The
colourful wings of the various animal species either play important roles in courtship
display or rather in clever camouflage.
Escher and the Droste effect
prof. dr. H.W. (Hendrik) Lenstra
In 1956, the Dutch graphic artist M.C. Escher made an unusual
lithograph with the title 'Print Gallery'. It shows a young man
viewing a print in an exhibition gallery. Amongst the buildings
depicted on the print, he sees paradoxically the very same gallery
that he is standing in. A lot is known about the way in which
Escher made his lithograph. It is not nearly as well known that it
contains a hidden 'Droste effect', or infinite repetition; but
this is brought to light by a mathematical analysis of the studies
used by Escher. On the basis of this discovery, a team of
mathematicians at Leiden produced a series of hallucinating
computer animations. These show, among others, what happens
inside the mysterious spot in the middle of the lithograph that
Escher left blank.
Is Beauty a Sign of Truth in Science?
dr. J.W. (James) McAllister
The idea that beauty is a sign of truth in science is intriguing and attractive. It recalls the ancient doctrine of the unity of the virtues, and it seems to promise scientists a route to identifying progress that does not depend on empirical tests. In this lecture, I will try to demystify the discussion by asking what we would need to establish in order to conclude that beauty is a sign of truth. We will see that the most plausible model of scientists’ aesthetic preferences suggests that there is a link of a particular sort between beauty and truth, and that scientists can use this link to pursue truths, but that the resulting practice is still based on empirical data.
James W. McAllister, Beauty and Revolution in Science. Ithaca, N.Y.: Cornell University Press, 1996.
James W. McAllister, “Is Beauty a Sign of Truth in Scientific Theories?”, American Scientist 86 (1998), pp. 174–183.