Sylvanshine is an
optical phenomenon
Optical phenomena are any observable events that result from the interaction of light and matter.
All optical phenomena coincide with quantum phenomena. Common optical phenomena are often due to the interaction of light from the sun or moon wit ...
in which
dew
Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening due to condensation.
As the exposed surface cools by radiating its heat, atmospheric moisture condenses at a rate greater than that at wh ...
-covered
foliage
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...
with
wax
Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to give low ...
-coated leaves
retroreflect beams of light, as from a vehicle's
headlight
A headlamp is a lamp (electrical component), lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage (language), usage, ''headlamp'' is the term for the ...
s. This effect sometimes makes trees appear snow-covered at night during the summer. The phenomenon was named and explained in 1994 by Alistair Fraser of
Pennsylvania State University
The Pennsylvania State University (Penn State or PSU) is a Public university, public Commonwealth System of Higher Education, state-related Land-grant university, land-grant research university with campuses and facilities throughout Pennsylvan ...
, an expert in
meteorological optics
Atmospheric optics is "the study of the optical characteristics of the atmosphere or products of atmospheric processes .... ncludingtemporal and spatial resolutions beyond those discernible with the naked eye". Meteorological optics is "that par ...
. According to his explanation, the
epicuticular wax
Epicuticular wax is a coating of wax covering the outer surface of the plant cuticle in land plants. It may form a whitish film or bloom on leaves, fruits and other plant organs. Chemically, it consists of hydrophobic organic compounds, mainly str ...
on the leaves causes water to form beads, which in effect, become
lenses
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
. These lenses focus the light to a spot on the
leaf surface, and the image of this spot is directed as rays in the
opposite direction.
References
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Atmospheric optical phenomena
{{optics-stub