The 'water in the road' mirage
Commonly associated with nature, mirages are visual illusions
where what we see is correct, but unusual. Mirages in nature
are most commonly caused by unusual bending of light under unusual
air conditions. The view is so abnormal that the viewer sometimes
'can't believe his eyes' or radically misinterprets the image.
The most famous mirage is when it erroneously appears as if
a pool of water is in the desert. More than a few thirsty wanderers
have found nothing but disappointment ahead. The earlier pictured
'water in the road' is the same type of mirage. Another mirage
is for sailors or to see an upside down ship in the sky, even
when there isn't one visible on the sea. Enough to convince a
pirate to switch to a better class of hooch.
These three particular mirages happen when there are abnormal
layers of hot versus cold air that cause the light to refract.
or bend, off its normal, straight course. This bending causes
an object to appear in an unexpected place. In the desert and
highway a piece of the sky appears below the horizon, and is
often wrongly interpreted to be water. At sea a ship 'is bent'
upwards so it appears in the air.
A mirage is called a superior mirage where the object
appears above where it normally appears (boat in sky). An inferior
mirage is when the object appears below the where it normally
appears (sky in desert).
The inferior mirage happens when there is hot air near the
ground. It shouldn't surprise that inferior images commonly happen
when the ground surface is hot (desert, hot summer highway).
A superior mirage happens when there is cold air near the
surface. It shouldn't be surprising that superior mirages commonly
appear when the ground or water surface is cold, like the cold
sea or frozen lake. Superior mirages commonly appear in frigid
areas, including the artic.
Sunrise mirage. One of the striking superior mirages
is a sunrise mirage. These are seen over frigid areas, such as
frozen lakes or sea. With these mirages, the light is bent upwards
along the earth's curved service making the sunrise appear before
it normally appears. The sun also appears distorted from normal
(see below) and sometimes two suns are seen at once, one superimposed
over the other.
sunrise mirage in Minnesota
Water causes distortions similar to outdoor air mirages, the
light bending from air to water or water to air (or air to water
to air, etc). A pencil or hard boiled egg distorts from normal
appearance in a glass of water. The experienced spear fisher
knows to spear to the side of the image of the fish or he will
miss. Stones appear to ripple and wave in a crystal clear brook.
One can study how mirages work with a simple drinking glass or
bathtub of water.
The mirages aren't wrong views of an object, just different
than normal. Our normal vision involves distortions, including
to color, details and angles, so one can hardly claim our normal
vision is perfect and anything different imperfect. People with
20/20 vision intentionally distort their vision with magnifying
glasses, binoculars, periscopes, video cameras and UV glasses
when they need to get a better look.
When you view a bird through binoculars the lens distorts
the light to make the bird appear larger and more detailed. You
don't consider the binocular view of the bird wrong. You consider
the binocular view to be more reliable than your naked eye view
("I thought it was a hawk, but it's just a crow.")
A submerged submarine's periscope bends light via mirrors so
a sailor can see above water. The sailor doesn't consider the
view make believe. He considers it a view of reality.
Humans classify views as mirages when they are abnormal, unexpected
and mysterious (at least to the viewer). There are many brilliant
atmospheric effects that aren't considered mirages, as they are
commonplace and well understood. Little is more magnificent than
a rainbow, but they are frequent and people know how they are
formed (or, when they don't know exactly how it works, that there
is an scientific explanation). Fog, snow, sunsets and seeing
our reflection in puddles would be considered astounding happenings
if they weren't so common and well understood.
That thousands of pounds of bright white snow changed into
grass in one (hot) day doesn't cause you to write to Ripley's
Believe It Or Not. You are well aware heat melts snow and underneath
the snow on your lawn is grass. You just mowed that grass a few
months ago. Ripley himself likely had this occur on his lawn
numerous times. The changing of the season is impressive to see,
but is only a mirage to folks like toddlers who have no experience
or memory of it.
After waking up in the morning and seeing the season's first
blanket of snow covering the ground, my very young sister turned
to my dad and said, "Daddy, how'd you do that?"
When people move to new geographies, they will often experience
new weather phenomena. When I moved to Seattle, I experienced
unusual (to me) night lighting effects caused by Puget Sound
and clouds. One night I thought there must be a large fire in
the distance across the sound. I later found out it was the lights
of a distant hill-hidden town reflecting off of low clouds. This
created a low, fiery-like glow. I see this lighting often and
it no longer fazes me. The first time I saw it, it was a mirage.
Now when I see it it's a town light reflecting off of low clouds.
Due to the unique refractive qualities, fine diamonds often
disappear when placed in clear water. Placing a gem in water
is a common method used to identify a diamond.
(c) david rudd cycleback, cycleback.com
all rights reserved