Hello everyone.
Before science, the flash of lighting that
followed a crack of thunder was the will of
Greek gods or a violent outcropping of animism.
Now we know a bit more about lightning.
We know that it can be hotter than the surface
of our Sun; we know that it can absolutely
strike in the same place twice;
and we know that when it hits sand, it can
create wonderful art.
And we know people can mistake that art for
a stick in the sand.
A single bolt of lightning can deliver 5 gigajoule
of energy enough to power an average U.S.
household for more than a month.
When such a powerful lightning bolt strikes
a sandy area like a beach or a dune, the sand
particles can melt and fuse together in less
than a second.
Sand melts at about 1800 degrees Celsius,
but the temperature in a bolt of lighting
can reach 30,000 degrees, or more than five
times the temperature on the surface of the
sun.
If conditions are right, the fused sand forms
long hollow tubes called fulgurite.
The term comes from the Latin word fulgur,
which means "lightning".
Although lightning strikes earth at least
a million times each day, only rarely does
a fulgurite form.
Fulgurites are usually found beneath the surface
of the sand, generally decreasing in diameter
and sometimes branching outs as they descend.
Their shape reflects the path lightning bolt
took as it dispersed into the ground.
Because of this, fulgurites are sometimes
called "fossilized lightning".
Fulgurites look like roots, due to its branching,
and have a rough surface, covered with partially
melted sand grains.
But the inner surfaces are usually smooth
and glassy due to rapid cooling and solidification
of the sand.
The size and length of a fulgurite depends
on the strength of the lightning strike and
the thickness of the sand bed.
Many sand fulgurites average an inch or two
in diameter and can be up to 30 inches long,
but fulgurites as long as 16 feet have been
found.
Some fulgurites can penetrate deep into the
soil, sometimes occurring as far as 49 feet
below the surface that was struck.
Fulgurites can also form when lightning strikes
rock, occurring as coatings or crust of glass
and sometimes as veins on the rock surface
lining preexisting fractures within the host
rock.
Fulgurites have been described as early as
1711 and are found all all over the world,
from mountain peaks to the Sahara desert,
but are considered to be rare.
They aren't precious but are appreciated by
many for their scientific value.
By studying the distribution of fulgurites
over a specific area, for instance, one can
infer the occurrence of thunderstorm activity
in the area during a certain period, which
in turn can help understand past climates.
250-million-years-old fulgurites found in
the Sahara has shown, or rather confirmed,
that the desert was once a fertile region
where rain thunderstorms were common.
Although most collectors seek out fulgurite
solely for its looks, some people believe
the lightning stones hold magical abilities
to help focus divine energy, enhance creativity,
or heal various illnesses.
Perhaps not surprisingly, some people enjoy
making their own fulgurites, either by sticking
lightning rods in sand before thunder storms
or using a high-voltage power supply in a
lab.
The resulting fulgurites can be even more
attractive than those created naturally, although
obviously safety is paramount when engaging
in these activities.
