Bad Astronomy: Misconceptions and Misuses Revealed, from ...

SHADOWS IN THE SKY 119
eaten is a common thread. Others have seen it as a bad omen, so
they pray during eclipses. Still others avert their eyes, lest they have
a spell of bad luck cast over them . . .
. . . which brings us to a very interesting and somewhat controversial
point about the Sun and eclipses. How many times have
you heard that looking at an eclipse will make you go blind? Every
time a solar eclipse rolls around, the news is full of warnings and
admonitions. The problem is, they never say exactly why you can
go blind, or what degree of eye damage you might suffer. Worse,
they sometimes give incorrect advice on viewing an eclipse, increasing
the danger.
I’ll cut to the chase: viewing an eclipse can indeed be dangerous.
Obviously, looking at the Sun is very painful, and it is extremely
difficult to do so without flinching, tearing up, or looking
away. The Sun is just too bright to look at. Every astronomy textbook
I have ever read has an admonition against looking directly
at the Sun, and it is common knowledge that looking at the Sun,
even briefly, can cause permanent damage to your eyes.
While researching information on solar eye damage for this
chapter, I stumbled across an amazing irony: while it is dangerous
to view an eclipse with the unaided eye, it is actually far less dangerous
to look at the Sun when it is not eclipsed! This may sound
contradictory, but it actually is due to the mechanisms inside the
eye that prevent overexposure from light.
There is copious evidence that little or no long-term damage
results from observing the uneclipsed Sun. I was shocked to find
this information; I have been steeped in a culture that says looking
at the Sun with the unaided eye will result in permanent and total
blindness. However, this is almost certainly not the case.
Andrew Young, an adjunct faculty member of the San Diego
State University’s Department of Astronomy, has collected an astonishing
amount of misinformation concerning solar blindness (see
http://mintaka.sdsu.edu/GF/vision/Galileo.html). His research flies
in the face of almost all common knowledge about solar blindness.
He is quite strong in his statement: under normal circumstances,
glancing at the Sun will not permanently damage your eyes.