CEBU, Philippines - Solar halos or sun dogs (also called mock suns or false suns because the bright spot in the sky resembles a small sun to the right and/or left of the actual sun) make man suffer from both physical and mental blindness.
Look at what you’ve done last May 7! You’ve taken an “unprotected” look and a couple of snaps, in wonder at that brightly colored oval around the sun. Afterwhich, you jumped into passing around text messages associating the optical phenomenon to that of a paranormal activity coupled with doomsday tales.
Well, you could be heading for doom in a way. No, not exactly you - but your (very sensitive) retina. Cebuano astronomer Christopher Go said that we are to shield both eyes when looking at a sun dog - common name for an optical effect known as “parhelion” or a type of halo usually found in pairs, on the edges of a 22-degree halo on either side of the sun formed when plate-shaped ice crystals drift down through the sky with their flat faces almost horizontal.
“I would like to emphasize to those photographers and viewers about the dangers of looking at the sun directly either with a camera or with the naked eye. Doing so will result in permanent blindness,” Go warns.
In an electronic mail exchange, Go shared tips to never stare at a sun dog even for a moment; to preferably, hide from the sun behind the edge of a building or a post; to take care when photographing halos if the unshielded sun is in the field of view; and reiterated that it is dangerous to look at the sun through some camera viewfinders, especially SLRs (single-lens reflex cam).
Another site – wxdude – affirms that to see a sun dog or to photograph it, you need to shield your eyes from the sun’s rays with the edge of a building or other object, as looking into the sun can cause eye damage, even blindness. “So please always block the sun’s view when looking upward. And when you do, you may see other optical effects around the sun or moon including arcs and coronas which are all effects of light passing through differently shaped ice crystals,” the wxdude content reads.
Sunlight, moonlight and water vapor work the angles of the atmosphere to produce brilliant, evanescent light shows and or optical phenomena. Says Wisconsin sky observer Anita Carpenter: Our atmosphere – the gaseous envelope surrounding the Earth – is “composed of several gases, primarily nitrogen, oxygen, argon and carbon dioxide. Water vapor and minute bits of dust, salt and clay-silicate particles swirl about in the mixture.”
“The atmosphere has four vertical layers that radiate from Earth and vary by temperature and composition. Proceeding from the ground outward, they are the troposphere, stratosphere, mesosphere and thermosphere.”
“All of the optical phenomena – halos, sun dogs, sun pillars, coronas and rainbows – are produced at specific levels in the troposphere, which extends from the surface up to about 12 kilometers, eight miles or 42,000 feet depending on which measuring stick you pick.”
Further, halos appear in our skies far more often than do rainbows. According to a similar site used by Go as cross-reference – atoptics - in the United Kingdom, halos can be seen on average twice a week in Europe and parts of the United States. The 22° radius circular halo and sun dogs are the most frequent.
Halos on 22º radius are visible all over the world and throughout the year. Look out for them (with eye care!) then whenever the sky is wisped or hazed with thin cirrus clouds. These clouds are cold and contain ice crystals in even the hottest climes.
Does it foretell of rain? Not necessarily. Atoptics mentioned that high cirrostratus cloud forms the halo and this same cloud is on the advancing edge of warm fronts with their associated heavy rain. If a wind stirs from the southwest, the sky becomes hazy, a halo forms around the sun which is then dimmed and finally obscured by increasingly thick cloud then rain is likely within a few hours. But many halos are not associated with frontal systems and to see one is not a reliable sign of bad weather.
“They are things of beauty, not bad news,” it added. Certainly, none of the bad omen the awesome sight had stirred on May 7, huh?
Another health concern, I would want to raise is the tendency of man to be blind to things we are not aware of that exist. So, it really pays off to learn atmospheric optical effects to avoid labeling scientific phenomena as “strange” or “signs of the end times.”
The next time the sky bothers you, email chris@cstoneind.com for “heavenly” answers. Go has been an amateur astronomer since 1986, the year of the return of Halley’s Comet and studied at the University of San Carlos where he received a Bachelor’s degree in Physics. While a student there, he along with his friends organized USC’s first ever Astronomical Society.