MANILA, Philippines - A lunar halo amazed Filipinos last Monday night, with many sharing their photos of the phenomenon in the social networking site Facebook.
The moon halo is an optical effect caused by the refraction of moonlight from ice crystals in the upper atmosphere, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).
Norman Marigza, an astronomy professor at the Rizal Technological University, explained that a drop in temperature in the upper atmosphere leads to the formation of ice crystals. The icicles refract the light like a glass, resulting in the formation of a ring around the moon.
But the moon halo could also signal an approaching thunderstorm, said Jose Mendoza, chief of the PAGASA Astronomical Publication Unit.
“Halos around the moon – or sun – are a sign of thin cirrus clouds drifting high above our heads. They are a sign of nearby storms,†according to the website earthsky.org.
Mendoza said the astronomical event is a common occurrence.
He also said there are two types of halo: 22 and 45 degrees. The halo observed last Monday was 22 degrees, which is more common. – With Dino Balabo