Why is there a halo around the sun?

Yesterday around midday in Trinidad one could see what appeared to be a rainbow around the sun. I attempted to take a picture but alas all I managed to capture was a picture that almost blinded anyone who saw it. There is something to be said about having a good camera ne? So instead here are some of the images that my friends managed to capture.

As the day progressed however, I was alerted to the growing panic that the appearance of the halo was causing by a few of my friends who had become convinced that it was a sign of some sort. Of what they didn't know but it was most definitely a sign! By 6 p.m. the general consensus was that it was a sign of the apocalypse; at this point I was most dissapointed in them truth be told. So I fired up the old Encyclopædia Britannica and looked it up.

Halo; any of a wide range of atmospheric optical phenomena that result when the Sun or Moon shines through thin clouds composed of ice crystals. These phenomena may be due to the refraction of light that passes through the crystals, or the reflection of light from crystal faces, or a combination of both effects. Refraction effects give rise to colour separation because of the slightly different bending of the different colours composing the incident light as it passes through the crystals. On the other hand, reflection phenomena are whitish in colour, because the incident light is not broken up into its component colours, each wavelength being reflected at the same angle.
The most common halo is the 22° halo, a series of coloured arcs, or in some cases complete circles, of 22° angular radius with the Sun or Moon at its centre. The order of coloration is red on the inside and blue on the outside, opposite to that of the atmospheric corona.
Less frequently observed phenomena, such as parhelia, sun pillars, tangent arcs, sun crosses, and others, also are attributable to the reflection or refraction of sunlight or moonlight by ice crystals.

So as you can see from the above its a perfectly harmless, beautiful phenomena. I really wish that people would try to educate themselves as opposed to panicking about anything that is the slightest bit odd.

References 

* halo. (2012). Encyclopædia Britannica. Encyclopædia Britannica Ultimate Reference Suite. Chicago: Encyclopædia Britannica.