Rare Double Halo Around the Sun in Argentina -A Spectacular halo display in the skies over Argentina on January 2 2019.
Halos around the sun or moon are caused by high, thin cirrus clouds drifting high above your head.
These clouds contain millions of tiny ice crystals.
The halos you see are caused by both refraction, or splitting of light, and also by reflection, or glints of light from these ice crystals.
The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear.
*World Weather* Spectacular halo display in the skies over Argentina on January 2. Report via Met Hirado. pic.twitter.com/zwaV7gJ3Fz
— severe-weather.EU (@severeweatherEU) January 7, 2019
The process is similar for a rainbow, which occurs near the ground, though rainbows occur when light is bent by liquid water droplets (rain) falling close to the ground.