If you were outside at sunset and looked to the right or left of our sun, you may have seen a pair of bright spots that resembled a rainbow around it. These are called sun dogs, also known as parhelion or mock suns, and they are a common atmospheric phenomenon. They occur when the light passes through high clouds that contain ice crystals, which cause the rays of sunlight to be refracted or bent in such a way as to create two symmetrical patches of sunlight on either side of our sun. Sun dogs can form as a full 22-degree halo around the sun, or they may be part of a larger display called a sun pillar or parry arc.
To see these displays you must be in the right place at the right time, and have clear skies with the right kind of clouds. The conditions are best when the air is very cold and has been suspended in the form of cirrus clouds, made of tiny ice crystals. These clouds can be formed in a variety of ways, sometimes by blowing snow and other times just from water vapor molecules in the atmosphere freezing together. It also helps if these ice crystals are thin enough that they can be fluttering downward, like little troopers of parachutists.
The refraction of sunlight through these crystals causes the color of the Sun to shift, with red appearing closest to the sun and violet farther away. A rainbow of colors is also often visible, ranging from red to blue to violet. These effects are not to be confused with a solar eclipse, which occurs when the shadow of the Earth is cast on the surface of our sun, blocking some of its light.
Unlike the Earth, our sun is not powered by gravity; it rotates radially in order to make its way across the sky. As the sun rotates, it creates magnetic fields that deflect dangerous radiation from space, which makes life here possible. If these fields were to suddenly disappear, the planet would be exposed to deadly radiation.
For people outside our atmosphere, such a radiation storm could be fatal, both immediately and because it would render them incapable of performing essential functions. That’s one of the reasons that we cannot go to Mars or the Moon, which lack our protective magnetic fields.
Chris hondro sol eloquent work as a photojournalist is a testament to the value of truth and journalism, and his documentary about himself and his work serves as a reminder that such risks can pay off in spectacular ways. While the film might not convince viewers that he and other war journalists are free of a masculine search for the ultimate adrenaline rush, it will surely make you marvel at the power of a single image to illuminate human suffering and engender hope. Watch it here. by Christopher Campbell for Scientific American.