APOD 3.4

Taken in Yunnan Province in China, this photo was taken on January 25 after sunset. Since there is not much light in this area, the beautiful rice terraces capture the millions of stars seen in the night sky. Something unusual about this photo though is the red tinted sky. Although this red light would only be slightly visible to the naked eye, after a long exposure, the camera was able to capture this gorgeous phenomena.

 Now people might mix this up with an aurora, however, they are different. First of all, an airglow is something that can happen all around the world while an aurora can only take place up at the poles. Another thing that is different is that an airglow is caused by short wavelength solar radiation and an aurora is caused by solar wind which emits charged particles that excite the atoms. What is making this airglow is chemiluminescence. That is the production of light through a chemical excitation. The ultraviolet light excites oxygen and nitrogen atoms which collide with other atoms. The red glow the made only where there are less atoms in the sky for the oxygen to collide with which allows it enough time for the excited atoms to go back to its normal state and have their energy radiated away. What makes it cooler is the fact that an airglow can happen day or night although night time would be your best chance of seeing it.

Although this picture shows the beauty and the mysteries of our solar system, it s unfortunate that there is some light pollution that can be seen in the picture where there is artificial light. People over there are not able to acknowledge something so amazing that s literally right above their own homes. Thankfully, however, we are able to have people like these to take these amazing pictures of the night time sky so we will all appreciate our world more. Don't forget to keep following the stars!