Double rainbows unfolded in the sky over Shenzhen.

Lingnan: Beauty Beyond Borders | On the evening of July 17, the topic of #Shenzhen Double Rainbows surged to the top of the #Weibo Hot Search List. Netizens excitedly posted their stunning photos of the double #rainbows online. How do double rainbows form? One of the #rainbows that is brighter is called a primary rainbow, and the other fainter one is called a secondary rainbow. Generally, rainbows are formed when light from the sun is scattered by water droplets through a process called refraction. When #sunlight is reflected twice within raindrops, a double rainbow appears. #SplendidLingnan

7月17日晚，#深圳双彩虹#冲上了微博热搜榜首。网友也纷纷在网络上晒出自己拍的绚丽双彩虹。双彩虹是怎么出现的呢？其实，双彩虹一条叫虹，另一条叫霓。一般来说，当阳光经过水滴时，它会被折射-反射-折射出来，出现的就是常看到的单条彩虹。如果阳光经过折射-反射-反射-折射，多了一次反射过程，就是双彩虹。