India, Feb. 13 -- Ahead of Valentine's Day, a picture of the Northern Lights in Norway forming a heart has gone viral online. Though the photograph was posted on January 21, it is only now striking a chord with romantics. Photographer Kristoffer Vangen snapped the glowing green aurora as it appeared to shape itself into a clear heart against the dark night sky. He later shared the image on Instagram, where it began circulating widely, with social media users calling it "nature's Valentine" and "the sky in love." In the caption, Vangen revealed, "I always wanted to capture the northern lights shaped as something. Last Friday I finally got something! Perhaps a heart is a bit cliche, but I'm not complaining." The Northern Lights occur when charged particles from the sun collide with gases in Earth's atmosphere, releasing energy in the form of light. Although they most commonly appear green, they can also glow in shades of pink, purple, blue, or red. HTC...