New heat-sensitive postage stamps are coming June 20 from the United States Postal Service. The first-of-its-kind stamp transforms when touched and gently rubbed.
The stamp uses a combination of two photos. The first photo shows a total solar eclipse seen from Jalu, Libya, in 2006. When touched, a full-moon photo is momentarily revealed thanks to the body heat in your fingers. As the image cools, it reverts back to the eclipse photo.
How does it work? Thermochromic ink. The same mix of liquid crystals and dyes that can be found in mood rings. The ink is activated by the heat in your hands, revealing the moon photo.
The stamp will be released on June 20th. Also cool, the stamp will be a Forever stamp, meaning it’ll be worth the same amount forever. Or, at least as long as there is a USPS.