It seems everyone is preparing for the Great American Eclipse of 2017, even the U.S. Postal Service, which is now selling limited-edition, color-changing solar eclipse stamps!
The first-ever, heat-activated stamp uses thermochromic ink that is sensitive to the touch of your fingertip. Once you press your thumb over the black ink spot at the center of the stamp, the total solar eclipse will vanish and reveal a full moon.
As soon as you remove your finger, the ink will cool, and the image will return to the eclipsed Sun.
A sheet of 16 solar eclipse stamps is $7.84 and you can order them online while supplies last.