USPS reveals total eclipse Forever stamp

Heat-sensitive stamp will change when touched

Heat-sensitive stamp will change when touched

This is the first time in the history of the U.S. Postal Service when they use thermochromic ink for the design of a stamp.

The U.S. Postal Service is issuing a one-of-a-kind stamp Tuesday ahead of the coast-to-coast, total eclipse set to appear on August 21.

The stamp's image depicts a total solar eclipse seen from Jalu, Libya, in 2006, taken by retired NASA astrophysicist Fred Espenak, known as "Mr. Eclipse".

The Total Eclipse of the Sun Forever thermochromic ink stamps may be pre-ordered at usps.com/shop in early June for delivery following the June 20 nationwide issuance. This means that the image is sensitive to body heat, and changes if you touch it with your finger. As the moon passes in front of the sun, it should cast a shadow about 70 miles wide. Touching it reveals an image of the moon, and as it cools, it turns back to black.

Tens of millions of people in the United States hope to view this rare event, which has not been seen on the US mainland since 1979.

The last time a total solar eclipse swept across the USA from coast to coast was nearly 100 years ago.

The Total Eclipse of the Sun Forever stamp which commemorates the August 21, 2017, eclipse will be available June 20, 2017, for purchase.

A pane of 16 Forever stamps will be available Tuesday at post offices.

"A total eclipse of the Sun is simply the most lovely, stunning and awe-inspiring astronomical event you can see with the naked eye, but you've got to be in the 70-mile-wide path of totality that runs across the nation from OR to South Carolina", Espenak said. The next time a total solar eclipse will be visible from the USA, according to Espanak's website, is April 8, 2024. It will have its first-day-of-issue ceremony at the Art Museum of the University of Wyoming (UW) in Laramie on Tuesday afternoon, when the university will be celebrating the summer solstice.

Announced Thursday, the Forever 49 cent stamp comes out in June - on the summer solstice.