When you press a stamp onto a letter this summer, be sure to take a second look after you release your finger. The United States Postal Service is releasing a first-of-its-kind stamp that uses body heat to change images. It’s designed to commemorate the Aug. 21 total solar eclipse.
The Forever stamp features photographs taken by Fred Espenak, a retired NASA astrophysicist out of Portal, Ariz., who is known as Mr. Eclipse. One image shows a total solar eclipse as seen from Jalu, Libya, on March 29, 2006. Heat from your thumb or fingers will activate thermochromic ink on the stamp and reveal an underlying image of the full moon, also taken by Espenak. It reverts back to the eclipse image after it cools.
The special stamp is designed to help Americans commemorate a rare event — a total solar eclipse has not been seen on the U.S. mainland since 1979. And the USPS notes in a Thursday news release that the eclipse “will travel a narrow path across the entire country for the first time since 1918.”
For Pacific Northwesterners, it’s especially exciting, as the 70-mile-wide shadow path will appear first in Oregon (mid-morning PST). It will then run west to east diagonally across the country, touching portions of 14 states and exiting 2,500 miles and 90 minutes later off the coast of South Carolina (mid-afternoon EST).
The Postal Service cautions that thermochromic inks are vulnerable to UV light and should be kept out of direct sunlight as much as possible. A special envelope to hold and protect the stamp will be offered for an additional fee.