These self-adhesive USPS Forever stamps are being issued in Sheets of 20 Stamps These USPS Forever stamps will always be equal in value to the current domestic 1 ounce letter postage price This beautiful USPS Forever stamp can be used on RSVP envelopes often enclosed with wedding invitations, party invitations, thank-you notes, announcements, or any other correspondence. The Sun Science stamps highlight stunning images of the Sun that celebrate the science behind the ongoing exploration of our nearest star. The striking colors do not represent the actual colors of the Sun as perceived by human eyesight. Instead, each image is colorized by NASA according to different wavelengths that reveal or highlight specific features of the Sun’s activity. Art director Antonio Alcalá designed the stamps with digital images from NASA’s Solar Dynamics Observatory, a spacecraft launched in February 2010 to keep a constant watch on the Sun from geosynchronous orbit over its ground station in New Mexico.