(01 of12)
Open Image ModalThis is the Pioneer Plaque, one of two cosmic dog-tags attached to the Pioneer 10 and 11 spacecraft, the first human-made matter to leave the solar system. \r\n\r\nCarl Sagan and his wife Linda, along with astronomer Frank Drake, designed the plaque. It contains a map of the solar system with the path of the spacecraft, as well as images of a man and a woman, which were criticized for their nudity when the plaques were created.
(02 of12)
Open Image ModalThe Golden Records, sent out with the Voyager I and II spacecraft, contain diagrams representing basic scientific concepts, but may be most notable for their inclusion of music, ranging from Chinese musician Guan Pinghu to early rocker Chuck Berry. \r\n\r\nThe records will remain on the interstellar probes for their multi-millennial mission, passing relatively close to a star in about 40,000 years. If extraterrestrials can manage find these needles in the galactic haystack, they\'d almost certainly be advanced enough to find us.
(03 of12)
Open Image ModalThe Arecibo message, which was broadcast as a radio signal in 1974, contains a representation of the numbers 1-10, as well as various information about the chemicals that make up life on this planet. At the bottom, there\'s even a diagram of the picturesque Arecibo telescope.\r\n\r\nFrank Drake and Carl Sagan also contributed to the design, which is depicted here in color to remove ambiguity from the different parts of the message. \r\n\r\nWe definitely can\'t expect a reply to this one; it will take 25,000 years to reach its target and another 25,000 before we\'d receive any response.\r\nDonald Campbell, professor of astronomy at Cornell University later confirmed this, saying, \"It was strictly a symbolic event, to show that we could do it.\"
(04 of12)
Open Image ModalThe first Cosmic Call message, sent out from a radio telescope in Ukraine, included a signal with this information. It\'s a sort of numerical dictionary, which matches up binary representations of numbers with the symbols that will be used to represent them in the rest of the message. Subsequent parts of the message go on to define mathematical operations and fundamental scientific facts. A detailed explanation can be found here.\r\n\r\nCanadian physicists Yvan Dutil and Stephane Dumas led the efforts to send the Cosmic Call, which was sent alongside a transmission of the Arecibo message. \r\n\r\nImage courtesy Yvan Dutil and Stephane Dumas.
(05 of12)
Open Image ModalThe Teen-Age Message, composed in part by teens from across Russia, was broadcast in August and September 2001. In addition to bilingual greetings in Russian and English, the broadcast includes the \"1st Theremin Concert for Aliens,\" a series of famous melodies played on the electronic instrument. The image above contains several glyphs representing various aspects of humanity and life on planet earth. \r\n\r\nImage: Alexander Zaitsev
Polonnaruwa Meteorite -- Dec. 29, 2012(06 of12)
Open Image ModalPictured is a small piece of a meteorite that fell near the ancient Sri Lanka city of Polonnaruwa on Dec. 29, 2012. Using a scanning electron microscope, scientists at the U.K.\'s Buckingham Center for Astrobiology and Cardiff University produced the following images. Note: the measurements on the images are indicated in micrometers. To understand how small these fossilized objects are, 1 meter = approximately 3 feet, while 1 micrometer = 1 millionth of a meter. (credit:Courtesy of Wickramasinghe, Wallis et al)
Diatom fossil from the Polonnaruwa meteorite(07 of12)
Open Image ModalThe following images look like something from a science fiction movie, but were produced with a scanning electron microscope focused on a meteorite that reportedly fell in Sri Lanka on Dec. 29, 2012. This first image shows a diatom (algae) fossil at high resolution from the Polonnaruwa meteorite. (credit:Courtesy of Wickramasinghe, Wallis et al)
Another fossil from Polonnaruwa meteorite(08 of12)
Open Image ModalAn embedded fossil from the Polonnaruwa, Sri Lanka meteorite. (credit:Courtesy of Wickramasinghe, Wallis et al)
Filamentous fossil diatom from Polonnaruwa meteorite(09 of12)
Open Image ModalPictured is a fossil diatom (algae) with frustules, or walls, showing intricate microstructure. (credit:Courtesy of Wickramasinghe, Wallis et al)
Ovoidal ribbed structure in the Sri Lanka meteorite(10 of12)
Open Image ModalThis ovoidal, or egg-shaped, ribbed structure was found in the rock matrix of the Polonnaruwa, Sri Lanka meteorite. (credit:Courtesy of Wickramasinghe, Wallis et al)
External layer of a algae fossil found in Polonnaruwa meteorite(11 of12)
Open Image ModalThis is an image of the external layer, or frustule, of a diatom (algae) fossil found enmeshed in the rock matrix of the meteorite that fell near Polonnaruwa, Sri Lanka, on Dec. 29, 2012. The next slide is an extreme close-up of this image. (credit:Courtesy of Wickramasinghe, Wallis et al)
Close-up of previous slide(12 of12)
Open Image ModalThis is a close-up electron microscope image of the previous slide, showing the intricate layering (frustule) of a diatom (algae) fossil found in the meteorite which fell in Sri Lanka on Dec. 29, 2012. Scientists who research these microstructures are convinced it represents proof of extraterrestrial life. (credit:Courtesy of Wickramasinghe, Wallis et al)
