Now, he is trying to convince others of his theory, and in the process blames NASA for trying to hide the truth.
DiGregorio, the author of a book that has published in the past about possible life on Mars, believes the previously released NASA images provide clear evidence of fossil alien footprints on Mars. He believes the photo shows that small dents in the rock are actually long-footed fossils of some extraterrestrial life.
In the meantime, NASA explained that the core "foot print fossil" with DiGregorio's debate is actually much smaller than the photos, and NASA claims they are actually only about the size of sesame seeds. The agency thinks the weird shape is a by-product of the crystal structure in the rock and points out that there are striking resemblances between similar crystals found on Earth and DiGregorio's alien footprints.
"These shapes are characteristic of gypsum crystals," explained Sanjeev Gupta of NASA's Mars Curiosity Science Group. "These will form when salt is concentrated in the water." Of course, DiGregorio did not believe it to be a reasonable explanation, but instead decided to post his research at a conference later this year.