NASA caused a frenzy earlier this month by publishing images captured by its Curiosity rover showing what might have been signs of past lives, reports Daily Mail.
It was theorized that small shapes, between one and two millimeters wide and five millimeters long, may be traces of fossils. Tracing fossils are the dead remains of living creatures of things left behind.
Now, Barry DiGregorio, a researcher at the Buckingham Center for Astrobiology, has revealed that he believes traces of fossils are the only explanation.
Dr. DiGregorio told Daily Star Online: "If there are traces of fossils on Mars, as I believe they are and the new images of Curiosity show, it moved through ancient shallow marine sediments in a lake at Gale Crater."
"Fossils record the movement of soft-bodied creatures through marine sediments and mud, they are not bodily fossils."
After the discovery, Dr. DiGregio said he struggles to see how NASA will come to a different conclusion "If it's not about fossils, what other geological explanations will NASA present?"
Curiosity project scientist Ashwin Vasavada described the discovery as "unique" and promised that he would "not rule out" the possibility of tracking fossils.
Dr. DiGregorio said that probability alludes to the apparent fossils dating back 700 million years, at the moment when he believes that Mars could have prospered with life.
When asked how old they were, he told us: "Crater Gale sediment dating is about 3 billion years old.
"Gale Crater on Mars had the right physical and chemical conditions for life 700 million years ago and, during part of that history, it had a lake that could have harbored a wide variety of life."
Dr. DiGregorio now lives in New York, USA, and was a research associate for the Cardiff Center for Astrobiology, United Kingdom, between 1999 and 2010.
A spokesman for NASA said his Curiosity team is "considering multiple possibilities for the origin of dark and stick-like features."
They added: "Among those possibilities that do not necessarily involve any biology are the crystals, the minerals that filled the fractures in the bedrock and the minerals that filled voids where the original crystalline material dissolved."
"It's amazing what humans have been able to achieve in terms of spectacular and amazing discoveries outside our planet."
