posted 07-27-2021 01:15 PM               

Gilbert Levin, Tested for Life on Mars

Dr. Gilbert V. Levin, PhD, an outspoken American inventor, entrepreneur, and scientist who created and operated a controversial life-detection experiment on the Martian surface, has died. He was 97.

Levin grew up in the Baltimore, Maryland area. "I was reluctant to follow all of my relatives, brother and sister, into pharmacy," he remarked of his adolescence. "I wanted something else, and I had been leaning towards journalism." But as a high school student, he crossed paths with a sanitary engineer who fascinated young Levin with issues of treating wastewater and air pollution. "Seemed to me a place where innovation could thrive, and that appealed to me!"

During World War II, Levin served in the Merchant Marine as a radio operator. Afterward, he earned a Bachelor's in civil engineering (1947), and then a Master's in sanitary engineering (1948) – both from Johns Hopkins University. Subsequently he worked for a time at the California State Health Department. During this period, in 1951, Levin conceived of a way to rapidly test for the presence of E. coli bacteria at local swimming beaches. His idea involved "spiking" water samples with lightly-radioactive nutrients. If any nutrient was consumed by bacteria in the water, they'd give off radioactive carbon gases and be detected by an overhead Geiger counter. This approach dramatically slashed the time required to obtain test results from multiple days to a matter of minutes.

Throughout the mid-1950s and on into the 1960s, Levin worked as an Assistant or Adjunct Professor at Georgetown University in a variety of public health-related disciplines. His PhD (also from Johns Hopkins) came in 1963. Levin joined or created a succession of modest environmental consulting firms in the Maryland/Washington, D.C. area. These companies examined the likes of water pollution control and harmful waste by-products from ore mining. One early contract, from the Department of the Interior, investigated the possibility of desalinating seawater with algae.

Eventually Levin worked his way into NASA's brand-new field of astrobiology, slowly refining his "radioactive food" concept into a lightweight and dead-simple life-detection system. It even had the ability to collect samples by hurling sticky strings from its housing to land on the dirt and be reeled back in.

Come 1975, NASA dispatched twin Viking spacecraft to the Martian surface for the express purpose of testing for life. And Levin's experiment, now called "Labeled Release," was aboard. It shared space with two other complimentary experiments and the three tested for life in ways completely different from each other. Labeled Release ultimately passed all the pre-launch criteria for successfully finding life on Mars. However, the two other life-detection experiments produced results which were either inconsistent or straightforwardly explained by chemistry. A separate Viking experiment tested the soil for organic substances – necessary for life as we know it – and found none. In addition, conventional wisdom of the time said that Mars would, most likely, not have liquid water on its surface. As such, Levin's results were considered, by the greater scientific community, to have been the product of chemical reactions.

Since Viking, both liquid water and organic compounds have been found in multiple places on Mars, by much more sensitive instruments than what flew on the Vikings. In May of 2011, Levin insisted that the barriers to life on Mars: water, organics, and so on – have only been falling as new facts are learned about the planet. "The conditions on Mars are such that Earth life, some of it, would survive and grow. It's much harder now to say Mars can be sterile, than to say that it has life."

A man of constant activity, Levin spent time on the Johns Hopkins board of trustees, and continued his entrepreneurial ways. His companies were always small, and often struggled, but always sought to innovate. They created an organic process which removes chemicals from wastewater. They produced an eco-friendly compound to help reduce insect populations on livestock farms. They also invented tagatose: a sugar substitute derived from whey. All the while, Gil Levin tirelessly continued to assert – during interviews and in multiple scientific papers – that his Labeled Release experiment did indeed find life on Mars in 1976.

"I fortunately am not involved in looking for intelligent life. Can't even find that on Earth."