Did Life Come from Mars?

By Alice Orszulok

A key ingredient for life was more plentiful on ancient Mars than on Earth, a new study has revealed.

Not only was Mars once much more like Earth—with atmosphere, surface water and warmer temperatures—but scientists have found that a key ingredient for life may have been much more abundant there than on our home planet millions of years ago. This has opened up the idea that the key elements for life could have originated on the red planet before being brought to Earth on a meteorite.

This super ingredient is called phosphate. Phosphate is essential for building DNA, cell membranes and other parts of our bodies. In other words, life couldn’t have evolved without it.

“From what’s known, you can’t really have life without it,” says Christopher Adcock of the University of Nevada in Las Vegas. “It’s required for biological functions on a number of levels.”

On early Earth, billions of years ago, these phosphates were locked up in minerals, such as fluorapatite and whitlockite. These minerals had to be dissolved by sea water for the phosphate to escape. However, they dissolve very, very slowly, so concentrations of phosphate would have been very low.

This has led to what scientists call “the phosphate problem.” How did life get started on Earth if there wasn’t enough phosphate around when life was first beginning? Some have suggested the answer is that it didn’t, instead, it started on another planet, such as Mars, and made its way here by meteorites.

Mars has much more phosphate than Earth does, about five to 10 times the amount. Mars’s phosphate-bearing minerals, such as merrillite, don’t exist on Earth—except in meteorites that have come from the red planet. Scientists from the University of Las Vegas have shown that these phosphates dissolve about 45 times more fast than Earthly ones. They discovered this by recreating the conditions that would have existed on early Mars, where groundwater was eating away at merrillite and other fast-dissolving phosphates. In other words, phosphates would have been much more available on Mars than they were on Earth.

“What we’ve shown is that phosphate availability may not have been as much of an issue for Mars as it was on Earth,” explains Adcock.

Although it’s a fun theory to think that life started on Mars, there are still plenty of other alternatives that don’t involve alien molecules. Adcock says that their research only shows that the “phosphate problem” may not have been as significant on Mars like it was on Earth.

“We haven’t discovered life on Mars, nor have we presented evidence that it existed there,” Adcock cautioned. “However, we have shown that one potential roadblock for life to arise on Mars may not be such a roadblock after all.”

Source [University of Nevada]