In the next decade, space agencies plan to bring rock samples from Mars to Earth. But what if these rocks contain alien microbes?
Scientists are taking this concern seriously, as any unknown life could have unexpected effects on our planet. To prevent this, researchers have developed a powerful new method to detect life in Martian-like rocks.
A team, including scientists from the University of Tokyo and NASA, has successfully tested this new technique on ancient rocks from Earth that are similar to those on Mars.
Their breakthrough could strengthen the safety protocols for handling Martian samples.
The risk of alien microbes
Many sci-fi movies show scientists bringing back something dangerous from space, leading to disaster.
While this makes for great entertainment, the concern is real.
Even during the Apollo program, astronauts returning from the Moon were quarantined to prevent any unknown contamination. Now, with Mars sample return missions on the horizon, scientists are taking extra precautions.
To make sure Mars rocks don’t harm life on Earth, the international Committee on Space Research (COSPAR) has strict safety rules. A major part of these rules is being able to detect life in the samples.
However, since we’ve never brought Martian samples to Earth before, we need to test our methods on similar rocks from Earth.
A new life-detection method
Associate Professor Yohey Suzuki from the University of Tokyo and his team studied ancient basalt rock from Earth, which is about 100 million years old.
These rocks are a good comparison to the ones Mars rovers are collecting.
“At first, we tried using traditional instruments to find microbes in the rock, but they weren’t sensitive enough,” said Suzuki. “So, we needed a better tool—one that could detect tiny traces of life without destroying the rare samples.”
The solution was optical photothermal infrared (O-PTIR) spectroscopy, a cutting-edge method that uses infrared light to scan rocks. After removing the rock’s outer layers, researchers shine infrared light on the sample. A green laser then detects signals from the material, revealing microscopic details as small as half a micrometer—tiny enough to spot possible signs of life.
This technique is more precise than older methods and only slightly damages the samples, keeping most of the rock intact for future studies.
Suzuki and his team successfully detected microbes in 100-million-year-old basalt.
But their next goal is to test even older rocks, up to 2 billion years old—similar to the ones Mars rovers are collecting. They also plan to study other rock types, such as carbonates, which often contain life on Earth and are common on Mars.
“This is a really exciting time,” said Suzuki. “With our new tool, we might soon be able to answer one of the biggest questions of all time—has there ever been life on Mars?”
