Detecting life on Mars: A breakthrough in space research

For centuries, humans have wondered whether life exists beyond Earth. From ancient civilizations gazing at the stars to modern scientists sending robotic explorers to distant planets, the search for extraterrestrial life has been one of the most fascinating pursuits in human history.

Now, within the next decade, space agencies plan to bring samples of Mars rock to Earth, marking a major step in this quest.

These samples may contain clues to the planet’s past and, potentially, signs of life. However, scientists must approach this mission with caution.

The possibility that Mars samples could contain unknown microbes raises concerns about contamination and unforeseen consequences. To address this, researchers are working on new methods to detect life.

For the first time, a team of scientists, including experts from the University of Tokyo and NASA, has successfully tested a technique capable of identifying life in ancient Earth rocks similar to those found on Mars.

Studying ancient rocks on Earth

The international Committee on Space Research (COSPAR) developed safety protocols for handling Martian samples.

These guidelines cover the collection, transport, and analysis of Mars rocks. The key challenge is detecting life in these samples, especially when none have been brought to Earth before.

To tackle this problem, a team led by Professor Yohey Suzuki at the University of Tokyo examined ancient Earth rocks rich in microbes. These rocks resemble those expected from Mars. The goal was to find a reliable method to detect life in such samples.

New method to detect life on Mars

“We first tested conventional analytical instruments, but none could detect microbial cells in the 100-million-year-old basalt rock we use as the Martian analogue. So, we had to find an instrument sensitive enough to detect microbial cells, and ideally in a nondestructive way, given the rarity of the samples we may soon see,” said Suzuki.

“We came up with optical photothermal infrared (O-PTIR) spectroscopy, which succeeded where other techniques either lacked precision or required too much destruction of the samples.”

O-PTIR spectroscopy uses infrared light to analyze prepared rock samples. Scientists remove the outer layers of the rock and slice them into thin sections.

While this process is slightly destructive, it preserves most of the material for future studies. This approach is similar to how Apollo moon samples were preserved for decades.

Revealing microscopic details in rocks

A green laser detects signals from the exposed rock, revealing microscopic details. This method can identify structures as small as half a micrometer. Such precision allows researchers to determine whether a structure was once part of a living organism.

“We demonstrated our new method can detect microbes from 100-million-year-old basalt rock. But we need to extend the validity of the instrument to older basalt rock, around 2 billion years old, similar to those the Perseverance rover on Mars has already sampled,” said Suzuki.

“I also need to test other rock types such as carbonates, which are common on Mars and here on Earth often contain life as well. It’s an exciting time to work in this field. It might only be a matter of years before we can finally answer one of the greatest questions ever asked.”

Detecting life in Mars samples

The possibility of discovering life on Mars is closer than ever. With space agencies preparing sample return missions, scientists are refining their methods to ensure they can detect biological material with accuracy.

O-PTIR offers a promising way to analyze these samples while preserving them for future studies.

If signs of life are detected in the rock samples from Mars, the implications will be profound. This would mean that life is not unique to Earth and that it may exist elsewhere in the universe.

Even if the samples contain no traces of life, they will still provide valuable insights into the planet’s geological history and climate evolution.

As technology advances, the search for extraterrestrial life continues to evolve. With each discovery, we come closer to answering one of the most fundamental questions in science: Are we alone in the universe?

The study is published in the International Journal of Astrobiology.

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