Could microbes from Earth survive on other worlds? New research suggests that the answer may be yes.
Ph.D. candidate Tommaso Zaccaria studied whether tiny organisms from Earth could stay alive under conditions similar to those found on the moon, Mars, and the icy moons of Jupiter and Saturn.
These places are of special interest because scientists believe they contain or once contained water, which is considered essential for life.
In the past, space agencies worried mostly about whether astronauts might bring dangerous alien organisms back to Earth. Today, scientists are also asking the opposite question: Could we accidentally carry Earth life into space and contaminate other worlds?
This concern is not new. The first astronauts left waste on the moon, and spacecraft sent to Mars decades ago were not sterilized as carefully as they are today.
To investigate, Zaccaria recreated the harsh conditions of these distant environments at the German Aerospace Center. He exposed microorganisms to intense radiation, extreme cold, and severe dehydration.
Many of the microbes tested came from some of Earth’s toughest environments, including Antarctica and areas near volcanoes. Surprisingly, several of them survived the simulated space conditions. Yeasts performed especially well.
The researchers found that yeasts have impressive defense systems. They can increase their ability to repair damaged DNA and switch on chemical processes that help protect their cells from extreme stress.
Zaccaria also studied well-known human pathogens, including Klebsiella pneumoniae, a bacterium that can cause pneumonia. These pathogens became smaller after experiencing Mars-like conditions, but they did not die.
Even more surprising was how the human immune system reacted to them. In laboratory experiments, immune cells from human blood responded less strongly to the shrunken pathogens.
This finding could be important for astronauts. Spending long periods in space already puts great stress on the body. Astronauts often experience changes in their sleep patterns, diet, gut health, and social interactions. They are also exposed to radiation and spend months living in confined spaces. All of these factors can weaken the immune system, making infections potentially more dangerous.
The study also examined another possible threat: dust from the moon and Mars. Using materials designed to mimic the surfaces of these worlds, the researchers compared their effects on lung tissue with ordinary sand from Earth.
The results were concerning. Simulated Martian dust damaged the lungs’ protective lining and increased the risk of infection. Material resembling lunar dust caused even greater harm. Earth sand did not produce the same effects.
The researchers say these findings matter not only for future space missions but also for people on Earth. Astronauts often show signs of weakened immunity and faster biological aging. By studying how the body changes in space, scientists may gain new insights into aging, immune health, and why some people are more vulnerable to disease than others.
In the search for life beyond Earth, scientists may have discovered something unexpected: some forms of life from our own planet are far tougher than we ever imagined.
Source: KSR.
