New Microbe Research Suggests the Key to Finding Aliens Is Hiding in the Stratosphere
Despite being a haven for life, Earth has some pretty inhospitable environments—the deep ocean has enough darkness, low temperatures, and pressure to kill almost any living thing with bones, while deserts like Death Valley in California are routinely used to simulate the surface of Mars. Even Earth's own atmosphere, supposedly the model for a life-giving mix of oxygen and nitrogen, has some incredibly hostile portions, especially the stratosphere. In fact, the conditions in our stratosphere are actually pretty close to an alien planet, and new research says that studying the microbes that live there may offer some insight in how to look for life on other planets—and keep us from infecting those worlds with our own bacteria.
According to research from the University of Maryland School of Medicine, the lower stratosphere is dry, cold, exposed to a lot of UV radiation, and low-pressure, making it deadly for most microbes.
On the other hand, these traits make it "a great proxy" for conditions on Mars, which has a thin atmosphere that doesn't protect its surface from a lot of solar radiation. There are microscopic lifeforms that can handle it, though—extremophiles, a type of microorganism that can survive in extreme conditions.
According to microbiologists Shiladitya DasSarma, "There's a wide variety of stress-survival mechanisms. For UV, a number of [extremophiles] have DNA damage-repair mechanisms. Others have additional, more quiescent methods, like extreme halophiles that can survive very low-water situations because their proteins are designed to hold onto whatever small amount of water is present."
DasSarma's team wants to conduct a large-scale study of life in the (largely unexplored) stratosphere to get a handle on what kinds of extremophiles live there.
From there, we can get a picture of what life might look like on other planets, says Dr. David J. Smith, a NASA microbiologist: "When we measure the response of terrestrial life in extreme environments on Earth, we can learn more about habitability across the Solar System and where to refine the search for life elsewhere."
At the same time, we'll also learn more about how to prevent the spread of our microbes to planets whose biomes may not be able to handle an influx of invasive Earth bacteria. No one, not even microorganisms, should have to deal with an alien invasion.