In the new movie “Project Hail Mary,” an alien microbe known as Astrophage dims the sun by consuming its solar energy, putting Earth at risk. The concept is fictional, but some Michigan State University scientists believe life on other planets isn’t at all far-fetched.

Known as astrobiologists, they’re not searching for little green men. Matt Schrenk, a Michigan State University earth and environmental sciences associate professor, said “Project Hail Mary” is right about a key concept — If alien life-forms exist, they’re most likely to be microbes.

No one has found them yet, and a killer microbe like the one featured in the movie is less realistic. But that doesn’t mean we’ve given up looking.

“We have one data point about life in space, and that’s here on Earth,” Schrenk said. “But even here, where we can grab samples and study all the life that exists, we discover new things all the time about the limits of life and how life has adapted and evolved to the environment.”

Looking for a needle in a haystack

A problem in the search for life on other planets is the sheer number of places to look. Beyond our solar system lie thousands of other planets, with the new James Webb Space Telescope discovering more nearly every day.

When astrobiologists look for life, they often look for water. All life as we know it requires water to survive.

Rocks on other planets like Mars reveal evidence of long-lost water. Some of Schrenk’s students study a process called serpentinization, where rocks react with water and create energy. This process leaves behind telltale signs such as vein-like lines and a greenish color. Some scientists try to interpret the chemistry of planetary atmospheres, while others search for altered minerals and ices on the surface of other planets and moons.

“Astrobiology is a lot of things,” Schrenk said. “It’s truly about looking at physics, chemistry and biology and how they’re all linked together.”

Adapting to extreme conditions

In Schrenk’s lab, graduate students investigate how life can survive in extreme environments. Aptly called extremophiles, these microbes can be found even in deep ocean vents, inside hot springs and even in nuclear waste sites.

Ella Cardoza, a second-year graduate student in Schrenk’s lab, is especially interested in Europa, one of Jupiter’s moons. Beneath Europa’s icy surface lies an ocean deeper than anything found on Earth. If life can exist in high-pressure environments like Earth’s deepwater oceans, maybe it could exist in Europa’s.

Cardoza performs experiments with microbes collected from ocean floor vents. She tests the limits of these hardy organisms inside the confines of a lab with high-pressure pumps and other experiments.

“If there’s life down there, it has to be adapted to high pressure,” Cardoza said. “So I study adaptations that microbes use to combat that pressure.”

How close to reality is “Project Hail Mary”?

We know microbes can survive in space because they’ve survived on space shuttles. Astronauts take special care to disinfect spacecraft to ensure they don’t introduce a new microbe to a planet.

But whether microbes native to space can exist is still up for investigation.

Astrophage could have been inspired by microbes that exist in extreme environments, such as the colonies that thrive in Yellowstone National Park’s hot springs. Bacteria there absorb energy from light while surviving temperatures higher than 170 degrees Fahrenheit.

In the movie, Astrophage releases infrared radiation that’s eventually used to fuel spacecraft. While that’s not quite how today’s spacecraft travel beyond Earth’s atmosphere, the idea is based on real science. Below the ocean’s surface lie deep sea vents and volcanoes, with organisms that can even harness their infrared heat as a source of energy.

“Environments like that are extreme in relation to humans,” Schrenk said. “It’s why they’re called extremophiles. Our point of view is water and the Earth’s surface and room temperature conditions. We’re so tied into what we know that we can’t imagine what other possibilities there could be.”

Jack Marean, a first-year biochemistry and molecular biology major, is part of an active Astrobiology Club on campus. As a fan of the book, he’s excited to see “Project Hail Mary” bring to life the enthusiasm of scientists about their work.

Since arriving on campus, he’s noticed a contagious excitement as his professors talk about science. The way the book captures his is spot on, he said.

Alexandra Grabowski, a senior geological sciences major, added that the interdisciplinary teamwork it takes to pull off such a major project like that in “Project Hail Mary” is very true to life.

What does the movie get wrong?

Schrenk said the idea that a bacteria could breed on Venus defies the constraints of reality. The boiling-hot temperatures would instantly turn water into steam, and the air pressure is too low to keep liquids from evaporating. He admits he can’t quite get on board with that idea.

And, of course, Astrophage doesn’t exist. Like any science fiction movie, the viewer must suspend some level of reality to fully enjoy it.

But for the most part, “Project Hail Mary” is a great way to explore what life on other planets could look like beyond the Marvin the Martian stereotype.

“Life has made some amazing adaptations,” Schrenk said. “We already know this on Earth, and I think it’s certainly possible in the context of the universe too.”