Venus is the only planet in our solar system that’s actually hotter than another planet (Mercury) that orbits more closely around the sun. That’s one reason it came as rather shocking news this week that Venus might be the first place where scientists confirm the existence of extraterrestrial life.
The planet, often the most visible planet in the night sky, is an amazingly inhospitable place: Its atmosphere contains droplets of corrosive sulfuric acid, and its surface temperature averages more than 800 degrees. Its massive, dense clouds exert a pressure on its surface about 90 times greater than what we feel in Charleston. For something comparable, you would have to dive 3,000 feet below the ocean’s surface.
But scientists using some of our most powerful telescopes announced they have detected a molecule — phosphine — that might exist only because it was emitted by something that’s alive.
Chris Fragile, a professor with the College of Charleston’s Department of Physics and Astronomy, heard the news of the discovery Monday and realized that mankind might have taken a significant step toward our long-standing goal of finding life outside our planet. “It’s hugely exciting and groundbreaking in terms of significance,” he says.
Sarah Stewart Johnson, head of Georgetown University’s Johnson Biosignatures Lab, told The New York Times, “This could be the first observation we’ve made which reveals an alien biosphere and, what do you know, it’s on the closest planet to home in the entire cosmos.”
Of course, there’s more work to be done: Additional telescope observations and maybe even future space missions will be necessary to confirm life on the planet named after the Roman goddess of beauty. No one has a specimen or a picture just yet. It won’t be easy, since the planet has melted down or crushed dozens of previous spacecraft within minutes of attempting to land there. Only two managed to get pictures of the planet’s surface before their demise.
Phosphine is a pyramid-shaped molecule with three hydrogen atoms bonded to an atom of phosphorus. While it’s also present around Saturn and Jupiter, experts don’t believe smaller planets such as Venus have enough energy to produce a lot of phosphine — but microbial organisms that don’t require oxygen could. We have it in our intestines; it’s also in some deep-sea worms and in environments with anaerobic organisms.
“On Earth, biological phoshine comes from bacteria that’s decaying, basically,” Dr. Fragile says. “The question is where exactly would that be happening on Venus or in Venus’ atmosphere? It could be this is a form of life that’s very different from what we’re used to.”
Paul Byrne, a planetary scientist at North Carolina State University who was not involved in the research, told The Times that while he was skeptical of Venus’ phosphine coming from a life form, “I don’t have a better explanation for what it is.”
Theoretically, this life form could have evolved in a high-acid environment with protective outer layers not unlike microorganisms in Earth’s extreme environments. As Venus grew hotter, it could have evolved to exist in the clouds, surviving and reproducing inside droplets of sulfuric acid and water. Or not.
“Because of how extraordinary this would be if it is biological, it’s realistic to be a bit skeptical at this point,” Dr. Fragile says. “It’s import to rule out other possibilities.”
So the discovery should affect NASA’s thinking as the agency considers where to invest its limited budget in future unmanned space exploration. In the past decade, it has focused mostly on Mars, but now there’s more reason than ever to take a closer look at our other next-door neighbor.