Astronomers find new clue in hunt for life in the universe

A team of astronomers used NASA's James Webb Space Telescope to make an exciting discovery about markers of life on the planet K2-18b. Credit: Getty Images/murat4art
As long as there have been humans, we have looked to the sky and wondered what — and who — was out there, and where it all came from.
One who did that ages ago, the ancient Greek philosopher Democritus, proposed that the universe contained many worlds, some old, some new, all with beginnings and ends.
In recent centuries, the search for life on other worlds has picked up steam with occasional revelations piquing the probe. One such moment came this past week when a team of astronomers using NASA’s James Webb Space Telescope announced they had discovered markers of life in the atmosphere of a distant planet.
Not life itself, to be clear, but markers of life.
That's what you call a molecule like dimethyl sulfide (DMS) detected in the atmosphere of a planet known as K2-18b. This is intriguing because on Earth, DMS is produced only by decaying marine phytoplankton and other similar microbes. The amount of DMS detected has some researchers thinking K2-18b is a watery world with oceans deeper than any on Earth.
The observation might not pan out — remember the theory at the beginning of the last century that Mars was laced with canals — which explains the scientific community's excited-but-cautious reaction to the news. Team leader and Cambridge University astrophysicist Nikku Madhusudhan said that detecting what's called a biosignature is "potentially one of the biggest landmarks in the history of science," while warning, "It is in no one’s interest to claim prematurely that we have detected life."
So how will this be received by the public? We are a curious species. We cast doubts on some things long and well-proved, while blithely embracing preposterous theories and conclusions.
Which is not to say this finding should not be greeted with a tinge of skepticism. It's a massive guess based on slender evidence but solid enough to warrant some enthusiasm.
What we can do is say thanks — for the people doing this work.
It's not easy. It's countless days of grinding leading to an occasional spark of discovery, followed by more endless grinding. Sometimes you never get the electricity. Sometimes you just get the proof that you were wrong. And on you go.
We owe a debt to everyone who puts in the time, whether they're hunched over a microscope, staring through a telescope, digging in deserts, wrestling with calculations, poring over streams of data, or trudging through muck, clambering up slopes, and generally braving whatever conditions nature throws at them to collect samples to be analyzed in labs.
Astronomers have been studying K2-18b since its discovery in 2015. That's 10 years so far. Now they're plotting their next steps to strengthen the evidence that DMS is present on the planet and confirm their hunch that it's teeming with microbial life. They know it lies in the habitable zone around its parent star. It would be a shame if budget cuts to NASA compromise those efforts and the building of stronger telescopes that can help produce more answers.
To a lay person, K2-18b sounds deceptively close. It's in our own Milky Way galaxy, after all, not one of the other 2 trillion or so observable galaxies in the universe. And it's only 124 light-years away — you say "only" until you realize that's 729 trillion miles.
In space, as on Earth, everything is relative. And that relativity has legs, one of which has to do with "biosignature molecules" like DMS. What we know about them comes from what we know of life on Earth. But what if life elsewhere is dramatically different? What if it does not require these molecules? What if it requires molecules we know nothing about, or molecules we do not consider essential to life? What if ...
One phase of the science is complete, now another starts.
There is joy in the journey, not just the arrival.
Columnist Michael Dobie's opinions are his own.