Imagine this: Tiny particles of dust and gas, swirling in the vast emptiness of space, eventually clumping together to form planets. Sounds simple, right? But how exactly does this cosmic alchemy happen? That's the fascinating question that astrochemist Julia Santos tackled during her PhD, and her findings have sent ripples through the scientific community.
Santos's research dives deep into the formation of methanol, a seemingly simple molecule, yet a crucial building block for more complex organic molecules in space. She aimed to understand the chemical processes that occur in these stellar nurseries – the birthplaces of planets, moons, and asteroids.
"I try to understand chemistry in space," Santos explains. "When we think of a planet, we picture it as a core with a mantle, surface and atmosphere. To form these elements, you need the right mix of atoms. I want to understand how these ingredients are distributed in the universe. Is it different around other stars or was Earth just lucky with the present ingredients?"
Understanding the Chemistry of Cosmic Nurseries
When a star ignites, it's surrounded by a swirling cloud of gas and dust. This is the raw material from which planets, moons, and asteroids are born. But the journey from dust to a fully formed planet is a complex chemical dance. Santos sought to illuminate the initial steps of this process.
"How do molecules become more complex? How are they formed and destroyed? Are they in the gas phase or solid? Those are the questions I want to answer," she explains. "In my PhD, I focused on dust grains—and the ices that form on them— because they create a fertile environment where chemistry thrives."
Simulating Space in a Lab
To unravel these mysteries, Santos primarily used lab experiments. "In the solar system, you might be able to send a probe to a comet. But further away? That’s simply impossible," she notes. "Therefore, we simulate interstellar space on Earth in an experimental setup with extremely low temperature and pressure." Her research spanned various approaches, from hands-on lab work to chemical studies and observational programs. "I need that to stay motivated. Although hands-on experiments are especially gratifying."
Debunking a 20-Year-Old Paradigm
But here's where it gets controversial... Santos's most significant achievement came during her PhD. For 20 years, the scientific community had accepted a specific model for methanol formation. But Santos's research challenged this long-held belief. "I studied a lot of different chemical reactions. The main one was the formation of methanol. This is a simple molecule but in space we consider it complex," she explains. "It is the protagonist in the story of astrochemistry. The basic ingredient needed for many other organic molecules.”
"I confirmed that there is another mechanism that is more important," she states. "We published this in 2022, and since then, observations and models have already supported it. That is the only empirical evidence we have in astronomy, so that was really cool!"
A Hub for Astrochemistry in Leiden
Santos emphasizes the unique environment in Leiden, with its exceptional facilities and expertise. "Astrochemistry is very multidisciplinary. It encompasses geology, engineering, astronomy, and chemistry. And Leiden has it all. That was very helpful and enriching."
The Challenges
Her journey wasn't without its hurdles. "My promotor Harold Linnartz passed away unexpectedly. That was a difficult time," she says. "And right after, we had to move the lab to the Gorlaeus Building. So I couldn’t do experiments for a substantial part of my PhD. Luckily, Ewine van Dishoeck was very welcoming and took me into her group."
Santos is now continuing her research at Harvard University with the prestigious 51 Pegasi b Fellowship.
What do you think? Does it surprise you that a seemingly simple molecule like methanol could be the subject of such groundbreaking research? Do you find it fascinating that a long-held scientific belief could be overturned? Share your thoughts in the comments below!
