From Interstellar Clouds to Planets: JWST, Lab Simulations, and the Chemistry of Star Formation

Podcast overview

NASA's Curious Universe delves into how clouds of gas and dust in space evolve into stars and the planetary systems that orbit them. Host Jacob Pinter chats with Evina van Dishoek, an astronomer at the University of Leiden, about how laboratory experiments on Earth and infrared observations from the James Webb Space Telescope illuminate the chemistry of star formation. Webb, positioned a million miles from Earth, sees inside dark clouds with its infrared vision, while the ground of the Netherlands provides a close up view of dust and ice chemistry. The episode also touches on the collaboration with ESA and ALMA and the ongoing search for the ingredients that may seed life in emerging planetary systems.

• JWST’s infrared capabilities uncover molecules hidden in cold clouds
• The lab on Earth provides tractable timescales to study space chemistry
• Water, simple organics and ices on dust grains are building blocks inherited by forming planets
• The cake versus recipe analogy helps conceptualize how stars and planets form

Introduction and framing

The podcast opens with a vivid metaphor for the cosmic chemical laboratory between stars. In space, gas and dust form dense, cold clouds that slowly collapse under gravity to birth stars and their planetary systems. The host emphasizes that while telescopes let us witness the process, a lab on Earth can bring us hands-on intuition by simulating some aspects at extreme conditions. The conversation centers on how JWST and its instrument suite, especially the Mid Infrared Instrument (MIRI), are opening new windows into the chemistry of star formation.

James Webb Space Telescope and MIRI

The interview highlights JWST as a groundbreaking tool for infrared astronomy. Three of JWST’s four instruments focus on near infrared light, while MIRI observes the mid infrared. Infrared observations allow scientists to peer through dust and gas to detect molecules that would otherwise be hidden. A special refrigerator called a Cryocooler keeps MIRI cold enough to function, suppressing heat from the Sun and Earth that would blind infrared measurements. The host and guest discuss the excitement of the first data from JWST and how its spectral data reveals richer features than previous infrared observatories like ISO and Spitzer.

Evina van Dishoek and the lab analogy

Evina’s career path, from chemistry to astronomy, underscores the importance of interdisciplinary thinking. Her work focuses on how molecules formed in space contribute to the materials in forming planetary systems. In the lab, scientists study ice and dust grains at temperatures nearing absolute zero and in ultra-high vacuum, differences that help explain how simple molecules freeze out and react on dust grain surfaces to form water, carbon dioxide, methanol and more complex organics including sugars. The conversation emphasizes that Earth experiments compress astronomic timescales from millions of years down to hours or days, enabling practical exploration of reaction pathways and detection strategies.

Planet formation ingredients and the chemistry of clouds

The episode introduces an analogy that Recurs throughout the talk: a cake, its ingredients, and its recipe. The initial stage of star and planet formation involves cold clouds where atoms and molecules freeze onto dust grains, forming icy mantles. On grain surfaces, new chemical reactions occur, building molecules such as water and carbon dioxide. Webb can detect these ices and more complex molecules, including methanol, ethanol, and potentially simple sugars, suggesting that the raw ingredients for life begin in these early stages and can be inherited by nascent planetary systems.

Disks, planets and the chemistry of planet formation

Disk systems observed around young stars show that dust grains collide and grow into pebbles and planetesimals, the building blocks of planets. The Atacama Large Millimeter Array (ALMA) provides crucial observations of disks at millimeter wavelengths, revealing gaps and structures that trap dust in certain regions. Webb’s new spectroscopy and imaging reveal a wealth of carbon-rich molecules in some disks, while others show abundant water and CO2. These differing chemical environments could influence the types of planets that form and their potential for hosting water and organic materials on their surfaces.

Life in the cosmos and future directions

The show addresses one of the central questions in astrobiology: could there be life elsewhere, and how do we detect the signatures of life? While Webb helps identify the raw ingredients and how they assemble in forming planets, the guest notes that the exact steps to life are the domain of chemistry and biology beyond JWST. The discussion emphasizes a cautious but hopeful stance on detecting biosignatures, while acknowledging the need for future missions and instruments beyond Webb to capture more definitive signs of life.

Conclusion and curiosity

As the episode closes, Evina shares what still fuels her curiosity, including the fundamental question of how atoms come together to form molecules and how Earth’s history places our planet in a cosmic context. The Lobster Nebula image is promised for the episode’s web page, illustrating a nebula where newborn stars shape their environment. The host invites listeners to explore NASA resources for JWST news and to watch Cosmic Dawn for a deeper look at Webb’s development.