Are We Alone In The Universe? Sara Seager on Exoplanets, Venus, and the Hunt for Alien Life (Astrophysicist and Planetary Scientist at MIT)

A quick note before today's podcast: Last Thursday, we launched Part 1 of our four-part series on Founders Fund. If you haven’t read it yet, you can catch up on Part 1 here. For everyone following along, Part 2 drops this Thursday, June 19th.

In the meantime, we hope you enjoy today's podcast episode below.

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Why search for life beyond Earth? For MIT astrophysicist and MacArthur Genius Fellow Sara Seager, it’s not just a scientific question—it’s a deeply human one. Like creating art or studying philosophy, the search taps into our primal curiosity about who we are and whether we’re alone. Sara is a pioneer in the field of exoplanets: planets that orbit stars other than our Sun. Her early work was met with skepticism. Today, she’s one of the most respected voices in the field, with discoveries that have redefined our understanding of the universe. From detecting alien atmospheres to reimagining where life might exist, she shares how entrepreneurial thinking and intuition are fueling groundbreaking discoveries.

In our conversation, we explore:

• An explanation of exoplanets and the importance of their discovery

• The key technologies that enabled exoplanet detection

• Sara’s controversial discovery of phosphine gas in Venus's atmosphere and why it could be a sign of life

• An overview of Project Starshade, why NASA has currently shelved it, and why Sara continues to work on it anyway

• How scientific innovation often requires challenging authority and conventional wisdom

• How Sara approaches her research portfolio like an investment strategy, but with an inverse risk profile

• Why AI may someday explore planets we’ll never reach—and what that means for humanity

• Much more!

Explore the episode

Timestamps

(00:00) Intro

(04:07) What is an exoplanet?

(04:33) The diverse types of exoplanets, including the common Sub-Neptune type

(06:40) Why the search for habitable planets matters

(08:57) The timeline for finding life outside of Earth

(10:15) Parallels between professors and entrepreneurs

(11:37) Sara’s background and inspirations

(15:48) Why the study of exoplanets was initially viewed with skepticism

(18:38) Technology breakthroughs enabling exoplanet discovery

(21:05) Looking for atmospheric signals as signs of life

(25:48) The K2-18b debate and challenges of detecting life

(31:10) The Venus Life Finder Initiative and phosphine discovery

(37:38) The mission to explore Venus's atmosphere

(39:20) Goals of the first missions and the inspiration from a prior Soviet balloon mission

(41:58) An overview of the Starshade project

(47:44) Applications from the Venus mission that may benefit Earth

(48:50) Sara's scientific "investment portfolio" and the impact of the MacArthur grant

(52:46) The power of intuition

(56:09) Formative lessons from Sara’s childhood

(59:04) How Sara uses AI for administrative tasks

(01:00:38) The evolution of AI

(01:01:50) Sara’s speculation on life beyond Earth

(01:03:24) Where Sara's best ideas come from

(01:04:02) Final meditations

Follow Sara Seager

LinkedIn: https://www.linkedin.com/in/sara-seager-1352b85/

Website: https://www.saraseager.com/

Resources and episode mentions

Books

• The Smallest Lights in the Universe: A Memoir: https://www.amazon.com/Smallest-Lights-Universe-Memoir/dp/0525576258

• The Giver: https://www.amazon.com/Giver-Quartet-Lois-Lowry/dp/0544336267

People

• John Bahcall: https://en.wikipedia.org/wiki/John_N._Bahcall

Other resources

• Exoplanets: https://science.nasa.gov/exoplanets/

• Sub-Neptune: https://en.wikipedia.org/wiki/Sub-Neptune

• NASA’s Asteroid Bennu Sample Reveals Mix of Life’s Ingredients: https://www.nasa.gov/news-release/nasas-asteroid-bennu-sample-reveals-mix-of-lifes-ingredients/

• Seager Hair Transplant Centre: https://www.seagerhairtransplant.com/

• Kepler: https://science.nasa.gov/mission/kepler/

• Astronomers Detect a Possible Signature of Life on a Distant Planet: https://www.nytimes.com/2025/04/16/science/astronomy-exoplanets-habitable-k218b.html

• Astronomers may have found a signature of life on Venus: https://news.mit.edu/2020/life-venus-phosphine-0914

• Venus Morning Star Missions: https://www.morningstarmissions.space/

• Past Missions: https://www.morningstarmissions.space/pastvenusmissions

• Exoplanet Program: Starshade: https://exoplanets.nasa.gov/exep/technology/starshade/

• Project Starshade: https://www.projectstarshade.com/

• Coronagraph: https://science.nasa.gov/mission/roman-space-telescope/coronagraph/

• MacArthur Fellows: https://www.macfound.org/programs/awards/fellows/

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