Searching for Life in the Solar System | Alfonso Davila | Talks at Google

TL;DR

Scientists search the solar system for life to discover a second genesis, a form of life unrelated to life on Earth, and test whether life is a broader cosmic phenomenon rather than a unique event. Alfonso Davila focuses on potentially habitable places such as Mars, Europa, and Enceladus while developing life-detection strategies based on biology and biochemistry. Read on to understand the hypotheses and challenges guiding that search.

Transcript

[MUSIC PLAYING] SPEAKER: But today, we have a very exciting speaker here, Alfonso Davila. Alfonso. And he's here from Ames. He's been with Ames about 10 years, and has just recently become a civil servant, and before that was a contractor with SETI working at Ames. So. He is currently in the exobiology branch of NASA Ames, looking at terrestrial an... Read More

Key Insights

• 🛟 The search for a second genesis of life is driven by the need to understand the origin and possibilities of life beyond Earth.
• 🥮 Studying the organic chemistry of other planets and moons can provide insights into the likelihood of a second genesis.
• 😚 There is a need to differentiate between a close second genesis, where life originated from similar starting materials, and a distant second genesis, which would involve completely different biochemistry.

Questions & Answers

Q: Why are scientists searching for life in the solar system?

The central goal is to find a second genesis: life that does not share an origin with life on Earth. Alfonso Davila argues that one such discovery could indicate that life is a cosmic phenomenon rather than something that happened only once on our planet.

Q: What does “a second genesis of life” mean?

A second genesis is a form of life that is not related to life on Earth. It must represent an independent origin rather than Earth life transferred elsewhere or contamination from Earth.

Q: What is the 0-1-infinity rule in the search for extraterrestrial life?

The rule frames things as nonexistent, unique, or present in many forms. Because Earth already provides one example of life, the remaining question is whether life is unique or occurs in many forms; Davila believes one independently originated example would support the latter possibility.

Q: Which solar-system bodies are discussed as possible places to search for life?

The talk identifies Mars, Europa, and Enceladus as targets for life-detection research and mission concepts. Davila says the solar system contains several places where Earth microorganisms could potentially survive or even thrive.

Q: Why does Alfonso Davila focus on the solar system instead of exoplanets?

Davila notes that many exoplanets may be at distances from their stars where liquid water could remain stable on the surface. He focuses on the solar system because its potentially habitable locations are accessible enough to investigate directly for evidence of life.

Q: How does knowing only Earth life limit the search for extraterrestrial life?

Scientists have only one known example of life, so their ideas about life elsewhere are constrained by Earth biology. Although Earth contains extensive biological diversity, Davila says its life is fundamentally very similar at the chemical level.

Q: How can scientists distinguish a second genesis from Earth-related life?

The search uses an abiotic null hypothesis to examine whether evidence can be explained by prebiotic chemistry and a terrestrial null hypothesis to consider contamination or transfer of Earth life. Even when evidence cannot be explained by abiotic processes, distinguishing a close second genesis from a common ancestor remains difficult because current biochemical knowledge is limited.

Q: How does Alfonso Davila contribute to the search for extraterrestrial life?

At NASA Ames’ exobiology branch, Davila studies extreme terrestrial deserts as analog environments for assessing the habitability of other planetary bodies. He also advises the development of space-exploration instruments and helps create mission concepts for detecting evidence of life on Mars, Europa, and Enceladus.

Summary & Key Takeaways

• The speaker discusses the motivation behind the search for a second genesis of life and the importance of asking the question "why?" in scientific exploration.

• The possibilities of a second genesis of life are explored, including a potential common ancestor, a close second genesis with similar starting materials, and a distant second genesis with completely different biochemistry.

• The speaker proposes a two-fold hypothesis to guide the search for a second genesis of life: the abiotic null hypothesis which looks for evidence of prebiotic chemistry, and the terrestrial null hypothesis which examines the possibility of contamination or transference of Earth life.