Introduction and Background

• Jennifer Fick (Google cryptography/security engineer) hosts Dr. Aomawa Shields
• Dr. Shields: UC Irvine astronomy/astrobiology professor, author, mother, mentor, classically trained actor
• Work shown at Sundance Film Festival
• Honors: TED fellow, NSF career award, NASA habitable worlds/exoplanets research grant
• Discussion focuses on her book about life on other planets

Core Research Question and Methodology

• Primary question: "Are we alone in the universe?"
• Uses computer climate modeling adapted from Earth weather/climate prediction models
• Modifiable parameters:
  • Type of star planet orbits
  • Orbital shape and tilt
  • Planet's axis tilt
  • Atmospheric composition
• Goal: identify planets most likely to host habitable conditions across widest range of factors
• Work bridges observational astronomy gaps with computational modeling

Scale of the Universe and Probability of Life

• 10^22 stars in observable universe
• Analogy: equivalent to dry grains of sand on all beaches worldwide
• ~Every star has planets
• 20-25% of planets in habitable zones ("Goldilocks zone")
• 5,500 exoplanets discovered so far
• Few dozen potentially in habitable zones
• Reference to "Contact" movie quote: "If it's just us, it would be an awful waste of space"

Exoplanet Habitability Criteria

• Primary requirement: liquid water (common denominator for all Earth life)
• Planet size: 1-1.5x Earth size likely rocky with solid surface
• Temperature range: warm enough for liquid water, not too hot for evaporation
• Focus on earth-sized planets where "something could stand and oceans could flow"

Life as We Know It vs. Life as We Don't Know It

• Life as we know it: uses liquid water as solvent for metabolic processes
• Earth has astronomical diversity within this framework (microbes to elephants)
• Life as we don't know it: alternative biochemistry
  • Different solvents (liquid ethane/methane like Saturn's moon Titan)
  • Different backbone elements (silicon instead of carbon)
• Astrobiology is interdisciplinary: astronomers, biologists, geologists, oceanographers, glaciologists
• Field is 60-70 years old vs. astronomy's ancient origins

Climate Change and Earth's Habitability

• Same models used for exoplanets originally proved anthropogenic climate change
• Models show human-made CO2 impact through 2100s
• Natural cyclical CO2 changes exist, but current trend shows steep slope increase
• Global average surface temperature increasing by couple degrees minimum
• Shields taught energy/environment course as astronomer, learning alongside students
• Fossil fuel reserves are limited beyond climate impact
• Both/and approach: address Earth's climate change AND search for life elsewhere
• Understanding Earth's CO2 impact helps apply knowledge to other planets
  • Some distant planets could benefit from more CO2 (too cold)
  • Earth has too much CO2

Distance and Detection Challenges

• Closest potentially habitable planet: Proxima Centauri b
• Distance: 4 light years = ~40 trillion miles
• Current space propulsion inadequate for significant light speed fractions
• Reliance on telescopes and instrumentation improvements
• James Webb Space Telescope exceeding expectations
  • Originally not expected to study earth-sized planets effectively
  • Now confirmed presence of earth-sized planet
  • Moving toward atmospheric analysis capabilities

Observational Techniques and Limitations

Transit Technique

• Detects planets by measuring star brightness dips when planet passes in front
• Periodic dips indicate orbiting object
• Dip ratio determines planet size

Doppler/Radial Velocity Technique

• Measures gravitational effects on star's orbit
• Star and planet orbit common center of mass
• Star's "wobble" indicates planet mass
• Combined with transit data gives density (mass/volume)
• Density indicates composition: rocky vs. gaseous vs. water-rich vs. iron-rich

Current Limitations

• Can determine atmospheric composition of larger Jupiter/Neptune-sized planets
• Cannot yet analyze earth-sized planet atmospheres
• Limited surface composition data

Computational Modeling Advantages

• Can test unlimited surface compositions: ice, ocean, granite, vegetation, calcite, sand
• Can model various atmospheric compositions and scenarios
• Example predictions:
  • Ocean-covered planet too close to star → steam atmosphere → runaway greenhouse like Venus
  • Robust planets habitable across multiple atmospheric scenarios
• Models identify priority targets for telescope follow-up

Biosignatures and Detection Methods

• Biosignatures: biologically generated environmental impacts observable from space
• Gas combinations that only life could produce
• Surface detection: sunlight reflecting off liquids (but could be non-water liquids)
• Atmospheric analysis for life indicators

Computational Challenges and Future Directions

Current Model Types

• 1D models: fast but oversimplified, good for initial graduate student training
• 3D Global Climate Models: weeks to reach thermal equilibrium per simulation
• Multiple parameter variations require weeks upon weeks
• Some studies create hypothetical planets around different stars

Statistical and AI Integration

• Movement toward statistical frameworks for climate modeling
• Potential AI method applications
• Shields' concerns: maintaining scientific rigor and robustness
• Human analysis essential for distinguishing physical effects from model artifacts
• No substitute for human examination of climate data

Personal Journey and Career Path

• Left first PhD program, returned 11 years later ("solar cycle")
• First attempt: studying irregular and spiral galaxies
• Exoplanet field in infancy when first started (first exoplanet found year before)
• Second PhD attempt motivated by genuine love for field vs. expected path
• Different life outcomes: wouldn't have met husband or had same daughter
• Catalyst for leaving: discouragement both external and internal
• Believes things worked out as supposed to

Academic Power Structures and Inclusion

Advisor-Student Power Dynamics

• Shields recognizes tremendous influence as advisor
• Experienced discouragement as student: told to "consider other career options"
• Now understands she's not powerful enough to dictate someone's future
• Focuses on questions about passion and work ethic vs. career suitability
• Avoids discouraging statements about field appropriateness

Retention vs. Recruitment

• Not just about getting underrepresented students into programs
• Critical importance of keeping them there
• Students from marginalized communities carry additional burdens:
  • Family histories of racism and oppression
  • Legacy challenges beyond academic workload
• Professor sensitivity to unseen struggles
• Asking "How are you really doing?" vs. focusing only on academic performance

Rising Star Girls Program

• Middle school girls of color astronomy program
• Encourages bringing family backgrounds and breakfast table conversations
• Personal connection to universe essential before tackling "heavy math"
• Personal informs professional approach

Integration of Personal and Professional

• Personal feelings impact scientific ability daily
• To-do lists must adapt to personal state (e.g., three hours sleep)
• Humans aren't machines - feelings affect work quality
• Essential for both student success and professional achievement

Diversity and Scientific Progress

• Moon landing achieved with limited participation - only small fraction allowed at table
• Imagining potential if everyone included in scientific endeavors
• Affirmative action ensures everyone has place at table
• Eliminating affirmative action presumes equality already achieved (not yet case)
• If everyone included in answering "are we alone" question by 2050, goal potentially achievable
• Universal inclusion would accelerate scientific discovery

Future Observatory Missions

• LUVOIR (Large UV Optical IR Surveyor)
• HabEx (Habitable Exoplanet Observatory)
• Astro 2020 decadal survey recommendations
• ~6-meter mirror space telescopes needed
• Required light-gathering power for exoplanet atmospheric analysis
• Coronagraphy needed: block star light (100 million to 10^10 times brighter than planet)
• Missions still in concept phase
• Would provide bio-signature detection capabilities

Personal Authenticity and Self-Discovery

Gradual Change Process

• Doesn't require radical overnight changes
• Small incremental steps over time
• Examples: playing dusty guitar for 5 minutes, buying magazine on loved topic
• Ways to signal universe you're open to authentic self
• Dreams don't disappear when ignored - they eventually demand attention
• Physical/emotional effects of denying authentic self: gut feelings, soul sadness

Practical Steps

• Acknowledge suppressed parts of self
• Bring authentic interests into life weekly if not daily
• Small manageable steps signal openness to universe
• Universe responds with opportunities when you become open
• Miracles happen through openness rather than forced effort