Aomawa Shields: How we'll find life on other planets | TED

Scientific Concepts, Discoveries, and Nature Phenomena

• Searching for extraterrestrial life

  • Life is considered most likely where liquid water can exist.
  • This depends on whether an exoplanet receives the right stellar energy and maintains a suitable climate.

• Habitable-zone / “just-right” orbital distance

  • Planets must orbit at distances where they could be warm enough for surface water (lakes/oceans).
  • The video emphasizes that distance alone is not sufficient.

• Atmospheric effects and the greenhouse effect

  • Venus is used as a key example of how initial expectations can be wrong:
    • Although Venus appears benign, measurements show:
      • Surface temperature ~900°F (~500°C)
      • A thick atmosphere driving an extreme greenhouse effect, overheating the surface.
  • Conclusion: Atmosphere is crucial to climate and habitability, not just proximity to the star.

• Difficulty measuring exoplanet atmospheres

  • Exoplanets are:
    • Small and dim compared to their host stars
    • Very far away
  • Detecting atmospheric composition during transits is extremely challenging—compared to viewing a tiny object (a fruit fly) against a bright light source at enormous distance.

• Climate modeling to infer what atmospheres could allow habitability

  • Because direct measurements are hard, the work uses computer models to predict:
    • What kinds of atmospheres and orbital orientations/conditions could still produce surface water–friendly climates.

• Example exoplanets discussed

  • Gliese 667 Cc
    • A nearby candidate for surface water, but ~23 light-years away (beyond current direct atmospheric study).
  • Kepler-62f
    • An illustration-focused example:
      • ~1,200 light-years away
      • ~40% larger than Earth
    • The speaker’s NSF-funded modeling suggests it could be warm enough for open water for many types of atmospheres and orbital orientations.
    • Proposed follow-up: future telescopes should search for biosignatures (signs of life).

• Ice and planetary climate / albedo

  • Ice affects climate via how it interacts with light:
    • Blue ice reflects more short-wavelength (bluer) light
    • Ice absorbs longer (redder) wavelengths
  • This leads to a visual explanation: ice appears blue because redder light is absorbed before it reaches deeper layers.

• A climate “contradiction” involving cooler vs hotter stars

  • The speaker’s models indicate planets around cooler stars could be warmer than those around hotter stars.
  • Reason given:
    • Cooler stars’ light is more red/longer wavelength
    • Ice absorbs that longer-wavelength energy, potentially heating the ice and affecting surface temperature.

• Interdisciplinary approach (science + art)

  • “Science and art don’t often go together,” but combining them is presented as a way to broaden participation in astronomy (as a methodological/education approach).

Methodology / Approach (as Described)

• Use computer climate models to:
  • Explore how atmosphere, orbital geometry/orientation, and stellar spectrum change planetary surface conditions.
  • Test how different scenarios could still allow liquid water despite seemingly contradictory effects (e.g., ice absorption behavior under different star temperatures).
• Use future telescopes to:
  • Obtain observational follow-up on promising targets (e.g., Kepler-62f) for signs of life.

Featured Researchers or Sources (Named)

• NSF (National Science Foundation) — mentioned as funding support for the Kepler-62f work.
• Rising Stargirls — the speaker’s organization (education/outreach group).
• No individual researchers (beyond the speaker) are explicitly named in the subtitles.