• 00:01    |    
    Initial credits
  • 00:06    |    
    • What is a habitable planet?
    • Current potentially habitable exoplanets
  • 04:29    |    
    The circumstellar habitable zone
    • Run-away greenhouse vs. Frozen carbon dioxide
    • Redefining the habitable zone
    • Hydrogen atmosphere habitable planets
    • Rogue habitable planets
    • The dry planet theory
    • The challenge of finding earth-like exoplanets
  • 14:54    |    
    How to find and identify "earths" - Part 1
    • Transiting planets
    • Virtual trip of a planet in the habitable zone
    • Transiting Exoplanet Survey Satellite (TESS)
    • TESS Mission video
    • TESS's elliptical orbit
    • The James Webb space telescope
  • 37:17    |    
    How to find and identify "earths" - Part 2
    • Spatial resolutions
    • Direct imaging and pattern research
    • The internal coronagraph
    • The external coronagrah
    • Starshade and telescope launching
    • Laboratory starshade deployment demonstration
  • 47:22    |    
    Key point summary for all lectures
    • Planet ocurrence from Kepler
    • Known exoplanets by 2013 according to detection techniques
    • Mass radius diagram
    • Remote sensing for exoplanet studies
  • 51:01    |    
    Questions and comments section
    • How can you know if there is one planet or more in a multiple transit system?
    • How do you calibrate and align the satellite and the starshade properly?
    • What kind of information can you get using the starshade?
    • Why we will likely never find a rocky planet of 500 earth masses?
    • Have you taken account the possibility of finding moons around giant planets in the habitable zone?
    • Can we see moons using the starshade?
    • What is the best technique for finding an exoplanet when we can't see a transit?
    • Is there an estimated date for the TESS launch?
    • Is there exoplanet exploration in binary stars?
    • What is the upper limit of open mindedness when thinking of the habitable zone?
    • What liquid elements exist in exoplanets? Why look for liquid water?
    • Where is the weirdest place to find a planet?
    • What other items are there in astronomers' exoplanet wish list?
    • Have you found isolated planets that weren't orbiting a star?
    • What kinds of orbits do you find in exoplanet studies?
    • Pulsar planets and moon mass
    • Creation of rocky planets after a supernova explosion
    • What do you think about the field of radiation around the pulsar?
  • 01:14:14    |    
    Final words
  • 01:14:39    |    
    Final credits

Searching for Habitable Worlds

New Media  | 12 de diciembre de 2013  | Vistas: 21

Sara Seager speaks of the habitable zone, the area around a given star where scientists expect to find exoplanets with appropriate conditions to harbor life. A habitable planet is defined by the possibility of finding liquid water at its surface. Planets too far away from their stars are too cold, planets too close are too hot. Historically, the habitable zone has been estimated using several models, according to the limits where liquid water is a possibility. Seager suggests some of these models may be inaccurate, and too narrow-minded. The existence of hydrogen-atmosphere planets, rogue planets, and dry planets suggests that the habitable zone may be larger than predicted. The controversial role of water in planet formation provides further evidence for this theory.

The process of finding “earth-like planets” is no small task. Exoplanet detection techniques are numerous, and the future is full of promise. Seager introduces TESS, the upcoming satellite mission that seeks to track the entire sky for exoplanets in a period of two years. The James Webb telescope will help astronomers track atmospheres for TESS’s yield. The external coronagraph, a deployable starshade that will block-out star light to clear visibility, will reveal new habitable bodies. With exciting new possibilities, the quest for habitable “earth-twins” continues.

For an overview of exoplanet detection techniques, see: Exoplanet Detection: Techniques I and Exoplanet Detection: Techniques II.






Sara Seager is an astrophysicist and planetary scientist at the Massachusetts…


Nuestra misión es la enseñanza y difusión de los principios éticos, jurídicos y económicos de una sociedad de personas libres y responsables.

Universidad Francisco Marroquín