11. Life: Astrobiology (ACC)

Astrobiology: Life in the Universe 

Major Theme: Life may not be unique to Earth

Learning Objectives

  • Explain our current understanding of how and when life began on Earth and how it has evolved.
  • Explain how life is a structure that has evolved through the action of the physical and chemical processes that shape the universe.
  • Describe the locations in our Solar System and around other stars where astronomers think life might be possible.
  • Describe some of the methods used to search for intelligent extraterrestrial life.
  • Explore the SETI program
  • Apply the Drake Equation using our latest assumptions

Outline:

Life evolves on Earth

  • The origin of life on Earth
  • When life began
  • Increasing complexity
  • Evolution as a mechanism of change.

Life involves complex chemical processes

  • All of science is interconnected.
  • Ingredients for Life
  • Origins of Life: the primordial soup, DNA / RNA
  • LUCA and the tree of life
  • Timeline for development of life

Where do astronomers look for life

  • The search for life in the solar system
  • Habitable zones
  • Remaining planetesimals.
  • Planetary systems are common.
  • The search for extrasolar planets
    • The radial velocity method.
    • The transit method.
    • Microlensing.
    • Astrometric method.
    • Direct Imaging
  • The discovery of extrasolar planets.

The search for sign of intelligent life

  • The Fermi Paradox
  • Sending messages
  • The Drake Equation
  • Technologically advanced civilizations and SETI

Activities & Assignments:

Read Astronomy textbook: Chapter 21 (sections 21.4-6); Chapter 30.

Notes and class handouts are stored in the course Astrobiology folder 

Activity – Search for types of extremophiles on Earth with “Alien Safari” – for each of the six “life zones”, name and describe the associated life form and their location of Earth. Then select a solar system habitat and predict which type of extremophile might be living there.  Defend your thesis! (hint: use the CER thesis format).

Extra Stuff:

  • Timeline for the development of life (Timothy Ferris)
  • AstronomyCast, Episode 143: Astrobiology (listen to this podcast for an introduction to this unit)
  • AstronomyCast, Episode 209: Exotic Life (define ‘extremophiles’ and describe specific examples mentioned in the podcast)
  • Fermi Paradox – “Where are the aliens?” and the Drake Equation: estimate number of intelligent civilizations in our galaxy. Possible answers to this paradox that we discussed in class include: “The Christmas Tree Phenomenon”, the Rare Earth Hypothesis, we are quarantined, we have a very small detection radius (< 25 light years), and They are here already!
  • Planet Quest : Search for Habitable Planets.  In this activity you will learn about the history for the search for extra-terrestrial planets and the factors that make a planet habitable.
  • Kepler Observatory’s Tally of Alien Planets.
  • Star Chart of the Month

Final Exam Preparation:

There is also a study guide in this unit’s Notes Folder.

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