Ch. 12 Flashcards
SETI
Search for extraterrestrial intelligence
Drake equation is used for what
To estimate the number of intelligent civilizations in our galaxy
The number of habitable worlds in the galaxy is the product of
The fraction habitable planets, the fraction of worlds with life, the fraction of worlds with intelligent life, the fraction of time any civilization lives
How many stars fall in the galactic habitable zone
10%
Percent of stars with planets
70%
Ratio of life bearing worlds
1 in 5
Life on Earth seemed to be
inevitable and robust
Convergent evolution
argues for widespread intelligence examples are eyesight
Encephalization qutients
The ratio of brain to body mass
Human EQ
7
Radio
allows communication between worlds
Challenges of radio
You need to know which station to tune to (band) and know the right bandwidth
Three signal categories of SETI
Local communications, interplanetary or interstellar signals, signal beacons
Local communications of SETI include
Earth-based TV and radio signals
Radio was used by SETI because
cheap, easy and simple to discover
Kardashev Scale
Attempts to classify different rankings of civilizations based upon technological capacity to harness and utilize energy sources
Types on Kardashev scale
Planetary (1), Stellar (2), Galactic (3)
Planetary scale
civilizations are capable of using the resources of their home world
Stellar scale
civilizations are capable of using the resources of their home star
Galactic scale
civilizations are capable of using the resources of their home galaxy
Humans are where on the Kardashev scale
0.72
