Drake Equation

A Drake Equation is a mathematical equation that estimates the number of extraterrestrial civilization that may exist the Milky Way galaxy.

• Context:
  • It is a real-world function specification for a count estimate of the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy.
  • It was proposed by astronomer Dr. Frank Drake in 1961.
  • It can be represented by [math]\displaystyle{ N = R_{\ast} \cdot f_p \cdot n_e \cdot f_{\ell} \cdot f_i \cdot f_c \cdot L }[/math]

    where:

    • N = the number of civilizations in our galaxy with which radio-communication might be possible (i.e. which are on our current past light cone);
    • R_* = the average rate of star formation in our galaxy.
    • f_p = the fraction of those stars that have planets.
    • n_e = the average number of planets that can potentially support life per star that has planets
    • f_l = the fraction of planets that could support life that actually develop life at some point
    • f_i = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
    • f_c = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
    • L = the length of time for which such civilizations release detectable signals into space.
• Example(s):
  • …
• Counter-Example(s):
  • Kardashev Scale,
  • Planetary Habitability Measure.
• See: Intelligent Extraterrestrial Life, Extraterrestrial Life, SETI, Guesstimate, Astrobiology, Astrophysics, Astronomy, Cosmology.

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References

2023a

• (ChapGPT-OpenAI, 2023) ⇒ https://chat.openai.com/chat Retrieved:2023-03-26.
  • Q: What is the Drake Equation?
  • A: The Drake Equation is a mathematical equation proposed by astronomer Dr. Frank Drake in 1961 to estimate the number of extraterrestrial civilizations that may exist in our galaxy with which we could potentially communicate. The equation takes into account various factors that are believed to affect the probability of the existence of intelligent alien life.

    The equation is expressed as:

    [math]\displaystyle{ N = R_* \times f_p \times n_e \times f_l \times f_i \times f_c \times L }[/math]

    Where:

    • $N$ = the number of civilizations in the Milky Way Galaxy whose electromagnetic emissions are detectable.
    • $R_*$ = the rate of formation of stars suitable for the development of intelligent life.
    • $f_p$ = the fraction of those stars with planetary systems.
    • $n_e$ = the number of planets, per planetary system, with an environment suitable for life.
    • $f_l$ = the fraction of suitable planets on which life actually appears.
    • $f_i$ = the fraction of life-bearing planets on which intelligent life emerges.
    • $f_c$ = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
    • $L$ = the length of time such civilizations release detectable signals into space.

The Drake Equation is not a definitive answer to the question of the existence of extraterrestrial life, but rather a framework for organizing and thinking about the various factors that may be involved.

2023b

• (Wikipedia, 2023) ⇒ https://en.wikipedia.org/wiki/Drake_equation Retrieved:2023-3-26.
  • The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy.

    The equation was formulated in 1961 by Frank Drake, not for purposes of quantifying the number of civilizations, but as a way to stimulate scientific dialogue at the first scientific meeting on the search for extraterrestrial intelligence (SETI). The equation summarizes the main concepts which scientists must contemplate when considering the question of other radio-communicative life. It is more properly thought of as an approximation than as a serious attempt to determine a precise number.

    Criticism related to the Drake equation focuses not on the equation itself, but on the fact that the estimated values for several of its factors are highly conjectural, the combined multiplicative effect being that the uncertainty associated with any derived value is so large that the equation cannot be used to draw firm conclusions.

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