Where Is Everybody

Fermi's Paradox asked 'Where is everybody?' meaning extraterrestrial aliens, implying given the vastness of the universe and long time it has existed, there should be advanced extraterrestrial civilizations throughout the universe. The Drake equation aimed to answer that question quantitatively, estimates how many active civilizations there are in the galaxy right now. Using numbers by Andrew Dessler,

$$ N = R_* \cdot f_p \cdot n_e \cdot f_l \cdot f_i \cdot f_c \cdot L $$

$R_*$: Number of civilizations with which humans could communicate. Recent estimates suggest about 2 new stars are formed in the Milky Way every year.

$f_P$: The average number of planets that can potentially support life per star that has planets. Most stars have planets, estimate 0.9.

$N_e$: Assume 1 in 5 of stars with planets has a planet in the habitable zone, 0.2.

$f_l$, $f_i$, $f_c$ : The fraction of planets that could support life that actually develop life at some point, develop intelligent life, and develop a technology that releases detectable signs. Wild guess all 0.1.

$L$: The length of time for which such civilizations release detectable signals. Unknown, Dessler assumes advanced civilizations last for ten million years.

"%d planets" % (2 *  0.9 * 0.2 * 0.1 * 0.1 * 0.1 * 10*1e6)

Out[1]: '3600 planets'

But if "instead of 10,000,000 years, advanced civilizations last only 10,000 years", then

"%d planets" % (2 *  0.9 * 0.2 * 0.1 * 0.1 * 0.1 * 10000)

Out[1]: '3 planets'

If advanced civilizations last on average only 1,000 years, due to, well perhaps some kind of catastropy hits them all, then

"%0.2f planets" % (2 *  0.9 * 0.2 * 0.1 * 0.1 * 0.1 * 1000)

Out[1]: '0.36 planets'

which shows why we are the only one, and "there is no one else". And btw we will likely go extinct, lose the civilization we built before our 1000 years are up due to the climate, nuclear war or some other artifact of modernity.

That is the answer to "where is everyone?", they are all dead due to one catastrophy or another, not reaching and staying at the level where they could contact anyone alive like them (us, in this case).

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