This paper is an examination of the probability of Life, Cognition, and Technology developing on exoplanets within 100pc (~326 lightyears) around Earth. In it, we examine the potential rapid evolution of life on Earth early into its history, the length of time cognition appears to have existed, and what constitutes technology. This is anthropocentric (focusing on Earth's history) intentionally, to constrain results and present a conservative baseline. Our framework reaches an approximate population of 4,800 life bearing worlds, between 1,900 and 3,300 cognitively active worlds and between 840 and 1,400 technologically active worlds - meaning tool building species. The space interacting result of ~3.4 translates to being detectable due to their current activity and our temporal alignment with them. The 3.4 value includes Earth. The formula finds that there is a probability of ~0.1 space capable species existing within 100pc of Earth.
Mitchel Lemley (Sat,) studied this question.
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