Black Patches In Stool

50 solutions to the Fermi Paradox (30 th solution): There are plenty of CETs, but only within each particle horizon

The biggest proponent of this solution to the Fermi paradox is Michael Hart. To fully appreciate your argument we should understand the concept of particle horizon .

The easiest way to explain it is to assume that the universe is static. Obviously, we know that this is not true, our universe is continually expanding generating more and more space, but anyway, this expansion does not invalidate the reasoning Hart.

Imagine, then, an infinite universe in which galaxies are distributed uniformly, as more or less observe today, slightly less than 14,000 million years after the Big Bang. Surprisingly, the sky does not appear dazzlingly awash with light from the endless galaxies (remember the Olbers paradox). The key lies in the finiteness of the speed of light, so that no signal or influence may have reached us from regions beyond about 14,000 million light years. This distance marks the particle horizon and is the effective size of the observable universe . Nothing is beyond the horizon has had time to reach the observer. Hart

reasoning as follows: First, suppose that the universe is infinite. Since its inception took place some 14,000 million years, the size of the observable universe is given by the distance to the particle horizon. Second, suppose that biogenesis (the development of life from inorganic molecules) is extremely rare (many biologists believe otherwise, but our knowledge of the subject is not too deep). It follows, therefore, that in an infinite universe there will be an equally infinite number of planets with life, but whose respective particle horizons there is only one planet with life.

As Hart notes, the idea can be easily distorted. For example, aliens may visit Earth, or SETI could succeed and signs, or astrobiologists could prove that life spontaneously arose on Mars, regardless of the Earth. However, in the absence of previous evidence, Hart argues that the Fermi paradox leads to a chilling conclusion: we are the only civilization within our own particle horizon. Although the universe contains an infinite number of advanced civilizations, for all purposes, we are alone ...