One of the biggest unanswered questions is if we are alone in the universe. Is life bound to our planet, as an extreme coincidence that hasn’t happened anywhere else, or have we just not been looking hard enough? Life may look different on other planets, very different. The cells we are all too used to may be replaced by elongated bodies of liquid catalysts, or whatever. Standard senses may not exist in ways we expect. Whatever it is, if it’s out there, we want to find it, it’s human nature.
The WOW Signal
On August 15, 1977, the Big Ear radio telescope picked up a certain unexplained signal. The unexplained intensity compelled the astronomer, Jerry R. Ehman, to write “Wow!” and circle the readout in red pen on the printed transcript. The source of the signal came from the constellation of Sagittarius and was assumed not to be the result of a malfunction.
There are many hypotheses including certain comets, terrestrial signals reflected off of space debris, etc. but both have untied ends. For example, why couldn’t other telescopes pick up on those comets, and how could a randomly floating space object reflect a signal from the same source to the same destination for 72 whole seconds? This leads us to what some call the most reasonable explanation: It was artificial. There are aliens doing what we’re doing now, screaming at the top of our lungs with radio signals at promising spots in the galaxy.
One human is about one cubic meter in volume. The number of possible combinations that you can arrange quantum (really small, really really small, really really really small) particles within a cubic meter is about 101070. That means a universe that is the cube root of 101070 (no calculator could solve for that number, sorry), you would expect to see an exact copy of yourself somewhere within that universe.
Now scale that down to find the probability of any type of life (not just an exact copy of you) and the size constraints fit within the visible universe. So where are they?
The Drake equation predicts the most likely number of active, communicative extraterrestrial civilizations in our galaxy.
However, we cannot be certain of all the variables so here’s a more accurate version: