A Card from ET for the holidays
Most all people, including most scientists, assume ours is not the only inhabited planet in the Universe. The very number of stars, with 100sextillion (quite a sexy, scintillating number) added recently to the tally, tells us this is an awful lot of real estate for one tiny world, such as ours to inhabit. The recent discovery of Gliese 581, although orbiting a red dwarf, may be promising for an Extraterrestrial mailbox.
This tells us nothing of course, about what kind of alien life there might be. The idea of carbon based life forms, and curiously hominid looking aliens has been around forever. The idea of other life forms, such as the silicon based Horta, of Star Trek fame, is new to the last two centuries. The recent announcement too, of arsenic based life-forms found by NASA in Mono Lake, certainly adds to the intrigue and possibilities.
We also do not know at what stage we may find life, or they may have found us. Bacterial life has certainly been on this planet far longer than human life. Dinosaurs ruled for nearly 200 million years, before a mammal friendly meteor knocked them off their pedestal of supremacy. These mammals have ruled since then, for a small fraction of that time, about sixty million years. This is barely time for a blink in the twinkling eye of a distant star system to have sent, or received any inter-galactic mail.
The Drake equation, N=R*fp ne fi fi fc L, tells us with a brief formula that if one took N to be Number of communicative worlds, then factored the rate of suitable sun like stars, and the fraction of those stars with orbiting planets, and the fraction of those planets which could be earth like, and the fraction of those earth like planets where life exists, and the fraction of those life bearing planets, where intelligent life arose, then the fraction of those intelligent life planets where communication means are developed, and the fraction of those planets with such ability to be factored in the Lifetime (L) of such civilizations, one could expect a small, but significant fraction of intelligent life.
Our solar system is expected to have a life span of only ten billion years, not much time for civilizations to really cover billions of light years of distance, effectively. This is why worm holes and warp drive are as standard issue in science fiction as red shirts.
Frank Drake’s own current solution is updated upon new information by SETI and other enthusiasts, and suggests about 10,000 communicative civilizations in our Milky Way. Of course, with the closest one being 1500 light years away, that is a distance that if we were to achieve life speed, or if they already have, word from them would need to have been dispatched at least 1500 years ago to get here before the Christmas eve deadline.
What about E.T.? What about UFOs and the visitors who may have come here long ago? Of course all science must forever keep an open mind. The best guess is usually based upon the most likely, and probable explanations.
In the case of UFOs, one might come up with an equation similar to the Drake equation that counts which sightings are most likely to have average explanations, which of those remaining sightings show movements suggesting engineering, which of those showing such movement can be dismissed as earth based, and which of those remaining have no explanation. It is of course, these last “flying saucers” or spacecraft, that are of most interest for E.T. chasers and alien abductees who want their sweatshirts back.
There are certainly plenty of criticisms with Dr. Drake’s equation. One is the assumption that all intelligence would even develop “civilization.” Dolphins are very intelligent, as are chimps, but looking at earth as a whole, the most successful species are those that have survived already for millions of years as compared with humankind’s piddly little 50,000 years of “intelligence.” Also, could one not say a forest, supplying and regulating itself has a form of natural intelligence greater than anything devised by us? Then there are rock eating “bacteria” that appear to have been around 3.5 billion years, blowing even the sponges out of the water with their suggested long reign of over 800 million years.
All questions are open to inquiry. Keep an open mind, and keep watching the skies. But really, don’t drink too much beer, it creates too many fallible variables