Witt: Is there alien life? It will be a long wait
Well, this could be one of those good news-bad news stories. The definition of either will depend on the viewpoint of the reader.
Science Alert, in its June 16 newsletter, noted that astronomers have recently calculated there could be as many as 36 alien civilizations in the Milky Way.
Good news: there may be other life out there somewhat similar to that of earth which is anxious to communicate with us.
Bad news: those life forms may be like the ones in the film “Independence Day,” intent on wiping out humans.
Regardless of whether or not those civilizations exist, and whether or not they have peaceful or other intentions, the likelihood of any communication with them — at least on a time scale which has much meaning for anyone living right now — is extremely remote. That is especially true of potential physical contact.
All the factors that go into prognosticating the existence of other intelligent life in just this one galaxy are astronomical (pun intended).
The Milky Way is about 150,000 light years across and contains between 100 billion and 400 billion stars. Pretty wide margin for guesswork.
Of that number of stars, whichever is the correct number, perhaps 7% are similar to our Sun. These are called G-type stars.
Based on probability, astronomers have estimated there could be 6 billion Earth-like planets amongst those stars.
They have categorized “Earth-like” as having mass between .75 and 1.5 times that of Earth and a distance from their related sun of .99 to 1.7 the distance of Earth from the Sun. Earth’s distance from the Sun is called an Astronomical Unit (AU), 93 million miles.
Also entered into the equation is the probable age of the planet, set at between 4.5 and 5.5 billion years, and the amount of time it might take for an intelligent civilization to emerge, plus the length of time that such civilization might have developed the ability to communicate across space. In the case of Earth, those communication abilities have only existed for 125 years.
If those 36 civilizations were scattered throughout the vast reaches of the galaxy, it could mean that the distance between any two could be 17,000 light years. Since any signals which might have gone into space from Earth have had only 125 years of travel, it is obvious that there is going to be a really long time before that signal reaches anyone else if our nearest neighbor is 17,000 light years away.
If those folks up there want to respond, earthlings would have to wait another 17,000 years for the reply. That’s a long time to be on hold (even eclipsing the wait time when one calls the Social Security office).
So the folks at SETI (Search for Extraterrestrial Intelligence) are most likely going to be sitting around twiddling their thumbs for a very long time indeed unless, of course, some civilizations out there on the fringes of the Milky Way began broadcasting a very long time ago.
When we choose to respond (if we do) the beings out there will be waiting for the return call for quite a while as well, at least if the laws of physics as we know them are the same everywhere.
It’s easy to see that, with all the variables and assumptions that go into trying to ascertain the number of other intelligent beings in our galaxy, the likelihood of being very close to accurate is pretty slim.
As for actually meeting others from beyond our terribly small solar system, don’t hold your breath.
Chuck Witt is a retired architect and a lifelong resident of Winchester. He can be reached at firstname.lastname@example.org.