Can you count the number of stars in the night sky? You can try. But the better your vision is, and the more powerful your telescope becomes, the more stars appear. Until today mathematicians have a name for the seemingly endless number of stars – QIF. Which stands for ‘Quasi InFinite.’ They got tired of writing out all those zeroes!
Ever since the idea that our planet Earth circled the Sun became prevalent, lay people and scientists have been asking themselves what if . . . What if there were other suns like ours out there with planets like ours? Is that possible? Probable? Utter nonsense?
Due to the terrific advancements in astronomy and astrophysics in the last few years, that wondering can be settled once and for all: YES, there are other planets circling other suns!
Let’s pause a minute to explain the word exoplanet. Just so nobody gets confused. The word ‘exo’ is Greek, and means ‘outside.’ Planet is also of Greek origin, originally as ‘planetes,’ which means ‘wandering star.’ Mercury, Venus, Earth, Mars, and the other members of our solar system are known as planets. But anything outside of the influence or orbit of the Sun automatically becomes a possible exoplanet.
These exoplanets cannot be seen yet by our telescopes. Because, after all, their suns are millions of light years away from us, and sighting a tiny planet circling such a distant star would be like looking for a candle flame in front of a search light. So if we can’t directly view an exoplanet, how do we know they exist?
Scientists use the principle of reflexive motion to discover faraway exoplanets circling faraway stars. As the exoplanet circles its sun, its gravity tugs on the star – causing it to wobble slightly and travel in its own very small orbit instead of standing stock still. The same thing happens to our own Sun. It wobbles like a gigantic ball of gelatin. And circles around itself in a very small orbit.
Do stars without exoplanets stay stock still, then? Well, yes and no. They are not influenced by any gravitational forces outside of themselves. But, like all stellar matter in the universe, stars are traveling away from the center of things at a tremendous rate. Anywhere from twenty to two hundred light years a minute! If you want to give yourself a good reason for insomnia, start worrying about what will happen to everything when this universal expansion finally becomes subject to entropy and starts shrinking in on itself. Will we be crushed into teeny tiny people pills or what? Or what, as it turns out, is the answer. The momentum of expansion right now has no end in sight. Everything will continue to grow farther away from everything else for the foreseeable future. Sounds like a family reunion gone bad, doesn’t it?
Another dead giveaway for exoplanets is radio waves within a certain band width. Did you know that each planet in our solar system has its own unique vibration that creates a particular note? Poets and philosophers call this “The Music of the Spheres.” Scientists, always less romantic, call it just plain old planet pitch. With the sophisticated and powerful radio wave trackers we have today, it is relatively easy to pinpoint planet pitch out in the vasty deep. Which indicates an exoplanet. Which comes in handy when the star it’s orbiting doesn’t show up at all. Which can happen when the star in question is a pulsar, a star that blew up millennia ago and is nothing but a radioactive cinder now. Astrophysicists continue to find new exoplanets around dead stars all the time. While intrinsically interesting for research purposes, such exoplanets are lifeless, sterile balls of rock. No little green men on them!
What tickles the public’s imagination, and even gets scientists to blink more than once, is the thought of an exoplanet circling a regular yellow star like ours, on which life may have begun.
The conditions for the creation of life, and for sustaining it and evolving it, are so numerous and particular, not to say still so mysterious, that no scientist worth their salt will make a prediction as to the probability of life on other exoplanets. Luckily there are trained researchers out there, called theoreticians, whose job it is to cook up the wildest possibilities and bring them to life. In the old days we’d call them storytellers.
Theoreticians say that with a nearly infinite number of stars and exoplanets out there, there has to be the possibility that life has sprung up on some of them. Sort of like the idea that if you give enough monkeys enough typewriters (or word processors) they will eventually type out the complete works of William Shakespeare. It just stands to reason, doesn’t it?
So will the aliens be landing in the local park anytime soon?
Theoreticians say don’t hold your breath. After all, how would they know we exist? And why would they want to come see us anyway? Is mere curiosity enough to motivate sentient beings to travel millions and billions of light years away from their own world so they can drop in on us for tea?
Theoreticians say THAT possibility is a 99.9999% no go.