Over the centuries – and millennium — there has been speculation on whether we on Earth are alone in the universe. We live in a solar system which circles our Sun and yet we live in the Milky Way Galaxy that hosts billions of stars. And beyond the galaxy are billions of light years of distance. What if. . . . ?

“Exoplanets” are planets that have been discovered around the universe — circling stars just as the Earth revolves around our Sun. The first exoplanet was identified in 1992 and since then thousands more have been discovered. Rather than spotting the exoplanet telescopically, they are found mostly by observing “dips” in a star’s light (transit photometry) or measuring stellar “wobbles” caused by gravity (radial velocity). And this all keeps gravitating back to whether there may be life on distant (exo)planets. There are a lot of factors to consider: gravity; temperature; radiation; water; atmospheric pressure; gasses; and so on). The Earth is considered a “Goldilocks” planet — implying a perfect balance for life-sustaining conditions. Earth lies between two planets that are uninhabitable. Life elsewhere? Let’s look at the scientific time line:

13.5 billion years ago – The “Big Bang”

4.5 billion years ago — The Earth was formed

4 billion years ago — Earth experiences micro organisms

85 million years ago — Primates diverge from mammals

300,000 years ago — First homo sapiens

3500 B.C. — Recorded history begins – Early Dynastic period of Egypt

Soooooo. . . . if we assume that (reasonably) intelligent life on Earth has been around for the last 10,000 years, and we convert 1/400,000 (division into Earth’s age) to a decimal form, that would be .0000025. In other words, that decimal would be the percentage of time intelligent life has been on Earth. Even assuming habitability of certain exoplanets for life forms, presumably those exoplanets thousands of light year distance would still have a need to “grow.” And to mature to a similar level of intelligence and interest in communicating with exoplanets . . . . like Earth. Some scientists believe there are many exoplanets that have life forms. Yet others have commented that they are not so sure . . . .