a short essay on ` is humanity alone in universe?' for 6 class student
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When they first began their science careers, neither Phillips Professor of Astronomy Dimitar Sasselov nor sixth-year graduate student Elisabeth Newton intended to search for extraterrestrial life—but that is exactly what they are both doing today.
“My initial interest was in the physics of stars and cosmology,” says Sasselov.
“I majored in physics in college,” says Newton, “and astronomy offered the most interesting physics.”
Now working at the Harvard-Smithsonian Center for Astrophysics (CfA), Sasselov and Newton are engaged in a quest to answer one of the most fundamental questions facing humanity: Are we unique—and alone— in the universe, or are we ordinary, with an expansive social network waiting for us “out there?”
Sasselov, Newton, and their colleagues now believe that the answer to that question is tantalizingly close after thousands of years of speculation, theorizing, and—finally— some solid scientific research.
The Debate
What at first appears to be a very modern query is actually ancient in its origins. Since human beings began to ponder the “big questions,” the desire to understand what exists beyond the confines of the Earth continually surfaces. According to Michael J. Crowe (author of The Extraterrestrial Life Debate 1750–1900), no less a philosopher than Aristotle argued in the 4th century BCE that a so-called “plurality of worlds” could not exist because every solar system required a Prime Mover to keep it going, and he had trouble imagining an infinite number of those.
Since human beings began to ponder the “big questions,” the desire to understand what exists beyond the confines of the Earth continually surfaces
Around the same time, Epicurus penned a remarkably modern rejoinder to the Aristotelian perspective. He suggested that atoms were infinite in number and argued that “…there are infinite worlds both like and unlike ours.” Epicurus asserted that some of these worlds would sustain life similar to Earth.
Aristotle and Epicurus shared common ground in that they had absolutely no observational data on which to base their opinions, meaning that the controversy surrounding the possibility of extraterrestrial life raged on right through the Middle Ages and Renaissance up to our own time.
For example, Cornell Professor Carl Sagan, whose Public Television series Cosmos brought the concepts of astronomy to a broad audience, advanced a principle of mediocrity that echoed the writings of Epicurus. He argued that there was nothing special about our solar system or planet—there are billions and billions of stars in the universe, with many planets capable of sustaining life and intelligence.