As a part of the Phi Beta Kappa Visiting Scholar Series, University of Arizona Distinguished Professor Chris Impey spoke Tuesday night in a lecture titled “Cosmic Evolution: From Big Bang to Biology.”
“I was told you should never have a setup guy who’s more famous and funnier than you are, but I’m going to do it anyway,” said Impey as he played a clip from “The Daily Show with Jon Stewart” parodying the history of the theory of evolution.
The clip was the first in a series of pop culture references that Impey used to segue between facts and theories.
When he introduced the complicated and expansive subject of the size of the universe, he played a narrated tour through the stars, explaining that “a universe narrated by Morgan Freeman is a little more reassuring.”
At the onset of his lecture, Impey said he was disappointed that the science of evolution is “no longer always a safe science to teach.”
He supports the Big Bang theory, also known as the “day without a yesterday”, which scientists have theorized to have happened 13.7 million years ago. Impey explained that the universe, now large, empty and cold, was once hotter, smaller and denser. When the Big Bang occurred, the universe expanded at a speed even faster than the speed of light.
Even now, he said, “Regions that have never been visible to us are gradually coming into view.”
The largeness of the universe and the fact that a quarter of it is made up of helium was at first perplexing for scientists; if humans are mostly made up of carbon, nitrogen and oxygen, how was our creation possible in such a helium-filled universe?
The answer, Impey said, lies in the stars.
Most people think the main function of stars is to produce light, but in reality only 1 percent of stars produce light as a result of the “leaking” of certain elements. More importantly, stars eject the elements that make humans – carbon, nitrogen and oxygen – making life possible in the universe. As time goes on and more stars die, more of these elements will be in the universe making greater the possibility for new life to arise, he said. This constant increase supports the theory of evolution, Impey said, and gives us an explanation as to why it took us millions of years to evolve into the Homosapien species.
The answer to why life evolved here, he said, also lies in the stars.
Bigger stars have large areas around them called “habitable zones” in which there is potential for the existence of intelligent life. But the large stars have a have short lifespan – too short for intelligent life to evolve. In contrast, small stars live for a long time, but have “wafer thin” habitable zones. Earth’s star, the sun, is mid-sized, so it has both a long life and large habitable zone, making life possible.
Impey closed with a theory that intelligent life may be evolving right under our noses and may have even existed before us.
“Maybe alien life is to us as we are to bacteria,” he said. “When we look for signs of life on other planets and only discover lichen, we say, ‘Boring! Move on!’ I’m sure that, if an intelligent species were to stumble upon Earth before any significant life had formed, they would have found lichen and said the same thing.”
The formation of intelligent life on other planets could be in the process of happening right now, he said.
Students who knew little or nothing about physics or astronomy enjoyed the lecture, but many students who knew more were disenchanted.
“I found it very superficial,” said Physics major David Reeb, who has studied the subjects in-depth.
Graduate student Andreas Reinsch agreed. “When I compare this lecture with some of (Impey’s) other scientific talks, this one was much more basic.”