Ask the average person his or her birthday, and that person will respond immediately and confidently. Ask about the birthdays of parents or close friends, and the response may be slower but still accurate. But ask for the birthday of something we all share—our planet—and the response may well be a blank stare.
According to astronomy and astrophysics professor Eric Feigelson, this confusion is to be expected. "The birth of a planet is a slow and steady process," he explained. "We can't simply assign a birthday to it."
Feigelson, an energetic and impassioned speaker, kicked off this season's Research Unplugged schedule with a "Big Bang" on Wednesday. In a lively discussion with the audience, Feigelson shared his excitement about rapid advances in both knowledge and understanding ("which are different, if you think about it") within his field.
"I'd say the birth process of earth lasted for about 10 million years," said Feigelson. While this may seem like an incredibly long time for human beings, it's actually only about one-tenth of a percent of the earth's total age. Like human beings, the earth has not stopped aging.
Feigelson discussed the importance—and abundance—of meteorites on the earth's ongoing evolution. "Meteorites are falling all the time," he noted. "We just can't recognize them. They look like normal, everyday rocks." There are certain places, he explained, where meteorites are unmistakable, such as the desert, Antarctica and Greenland—flat terrains where rocks from space are easier to spot. Since meteorites are always falling, they continually contribute to earth's growth.
In its birth and growth processes, earth is not so different than other planets in the universe. As part of Feigelson's research, he and colleagues around the country study the process of planet formation. "We start with dust, which accumulates to pebbles, then eventually to an asteroid," he explained. "It just keeps going. It's still going."
The team hopes that its pioneering studies of X-ray emissions from young star systems, using powerful tools including the Chandra X-ray observatory, will yield new insight into these processes.
Feigelson fielded questions from the audience—some from participants with an advanced understanding of the topic, as well as some from those who were simply curious. Some participants wondered aloud about how planet formation sets the stage for life on our planet—and whether life might exist on other planets.
At this point, Feigelson scratched his head and reminded the audience of another upcoming Research Unplugged event with James Kasting on November 9, the last installment of this season's series. "Dr. Kasting will be able to answer these questions in greater detail," he said, referring to the upcoming lecture titled "Space investigators: Is there life on other planets?"
"What I can tell you, though," concluded Feigelson, "is that together our research tells the story of origins in the universe."
Eric Feigelson, Ph.D., is professor of astronomy and astrophysics. He can be reached at email@example.com. Anne Marie Toccket is an undergraduate communications student and intern for Research Unplugged. She can be reached at firstname.lastname@example.org.