Presentation on Earth-like planets kicks off semester’s astronomy talks

Posted October 19, 2015

The first of three astronomy talks and observatory viewings for the fall semester, “Earth’s Twin: Kepler-186f,” was presented by physics Professor Eileen Korenic on Oct. 14 at UW-River Falls.

Korenic’s talk focused on the discoveries of NASA’s Kepler space observatory since its launch in March 2009. She said that Kepler’s mission is to find planets that are similar to Earth.

In June 2014, NASA announced that Kepler-186f was the first Earth-like planet to be discovered. By the time Korenic had finished planning the talk and sending out the information to be promoted, Kepler-186f was no longer considered the most Earth-like.

“186f was all over the news, and that’s why I put it in the title, because I thought, ‘I’m going to be so fresh!'” Korenic said. “Since then, there have been a total of 11 up for consideration as Earth’s twins.”

The planet currently at the top of the list is Kepler-438b. Kepler-186f has dropped to 24th on the list since its discovery. The Kepler mission has discovered 1,031 confirmed exoplanets so far, according to NASA’s website.

Determining what makes a planet similar to Earth consists of four factors that make up the Earth Similarity Index: mean radius, bulk density, escape velocity and surface temperature, according to the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo. Korenic said that it really comes down to whether the water on the planet is liquid, not frozen or boiled away, and how much energy the planet receives from its star.

“So it could be that it’s the same size but much closer to a much smaller star, but that still counts in terms of energy reception,” Korenic said. “If it’s just the same kind of star as the sun but it’s way bigger than Earth, that seems not to make it as Earth-like.”

Korenic said that Kepler observes using a transit method, which involves pointing toward a star and measuring the dip in light as a planet passes in front of it.

“That’s like us being able to measure how dim a headlight would get from five miles away if a flea walked across it,” Korenic said.

An estimated 150 people attended the talk, according to Korenic. The final audience members to arrive had to sit on the stairs or against the walls, as the room only holds 90 seats.

“I’m really stunned that there are this many people,” Korenic said on the observatory deck after the talk. “I never quite know what’s going to take people’s fancy.”

UW-River Falls student Dominick Bolden said that he wasn’t shocked to learn that there are Earth-like planets that are not in our solar system.

“Given the sheer magnitude of space, it wouldn’t surprise me if we found anything out there,” Bolden said, “so it’s really not surprising when you think about it.”

Korenic started teaching astronomy at UW-River Falls in 1999 and said that she has been presenting the talks since 2004.

“After a couple of years, I thought it would be really fun to be offering some things for the general public and to students about current things in astronomy,” Korenic said.

One talk is generally given each month during the academic year. Korenic said that since observatory viewings are offered if the sky is clear enough, the talks have to be scheduled during times when the moon isn’t bright enough to limit the visibility of other objects through the telescopes.

Korenic’s next talk is titled “Well, duh!: The Gravitational Constant Is Constant” and will be presented at 8 p.m. Nov. 17 in 271 Centennial Science Hall.