The first results of a NASA satellite mission may reveal how earthly an earth-like planet elsewhere in space can be.
“One of the great aspects of the work that many teams are doing right now is to hunt for other earths,” said Geoff Marcy, astronomer at the University of California at Berkeley and investigator for the Kepler Mission. Marcy spoke recently to a packed audience at Northwestern University.
Marcy said researchers realized that the best way to search for habitable planets would be from outer space, where the Earth’s atmosphere couldn't alter the results of the telescope and researchers could more precisely measure the brightness of the stars.
NASA launched the Kepler Mission last year for that very reason. The Earth-orbiting satellite mission carries several special telescopes to find habitable planets where life could be sustained.
Kepler's main goal is to observe and photograph more than 100,000 stars incessantly to measure the brightness of those stars in hopes of discovering earth-like planets. It recently discovered five planets around other stars.
“When an earth happens by luck to cross in front of its host star, that earth will block a tiny fraction of the starlight,” he said. With the Kepler telescope, researchers can detect a change as small as 1 percent in the brightness of a star and analyze the results of the brightness of the star over an extended period of time.
Marcy explained that, although the dimming of the star is indeed tiny, it's a way to unambiguously detect any planets that cross in front of the star because the planet will rotate around that star continuously.
He also explained the results of the dimming of a star observed by the Kepler 17 telescope and how the star showed a pattern of consistently increasing and dimming in brightness.
“There is no question that this star has a planet orbiting it, blocking 1 percent of the light,” he said. From this information, he said researchers could deduce the size and rotation of the planet. “Spectacular evidence of a planet. Beautiful data. We’ve never seen anything like this,” he said.
Marcy explained that the results from the Kepler telescopes are sent to the Keck Observatory in Hawaii to verify the presence of planet and estimate their masses. The Kepler Mission can also measure the velocity of the star. The velocity measure is made when the planet is actually crossing the star. This allows the researches to understand more about the orbit, radius and geometry of the planet as it crosses at a slight angle because of the velocity effect.
The results of these findings are helping astronomers come one step closer to an earthlike planet, but that should not be equated with finding a habitable planet anytime soon.
“People think of oceans and dolphins and beings walking around when you say earth-like,” said Mark Hammergren, an astronomer with Adler Planetarium. He explained that the people believe an earth-like planet is one with similar living conditions to our Earth when that may very rarely be the case.
“How many habitable earths would you expect to find in our Milky Way galaxy?” asked Marcy as he shifted the discussion away from the Kepler Mission and onto a more theoretical topic of the chances of astronomers ever discovering life on other planets.
Marcy said he believed that there could be a likelihood of life on other planets, but that may not mean intelligent life.
“These are species that have adapted to Darwinian evolution to thrive in these hideous conditions,” he said. Marcy is speaking of species that were discovered to be living in some of the least hospitable places on Earth. One is Yellowstone National Park, inhospitable because of the boiling hot water, frigid temperatures and the highly acidic water that erupts from the hot springs. Yet the place sustains life.
“These multitudes of species are not only thriving [there], but they would die at room temperature.”
Marcy said there is almost no dispute that there is life in the universe. But scientists can't be certain about the intelligence of this life.
“Biologists aren’t really in dispute about the prevalence of elementary, primitive single cell life elsewhere in the galaxy, but what they are not in agreement about is intelligence,” said Marcy.