'New estimate for alien Earths: 2 billion in our galaxy alone'

'New estimate for alien Earths: 2 billion in our galaxy alone'

A new study reveals that roughly one out of every 37 to one out of every 70 sunlike stars in the sky might harbor an alien Earth, space.com reported. These findings hint that billions of Earthlike planets might exist in our galaxy, researchers added. These new calculations are based in data from the Kepler space telescope, which in February wowed the globe by revealing more than 1,200 possible alien worlds, including 68 potentially Earth-size planets, the report said. Scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., focused on roughly Earth-size planets within the habitable zones of their stars ― that is, orbits where liquid water can exist on the surfaces of those worlds, it said. After the researchers analyzed the four months of data in this initial batch of readings from Kepler, they determined that 1.4 to 2.7 percent of all sunlike stars are expected to have Earthlike planets ― ones that are between 0.8 and two times Earth's diameter, the report said. "This means there are a lot of Earth analogs out there ― two billion in the Milky Way galaxy," researcher Joseph Catanzarite, an astronomer at NASA's Jet Propulsion Laboratory, told SPACE.com. "With that large a number, there's a good chance life and maybe even intelligent life might exist on some of those planets. And that's just our galaxy alone ― there are 50 billion other galaxies." After three to four years of Kepler data are investigated, the scientists predict a total of 12 Earthlike worlds will be found, space.com said. Four of these have already been seen in the four months of data released so far, they added. Kepler mission scientists have estimated that, altogether, there could be 50 billion planets in the Milky Way, though not all would be Earth-size worlds within the habitable zone of their local stars, it said. ‘지구와 같은 외계행성 20억개나 있다’ 은하계에 있는 별들 가운데 70분의 1은 태양과 같은 항성이고, 이런 별들은 37개에 하나 꼴로 지구와 비슷한 행성을 갖고 있어 그 수가 약 20억개에 달하는 것으로 나타났다고 스페이스 닷컴이 22일 보도했다. 이 새로운 계산은 (외부 행성을 찾기 위해 지난 2009년 발사된) 케플러 망원경의 자료를 분석한 것에 근거를 두고 있는데 이 자료는 지난 2월 68개의 지구 크기와 같은 별을 포함 1,200개가 넘는 외계세계가 있다고 밝혀 지구인을 놀라게 했다. 미항공우주국(NASA) 제트추진연구소 과학자들은 중심별과 알맞은 거리에 있어 액체 상태의 물이 존재하는 지구형 행성들에 중점을 뒀다. 자료를 분석한 결과 과학자들은 태양과 비슷한 모든 별의 1.4-2.7%가 지름이 지구의 0.8-2배인 행성을 거느린 것으로 나타났다고 밝혔다.