First, a climate conducive to life on Earth depends upon the extraordinarily narrow orbital parameters that define a continuously habitable zone where water can exist in a liquid state.

首先，地球上适宜生命存在的气候取决于极其狭窄的轨道参数，这些参数定义了一个持续可居住的地带，在那里水可以以液态存在。

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We are finding Earth-size planets. Not in the habitable zone.

我们正在搜索不在适居带的地球般大小的行星。

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Kepler is the first telescope to be designed to find Earth-sized planets that orbit in the "habitable zone" where temperatures are neither too hot nor too cold for water to remain in its liquid state.

开普勒号则是第一个设计用来寻找地球大小的行星的望远镜，这些行星的轨道处于“可居住区域”内，温度既高也不太低，水份可以以液态形式存在，适宜生物生存。

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"If the Wright brothers were starting out today they'd never get off the ground, " fumes Ky Michaelson, who spent two years dickering with bureaucrats at an offshoot of the FAA to get a license to launch to 390, 000 feet, well past the boundary zone between the Earth's atmosphere and space.

FORBES: "Let's Punch A Hole In the Sky"

Fischer is going after Earth-like planets in the habitable zone.

CNN: Kepler or not, we'll find life in space

This past December, for example, NASA's Kepler space telescope confirmed its first planet in the habitable zone, a "super Earth" known as Kepler-22b that's thought to be 2.4 times as wide as our planet.

MSN: Does 'potentially habitable' alien world exist? - Technology & science - Space - Space.com | NBC News