最常见的一种说法是它们可能包含来自其他行星的访客。
The most popular one is that they may contain visitors from other planets.
但我们知道，行星的情况不同。
发现系外行星的“黄金时代”。
广角：外部行星的年龄。
这一定义将会大大地加长太阳系行星的名单。
Such a definition would greatly expand the list of planets in the solar system.
我们有分担保护这颗行星的责任。
目前用于寻找太阳系外行星的技术包括
The primary techniques currently used to find exoplanets include
这就意味着月球可以充当一个去其他行星的中转站。
This means the moon can act as a stepping stone to other planets.
这张艺术概念画展示了已知最小的拥有行星的恒星。
This artist's concept shows the smallest star known to host a planet.
行星的发现来自一瞬间。
该探测器第一次在木星这个气体行星的大气层里采样。
The probe was the first to sample the atmosphere of a gas planet.
拿行星的论证，晨星和昏星的那个例子来说。
Look, take the argument of the planets, the Morning Star and the Evening Star example.
而和土星同样是巨大气质行星的木星却有4颗大卫星。
But Saturn's fellow gas giant planet Jupiter has four big moons.
这就是为何要寻找轨道合适的小行星的原因。
That is the reason for the search for asteroids with appropriate orbits.
这束X射线的强度暗示，它具有小行星的质量。
The x-ray intensity suggests it had the mass of a small planet.
没有这个行星的某种反作用，雪片不可能掉下来。
天文学家早就认为，几大行星的轨道是可以预测的。
Astronomers had thought that the orbits of the planets were predictable.
行星的光面(白昼侧)与太阳风有着最直接的接触。
The dayside has the most direct contact with the solar wind.
当行星被巨大的陨石撞击时，它们离开了行星的表面。
They were blasted off that planet's surface when it was hit by huge meteorites.
一旦质量超过这个限度，就开始进入气态巨行星的行列了。
Once the mass goes beyond that point, you start to get into gas giant territory.
他们估计这颗行星的质量大约是地球的5.9到7.5倍。
They estimated the planet's mass as 5.9 to 7.5 times that of Earth.
首先是新行星的位置非常接近其所属恒星，其次，它虽小却相当沉重。
The first is its location so close to its parent star. Second, despite its size, it is quite heavy.
首先是新行星的位置非常接近其所属恒星，其次，它虽小却相当沉重。
这些已知行星的数量增至过去的2倍，并显示了这些行星的普遍存在。
That haul has more than doubled the number known, and suggests such planets are common.
突然有一天,一个巨大且极具摧毁性的小行星的降临灭绝了所有的恐龙;
Then one day a big, bad asteroid came along and wiped out all the dinosaurs.
但是，直到今天，我们都没有“当场”捕捉到这种小行星对小行星的碰撞。
But until now, no such asteroid-asteroid collision has been caught "in the act".
约曼斯表示，在可预知的未来，对近地小行星的探测研究仍然会继续下去。
Still, Yeomans admits that the NEO search will likely continue for the foreseeable future.
哪些行星可以维持生命的存在？
行星上的岩石也很重要。
这些行星上的温度足够高，足以让液态水存在。
It would have been warm enough on these planets for liquid water to exist.
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