早期地球含有丰富的放射性物质。
进化：早期地球赋予生命提升的小小的化学变化。
Evolution: small changes in the chemistry of the early Earth gives rise to life.
在碰撞动能转变的热能作用下，造成了早期地球的表面熔融。
With the effect of that collision kinetic energy converted into heat energy, the surface of the early earth melted.
但是早期地球的水是由载满了冰的彗星带入的观点依旧很流行。
But the idea that the early Earth got its water from ice-laden comets ploughing into its surface is still popular.
这就意味着在早期地球表面巨大的海洋中各种构成生命的基本成分是很常见的。
The finding could mean that various building blocks of life were common in pools of water on the surface of the early Earth.
绝大多数的专家都相信，月球是在一个巨大行星与早期地球碰撞过程中所产生的碎石组成的。
Most experts believe a huge impact early in Earth's history ejected material into space that became the moon.
是什么使得这项研究如此重要呢？那就是它们是建立在早期地球更一般的现实环境的基础之上。
What makes both studies so potentially important is that they're based on a more realistic picture of conditions on early earth.
绝大多数的专家都相信，月球是在一个巨大行星与早期地球碰撞过程中所产生的碎石组成的。
Most experts believe a huge impact early in Earth's history ejected material into space that became the.
如果它能给出证据证明这些大陆曾经是连接在一起的，它能告诉我们很多关于早期地球地质的信息。
If they show evidence of once have been joined, that could really tell us a lot about the early history of the planet geology.
研究者说这些早期的冒险者可能在海边的沙质滩涂地来回搜寻那些布满早期地球的光合细菌的菌褥。
These early pioneers may have explored sandy tidal flats to graze on the MATS of photosynthetic microbes that literally covered early Earth, the researchers say.
在他们对于在我们这颗行星的卫星上是否有水的追求下，研究者们不得不依靠美国阿波罗太空任务带来将20世纪60年代末和70年代早期地球月球岩石带回地球进行分析。
In their quest for water on our planet's satellite, researchers have had to rely on the analysis of lunar rocks that US Apollo space missions brought to Earth in the late 1960s and early 1970s.
今天的火山是由地球形成早期被困在地球内部的气体所形成的。
Volcanoes today are the result of gases that were trapped in Earth's interior during the planet's early stages of formation.
因为早期的地球大气中缺乏氧气，所以也缺乏起保护作用的臭氧层屏障。
Because early Earth lacked oxygen in its atmosphere, it also lacked a protective ozone barrier.
现在，许多科学家把早期造成地球变暖的大部分原因归结于厌氧微生物——产甲烷菌——它产生了温室气体甲烷。
Many scientists now attribute much of the warming of early Earth to oxygen-intolerant microbes—methanogens—that produce the greenhouse gas methane.
地球上早期的生命形式被限制在海洋里，因为水是帮助它们抵御紫外线辐射的唯一有效保护。
Early life-forms on Earth were confined to the oceans because water was the only available protection they had against ultraviolet radiation.
在我们这个时代，人类的精明已足以掌握地球的深层奥秘，其程度远远超过了早期人类的能力。
In our times, human shrewdness has mastered the deep mysteries of the earth at a level far beyond the capacities of earlier peoples.
从理论上讲，细菌可能是在火星的早期发展起来的，其中一些是由陨石带到地球的。
It is theoretically possible that bacteria developed on Mars early in its history and that some were carried to Earth by a meteorite.
我们必须想象早期的地球是岩石材料、金属和封闭气的混合物，受到较小的星子的持续轰击，没有多少大气。
We must imagine the early Earth as a mixture of rocky materials, metals, and trapped gases, subject to constant bombardment by smaller planetesimals and without much of an atmosphere.
地球之所以能够维持生命，是因为它相对于太阳的位置为它提供了足够的热量，但热量没有多到可以让早期的细菌进化。
Earth has been able to support life because its position relative to the Sun provided it with enough heat, but not too much heat for early bacteria to evolve.
现代火山释放出的气体混合物类似于这种早期的大气，这表明它（地球）起源于火山喷发。
Gas mixtures emitted from present-day volcanoes resemble this early atmosphere, suggesting its origin from volcanic eruptions.
它被称为“明亮的早期的太阳解决方案”，根据该方案，太阳将提供足够的热量，使地球和火星上的水变成液体。
It is called the bright-young-Sun solution, according to which the Sun would have provided enough heat for the water on Earth and Mars to be liquid.
早期人类似乎扮演了终结者的角色，使其他九种超过一吨的哺乳动物彻底从地球上消失。
Early humans seem to have played a major role in finishing offnine other mammal species that weighed over a tonne.
当我们的太阳后来温度变得更高时，早期细菌持续清除大气中的二氧化碳和甲烷，使地球的气候不至于变得太热而无法维持生命的存在。
When our Sun later became hotter, the continued removal of atmospheric carbon dioxide and methane by early bacteria kept Earth's climate from becoming too hot to sustain life.
米兰科维奇在20世纪早期提出，冰河时代是由地球绕太阳运行轨道的变化引起的。
Milankovitch proposed in the early twentieth century that the ice ages were caused by variations in the Earth's orbit around the Sun.
这个理论就是：在地球和火星的大气层里有足够的温室气体，来帮助提升温度，从而弥补了早期的太阳提供的较低的热量。
The idea was that trapped greenhouse gases in the atmospheres of Earth and Mars might have caused temperatures to raise enough to compensate for the low heat the young Sun provided.
在地球早期，整个星球上有无数的光合细菌在进行光合作用。
In Earth's early days, all over the planet countless photosynthetic bacteria performed photosynthesis.
这个谜题的答案在于早期光合生命形式的新陈代谢活动，这种活动缓慢但一定改变了地球大气的化学成分。
The answer to this riddle lies in the metabolic activity of early photosynthetic life-forms that slowly but surely transformed the chemical composition of Earth's atmosphere.
复杂的生命在地球表面进化，而不是在火星或太阳系的其他行星上，因为在那些行星上，早期的地表生命被紫外线杀死了。
Complex life evolved on the Earth's surface, but not on Mars or other planets in the solar system because on those planets, early surface life was killed by UV radiation.
如果大气中的甲烷和二氧化碳像地球最早期的大气那样丰富，那么地球的温度对今天生活的大多数物种来说可能太热了。
If atmospheric methane and carbon dioxide were as abundant now as they were in Earth's earliest atmosphere, the planet's temperature would likely be too hot for most species living today.
因此，一些科学家推断，地球早期的大气与现在的不一样，主要由氢、甲烷和氨构成。
Therefore some scientists postulate that the Earth's earliest atmosphere, unlike that of today, was dominated by hydrogen, methane, and ammonia.
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