小行星

The Earth was made by the collision of billions of planetesimals, chunks of rock and ice much like today's asteroids and comets.

地球是由像现在的行星和彗星一样大块的岩石和冰块组成的数十亿的小行星碰撞而形成的。

Or arrived as part of a late-accreting veneer of icy planetesimals, that is, comets

或者是来自于后期增生的冰质小行星体——彗星。

Gravity pulled these planetesimals together, and the young Earth grew slowly, like a snowball, as more and more pieces collided with it.

万有引力将这些小行星体聚在一起，年轻的地球慢慢成长，越来越多的碎片与它碰撞，就象滚雪球一样。

The Earth was made by the collision of billions of planetesimals, chunks of rock and ice much like today's asteroids and comets.

地球是由数十亿颗星子（即由大块岩石、像今天的小行星和慧星般大小的冰组成）碰撞而成。

Gravity pulled these planetesimals together, and the young Earth grew slowly, like a snowball, as more and more pieces collided with it.

当越来越多的碎片与地球相撞时，重力使那些小行星靠拢，年轻的地球慢慢地成长，就像一个雪球。

Gravity pulled these planetesimals together, and the young Earth grew slowly, like a snowball, as more and more pieces collided with it.

地心引力将这些小行星结合起来，地球形成初期成长的很慢，就像是个越滚越大的雪球。

A planet on the other hand is built up out of the dust that surrounds a star. When a star is formed there is still a disk of gas surrounding it. As this gas cools, it condenses and forms solid grains. These grain particles accrete into large bodies called planetesimals, which then collide and accrete to make protoplanets. These protoplanets evolve into planets like the planets in our own solar system.

行星演化与恒星不同：恒星形成之后，周边的气体尘埃云冷却之后凝结形成，成为行星雏形，众多小行星雏形聚合碰撞，演化成成熟的行星；没有内部的核聚变；质量超过木星13.6倍，就会产生核聚变，如果还未至木星86倍，尚处于棕矮星的阶段，将会向恒星演化；持久的核聚变需要足够大的质量来支撑，温度也不足支撑氢向氦的转变。

"That you can turn your back on Kenya and go live on some terraformed planetoid, just because you want to wake up to the sight of a handful of animals grazing."

&你把肯尼亚背弃了，然后再搬到一颗什么改造成地球的小行星上去住，其实就因为你想要每天早上醒来时能看见一群食草动物！&

But there are also thousands of asteroids whose orbits put them on a collision course with Earth.

然而仍有数以千计的小行星，其运行轨道使其处在与地球相碰撞的位置上。

Small asteroid 2008 TC3 fell to Earth at dawn on October 7, 2008, tracking through the skies over the Nubian Desert in northern Sudan.

2008.10.7拂晓，编号2008TC3的小行星穿过地球天空落入苏丹北部的努比亚沙漠。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了