Right now, galaxies are merrily churning away, converting nebular gas into stars.

现在，星系正在愉快地旋转着，将星云气体转化为恒星。

A few billion years after the nebular gas runs out the only stars left will be those long-lived red dwarfs.

在星云气体耗尽几十亿年后，剩下的恒星将是那些长寿的红矮星。

Unless the solar wind blew all the nebular particles far away from the planet.

除非太阳风把所有的星云粒子都吹到远离星球的地方。

A protostar with a surrounding nebular disk forms at the center of a cloud core, collapsing from inside out.

2. 在云核中心，一颗原恒星与其周围的星云盘形成，其坍缩过而外进行。

In 1873 French scientist, Edouard Roche proposed that the Moon simply formed alongside the Earth out of essentially the same nebular cloud of particles and gasses.

1873年法国家爱德华·洛希提出月球只是在地球旁边形成的，本质上是相同的粒子和气体的星云构成的。

Scientists have had a basic understanding of how the solar system formed since at least 1755, when the philosopher Immanuel Kant proposed the nebular hypothesis.

家们自1755年以来就基本了解了太阳系是如何形成的，当时哲家伊曼努尔·康德提出了星云假说。

But, if we trust the nebular model, and believe they evolved out of the same disk as Earth, something must have happened to make them that way.

但是， 如果我们相信星云假说， 并认为它们是从与地球相同的盘状结构中演化而来的话，那么一定发生了某些事情使它们变成了那样。

The nebular model tells us that, back when Mars was forming, there should have been enough material in Mars's part of the disk for it to grow much larger.

星云模型告诉我们， 当火星形成时，火星所在盘区应该有足够的物质让它长得更大。