To evolve into our current solar system, the original version probably had a fifth gas giant, computer simulations indicate. John Matson reports.

计算机模拟表明，要演变成我们目前的太阳系，最初的形式可能存在第五个巨大的气体行星。John Matson报道。

Jupiter, Saturn, Uranus and Neptune. Those are the gas giants, the four heavyweights of the solar system. But was there once a fifth?

木星，土星，天王星和海王星。这些都是气体行星，太阳系的四个重量级。但曾经存在第五个行星吗？

Maybe so, says a new study by David Nesvorny of the Southwest Research Institute in Boulder, Colorado. He used computer simulations to explore what the solar system may have looked like some four billion years ago.

也许是这样，位于科罗拉多，博尔德市的西南研究所的David Nesvorny对这项新研究如是说。他利用电脑模拟来重现太阳系四十亿年前可能的样子。

Early on, the giant planets migrated, tugged on each other and generally shook things up before settling into their current orbits. So the simulation tested different initial arrangements of planets to see which would evolve into the solar system we know so well.

初期，在这些巨大行星进入现在的轨道之前，他们会迁移，彼此牵引并且震荡。所以，该模拟测试了行星各种不同的开始布局，以便发现哪一种布局可以演变成我们所熟知的太阳系。

With just four giant planets at the outset, the solar system hardly ever wound up looking like ours. But with a fifth planet, the simulations produced familiar solar systems 10 times more often. [David Nesvorny, "Young Solar System's Fifth Giant Planet?" on arXiv.org]

开始只有4个巨大行星时，太阳系并不像现在这样有生气。但是加入第五个行星后，模拟10多次都重新了我们所熟知的太阳系。 [David Nesvorny, "Young Solar System's Fifth Giant Planet?" on arXiv.org]

So what happened to the extra planet? It would have run afoul of Jupiter and been chucked into interstellar space. Astronomers have recently discovered that the galaxy is filled with such orphaned planets. Billions of them. So, if an extra planet did get cast out of the solar system, at least it has plenty of company.

这个特别的行星发生了什么？他可能与木星运行相冲突并被抛到了星际空间。天文学家最近发现星际间充满了这样的孤立行星，亿万多的行星。所以，如果这个特别的行星的确被抛出了太阳系，至少他有很多的同伴。
—John Matson