"Computational Planet, Star and Galaxy Formation: Bridging the Scales"

计算机模拟实现了天文学家看到星系的梦想，星系变化如此缓慢，它们以美丽而静态的星云的形式固定在天空中，被数十亿颗恒星照亮，在他们眼前进化。当加速到数百万年的瞬间时，星系是动态的地方，在那里恒星不断地诞生和爆炸死亡。我们现在可以人工地产生带有精致螺旋图案的盘状星系，这些星系由闪闪发光的气体、尘埃和恒星组成，与附近天空中的星系几乎一模一样。挑战在于把事情做到极致：当星系相互碰撞，产生巨大的新恒星爆发，并将物质驱动到超大质量黑洞中，这些黑洞的大小相当于潜伏在天空中几乎每个星系中间的小星系。这些合并在早期宇宙中是很常见的，当时星系是更加狂暴的地方，更像是风暴肆虐的云，而不是螺旋盘，并且饱和的气体、尘埃和辐射水平远远高于我们今天的银河系。

Computer simulations enable the astronomer's dream of seeing galaxies, that change so slowly they appear fixed on the sky in the form of beautiful but static nebulae lit by billions of stars, to evolve before their very eyes. When sped up so that millions of years pass in moments galaxies are dynamic places, swirling vortices where stars are constantly being born and explosively dying. We can now artificially generate disk galaxies with delicate spiral patterns of sparkling gas, dust and stars almost identical to those nearby in the sky. The challenge is to take things to the extreme: to model galaxies as they smash together and create giant bursts of new stars and drive material into super-massive black holes themselves the size of small galaxies lurking in the middle of nearly every galaxy in the sky. These mergers are commonplace in the early universe when galaxies were far more violent places, more like storm wracked clouds than spiral disks and saturated with levels of gas, dust and radiation far above what our Milky Way Galaxy experiences today.