天文学奖
2016

2017年度邵逸夫天文学奖颁予西蒙 • 怀特 (Simon D M White)以表彰他对理解宇宙里结构形成的贡献。他运用强大的数值模拟，揭示在早期的宇宙中的微小密度涨落怎样发展成现今宇宙所看见的星系和其他非线性结构，提供了有力的证据支持具有平直几何、并由暗物质和宇宙学常数所支配的宇宙模型。西蒙 • 怀特 是德国马克斯普朗克天体物理研究所所长。

最近在宇宙学中非常重要的一项成果是标准宇宙学模型的发展，它解释了宇宙中很多不同类型的观察现象。在这个模型中，微小的初始密度涨落在大爆炸之后不久存在，可能是通过量子涨落而产生。从那时至138亿年之后的现在，这些微小的涨落发展成为当前拥有丰富结构的可见宇宙∶无论在尺码、质量、光度和外观均涵盖宽广范围的各种星系，巨大的星系团，以及一个庞大而复杂的气体和星系宇宙网，连接著最大的星系团。这个宇宙结构的演变，原则上由众所周知的万有引力定律、流体动力学和相对论所确定，但解决这些方程式一直是个艰巨的挑战。

Perhaps the most important recent result in cosmology is the development of a cosmological standard model that explains a remarkable variety of observational phenomena in the Universe. In this model, small initial fluctuations in density existed near the Big Bang, perhaps generated via quantum fluctuations. Between that time and the present, 13.8 billion years later, these small fluctuations developed into the rich observed structure that characterizes the current Universe: galaxies with a wide range of sizes, masses, luminosities, and appearance; groups and gigantic clusters of galaxies, and a vast, complex cosmic web of gas and galaxies connecting the largest clusters. The evolution of this cosmic structure is determined in principle by the well-known laws of gravity, hydrodynamics, and relativity; but solving these equations has been an immense challenge.

Over the past four decades Simon White, together with an exceptional group of collaborators and students, has developed N-body computer simulations as a new tool of extraordinary power, yielding fundamental insights into cosmic structure formation. The recent “Millennium simulation” captures with great precision the time evolution of cosmic structure between 10 million years after the Big Bang to the present, with over 10,000 million particles representing dark matter distributed in a cube of 2.2 billion light years on a side. In post-processing of this simulation, White, Springel and their colleagues also added models of the small-scale physical processes that govern the evolution of normal matter within the dark matter halos. The formation of stars in galaxies results from a competition between gas cooling and the ejection of matter from the galaxies through the action of supernovae and massive black holes. These semianalytic methods were first proposed by White and Frenk in 1991, and their current predictions for galaxy properties match a remarkable variety of observations, such that such simulations are beginning to approach the age-old dream of “creating the Universe in a computer”.