The equilibrium and fluctuations of an ideal gas in a rigid container are studied by every student of statistical mechanics. Here, we examine the less well-known case when the box is floating freely; in particular, we determine the fluctuations of the box in velocity and position due to interactions with the gas it contains. This system is a toy model for the fluctuations in velocity and position of a black hole surrounded by stars at the center of a galaxy. These fluctuations may be observable in nearby galaxies.

中文翻译：

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自由浮动箱内理想气体的热平衡

每个统计力学的学生都研究了刚性容器中理想气体的平衡和涨落。在这里，我们研究了一个鲜为人知的盒子自由浮动的情况；特别是，我们确定了由于与其中所含气体的相互作用而导致的盒子速度和位置的波动。该系统是一个玩具模型，用于模拟星系中心由恒星环绕的黑洞的速度和位置波动。在附近的星系中可以观察到这些波动。