2020/12/24 by Scott Tremaine, Bence Kocsis, Abraham Loeb
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Ideal (ethics) #Ideal gas #Mechanics #Observable #Physics #Position (finance) #Quantum mechanics #Stars #Statistical mechanics #Statistical physics #Thermal #Thermal equilibrium #Thermal fluctuations #Thermodynamics #astro-ph.GA
paper · pdf · doi:10.1119/10.0004955
published in American Journal of Physics 89(8), 789-792 (American Institute of Physics) · 5 pages, no figures, submitted to American Journal of Physics
arxiv created 2020/12/24 · openalex publication_date 2021/07/20 · arxiv updated 2021/08/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.