Exploring galactic magnetism

在天文学中，我们试图了解宇宙的起源和演化。我们研究物质如何与引力场和电磁场相互作用。众所周知，引力在宇宙过程中扮演着巨大的角色。例如，引力场可以由我们可以看到的物体产生，如恒星、行星、卫星和星系。事实上，正是对引力及其在宇宙中的作用的探索激发了牛顿在物理学中的许多经典作品。然而，磁场在恒星、星系和其他天体物理系统的演化和结构中也很重要，这一点鲜为人知。磁场可能以这种方式重要这一事实直到20世纪40年代才被提出。磁场是由电流产生的，与重力不同，我们既看不到电流，也看不到磁场。我们所能做的就是寻找两者的微妙影响，并试图推断正在发生的事情。我们正在观察的东西总是很远，而我们正在处理的信号很微弱，这一事实加剧了这一点。推进我们对宇宙磁场的了解是困难的。

In astronomy, we try to understand the origin and evolution of the cosmos. We study how matter interacts with gravitational and electromagnetic fields. It is common knowledge that gravity plays a huge role in cosmic processes. For example, a gravitational field can be produced by objects that we can see such as stars, planets, moons, and galaxies. Indeed, it was the quest to understand gravitation and its role in the Universe that motivated much of Newton's classic works in physics. It is much less well known, however, that magnetic fields are also important in the evolution and structure of stars, galaxies, and other astrophysical systems. The fact that magnetic fields might be important in this way was only put forward in the 1940s. Magnetic fields are produced by electric currents, and unlike with gravity, we can "see" neither the currents nor the field. All we can do is look for subtle effects of both and try to infer what is happening. This is exacerbated by the fact that what we are looking at is invariably far away, and the signals we are working with are faint. Advancing our knowledge of cosmic magnetic fields is difficult.