One of the most astounding features of jets is the pencil-thin shape that they can maintain despite traveling hundreds of thousands of light-years, far beyond the confines of their parent galaxies.

• 喷流最令人诧异的性质之一是，即使已横越数十万光年，远超出母星系的掌控，它们仍能维持铅笔般的纤细外形。