[داعية المستقبل]

أ . علي ..
هذا السؤال ماعرفت احلة وهو برضه في (الفيزياء الحديثة ) :

In its frame of reference , a proton takes 5 min to cross the milky way galaxy , which is about 105 light-years in diameter
a) what is the approximate energy of the proton in electronvolts ?0

b) about how long would the proton take to cross the galaxy as measured by an observer in the galaxy's reference frame ?0

وجزاك الله خيرا ...