The unexpected discoveries we make in Physics are always my favourite. And there’s one discovery from the ARCADE program in 2006 that still hasn’t been explained: space roar.
A hum of radio light coming from every direction in the sky that was 6 times brighter than what we expected to find and we still don’t know what’s causing it nearly 20 years later.
In fact, no one can even agree whether it’s coming from something inside our galaxy of stars, the Milky Way, or if it’s coming from outside our galaxy somewhere in the distant Universe…