My textbook says talking about Cygnus X-1 (the first black hole to be identified as such) has variations in brightens of the order of 0.01 seconds and that this means that it's dimeter must be on the ...
As we all know, the stars we see in the night sky might already be dead. I was wondering though, when was this fact or conclusion commonly established? Today, most people (let's assume with an above ...
How is the speed of light calculated? My knowledge of physics is limited to how much I studied till high school. One way that comes to my mind is: if we throw light from one point to another (of known ...