I know that the title is not really clear. That's because I don't know what i'm searching for, unfortunately. Let me explain with an example: Yesterday i was watching a youtube video , more precisely a lecture from MIT. Looking through the comments i found out that the professor from that lecture studied computer science at the University of Waterloo. I have never heard about the University of Waterloo before (until yesterday). Today, while checking my emails i was surprised to see that i got a suggestion to read an answer to a question : "How valuable is the University of Waterloo's computer science program? " I know that with computers may not be so mysterious since they know what content we see on the internet and may use it for making suggestions. The thing is that these kind of situations occur really often even without technological "help".
For example: Some time ago my sister told me about neutron stars. It was fascinating. The next day, during a lecture, my physics professor used neutron stars as an example for a problem.
I had never heard about neutron stars before my sister told me about them and i was shocked to hear my professor that day. I haven't heard about those stars since then.
Or even everyday things: there is a song you didn't listen to for a very long time. Let's say a year. One day you think about that song. Some hours later you hear it playing randomly in a tv show you are watching.
My question is : do these situations have a name ? It happens so often that i already gave it a name but i would like to know if there is some official version
Do they have an explanation from a psychological point of view or they are just fortunate coincidences?