node.js - Is there a single event loop for the entire Node runtime?

Question

After reading this post, it has given me the impression that Node starts its event loop only when I start a server, with the listen() method.

Is that true ?

What happens if I start multiple servers on different ports ? Does that mean there are multiple event loops per server ?

Also what happens if on one terminal I write-:

node server1.js

and on the second terminal I write

node server2.js

How may node processes will be there and how many event loops will be running ?

So does the event loop start up with the node.js runtime or is it specific to the starting of an app/server ?