[Grammar] present simple with past meaning

[CarloSsS]

I often hear present simple being used with past meaning. I've consulted PEU from Swan, but haven't found the explanation and usage. Why do the following sentences have present simple in them when obviously they refer to past? How do I know that I can use present simple like that?

• I hear that you are good at sports. (Why not "I heard that you were/are"? Obviously the speaker heard it (probably once) in the past, and doesn't hear it on regular basis.)
• It turns out that he isn't that good at sports. (Why not "It turned out that he wasn't/isn't"? Again it showed that he wasn't good at sports in the past.)

Would anybody please explain this to me?

 

[5jj]

I hear that you are good at sports. (Why not "I heard that you were/are"? Obviously the speaker heard it (probably once) in the past, and doesn't hear it on regular basis.)

It's similar to "The Bible tells us ...", "Darwin explains ..." The current relevance of the information reported is important to the speaker.