Why do people use "I hear that..." when talking about the past?

I often see that people write ‘I hear that…’ meaning the past. For example:

I hear that Sally has won in lottery.

(If I remember correctly it is used in English Grammar in use by Cambridge University)

Why is it used? Shouldn’t be ‘I heard that…’ when we mean the past?

Solution 1:

'I heard' is past tense and indeed means that you had heard something previously.

'I hear' is different. It is present tense of course, but it is more figurative in the context you are talking about. It means something along the lines of 'The rumour is', not that you are literally hearing something.

Solution 2:

To me, ElandilTheTall is right, I hear that is more figurative. But I also think it can imply common knowledge.

When you say I heard that you probably have a specific source that told you about it in mind. A friend, a newspaper, the internet, etc.

When you say I hear that you imply that it's common knowledge, although this is likely the first time you've talked about it, you assume either that the person you are speaking to already knows about it, or the person you are speaking to should already know about it.