What are the more/less hard sci-fi mysteries?

[Jaol]

Hi, without too many spoilers, can you say which mysteries are more hard sci-fi, and which less?

E.g. I would say Beyond Earth is reasonably hard. And Inner Light is not particularly.

 

[Promethian]

Poorly defined terms are poorly defined. Your example does not disambiguate like you think it does.

 

[MarQan]

Marsgate seems pretty hard sci-fi. It has that "but why tho?" feeling to it, but nothing magical.

 

[Miravlix]

The Power of Three, Inner Light, The Dredgers, Spheres all seem like fantasy mysteries to me.

Wildfire, Beyond Earth, Marsgate, The Last War all seems to stay within current known realistic scenarios.

Not sure what category the AI one belongs in, but I guess it is hard scifi.