Stephen Baxter has some seriously deep, science based, hard Sci-Fi.. a lot of it leaves you feeling.... ehhhhh... lol.. But very good, very engrossing. He also did a really great collab with Terry Prattchet before he died called The Long Earth series. Someone mentioned the Bobiverse books, which are good light Sci-Fi. You want some some good hard sci-fi look up Alistair Reynolds, Peter F. Hamilton, or Neal Asher.