What is hard science fiction?
Hard science fiction exists inside the realm of scientific possibility. That is, anything that occurs in the story is not outside the known physical laws of the universe.
“Hard” science fiction is based on reality, the real world, as science has discovered and explained it. But it goes a step farther, beyond the known and into realms that have not been discovered and explained yet.
Hard SciFi Physics
Hard Scifi Astronomy and space
Contact: A Novel by Carl Sagan
Old Man's War by John Scalzi
BLINDSIGHT (Firefall, 1) by Peter Watts
The Martian by Andy Weir
Seveneves by Neal Stephenson
Computer Science Hard SF Books
Good players: A Novel by Damien Broderick
Rainbows End: A Novel with One Foot in the Future by Vernor Vinge
Wake by Robert J. Sawyer
Nexus: Nexus Arc Book 1 by Ramez Naam
Memories With Maya by Clyde DeSouza
Best Hard SciFi books of 21st century
Super Sad True Love Story By Gary Shteyngart (2010)
How to Live Safely in a Science Fictional Universe By Charles Yu (2010)
Hav By Jan Morris (2006)
Rainbows End By Vernor Vinge (2006)
The Humans By Matt Haig (2013)
Moxyland By Lauren Beukes (2008)
The Quantum Thief By Hannu Rajaniemi (2011)
All the Birds in the Sky By Charlie Jane Anders (2016)
Time travel
How to Live Safely in a Science Fictional Universe By Charles Yu
Dark Matter: A Novel by Blake Crouch
Eine Reise durch die Zeit: A Journey through time: (Dark Original Novel) by H G Tannhaus
Recursion: A Novel by Blake Crouch
The Three-Body Problem: by Cixin Liu
Dark forest: 2
Death's End : 3
Timescape by Gregory Benford
Exhalation by Ted Chiang
All-Time Best Hard-Scifi Authors
Gregory Benford
Stephen Baxter
Greg Egan
Ted Chiang
Liu Cixin
Arthur C. Clarke
Isaac Asimov
William Gibson
Carl Sagan
Peter Watts
Greg Bear
Larry Niven
Robert A. Heinlein
Bookmarks of listed Hard Scifi books
Best 21st Century Hard Science Fiction Novels | What Should I Read Next?
These 11 Underrated Sci-Fi Novels Need To Be on Your Reading List
Best 21st Century Hard Science Fiction Novels | What Should I Read Next?
Ten Classic Hard Science Fiction Novels featuring Physics and Astronomy - SFWA
All these books and authors are written, as far as I know, and have read some, most of the best books are unexplored, comment on your favorite Scifi or Hard Scifi books or authors.