Read 55 of Stephen Hawking’s Research Papers for Free

Over the course of his life, famed physicist Stephen Hawking wrote dozens of papers that explored the mysteries of time and space. From his 1966 thesis onward, he helped revolutionize the field of astrophysics and define what we know about the universe by diving into topics like string theory, black holes, and the Big Bang.

In the wake of his death last week, the American Physical Society (APS) has released 55 of his studies to “mark the passing of Stephen Hawking.” You can read them here. To fully understand the gravity of what’s going on here, you may want to brush up on your physics: There’s a reason Hawking is considered one of our preeminent geniuses. A huge number of them deal with wormholes and black holes, including this banger on black hole “soft hair,” or zero-energy particles that store information from the stars black holes gobble up.

These 55 papers are found in the journals Physical Review D and Physical Review Letters, which are published by the APS. These studies, published from 1965 to 2016, the APS states on its site, “probe the edges of space and time.” The first paper published here, “Occurrence of Singularities in Open Universes,” was written a year before his infamous 1966 thesis on expanding universes and marks the start of his work that deals with the universe beginning from a singularity.

Some of the papers also are also an exercise in some fanciful titling by Hawking and his coauthors, including “Brane New World” and “Living With Ghosts.” The latter deals with how gravitational dimensions affect ghost states — which are unphysical states on the wrong side of the kinetic term, and not actually ghosts.

When you’re done with the classics, you can move on over to a new hit titled “A Smooth Exit from Eternal Inflation?” This final paper from Hawking, co-authored with theoretical physicist Thomas Hertog, Ph.D., was submitted two weeks before Hawking’s death and currently exists in its preprint form.

While it doesn’t exactly predict the end of the universe, (something Hawking liked to discuss on in his free time), it does propose a new way to detect the ‘multiverse’: a mathematical road other scientists can explore, ensuring Hawking’s work lives on in the future.