Timelike Infinity is a science fiction novel by Stephen Baxter. Humans have become nearly immortal through the use of nanotechnology, space is opening up too, through the use of wormhole technology. There is a project to open up time also; by towing a wormhole through a 1500 relativistic round trip. Instead of people 1500 years advanced, a small rabble of humans appears from the wormhole; Wigner's Friends, closely followed by the future conquerors of humanity.