The second major event referenced in Picard is the Romulus supernova, which was actually a major plot point in J.J. Abrams' 2009 Star Trek reboot. In that film, a rogue group of Romulans led by Captain Nero chase the old Ambassador Spock (Leonard Nimoy) through a black hole when their planet is destroyed in the year 2387 — taking them way back in time and creating a parallel universe. But Picard is set in the prime Star Trek universe that Spock and Nero left behind, not the one with Chris Pine and Zachary Quinto, so all you need to take away from this information is that the planet Romulus is kaput thanks to a supernova that Spock failed to eliminate. Also, if Picard ever mentions that Ambassador Spock has been missing for the past decade, you know why and you know where he went: the parallel universe in which Star Trek, Star Trek: Into Darkness, and Star Trek: Beyond take place.