When asked what he thought the greatest development since the 22nd century had been, Riker responds that it is the warp drive, and that 200 years earlier humans lacked warp drive and were confined to a single sector of space. Star Trek The Next Generation takes place in the 24th century. Warp drive was developed by Zefram Cochrane in the mid-21st century, nearly 300 years before this story takes place. This future fact was established in the original series story "Metamorphosis" and expanded upon in the Next Generation film "First Contact."
Rasmussen is leaning against the door in Picard's room but the door remains closed.
Worf refers to the seismic activity on Penthara IV as "earthquakes." Since it's not Earth, he should have said "land quakes" or simply "quakes."
The Professor claims to be a historian from the future, and Picard seems to accept this, saying in the crew briefing that the Professor's credentials seem to be in order. How can you verify credentials which don't exist yet?
Rasmussen claims that he is from the late 26th century and has traveled nearly 300 years back in time to meet the Enterprise. That would have taken him to the late 23rd century. The adventures of Picard & Co. however are set in the second half of the 24th century (around 2368), which is, at best, a little over 200 years before Rasmussen's alleged origin. This, however, foreshadows that Rasmussen is not what he says he is; a historian traveling to the past would know exactly how many years ago he was going, instead of estimating and getting it wrong.
However, the crew of the Enterprise would easily be able to do the simple arithmetic and immediately find the hole in his story.
However, the crew of the Enterprise would easily be able to do the simple arithmetic and immediately find the hole in his story.
Incorrectly regarded as goofs: It was said how could Picard verify the credentials of the impostor, such credentials must be nonexistent. But that is not really a plot hole, because the impostor stole the name and credentials from the real historian, together with his ship and clothing. So he gave Picard the original, valid credentials of the person he robbed.
Rasmussen repeatedly tells the crew of the Enterprise that he cannot divulge future information due to the danger that it might alter the timeline. Even if he is a fraud, both he and the Enterprise crew should still be aware that his very presence there would alter the timeline. He threw the Enterprise off its planned schedule and altered the schedules of many officers aboard just by interacting with them at all.
At the very beginning, Geordi says that they are already seeing "climactic" changes. Climactic changes are changes relating to a climax or tension point. What he means is that the planet is experiencing "climatic" changes, which are changes related to climate.
Rasmussen likens observing Data with coming across "a Gutenberg Bible". It is a common misconception that Gutenberg Bibles are very rare, whereas the entire point in how Gutenberg's way of printing was that his Bibles are less rare than previous versions, which were handwritten. From Gutenberg onward Bibles were a household item, and cheap.