It's a good question, Doctor Cornelius! (Welcome to NarniaWeb by the way! )

The only explanation that I have been able to muster over these many years is that Narnian time is not exactly linear in nature. That is to say, if you were to plot the two times graphically, our world would have a linear representation, while the Narnian world might have an exponential representation. (That's the math nerd in me. . . . but it's as close as I can get)

I'd love to hear other people's thoughts.

As an analogy, I like to think about how early astronomers observed the Solar System. The planets appeared to have really strange movements, speeding up, slowing down and sometimes even going backwards for a while. Then it was discovered that all the planets, including our own, went round the Sun and not the Earth; and the weird paths of the planets resolved into simple ellipses and the speeds of rotation became constant, though different for each planet.

That's how I imagine the relationship between our time and Narnian time. The time of the Narnian world appears to speed up and slow down relative to our own; and, although Lewis didn't include the idea in his books, I think it's also possible that it could have appeared to go backwards relative to our time on occasion. Yet seen from the perspective of the "Sun" - Aslan's Country, to which all real worlds connect - all the space-times of all the worlds move in simple paths at constant (though different) speeds.

Does that make any sense to anyone else?

Retrograde motion of the worlds, revolving around Aslan's country?! I LOVE that idea!

The time of the Narnian world appears to speed up and slow down relative to our own; and, although Lewis didn't include the idea in his books, I think it's also possible that it could have appeared to go backwards relative to our time on occasion.

He doesn't include the idea - but doesn't he give a couple of instances of it?

The pirates that got into a cave in our world and ended up in the Narnian world and peopled Telmar - isn't possible that they left our world in the late 19th century - in other words, before Digory was born or at least before he saw the creation of Narnia?

This isn't necessarily a good example, because we don't really know all that much about when those pirates lived in our world.

But my second example has its problems the other way round, because we know so little about what happened in Narnia in that case, or when it happened - while we know a lot more about its time frame in our world.

I'm thinking of the painting in Eustace's house in Cambridge - the painting of the Dawn Treader.

Who made it? When was it made? Where was it made? Surely it must have been made in Narnia - "she's such a very Narnian ship" - and somehow gotten into our world?

We know more about its history in our world - it was a wedding present for Eustace's parents. Which means that it must have been around in Cambridge well before the Pevensies went through the wardrobe.

So if it indeed came from the Narnian world, then Narnian time would have appeared to go backwards relative to our time on this occasion.

I always assumed that the picture was made in our world, and Aslan just used it to bring the three children into Narnia. He knew all things that would come from that painting when the artist sat down to make it. I never thought it had anything to do with the time.

I do often wonder about the pirate thing though. Assuming even a partially linear flow to time, the pirates would've have to have been roaming the seas in the year between LWW and PC. I'm pretty sure that there wasn't much organized piracy going on in the 1940's, especially in Northern Europe (I'm guessing this based on the light skin and blonde hair of the Telmarines).

I do often wonder about the pirate thing though. Assuming even a partially linear flow to time, the pirates would've have to have been roaming the seas in the year between LWW and PC. I'm pretty sure that there wasn't much organized piracy going on in the 1940's, especially in Northern Europe (I'm guessing this based on the light skin and blonde hair of the Telmarines).

Exactly - which is why I'm convinced that Narnian-world time and our time have to go in opposite directions occasionally. Aslan tells the Telmarines at the end of PC that the race of pirates has died out on the island in our world, which would have been only a few months after they arrived on the island if it happened during the year between LWW and PC. It's possible, but it seems unlikely.

The fact that Caspian is blonde does certainly imply that at least some of the pirates were of European descent, but there have been pirates of European descent all over the world for centuries . Also, in PC, Aslan says that the pirates brought their "island women" with them. This suggests that the pirates were probably operating in Southeast Asia, not Europe. Maritime piracy is a problem in Southeast Asia to this very day, so it's very possible that European pirates operating in Southeast Asia could have entered Narnia in the first half of the 20th century, if we accept the premise of Narnia at all.

Overall, I see no evidence that Narnian time can move backwards relative to ours, though I see no evidence against it either, maybe we just don't see instances of it in the stories.

As for the differences in time, it helps to understand the Narniaverse as a completely distinct universe. Space-time is fluid and pliable, and the flow of time in one universe would have no bearing or effect on the flow of time in another. It makes perfect sense that, as Lewis put it:

If you went back to Narnia after spending a week here, you might find that a thousand Narnian years had passed, or only a day, or no time at all

It also makes sense that no time would pass when you returned to your point of entry, because you are leaving your universe, and would have to return to a point in space-time, not just a point in space.

Looking at the passage in "Prince Caspian", I noticed the following:

Many years ago in that world, in a deep sea of that world which is called the South Sea, a shipload of pirates were driven by storm on an island.

(Emphasis mine.)

However our time and Narnian time relate (or don't relate) to each other, I'm sure that Aslan knew what year it was in our world when Peter, Susan, Edmund and Lucy arrived in Narnia and would return to in a few minutes' (Narnian) time. So this phrase "Many years ago" suggests that when the pirates left our world and arrived in Telmar, it wasn't the 1940s. I would hazard a guess that it was unlikely to be after 1900 - depending on how you interpret the word "many", but personally I think even twenty or thirty years wouldn't qualify as "many" in this context.

I agree with Anhun that the Narnian world is a completely separate space-time to ours and so it's impossible to try to establish some kind of relationship between our time and theirs. But even if we could, we're given too few points of contact to come up with a reliable equation. As a comparison, I once tried working out an equation for warp speeds (in the Star Trek universe) based on the information provided in the various TV series (e.g. Warp 0 is zero, Warp 1 is the speed of light, Warp 10 is infinite speed - contradicted in other episodes). The simplest equation I could think of then indicated that at maximum warp, Voyager would have taken something like 0.000097 nanoseconds to return from the Delta Quadrant.

Returning to the Narnian situation, I can imagine that even if someone had come up with a potentially viable relationship between our time and theirs, Aslan would have thrown a spanner in the works and had someone appear in (or from) completely the wrong time. I think his (and Lewis') sense of humour was like that.

Star Trek has had so many different creative minds involved over so many years that holding them to any sort of internal consistency would be unfair. I know that using the warp formula from the original series, it would take Voyager ~75 years to return to the Alpha quadrant.

We are trekkie, you will be assimilated.
. . .

Does it say in the books that the Pirates didn't enter the Narniaverse until after the events of LWW? I know they hadn't invaded Narnia itself, but I could have sworn there was something in HHB to indicate that they were already in Telmar. Can't find it through skimming. I don't own a copy of PC.

HHB only says that the Hermit can see in his mirror pool "what robbers or wild beasts stirred in the great Western forests between Lantern Waste and Telmar" - there is no other mention of Telmar, and no mention of pirates.

That wouldn't make it impossible for them to be in Telmar at the time of LWW, though. They must have been there for quite a while before they invaded Narnia.