MIT TIME TRAVELER CONVENTION UPDATE: This has been posted on the convention's website:

Update:The convention was a success! Unfortunately, we had no confirmed time travelers visit us.
We did, however, have a great series of lectures, awesome bands, and even a DeLorean. We regret having had to turn away visitors, but there were capacity restrictions governing Morss Hall.

Check this space for photos, commentary, and more.

Well, this result could mean any number of things.

1. Time travel really is impossible.

2. Time travel is possible but no time machines have been invented yet and when they are, they won't be able to travel further into the past than when they were built.

3. Time travel is possible, but the many-worlds interpretation of quantum physics is correct, and time travelers who went to the convention started new branches of the multiverse. It happens that our branch descends from the original universe, so we don't get any time travelers this time.

4. Time travel is possible, even easy, and there's only one universe. According to "Niven's Law," the only stable configuration in such a universe is a history in which time travel is never invented. So time travelers keep changing things at will until by chance they do something that prevents time travel from being invented every time it might have been. The practical result from our viewpoint would be that every time a researcher was on the verge of building a time machine, that researcher would slip on a banana peel and suffer a fatal injury, or a mega-asteroid would destroy all life on that planet, or the like. Professor Mallett, be careful!

5. The convention's organizers are fibbing. Time travelers actually came in droves and threw a big party with the attendees in a gigantic, lavishly furnished ballroom hidden in a spatio-temporal vacuole and discreetly connected to the convention site through a broom closet or bathroom stall. After all, what would be the point of stirring up the indigenous primitives and maybe causing riots and such that could disturb future timelines or spoil the party? Better just to keep things quiet. The attendees, of course, duplicated themselves for the duration and stayed in Morss Hall so as to give the appearance that the convention was going on without any time travelers. (Why do you think that no television cameras were allowed? Buwahahahahahahaha!)

6. Someone in the future is going to throw a better party for time travelers.

UPDATE: Welcome Instapundit readers! If you'd like to know more about this blog, you might be interested in reading this brief article I published recently on blogging on ancient history (and how the media screws up that topic too).

UPDATE: Here is a link to an audiotape of The Moment. Here are some photos of the convention. Here is a report of a time traveler who was turned away. And Rick Lippincott proposes a seventh reason. But if people in the future can manage the time travel part, I doubt that aiming for the right part of space would be a big challenge for them.

UPDATE: My eight-year-old son proposes another reason (#8?): a working time machine won't be built until so far in the future that, despite our best efforts, this time traveler convention has been completely forgotten.

Also reader Michael C. Grant e-mails:

Let's expand on your reason #5.

Perhaps it is possible for a stable single-universe to exist even if time travel has indeed been invented. Let's say that someone in, say, the year 2150 achieves the first successful time travel device. This person would immediately be met by visitors from the future who have developed a full understanding of the dangers of time travel to the space-time fabric, and how to avoid them. Together they would take steps to insure that no fatal damage to the space-time fabric ever occurs, by building safeguards into the new invention as well as imposing a system of rules for using it.

So for example, perhaps time travellers would never endeavor to reveal their identities as members of the future in eras where time travel itself had not yet been stabilized. Thus they would travel back to, say, prehistoric days to watch dinosaurs, but they wouldn't appear on Ben Franklin's doorstep---or to a time-travel convention in 2005.

Actually that's an interesting expansion on both reasons #4 and #5.

And thanks also to many other bloggers for their links to this post.

UPDATE: Another reason! This one from reader Ben Skott:

You're missing a reason. Maybe our era has a reputation of being particularly boring and materialistic, or violent, or any number of distastful things, so no time travellers ever bother coming.

Wouldn't surprise me.

UPDATE (10 May): Reports on the convention in Wired News and the Harvard Crimson.