Joe Sinkula, age 11, of Corona Del Mar, California, for his question:

Was there really a lost continent?

Certainly our few major land masses have remained sedately in place in recent history, but human history is merely a drop in the bucket compared with four billion years of restless planetary history. Earth scientists have traced back mountainous upheavals and immense reversals of land masses and seas. What's more, slowly through the ages the continents have been global travelers. Even.the experts no longer discount the idea of a lost continent.

But one thing is impossible to explain. It is the lingering old legend of Atlantis, a continent or large island lost in the Atlantic Ocean. On the basis of our present knowledge the loss of a major land mass during the short span of human history seems most unlikely. Yet mankind has told and retold the old story. As of now, we have a double mystery. We have no positive proof of Atlantis and certainly no reliable explanation of how even our earliest ancestors could have witnessed the event, if it occurred at all.