Gavin Nicholson, age 8, of Ottawa, Ontario, Canada, for his question:

Why is the moon seen under total eclipse?

A few weeks ago, a lot of young star gazers had a chance to behold their very first eclipse of the moon. Many of them were surprised. They knew, naturally, that an eclipse hides the sun or the moon. This idea leads one to suppose that the sun or the moon disappears out of sight. Well, this notion is true and also untrue. It is true in a total eclipse of the sun. It is untrue in an eclipse of the moon. Naturally, there are reasons for this odd behavior. Eclipses happen when the sun, the moon and the earth line up in a straight row. The difference depends upon which of them is in the middle of the line.

When the moon is in the middle of the line up, its solid body passes directly bet¬ween us and the sun. From our vantage point on earth, we see the moon's dark round globe, the beaming sun and completely hide its shining face. This is an eclipse of the sun. When the earth is in the middle of the line up, we get an eclipse of the moon. But unless we are viewing the eclipse from somewhere near the sun, we can¬not see the solid body of the earth hide the moon. We see only the shadow of the earth as it falls on the moon's golden face. The passing shadow of the earth just dims the bright full moon. As a rule, it tinges the yellow face with dim, dusky copper. This is why we can still see the shadowy face of the moon during the eclipse.