Mike Boeger, age 10, of Hermann, Mo., for his question:

WHAT IS BEYOND PLUTO?

Little Pluto is way out there, pedaling around near the outside edge of the solar system. Its average distance from the sun is about 3,670 million miles, and all the planets are separated by many millions of miles. To us the solar system seems enormous. Actually, it's a very small item in the starry heavens. When we travel out beyond Pluto, we dip our toes into the vast ocean of outer space.

If we travel for about 26 million million miles in the right direction, we reach the star nearest to our sun. In a different direction we must travel twice as far to reach the next nearest star.  And all the stars we see are part of the huge milky Way galaxy. It has 100 billion stars. Way out beyond our galaxy there are millions of other starry galaxies:. And nobody knows where it all ends.