Jeff Minter, age 13, of Louisville, Kentucky, for his question:

What are black holes in space?

A few years ago, a couple of research teams presented some new evidence which seems to prove that the black holes of space really do exist. Previously, astronomers has suspected this to be true. They also had worked out some logical theories on what they are and why they are likely to exist. Long range radio telescopes had pinpointed several likely places where the mysterious black holes were likely to be.

So far as we know, the entire universe is filled with filmy stuff called plasma, a thinner than thin mixture of atomic particles charged with dynamic energies. The stars are dense concentrations of cosmic plasma, the planets and their moons formed from stars as they concentrated.

Space probing instruments have found strange pockets, somewhat like isolated prisons in the brightly populated universe. Maybe black holes are not the best name for such things because recent probes prove them to be occupied. In fact, a black hole seems to be occupied with perhaps the most dynamic of all cosmic materials. What's more it seems to be governed by a concentration of gravity, the most persistent of all cosmic forces.

Gravity, of course, is a built in property of matter and every speck of dust has its tiny quota. The massive stars have enormous quotas of gravity. The densest, more massive stars have even stronger gravitation. In all cases, this persistent force comes from the center of a massive body and diminishes with distance, this, we think, is what holds a great star together.

The mass of most stars ranges between ten times less and ten times greater than our sun. In these cases, the forces of gravity can hold the stars in shape. However, in more massive stars the usual operation of gravity appears to break down. This seems to happen in super dense stars packed with atomic nuclei.

The evidence suggests one of these so called neutron stars is at the core of the mysterious black hole. Such a dense star may be as massive as our sun, though only a few miles wide. Astronomers suspect that a neutron star forms after some of its fuel is consumed. Suddenly its gravitational energy collapses and shells of outer gases explode in a stupendous supernova.

The collapsed gravity concentrates in the remaining core, crushing the dense material into a massive midget, rotating at high speed. The surrounding gravitational field could be strong enough to isolate the neutron star in a black hole. No particles of matter, no light or other form of energy could escape or enter through the barrier.'

There is a lot of evidence that such black holes really exist, just as astronomers predicted. There also is evidence that they contain the cores of past supernovas. However, some energy escapes from the fast spinning midgets. It reaches us as pulsing radio signals    which is why these black hole neutron stars are called pulsars.

Chet Green, age 10, of Emmaus, Pennsylvania, for his question:

Does the wolf spider make a web?

The wolf spider is a born hunter, who catches his victims on the run. He has a battery of eight sharp eyes on his head to survey the scenery and eight long fast legs to run down his prey. No, the wolf spider does not build a web. After all, the mighty little hunter needs no trap to catch his food.

During the day, he dozes in the damp woods under a log or stone. Night is his time for hunting and soon after sunset, out he strides. This is the time when his favorite insects are likely to be out and about. What's more, this is a nice safe time to go hunting, for then the wasps that prey on spiders are sound asleep.