Mike wanted to know what happens to cosmic material that falls into a black hole. After it enters the funnel-like entrance, he asked, is there an exit? Are there theories about the back side of a black hole?

Several well-educated readers wrote in with detailed descriptions of black holes. Herb said they're thought to be collapsed stars with enormous mass and, therefore, enormous gravitational pulls, so great that even light can't escape.

He and Bert said there isn't really another side to a black hole. Shirley agreed, adding that they're roughly spherical, not funnel-shaped, with the captured material inside.

Herb guessed that Mike might be thinking of a wormhole, a hypothetical "tunnel" that provides a path from one part of the universe to another.

Steve said one of the latest theories is that a black hole forms an hourglass shape and the contents are spilled out the other side as if from a pepper shaker.

CSU astronomy professor Roger Culver says that, basically, is one of the theories about what happens to material that's sucked into a black hole: It pops up somewhere else. Another theory is that it eventually evaporates. Culver calls this discussion "the delicious borderline between science fact and science speculation and science fiction."

Here's your next challenge:

What do you call those annoying traffic lights in the middle of the block? There are a half-dozen or so on the stretch of 13th Avenue that I drive every day. Their only purpose seems to be to impede traffic. - Ron

Know what those lights are called and what they're for? Post your responses on the Ask! blog, blogs.com/denver/ask. While you're there, check out the other questions on the Ask! home page, or post one of your own by clicking on the link to the left on the page.