Extra fingers or toes occur in 1 in 500 babies

Question: From a West Baraboo, Wis., reader: "My cousin was born with six fingers. How often does this happen? Is the extra finger useful or does a surgeon remove it as soon as the baby is born?"

Answer: So-called "polydactyls" may have six or more digits on either their hands or feet or both, an inherited condition, says "Wikipedia, the free online encyclopedia."

The extra digits vary from small pieces of soft tissue to complete fingers or toes and occur in about 1 in every 500 babies, more in certain populations such as the Amish, where few outsiders join the group and marriage occurs within the community. In Western society, the extra digits are usually surgically removed early in life.

Whether these are useful is unclear, but one major league pitcher from the Dominican Republic reportedly had six digits on both hands and feet — nicknamed "the octopus." After the team won an important game, the manager jokingly asked him to "give me six."

Question: What's the surprise in store for many a new scuba diver bringing back objects found underwater?

Answer: Treasured coins, medallions, etc., seem to shrink once they're fetched out, a result of the quirky way light behaves underwater, going slower in the liquid, then faster (refracting) as it passes into the airspace of the diver's goggles, says Dennis Graver in "Scuba Diving, Third Edition."

Objects there seem about 25 percent closer and 33% bigger than they really are. Once brought up, on the other hand, they may explode into colorfulness. Down below, it is dark, especially in turbid water, forcing divers to use their night vision, which mutes color and fine detail. "Warmer" reds and oranges are absorbed while leaving the "cooler" blues, which is why deep clear water is blue and why "below 100 feet the underwater scene appears drab."

Question: Extreme summer heat raises the question: "Are greenhouse gases such as carbon dioxide in Earth's atmosphere a good or a bad thing?" Basically, greenhouse gases slow the escape of heat from a planet's surface, causing it to warm up.

Answer: This is not the same as asking "Is global warming a good or a bad thing?" Some greenhouse gases are present naturally in the atmosphere, and without them, the global average temperature would be about 59 degrees F, say Jeffrey Bennett and William Briggs in "Using and Understanding Mathematics: A Quantitative Reasoning Approach." That's the temperature of a deep cave. "Thus, the greenhouse effect is a good thing for life on Earth."