The television and film star best known for his role in the 1970s sitcom "MASH," is posing the question as part of the third annual "Flame Challenge." Alda helped organize the international contest as part of his work at the Stony Brook University Center for Communicating Science.
The university on eastern Long Island named the center in Alda's honor earlier this year; its goal is to get scientists in various disciplines to explain complex concepts in the simplest of ways.
This year's question was selected by Alda after receiving about 800 suggested questions from children. He explained that many question focused on issues about light and color, including the childhood classic: "Why is the sky blue?"