Puzzler...

Less than half of you got last the correct answer to week's puzzler (and I got one complaint about the obscurity of the question!).

Trofim Lysenko was a biologist working in the Soviet Union from about 1925 through the 1960s (he died in 1976). He promoted the notion of inheritence of acquired characteristics – an idea that was popular prior to the early 1900s, when science started to understand genetics. A simple example of inheritance of acquired characteristics: if you wanted pigs without tails, you'd cut off the tails of a male and female pig, breed them, and their descendants would have shorter tails. Lysenko (and other proponents of the inheritance of acquired characteristics) were not at all put off by the total failure of experiments to produce such results – they had an endless stream of explanations and flawed experiments “proving” the theory.

But Lysenko's main skills weren't scientific at all: they were political. By 1948 he managed to promote his ideas so effectively within Stalin's Soviet Union that he persuaded Stalin to legislate the “correctness” of his theories – outlawing Mendeleevian inheritance (modern genetics) in the process. Thousands of biologists were imprisoned or sent to gulags; hundreds died. Soviet biology, as a direct consequence, was set back decades, and was the laughingstock of the west. Not until 1964 – long after Stalin's death – was the official mandate for Lysenkoism removed, and not until then were Soviet biologist free to pursue modern genetics. It was a disastrous example of politicized science. Think about that, and then consider what has happened over the past few years with respect to the science of global warming. Political suppression of scientific debate is dangerous, and we have a frightening example of why in our recent history…

This week's puzzler is a science question: when wood is burning in a fireplace, you can see yellow or orange flames, sometimes blue flames, and red or orange embers. What is actually causing those yellow or orange flames?