Ask Mr. Science
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The ozone hole
came up as I started to answer a question about global warming. Clearly
these are two subjects which get mixed up a lot, so I decided to talk about
the ozone hole first. The ozone layer is near the top of the atmosphere, far above the troposphere, where all weather phnomena occur. Ozone absorbs UV radiation from the sun, thereby protecting plants, animals and people. Ozone gets destroyed by certain chemicals, most imortantly CFC's. CFC's are mostly used in refrigerators, airconditioners and spraycans. They were used there because they were very non-reactive and stable. Unfortunately they are so stable that they can survive for decades as they slowly diffuse throughout the atmosphere all the way up to the ozone layer. There they react with the ozone, if the temperatures are very low. This occurs in the winter over the south pole, and to a lesser extent over the north pole. It is no longer legal to produce these CFC's worldwide, and gases in new spraycans, fridges and airconditioners are replaced by others. This means that in a few decades, all the CFC's in the world's atmosphere should be gone and the ozone hole should be a thing of the past. However, there is an emerging illegal trade in CFC's, and this may delay the restoration of the ozone layer by a decade or more.
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Global warming
was the hot topic this week
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Meteorites
were the hot topic this week with the much-publicized arrival of the
Leonid meteor storm. We talked about how this is dust left behind by the
recent passage of come Temple-Tuttle, and that these are just tiny grains,
but that they could do damage to sattelites, and to the people aboard Mir.
All the details are in the links below:
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Just click here and type away!
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