Chinese lunar probe

21 January 2019

Cotton on the Moon?

You probably heard that the Chinese lunar probe, Chang'e 4, has successfully germinated a cotton seed.

Of course, it was never going to last long. China's space agency reported that all the seedlings in the experiment had died, only having lasted a few days in their special chamber. There's no prospect of having Moon farms growing cotton for terrestrial use.

Most of the explanations given by biologists about this is that the lunar night was coming. A day on the Moon lasts for about 28 Earth days, meaning it's night for about 14 Earth days. And it gets cold. Seriously cold. "Overnight" temperatures on the Moon go down to as cold as 180 degrees Celsius below freezing. Even in the biosphere there was no chance of fending that off.

Of course, the temperature problem reverses when the sun comes up again. "Mid day" temperatures on the moon get up to 100 degrees Celsius, boiling anything that has water.

Why are the lunar temperatures so extreme? The reason is the lack of atmosphere. Without air to scatter the light and its associated warmth, sunlight is really hot and shade is really cold. During the "day", astronauts could wear clothes and have shelter that cools them down, but in the night ... brrr.

Even without the temperature problems, the Moon isn't an environment that seeds could tolerate. They need air, including both carbon dioxide and oxygen, and in the longer term they also need nutrients, which may or may not be in the lunar soil.

Quite apart from that, the lack of a magnetic field on the Moon means that solar radiation would play havoc with genes in the DNA of any life staying on the Moon for extended periods.

So no, no farms, and not a great place for a holiday any time soon.

Image: China National Space Administration