From tiny seeds(种子), a great discoveries grow. A mini-garden carried on China's Chang'e 4 moon lander recently became home to the first plant to grow on another world.
This is yet another success for Chang'e 4. On January 2, the probe(探测器) became the first lander to touch down on the far side of the moon. This is the unknown face of the moon that is always looking away from us, so we never see it from down here on the earth. Although it is often regarded as the dark side of moon, the far side actually gets as much sunshine as the near side. For example, when all we can see is a silver silver of a new moon, the far side of the moon is in full sunlight.
Part of Chang'e 4's mission ((使命) is to see how a moon base could be built for humans, including exploring(探索) whether humans could grow food and other plant products there. Chang'e 4 carried a mini-garden with air, water and soil with seeds planted in it. When plants shoot on the earth, their stems grow away from the gravity (the force that keeps your feet on the ground), and so they always shoot upwards. The moon's gravity is a sixth as strong as the earth's, so Change 4's experiment was a test: would the earth plants know which way was up on the moon? Four days after landing, a tiny cotton shoot showed that they do.
Night has now fallen on the far side of the moon; sunlight will not return until the start of February. As a result, the cotton shoots died. Besides the darkness, the plants can't stand the cold (it can drop to-170°c on the moon at night). However, the experiment is a success, since it has proved that it is possible for plants to grow in space.
