The 30 Most Curious Mysteries of the Universe for Elementary School Students

Author: Ji Du Heng
Publisher:
Publish Date: 2006-08-01
Features: Why do humans search for another Earth? People have been imagining the existence of life forms similar to humans in some place in the universe since ancient times. Today, with highly developed science, humans have turned this ancestral imagination into practice by sending radio waves and spacecraft into space, persistently searching for planets with life beyond Earth. So, why do humans bear such great costs to search for planets with life beyond Earth? That is because none of us knows what changes the Earth will undergo in the distant future. If we truly find another planet with life, then when the Earth's environment deteriorates to the point where humans can no longer survive, humans can move to this planet to continue living. This is truly "prevention is better than cure"! Discovering the cosmic order through practice Ancient people, while observing the sun, stars, and moon, discovered that the universe also has its own inherent order. For example, as the Earth continuously moves, there are regular seasonal changes on Earth. Based on this change, people have summarized the 24 solar terms on Earth. Dividing these 24 solar terms into four equal parts yields the four seasonal transition points: the spring equinox, the autumn equinox, the summer solstice, and the winter solstice. On the spring and autumn equinoxes, the length of day and night is exactly the same. In the Northern Hemisphere of Earth, the summer solstice is the longest day of the year; conversely, the winter solstice is the longest night of the year. After the spring equinox, the days become longer and warmer; on the other hand, after the autumn equinox, the nights become longer and colder. Seasonal changes repeat year after year. This is because the Earth always orbits the sun in a specific orbit in a regular manner. The spring, summer, autumn, and winter beginnings are the starting points of the four seasons; the major and minor cold solar terms tell people that the coldest time of the year has arrived; the minor and major heat solar terms tell people that the hottest time of the year has arrived. P41-42