Little Doctor's Whimsical Journey

Author: Liang Shi
Publisher:
Publish Date: 2006-02-01
Features:
1. Getting Closer to the Sun
The relationship between the Sun and stars may seem completely different at first glance, even as if they are "enemies": as soon as the Sun rises, stars disappear. The Sun is so bright, how could it be compared to a small star? But this is only a superficial phenomenon. Science tells us that all stars are distant Suns, and the Sun is just an "average soldier" among stars, with no fundamental difference between them. In the world of stars, the Sun is actually an unremarkable, ordinary star. Among the stars visible to the naked eye, most are larger, brighter, and have higher surface temperatures than the Sun. Take Polaris (Dubhe, also known as "Gou Chen Yi" in Chinese), a second-magnitude star ranked only 47th in brightness, for example. Although its mass is only slightly more than twice that of the Sun, its radius is quite impressive: 54 million kilometers, which is 77 times larger than the Sun! The Sun looks truly "small" in comparison. Will the Sun go out?
Since the birth of life on Earth, all life has relied on the Sun's light and heat to sustain itself, reproduce, and thrive. The Sun symbolizes light and hope, and losing the Sun would mean darkness and the end of the world. So, will the Sun go out? Scientists confirm that this is indeed possible. As long as the "fuel" in the Sun is exhausted, the Sun will naturally go out—it's just a matter of time. According to the research and calculations of astronomers, the Sun's "fuel" is hydrogen. The Sun contains approximately 10^27 tons of hydrogen "fuel." The reason the Sun can continuously emit light and heat is because its hydrogen undergoes nuclear fusion under high temperature and pressure. The process of hydrogen nuclear fusion is as follows: First, four hydrogen atoms combine to form two deuterium atoms. Then, one deuterium atom and one hydrogen atom combine to form one tritium atom. Next, two tritium atoms combine to form one helium atom, releasing two hydrogen atoms in the process. This nuclear fusion process of hydrogen takes about 14 billion years. Even if the hydrogen fuel in the Sun is completely exhausted in the future, the Sun will not go out all at once. When the hydrogen in the Sun is depleted, it will begin to contract, and the central temperature will rise from the current 200 million°C to 100 million°C. At this point, another type of nuclear reaction will occur: three helium atoms will transform into one carbon atom, releasing a large amount of light and heat into space. This nuclear fusion process takes about 10 billion years. Just these two nuclear fusion processes alone take 20 billion years. So, what if the Sun completely goes out in 500 billion years? Don't worry, our Sun has already found a loyal "successor" to relieve the worries of life on Earth—Jupiter. Once the Sun goes out, Jupiter will faithfully serve humanity just like the Sun. According to the research and recent discoveries of astronomers, Jupiter is a liquid hydrogen planet with an extremely abundant hydrogen "fuel." The temperature of Jupiter is constantly rising, and its central temperature has now reached 280,000°C. Nuclear reactions similar to those occurring in the Sun are currently taking place within Jupiter. Many signs indicate that Jupiter is evolving into a star. Scientists predict that after billions of years of evolution, Jupiter will become the second Sun.
Is Sun activity related to human health?