Earthlings did not know much about stars, but they understood the basics.
Many people knew that different stars had different colors, which were related to the rate of nuclear reactions within them. Naturally, the frequencies of the light they emitted were different as well.
Take the Sun, the star in the Solar System. It was a middle-aged star that gave off white light. This stage was called the main sequence phase.
Among stars at the same stage, the colors were most varied—blue, green, yellow, cyan, and so on. They were all young and active, with no major problems for at least hundreds of millions of years. They could continuously give off light and heat, providing the possibility for life to emerge within their Planetary Systems.
But once they passed this stage, stars gradually began to decline, turning redder and dimmer.
Stars were essentially Nuclear Reactors. When the hydrogen within them was exhausted through fusion, their internal temperature and pressure rose to a certain level, and the stellar core collapsed, causing the temperature to increase further. This process continued until the Sun fused helium into carbon.
At that point, the star expanded and entered an extremely unstable state, swallowing other planets in its planetary system and bringing doomsday upon living creatures.
In his previous life, Su Ming had watched disaster movies about the Sun, such as "Knowing" and "Sunshine." It was roughly like that, only definitely more severe and more hopeless.
After the expansion and eruption came cooling and silence. Depending on their mass, these stellar "corpses" became different celestial bodies—White Dwarf Stars, Neutron Stars, black holes, and so on. That was beside the point, so there was no need to mention it.
In short, Rao, the star Krypton once possessed, was such a Red Sun with feeble heat. The fact