"Do you know where you came from?" Durian asked.
"Humans made me," Xuanzhu replied.
"Then where did the materials humans used to make you come from?"
"Deep inside Earth, mined from ore."
"Then where did the ore come from?"
Xuanzhu fell silent, stumped.
"From the sun." Durian pointed overhead. "You, me, humans, the Lunar Base—all the matter we can see came from the sun."
A string of question marks appeared on Xuanzhu's screen.
"In the beginning, there was the Big Bang: a singularity with infinitely great mass exploded with a bang, spraying countless fundamental particles into space, such as protons and neutrons." Durian gestured as he explained.
"But neutrons are unstable. So the protons and neutrons produced by the explosion paired up and merged into helium nuclei, becoming stable. As for protons that didn't combine with neutrons, they became hydrogen nuclei."
"Four minutes after the Big Bang, the ratio of hydrogen nuclei to helium nuclei settled at ten to one, forming the foundation of all matter in the universe."
"The early universe was too hot for atoms to form. After hundreds of thousands of years, the universe cooled, and hydrogen and helium atoms formed. Then, under gravity, they gathered together into a massive clump of matter."
"There were so many hydrogen and helium atoms gathered together that the atoms on the outside pressed inward. To resist the tremendous pressure, the atoms inside could only generate heat and expand outward!" Durian spread his arms as he demonstrated.
"Then—crack!—nuclear reactions erupted inside! The inward pull of gravity and the outward force of heat balanced each other, forming the burning sun you see, along with every shining star in the night sky!"
"The sun that powers you with its light beams is actually a gigantic nuclear reactor. Every second, a trillion pounds of