How many degrees did Nezha need to melt the goddess Shiji? Scientific interpretation: At least this number!

Recently, the movie "Nezha: The Devil Boy Conquers the Dragon King" has achieved great success worldwide, with box office revenue climbing all the way and successfully entering the top ten global box office charts. In this fantasy movie, there is a scene that is particularly eye-catching: Shiji Niangniang uses the entire mountain as her body and a giant hand made of boulders to hold Nezha down, while Nezha fights back with the powerful Samadhi True Fire, eventually melting most of the boulders, leaving only a few small stones. This scene is not only visually stunning, but also contains some interesting scientific knowledge. Today, we will reinterpret this wonderful scene from a scientific perspective.

Image source: MV of "It's Nezha"

There are two theories about the true body of Shiji Niangniang on the Internet: one is basalt, the other is limestone. Which theory is more reliable?

Question 1: What kind of rock is Shiji Niangniang?

According to the images in the movie "Nezha: The Devil Boy Conquers the Dragon King" and the analysis of multiple pieces of evidence, the body of Shiji Niangniang is made of basalt , a typical extrusive rock that is black, dense, and hard, and forms pores and almond structures during the cooling process. The following is the detailed analysis basis:

Hair and facial features: Several lines of evidence suggest that Shiji Niangniang's hair was black and had a porous structure, which is typical of volcanic rocks such as basalt. In addition, her face had a distinct almond-shaped structure, which is a characteristic of gases escaping from cooling volcanic rocks.

Physical properties of rocks: The body of the goddess Shiji is made of hard rock, and she left no traces when she broke the bronze mirror with her stone hands, which shows that the rock has a high hardness. Basalt is a common extrusive rock with high hardness and density, which fits this description.

Color and texture: The skin of the Shiji Niangniang is bluish-gray and has a dense texture, which is consistent with the color and texture of basalt.

Geological background: From a geological perspective, the word "ji" is explained in "Shuowen Jiezi" as "water hitting rocks", suggesting the relationship between rocks and water. The name and image of Shiji Niangniang are also closely related to volcanic activity and rock cycle.

Other supporting evidence: Multiple lines of evidence consistently indicate that the rock composition of Shiji Niangniang is extrusive rock among igneous rocks, especially basalt.

Nezha's Samadhi Fire seems to exist only in mythology, but can we explore how hot it is at least? By analyzing the physical and chemical properties of Shiji Niangniang, we can reversely infer the temperature range required to melt the stone, and we will know.

Then, the question of "how hot is the Samadhi True Fire at least" is transformed into: if you want to melt the stone of Shiji Niangniang, what is the minimum temperature required (after all, breaking through the Tianyuan Ding requires everyone's help, and Nezha's firepower cannot be separated)?

Question 2: What is the minimum temperature required to melt basalt? To melt basalt, the minimum temperature required depends on its water content and environmental conditions: Anhydrous basalt: At least 1100°C. Hydrous basalt: The minimum temperature is about 700°C. Mantle environment: The potential melting point is 1400°C to 1550°C. Industrial production: Usually between 1400°C and 1600°C. Therefore, if you want to melt ordinary basalt, the minimum temperature required is 1100°C (anhydrous condition) or 700°C (hydrous condition).

Let's take a step further and think about what chemicals are produced when basalt encounters such high temperatures? When the lava cools, will new rock types be produced?

Question 3: What happens to basalt after it melts? When basalt melts at high temperatures, its chemical composition changes significantly. There is evidence that basalt is mainly composed of silicate minerals, including olivine, pyroxene, and plagioclase. When basalt melts, its mineral components decompose and form a melt, which is mainly composed of silicates, iron oxide (Fe2O3), calcium oxide (CaO), magnesium oxide (MgO), etc. In addition, the melt may also contain small amounts of gases (such as water vapor, carbon dioxide, etc.), which may escape during the cooling process. When the lava cools, it will re-solidify into solid rock. The rock formed after the cooling of basalt lava is still basalt. However, in some cases, chemical changes during the cooling of the lava may lead to the formation of new mineral phases. For example, olivine, pyroxene and other minerals may be precipitated from the basalt melt during the cooling process. In addition, if the lava reacts with the surrounding basement rocks, new rock types such as alkaline basalt may also be generated. Therefore, the main chemical substances after basalt melts are silicates, iron oxides, calcium oxides, and magnesium oxides. When the lava cools, new basalt rocks are usually formed, but other types of rocks or minerals may be generated under certain conditions. In addition, under the premise that the composition has not changed significantly, the products of the re-cooling of molten basalt depend on the cooling rate. If it is cooled slowly, gabbro will be formed; if it is cooled quickly, basalt will be formed. Therefore, it is possible for molten basalt to cool back to basalt. It seems that the saying of Shiji Niangniang, "As long as the green mountains remain, there is no fear of running out of firewood" is still scientifically based!

Review expert: Lv Jian, deputy director of Zhejiang Geological Museum