Han Du had already returned, and the man stood on the opposite side of the river bank and stepped over.

"Brother Han, you're back, Captain Yu made a slip of the tongue, don't worry about it." Sun Zichao hurriedly caught up, and Han Du's return made him feel good.

Han Du could naturally guess why he welcomed him so much, of course, he wanted to take him out of this dangerous cave as soon as possible. But this is also human nature, after all, Sun Zichao's first expedition was a medium-difficulty task.

Yu Shengnan threw another freshly dried cigarette to Han Du and said, "Look at you are also a smoker, sit down and smoke and say, what's the situation over there?" After saying that, he continued to roast another cigarette.

Han Du's lighter couldn't be used when it got into the water, so he just sat down and lit his own cigarette on the flame of the cooker, Sun Zichao came over and said with a smile: "Sister Yu, can't you see that I smoke too?" Follow me. ”

Yu Shengnan looked at him with some disgust, and said with a straight face: "Of course I saw that you were a smoker early on, and it wasn't for your good if you didn't give it to you, if you don't learn well at a young age, what kind of cigarettes do you smoke." But he took out a wet cigarette and threw it to him, and let him dry himself.

The grandson was overjoyed, and put the wet smoke close to the cooker to bake the flame, and did not forget to defend himself in his mouth: "Sister Yu, here I must solemnly declare that I have reached the age of 18 and am already an adult!" ”

"What about 18 years old, isn't it just that Mao has just grown up, and in the eyes of my sister, he is a stinky boy who has not dried up." Yu Shengnan sucked the cigarette in his mouth, but his eyes looked at Han Du, and a puff of smoke spat into Han Du's face, "Say, what's the situation over there?" ”

Han Du waved his hand to disperse the smoke and said seriously: "There is good news, when I was looking for the leopard, I accidentally found the next layer of the cave, which is the same as the Peach Blossom Spring, especially the top of the cave is covered with glowing crystals, which are priceless at a glance." ”

Han Du's words immediately attracted the attention of others present, and Cui Kai and Lao Huang also moved closer, curious about what kind of peach blossom paradise it was.

Han Du opened his mouth and wanted to use all the gorgeous words to describe the magical scenery inside, but he held back for a long time and didn't say a word, and finally spread his hands and said: "It's indescribable, you can see for yourself." ”

Yu Shengnan and the four of them were speechless for a while, big brother, just say the last sentence directly, causing them to look forward to it for a long time in vain.

Now it's fine, the five of them immediately packed up their things and went to the cave with Han Du.

When they arrived at the end of the cave in the cave, Yu Shengnan, Cui Kai, Sun Zichao, and Lao Huang all looked at the huge cave space in front of them with surprised faces.

"How, isn't it indescribable?" Han Du, who was behind the four of them, asked with a smile.

"Indeed, Brother Han, you didn't lie to us, this scene can only be compared to the fairy world!" Sun Zichao's face was full of convincing.

"Han Du, see those spars at the top of the cave, do you know what kind of stone they are?" Yu Shengnan said this, obviously knowing these spars.

"If you know, just say it quickly, we'll go down and have a look in a hurry." Han Du urged.

"These spars, also known as fluorite, are a mineral whose main component is calcium fluoride, which fluoresces like fireflies when exposed to ultraviolet or cathode rays, but when fluorite contains some rare earth elements, it emits phosphorescence. I've been exposed to fluorite in some caves before, and it's the first time I've seen such a large area, and in fact, most of the night pearls we know are made of fluorite. ”

Yu Shengnan basically said professional terms, Han Du only understood a rough idea, but when it came to most of the night pearls were made of fluorite, he felt that it was much easier to understand, after all, the night pearls had heard it since he was a child, and he was very familiar with it.

"Excuse me, how does fluorite glow?" Han Du was still a little puzzled, and couldn't help but ask, in fact, he also wanted to test how extensive Yu Shengnan's knowledge was as a professional explorer.

"Very simply, the electrons in fluorite will enter the high-energy state from the low-energy state under the stimulation of external energy, and when the external energy stimulation stops, the electrons will turn from the high-energy state to the low-energy state, and this process will emit light."

Han Du couldn't understand these professional terms even more, and for the first time in his life, he knew what it meant to be unclear.

"Brother Han, what she said is in the clouds, no one knows if she made it up herself, anyway, we don't understand what she says, don't believe it easily, many of my buddies used to have this problem, and they didn't blush and beat their hearts when they covered people."

Sun Zichao's reminder seemed to have some truth, but it immediately displeased Yu Shengnan, she glared at Sun Zichao fiercely, and said in a deep voice: "The old lady never lies!" ”

"Okay, okay, I can testify, what our captain said is professional knowledge, if you don't believe it, you can check the information about fluorite on the Internet, it should be similar to what she said." Cui Kai immediately came forward to "persuade", but he seemed to have doubts, pointed to the bottom of the cave space and said, "Captain, you see, there are a lot of green plants below, there should be no sunlight shining into this huge cave space, could it be that they grow through the light emitted by fluorite?" ”

As soon as Cui Kai reminded him, everyone immediately realized that the appearance of these green plants was very strange, and everyone knew that the growth of plants could not be separated from sunlight.

Yu Shengnan pondered for a while, and finally looked at the dazzling fluorite on the top of the cave and said: "There is a possibility, fluorite is formed in the natural environment, its composition is very mixed, maybe the fluorite here is mixed with some special elements, so that the light it emits is similar to the sun, and because of this, the plants below can grow and survive." ”

Yu Shengnan's analysis is very reasonable, Sun Zichao has always had a big brain, and while agreeing with Yu Shengnan's speculation, he suddenly said nervously: "Some special element? Couldn't it be a radioactive element? Look at the strange-looking animals below, they look like they've been mutated by radioactive material! ”

"Possibly, should we stay away from this cave space?" Cui Kai looked at his captain.

Han Du was a little uneasy and depressed in his heart, if there were radioactive materials in it that could not enter, then his mission could only be stranded.

"Don't worry, I have a radioactive material detector in my backpack, wait for me to test it."

Sure enough, he is a professional explorer, and he really has everything in his bag, Han Du sighed secretly.

Yu Shengnan immediately took out a drone from his backpack, on which a radioactive material detector was mounted. Controlled by her remote control, the drone flew out and flew up and down, left and right along the huge cavern space.

In the end, she took back the drone, and Han Du and the others all came over to look at the detection record above, and under the large amount of data recorded, Han Du saw the final conclusion of the detector:

Alpha Ray 1.5

Beta ray 3.125

Gamma rays 0.14

Neutron ray 0.035

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