The rhizome system is expanding with full force, upward, left, right, and forward, and the extension distance has reached almost ten kilometers.

　　 Huogu didn't see anything like a support pillar along the way, and his curiosity couldn't help but become more vigorous.

　　 "The air environment is dominated by oxygen, which accounts for 67% of the air..."

　　 This is an astonishing proportion of air. You must know that during the period when the earth's oxygen content is the highest, the proportion of oxygen in the air will only reach 35%.

　　 Fortunately, Hogu can adjust the cells. When other organisms come here, they will immediately cause oxygen poisoning due to inhalation of excessive oxygen.

Huo Gu observes the surrounding environment. To be honest, this super-giant void is flat beyond Huo Gu’s imagination. If you only look at a small area, it is indeed ups and downs, but if you look at it, it is a straight surface. , It doesn't seem like nature can be formed at all.

　　 Even if Huogu's attention shifted to other places, the expansion of the rhizome system never stopped. Vaguely, Huogu noticed a columnar object in front of him.

　　 Support column?

　　 Huo Gu had such a thought.

　　 Hesitated again and again, Huogu did not slow down the covering pace of the rhizome system. Of course, he couldn't relax his vigilance against that columnar object. Huogu was ready to fight at any time.

It’s no wonder that Huogu is a soldier. In this unfamiliar environment, he encountered such strange things, especially when he was pushed into the hollow of the earth by some kind of unknown creature before. Huogu can no longer take the earth from the ancient universe of this planet. The Ming Gu Zhou set in.

　　 After a period of time, the columnar object changed from a vertical thin line to a vertical thin column. Huogu began to adjust the vitreous body of his eyes to the true face of the columnar object.

However, Huogu was disappointed that the pillar was not a solid, but a liquid. It was a water column formed by the falling seawater from the ocean above. Huogu could still see scattered floating motionless from the pool below the water column. The gourd and the titanium snail after losing their autonomy.

　　 "Although these organic materials are not sending charcoal in the snow, it is not bad that they are icing on the cake. Moreover, with this water source, the pressure on the subsequent supply delivery will be much lower."

　　 A cone-shaped creature quickly occupies this water area to collect organic materials in the seawater, and the rhizome continues to spread forward.

　　This kind of expansion continued for a while. Huogu finally encountered the edge of this super-giant cavity, but it was not the front, but the rhizome that expanded above and left and right, reaching the edge at a distance of about 100 kilometers.

　　 The rhizomes that touched the edge temporarily stopped spreading and expanding. Samples of these edge materials were collected and analyzed on the spot. Then, the results obtained complicated Huo Gu's mood.

The left and right sides are standard andesite, andesite, trachyte, trachytee, and other neutral volcanic rocks, but above it is a huge metal surface whose appearance is the same as the metal plates excavated in other holes before. It has become very rough after a long period of time.

　　 Huogu immediately commanded the left and right rhizomes to break open the volcanic rock. As expected, the same metal surface appeared as he continued to penetrate the volcanic rock about one meter thick.

　　 "Analyze the constituent elements of these metals and the half-life time they have experienced."

　　 Repeating what he had done in another underground hole, Huogu got the answer-800 million years, the same time as the metal plate.

　　 is not only time, but also the same elements, but there are subtle differences in proportions.

　　 "It seems that the metal plate should be part of the metal wall here."

　　 "Maybe, this is really an artifact..."

　　 Huo Gu thought for a while, then added another sentence.

　　 "...It could also be a comet that fell on this planet."

　　 Hogu thought of some comets that had been observed, and most of the area was covered with metal.

If it is that kind of comet, when it enters the planet, the metal will become molten due to friction with the atmosphere, completely enveloping the comet. If the comet was still rotating at a high speed when it fell, it would be easy. Form this circular cross section.

　　 This explanation seems to make sense, but later discoveries made this explanation untenable.

　　 The rhizome system that was spreading forward to explore, soon found a very strange place at a distance of about 100 kilometers.

　　 You can see a cube-shaped object, as if it was chiseled by hand, but it is integrated with the ground without any gap.

　　 The place near the cube is a mound. On this mound, Huogu can see a round object like a wheel.

　　 Three columnar stone pillars are placed where the cube and the mound are perpendicular to each other. They are not connected to the dome. They are about half a meter in diameter and three meters in length. They look like test tubes placed upside down.

　　 Just these things, nothing else.

　　 Huogu zoomed in and looked at everything here. It has been basically determined. These are not natural occurrences. The underground cavity it is currently in was created by intelligent life.

Roots analyzed the material of these objects~lightnovelpub.net~ The same as the metal wall of this underground cavity and the metal plate that was excavated, the half-life time is the same. Rather, it is because of this metal material that it can be It spans hundreds of millions of years and is presented to Huo Gu.

At that cube, Huogu used roots to clean up the dust that was attached and agglomerated to form rocks. It is precisely because of the accumulation of dust on a scale of hundreds of millions of years that the cube seems to be connected to the ground as a whole. .

　　 After carefully cleaning the dusty rock blocks, Huogu obtained several geometric figures from the side of the cube, and then it cleaned up several other dust-stacked objects.

　　 After Huogu learned about the situation in the mound through the roots, he was basically sure that the mound was once a vehicle-like means of transportation, but finally could not withstand the erosion of the years, so it became the mound of today.

　　The three stone pillars, Huogu guessed, are some kind of machine, the inside is a hollow structure, and the silicon component occupies one-half of it, and there is no geometrical figure similar to that existing on a cube.

Huo Gu can roughly guess what the purpose of this machine is. People are iron rice or steel. If you don’t eat, you die. In this desolate area where there is no shop in front of the village, this kind of machine not only guarantees food, but also allows intelligent creatures to continue. What can be other than sustaining the state of life?

　　 Regarding the cube, Huogu began to guess that it was a coffin, a dormant cabin, and the like. However, the rhizome could not find a particularly obvious gap in the cube. Obviously there was no such thing as a lid, so the guess was overturned.

　　 The spread of the rhizome to the front is still going on, unable to reach the edge, Huogu will not stop the spread of the rhizome.

　　 About 30 kilometers away from the strange place, a huge cube square appeared in front of the rhizome group, and tens of millions of cubes were displayed there.