Since Dong Chen appointed the asteroid belt to become the sword-bearing guard of the current earth civilization, Xiaoxing ...... Uh, little band...... No, it was the asteroid belt that began to exercise and practice martial arts without interruption.

In order to one day be able to use his martial arts to protect the earth civilization from being harmed by foreign civilizations, and to attack the foreign civilization so that it no longer dares to fight the idea of the earth civilization.

Of course, it is definitely not the asteroid belt itself that can hit the enemy, and Dong Chen can't command them, here we are talking about the "robots" on the asteroid belt.

The self-growth of intelligent machinery and equipment is quite fast, especially after receiving clear instructions and having the first manufacturing base, they can show amazing explosive power in the shortest possible time.

Since the construction of the first manufacturing base began last fall, almost half a year has passed now, and the asteroid belt has been quite busy, and many ships have been built.

Correspondingly, with warships, reconnaissance equipment for finding targets was also built, and the surrounding of the solar system was seen in a tight manner.

There are many versions of how humans determine the boundaries of the solar system, each with its own opinion.

Historically, before the discovery of astronomical telescopes, our knowledge of the boundaries of the solar system could only reach Saturn, so at that time Saturn's orbit was the boundary of the solar system.

Later, in 1781, Uranus was discovered, and the boundaries of the solar system expanded to the orbit of Uranus.

In 1846, Neptune was discovered, and the boundaries of the solar system expanded to Neptune's orbit.

Later, with the discovery of Pluto in 1930, the boundaries of the solar system expanded to Pluto's orbit again.

As a result, Pluto was kicked out of the ranks of planets after only a few decades of planets.

At the end of the last century, as the Kuiper Belt beyond Pluto was studied, the boundaries of the solar system were expanded to the edge of the Kuiper Belt at 30 to 50 AU.

Later, astronomers discovered many ecliptic discrete objects, and the boundaries of the solar system were further expanded.

In addition to using the orbits of the planets as the boundary of the solar system, there is also a theory that the maximum range of the solar wind is used as the boundary of the solar system, that is, the heliopause.

Of course, don't get me wrong, this is a serious astronomical name.

Although I usually brag that I can do anything, I can't do it.

The space between the stars is not empty, but is filled with low-temperature interstellar medium particles, which the sun constantly blows outward, called the solar wind.

The so-called heliosphere is the maximum extent in which the solar wind acts.

When high-velocity solar wind particles meet interstellar media particles, they push them outward, gradually slowing down themselves until they are unable to compete with interstellar media particles.

Figuratively speaking, the heliosphere is like a bubble blown outward by the solar wind, and the heliosphere is filled with solar wind particles, and beyond it is interstellar space dominated by interstellar medium particles.

The outermost boundary of the heliosphere is called the heliopause.

At this time, the boundaries of the solar system officially entered the astronomical unit distance in "hundreds", because the distance between the heliosphere and the sun is almost 100 astronomical units.

Moreover, the shape of this heliospherical roof is not a regular sphere, but an egg shape, which can reach hundreds of astronomical units at a relatively long distance.

When Voyager 1 crossed the heliopause in 2013, many astronomers announced that Voyager 1 had flown out of the solar system.

But other astronomers disagree, because they believe that the boundary of the solar system is even farther away, and that is the Oort cloud.

At this time, the edge of the solar system was directly supported to the distance of the astronomical unit in the unit of "10,000", and even officially entered the light-year distance sequence.

The Oort cloud is a hypothetical spherical cloud surrounding the solar system, filled with many inactive comets, and is also home to many comets that have no end in sight.

Astronomers generally believe that the Oort cloud is the remnant of the nebula that formed the Sun and its planets 5 billion years ago and surrounds the solar system.

It is about 50,000~100,000 astronomical units from the sun, and its maximum radius is about 1 light year.

That is, the radius reaches about a quarter of the distance between the Sun and Proxima Centauri, the nearest star.

In this way, the solar system is about a spherical shape with a diameter of two light years, and it is conceivable that the solar system is huge.

In addition to the Oort cloud, some scientists also consider the gravitational extent of the sun as the final boundary of the solar system.

Knowing that the distance between the Sun and Proxima Centauri, the nearest star, is 4.3 light-years, then the gravitational pull of the Sun will be at least half of that range.

In this way, the radius of the solar system would reach two light-years, which makes the solar system even larger.

If Voyager 1 wants to fly out of the solar system, it is estimated that it will take tens of thousands of years.

Of course, Dong Chen is not in charge of these controversies in the astronomical world, he is the most practical, because the maximum warning range of the detection equipment he uses is one light year, one light year in each of the four directions, so it is basically a firm look at the solar system.

But on the other hand, this point of light has reached outside the solar system?

What exactly is it?

“…… There are two possibilities, the unnatural possibility and the natural possibility, sir. ”

After eating, No. 1, who returned to the laboratory, gave Dong Chen a detailed introduction to the situation.

"The first possibility is spaceflight equipment built by intelligent beings, such as spaceships."

"Judging from this point of light, they should only have one spaceship, but according to the proportion, this spaceship should not be small, it may be an interstellar mothership, and the firepower should not be underestimated."

"If we don't understand what they are coming from, it's best for us to be prepared for defense, so that we don't lose the initiative in the first place."

"Well, defense preparations have indeed been made," Dong Chen said after looking at the three comparison charts repeatedly, "Is there any more specific data now?" For example, what is the speed at which it is traveling? ”

"It's not clear yet, sir, it's only known that it's close to the solar system, and the exact speed needs to be collected for effective calculations, only that it doesn't reach or exceed the speed of light." Number One said solemnly.

"It hasn't reached the speed ......of light," Dong Chen said with a deep groan, knocking on the table, frowning, "Then this spaceship may not be as big as we thought, and this reflected light point is just that they have unfurled their light sails." ”

"Maybe it has two energy systems, one from inside the spaceship and one from the outside of the energy source, plus the speed doesn't break through the speed of light, if it looks like this guy, this guy might be a weak chicken."

"Yes, sir," said One, "this assumption is also in my plan. ”

"This is not a natural possibility, but what about a natural possibility?" Dong Chen asked again.

"Another possibility is that the bright spot may be a red dwarf, or a brown dwarf."

"One ...... Large celestial bodies at the edge of the solar system? It could also be a star. Dong Chen hurriedly asked, "How do you say it?" ”

"Yes, sir, the possibility comes from a human hypothesis," One explained, "that the sun is not alone, but that there is another companion star, and what we see now may be it." ”

"You mean...... Nemesis, Nemesis, Nemesis?! ”