Su Han was completely stunned at this time.

The system is very clear about what it said.

There is a wave of aliens going to attack the earth.

And I need to wait before the aliens come.

Build a spaceship to escape.

No!

How could I be so unlucky!

Su Han didn't know what to say at this time.

A alien spacecraft that can wander between stars will be built within fifty years.

Thinking about it, it is almost impossible.

Because the most advanced rockets in his hands now can only sit around a hundred people.

Want to escape across the stars.

At least tens of thousands of people are needed!

Even if a spaceship with tens of thousands of people can be built, it should not be able to fly.

Even if you have the ability to build the spacecraft directly in space.

It is difficult to push this spacecraft than to climb to the sky.

Although Su Han has the best ion engine capability in the world.

But at most it can push the rocket to more than 100 kilometers per second.

The problem is that even if he can push the rocket to one ten thousandth of the speed of light, it will be useless.

Because the stars closest to Earth are also several light years away.

Even one tens of thousands of years can it take to fly to the speed of light.

Even if he flew to this speed, he would become a mummy.

Su Han is naturally a little overwhelmed now.

Unexpectedly, something happened.

The key is that you can’t discuss this kind of thing?

Because the system does not allow anyone to tell.

I wonder if this dragon is considered a human?

Su Han thought about it and decided not to take risks.

But don't say it straight.

It can still be discussed around the bush.

After all, it is impossible to build a spaceship so big that it is impossible to make others completely unaware of it.

Su Han thought of this: "Dragon! You said if I planned to build a spaceship that could span the star system, is this possible?"

Shenlong said: "It is logically impossible."

"Why do you say that?"

"Because the distance between stars is in light years. With the existing technology on Earth, the spacecraft can only increase the speed of light by one ten thousandth of the speed of light. At this speed, even if it is flying to the star system closest to the solar system, it will take tens of thousands of years. Humans cannot withstand such a long flight, either mentally or physically, and robots can do it."

Su Han frowned and said, "Isn't there such a hibernation warehouse in science fiction movies? Can't you complete the interstellar journey by sleep?"

Shenlong said: "The problem is that reality is not a science fiction movie. Nowadays, human research on metabolism is almost zero, especially the rules of protein and liquid regulation in deep sleep states, so it is impossible to complete the so-called deep space sleep technology in a short period of time. And even if you have this technology, it is useless. Because deep space sleep is just to slow down the metabolism speed and cannot be completely stopped. It may not be a big problem for hundreds of years. It is impossible for tens of thousands of years."

I have to admit that Shenlong said it is fine.

But Su Han is different now.

He has the opportunity to open up advanced technology.

So he doesn't think he can handle the deep space sleep technology.

Su Han thought of this: "What if we can't talk about deep space sleep technology? Just consider it from the perspective of spacecraft?"

Shenlong said: "That's not very likely. Even if you don't consider the time issue, you need a spacecraft and population that is large enough to complete the internal cycle. At least it must be able to carry tens of thousands of people. The weight of a spacecraft of ten thousand people may be as high as tens of thousands, or even hundreds of thousands of tons. Such a large spacecraft will definitely not be built on the earth. Because even if it is built, it cannot be flying. It can only be built in low-Earth orbit.

I want to build such a large spacecraft in low-Earth orbit.

Then there is a space elevator technology.

With the current material technology of the earth, such a huge space elevator cannot be completed.

And even if you can complete the space elevator.

It is impossible to build such a large spacecraft in low-Earth orbit, and it is impossible to make others unaware of it.

Countries around the world cannot accept that their bosses can build such a huge spacecraft.

In fact, this may cause a global storm, or even a war.

So the boss at the political level cannot complete the construction of such a huge spacecraft."

Su Han nodded when he heard this.

Want to build such a huge spacecraft in Earth orbit.

It is impossible to support a living politically.

Even if the senior management supports him, it is impossible for him to build such a huge spacecraft.

unless……

Unless it is not built on earth.

Moon?

Sure, not possible.

Too close to the earth.

Mars?

Mars can.

But the goal is not small.

If you transport a large amount of resources from the Earth to Mars.

It is impossible to hide it from other countries.

Because countries have their own satellites in Mars orbit.

So it is impossible to build a spacecraft on Mars.

It is possible unless you go further?

Su Han thought of this and said, "Dragon! You said that if I wanted to build a plank road openly and secretly travel to Chencang, I was using the excuse of immigrating to Mars on the surface, but in fact, I built a spaceship in another place. Which planet do you think is more suitable?"

Shenlong said: "If it is a planetary place, then only Mercury. Mercury is closer to the sun and has strong light. It should not be easy to be discovered when building a spacecraft. Moreover, Mercury is small in size. If it is built a space elevator, it is much less difficult than the earth. More importantly, Mercury has a large number of rare metals on it. It is of great help to build a spacecraft. The only problem is that the temperature difference between day and night is large. There are high requirements for the quality of materials. After all, high temperatures can easily cause mechanical problems. The durability of the equipment will be much worse.

Of course, there are some larger satellites that meet the conditions, such as Io, Io, and Titan. Of course, there are also some dwarf planets, such as Ceres between Fire and Wood, etc.

But I think the best thing is Mercury. Although Mercury has a relatively high temperature, there are still suitable places. For example, at the sunlight junction of Mercury's Arctic and South Pole, the temperature difference is much different. Moreover, there are huge craters in the Arctic and South Pole. These craters form cold traps. You can also try to build a base in the crater."

Su Han was also very satisfied with Shenlong’s suggestion.

For Su Han, building a spacecraft requires a lot of resources.

Although the satellites of those large planets are not small in size, they are still much worse than real planets.

Especially Mercury, a planet with relatively high metal content.

The question now is whether the advanced technology the system gives itself is enough to build a spacecraft that sails across star systems.

If the spacecraft is built using the current technological level on the earth.

This is no different from suicide.

Su Han thought of this and opened the skill list.

I found that all skills have been activated.

Including intermediate mathematics, intermediate physics, and intermediate chemistry in basic disciplines.
Chapter completed!