How long does it take for human beings to go to the "planet that resembles the most earth"?

"Gliese 581"This planet is at the closest distance as the planet that is most similar to the Earth at the present time and the average temperature is 0 to 40 degrees and water can exist as a liquid, so the possibility of existence of life forms It is almost certain that it will be an important planet in exploration outside the solar system in the future.

This "Gliese 581", the diameter is 1.5 times that of the Earth, the gravity is stronger than the Earth, and it is presumed that the surface is covered with rocks or is covered with sea like the Earth. A joint team of Switzerland, France and Portugal discovered using La Chiya Observatory 3.6 m telescope installed by European Southern Observatory (ESO) in Chile.

How far is it? The direction is towards Libra, the distance is 20.5 light years. I do not know whether it is close or far away, so I tried calculating a bit for how many years it will take with the current technological capabilities of humanity.
Asahi.com: "Earth-like planet" European astronomical observation Discover the rocks and the sea on the surface - Science

ESO 22/07 - Astronomers Find First Earth-like Planet in Habitable Zone

This is a forecast of "Gliese 581". It looks red is a red dwarf, the distance is as close as 1/14 of the distance between the sun and the earth. However, not only is the size smaller than the sun but also the temperature is low, the surface of "Gliese 581" is expected to be suitable temperature.


This is a picture of the "Gliese 581" of the real monster which is currently observed.


The direction is toward the Libra, the distance is 20.5 light years. It is the unmanned satellite Voyager 1, which aims to be out of the solar system, which is the fastest thing human beings have ever made, and the speed is 17.2 km / s. On the other hand, light is about 300,000 Km per second (108 million Km / h), which is fast.

In the past I saw Centaurs' s Alpha star in the distance of 4.22 light years73 thousand yearsIt seems to be. Up to this "Gliese 581" is 20.5 light years away from the Earth, so it will take about 350,000 4620 years to calculate ... ... It is necessary to develop something tremendous technology to immigrate, this is.

By the way, as a theoretically possible thing,Nuclear power promotionIt was said that in the past it could also proceed with a tenth of the light if you use it. In this case it will be possible to arrive at "Gliese 581" after 205 years, so it seems like there is a possibility, but if you accelerate so farVarious problems come upSo realization is slightly impossible.

In this way, it is said that they are coming to Earth as being aliens or extraterrestrial intelligent life forms, so that it is no longer a tooth-proof science power in humanity degree ... ....