Scientists often say that the earth under our feet is the only home of human beings, but astronomers do not think so, because the earth and the entire solar systemAt the end of the day, it's just one part of a hundred billion times the Milky Way.
Taking into account star types and habitable zone ranges, astronomers conservatively estimate that there are at least 20,000 Earths in the Milky Way, as well as several star systems with multiple planets such as the Solar System, with the Tau Ceti Galaxy and its potential planets always being the focus of astronomers and science enthusiasts.
The galaxy was on astronomer's radar back in 2012, when it was discovered that there were 5 terrestrial planets in its vicinity, 2 of which were located within the stellar habitable zoneAnd Tau Ceti itself is a yellow dwarf similar to the SunThere are no signs of a supernova explosion at all, which means that the planets in its vicinity will have a steady stream of energy** and plenty of time to give birth to life and even evolve civilizations.
The current scientific community believes that life on Earth originated near submarine volcanoes 3.8 billion years ago, but the history of the Earth is as long as 45500 million years, so the period between the birth of the Earth and the emergence of life is the steady amount of the sun's energy at work, and a similar process is entirely possible in the Tau Ceti galaxy.
The five terrestrial planets discovered so far, generally known as super-Earths, have a mass of about 2 to 7 times that of the Earth, and although they are generally very close to the star, the habitable zone will also be closer to the inner side of the star because the mass of Tau Ceti is a little smaller than that of the SunIn this way, it is normal to have 2 habitable planets.
For these reasons, the astronomical community has been listening for signals that there may be extraterrestrial civilizations on the Tau Ceti galaxy, and if it is only 12 light-years away from Earth, if there really are extraterrestrial civilizations there and have mastered radio technology, then it is possible for us to receive their electromagnetic waves scattered in space.
Compared with a century ago, astronomers only believed that planets existed in the solar system, and now astronomers have admitted that there are a large number of similar solar system star systems in the universe, and almost all stars have one or two planets nearby, and the number of planets in the entire universe, even the number of habitable planets, may eventually be more than the total population of the earth today, so there is no need for human civilization to stick to the earth under its feet.
However, when it comes to leaving the Earth, there is one problem that we can't get aroundThat's the speed of space.
The fastest probes at this stage, such as the Parker solar probe, can reach speeds of hundreds of kilometers per second when accelerated to the point with the help of a gravitational slingshot, but it still takes a week and half a year for the general launch vehicle to go to the moon and Mars, and the payload is very small compared to its own mass and volume, and most of the time is fueled by fuel.
With the current speed of space not even one hundredth of the speed of light, that is, 3,000 kilometers per second, it is difficult to explore the interior of the solar systemNot to mention flying out of the solar system to other planets in the universeTherefore, almost all scientists are looking forward to the advent of controlled nuclear fusion technology, with which future spacecraft can have speed guarantees.
Whether it is a planet in the solar system that is close at hand, or a distant exoplanet, they are just one of the countless planets in the universe, and human civilization, as a civilization with a history of science and technology of only a few hundred years, still has a long way to go in the future.