Is it possible that human natural enemies are on another planet?

Emigration to another planet is a way out and a long-cherished dream of mankind. Stephen Hawking, a famous physicist, said recently that human beings must emigrate to other planets in order to get rid of the fate of extinction. Hawking believes that as long as human beings are trapped on a unique planet, their long-term survival is in danger. Asteroids hitting the earth, nuclear war and other threats will destroy us sooner or later. However, if we expand into space and build self-sufficient settlements, our future should be secure. There is no place like the earth in the solar system, so we must look for another planet. And the use of more advanced space rockets to help humans move to a planet suitable for survival. This is the second time in half a year that he has made such amazing remarks. Griffin, director of NASA, also said that historically, species on a planet cannot survive forever. "We have conclusive evidence that on average, every 30 million years, species on earth will suffer massive destruction; One day we will definitely immigrate to another planet, but I don't know when that day will be. " There are four criteria for immigration destinations. What difficulties need to be overcome and when will it be realized? The first level of immigration: where to move. At the beginning of the 20th century, some people thought that Mars and Venus might be a good choice, but NASA soon found that other planets around the sun were not suitable for our survival. People on the surface of Venus must live at a temperature high enough to melt lead. As for Mars, living on it is like living twice as high as Mount Everest. Dr. Margaret Tenbar, an astronomer at the Carnegie Institution in Washington, DC, summed up four criteria for "the galaxy most suitable for life": 1, at least 3 billion years before planets can form and show complex life; 2. The volume of the central star should not exceed 1.5 times that of the sun, otherwise it is difficult to produce planets suitable for life; 3. There should be enough iron to form Earth-like planets; The central star should be neither a red giant nor a white dwarf, so that the complex life on the surrounding planets can exist for a long time. According to this standard, he concluded that there are five galaxies in the universe that meet the standard: one is CVn, the dog constellation 26 light years away from the earth; The second is HD10307; , 42 light years away from the earth; 3. HD 2 1 14 15, and its metal content is about half that of the sun; The fourth is Scorpio SCO18; ; The fifth one is Pegasus 5 1. Level 2: How do humans get to these planets? According to calculation, Alpha Centauri, the closest star to the Earth, is about 4.23 light years. At the current speed of the space shuttle, it will take 158000 years to arrive. This requires the vehicle to reach the speed of light. The American sci-fi movie Star Trek sets such a background: in the middle of the 20th century, engineer Koklen invented the "warp drive" which can fly faster than light. Because "warp speed technology" is the threshold to enter the galactic civilization family, human beings have been accepted into the interstellar Federation, and the level of civilization has reached a new level. In fact, scientists are moving towards this goal. According to New Scientist magazine, the US Air Force and NASA are currently secretly studying a "hyperspace engine". Scientists expect to make a prototype of "Hyperspace Engine" and test it within five years. Once the "hyperspace engine" is proved to be feasible, it only takes three hours from the earth to Mars, and it only takes 80 days from the earth to the planet with a distance of 1 1 light-year. Some scientists predict that it will be until the 26th century that a suitable spaceship will be made and flown to the destination planet. The estimated arrival time is 12500. The third level: how to solve the problem of life protection after human beings arrive at the planet. The United States, Russia and other countries have cultivated peas, wheat, corn, rice, onions, orchids and other 100 plants on the space station, and animals such as fruit flies, spiders and fish can grow and reproduce in weightlessness. If this technology can be applied, it will be easy to solve the problem of human survival. However, if human beings live in weightlessness for a long time, whether they can reproduce is also a problem. A French scientist found that the important structure of living cells could not be formed normally under weightlessness. This means that human beings cannot live and reproduce in near weightlessness for a long time. However, some scientists say that after human beings settle on another planet, their race and body structure will also change with the environment, and perhaps the problem of reproduction can be completed in another way. It's like returning to earth and moving to other planets. Dr. O 'Neill of Princeton University believes that the best way is to build a space city in space and gradually move all human beings to the space city. After hundreds or even thousands of years of recovery, the earth will become a group of animals without human intervention. Humans can also return to the earth. O 'Neill's Space City consists of a pair of cylinders. The inner wall of the Space City has a natural environment suitable for the growth of plants. There are roads, residential areas, commercial areas, work areas, etc. At one end of the space city is a solar power station, and at the other end is a hatch for parking the space shuttle or spacecraft. Hawking believes that as long as human beings are trapped on a unique planet, their long-term survival is in danger.