There were no humans on Earth, so how did the first man come about? Could it be from space?

It's not from space, it's the gradual evolution of cells in nature, into multicellular animals, and slowly, over time, finally into humans.

Adam was the first man on earth, and the second was his wife, Eve, and their descendants sinned with them, blinding the world from knowing that it was God.

It evolved from apes, and after a long period of evolution and gradual adaptation to the environment, it eventually evolved into humans. It's unlikely, as no human-like creatures have been found in space.

So how did the first man on the earth come about, in fact, it was evolved, and there is no particularity, and what many people say is that people were created by the Yellow Emperor, Nuwa created people, plants changed, animals changed, etc., and so on are completely unsupported by evidence, these claims are basically based on rumors, and the theory of evolution is the only thing that human beings can prove and explain today, and nothing else.

What would the Earth be like if there were no humans?

Streets and crops will disappear in the end, country roads will be covered with wild vegetation, and fields will be overgrown with weeds. It will take longer for city streets to disappear, but even city streets like London's will not take more than 50 years to disappear in the end.

Human architecture will also decay rapidly. First, wooden houses will disappear in 100 years, while skyscrapers made of glass and steel will collapse in 200 years, and houses with brick, stone and concrete structures will last longer, but they will also collapse after 1000 years. Although the pyramids have existed for 3,000 years, they will be in ruins 1,000 years after humans disappear.

If not, the bridge might last 200 years, but even the world's largest arch bridge will eventually collapse after 1,000 years. Within 250 years, the dam will also collapse.

Dennis Stevenson, director of the New York Botanical Garden, said that if humans disappear, New York will be completely occupied by alien plants, and there will be herds of wild wolves in New York** parks, and frogs in the beer pools of commercial bars.

The crops are gone.

The plants and crops cultivated by human beings will disappear in one or two hundred years. Thousands of years from now, Earth will return to a prehistoric wilderness. Without air pollution, the walls would be covered with moss, creepers, poison ivy, and carrots, cauliflower, cabbage, Brussels sprouts, cauliflower, and cauliflower, which were once indispensable on the human table, would degenerate into wild vegetables.

Heavy metal pollution left behind by humans is gradually diluted by plant absorption, reuse, and redeposit after hundreds of years, but what is left behind in oil storage tanks and various chemical, energy, and dry cleaning equipment will become a time bomb for contaminated soil.

Megafauna began to appear.

If humans disappear from the face of the earth, most of the 15,589 endangered animal species will recover to staggering numbers. Paul, an expert in paleoecology at the University of Arizona, said: "Megafauna weighing more than 450 kilograms on the American continent would triple the number of animals in Africa today.

In addition, excess carbon dioxide in the atmosphere will gradually dissipate over the next 200 years. In a few decades, the ozone layer will disappear, and the harm of ultraviolet rays will be greatly reduced. In 1,000 years, all the dams on Earth will be filled with silt, and the overflowing rivers will flow into the sea with abundant nutrients, and the vast majority of life in the oceans will be as prosperous as they were in prehistoric times.

Evidence of survival disappears after 200,000 years.

After the disappearance of humanity from the earth, the remains of civilization will disappear in 20,000 years, and in 50,000 years, these relics will become difficult to trace archaeological clues, because glass and plastic will all be dissolved. Only radioactive materials and a few man-made chemical contaminants will persist longer.

Man-made chemical pollutants will also collapse within 200,000 years, and there will be no "human product" to be found on EarthAlthough radioactive materials such as nuclear waste can last for 2 million years, no one will associate them with humans in the vast expanse of the earth.