"Human"

How long can humans survive on earth? This is a question that many of us want to know, and i believe that we do not want to wake up to a "Purgatory" Like venus, and hope that the earth can remain alive forever, so that we humans can continue and our generations can survive on earth forever. If the earth's environment were to change drastically and become an extremely hot planet like venus or mercury, then naturally everything in the world, including humans, would not be able to exist.

In theory, when a civilization develops into a civilization that can cross the stars, there is basically no risk of extinction

In fact, the earth's crust itself is a natural source of minerals, many soil and rocks contain a certain amount of salt, careful observation of cattle and sheep should know, cattle and sheep in the grass, but also often "eat soil" or lick the stone, they do so, in fact, the purpose is to obtain the salt

The solar system is a system of celestial bodies kept in motion by the sun's gravity, which means that all bodies within the effective range of the sun's gravity are part of the solar system, so by this definition, how large is the solar system?

It is proposed that birds originated from dinosaurs, and that "ancestor birds" are a transitional species between birds and dinosaurs.

If someone asks the question, are humans alone in the universe? I believe that most people would answer in the negative. In fact, the scientific community also generally agrees that there are a large number of intelligent civilisations in the vast universe, some of which may even be far ahead of our civilisation, and in order to better describe the technological level of intelligent civilisations in the universe, scientists have also proposed the concept of "Cosmic civilisation levels".

Compared to radio messages sent by humans, this method seems to be more suitable for intelligent civilizations to announce their presence in the universe, because this method belongs to the "broadcast" in space, and intelligent civilizations in all directions can be observed

How exactly did such a complex life emerge on Earth? This is a great mystery to modern humans, but we are almost certain that the "birth of life" is a process that has a very small probability of occurring.

The existence of reproductive isolation, so that these situations can not occur, even if there are some individuals of different species sometimes complete the mating, but they generally can not produce offspring, or produce offspring can not continue to reproduce