"earth"

In general, when a spacecraft, probe or rocket wreckage re-enters the atmosphere, they are fast, reaching several kilometers per second or even faster

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

It's good news that Earth has regained contact with Voyager 2 after such a long period of loss of control. But somewhat sadly, Voyager 2 is carrying very little battery power left

There is a view that the reason why the Earth looks round is because of the role of the Earth's oceans, which simply means that a large amount of seawater has "filled in" the undulations of the Earth's surface.

The earth has been spinning since its inception and has been doing so for 4.5 billion years now, so why has it not stopped yet?

In orbit for longer and longer periods of time, we need to solve not only inorganic resupply problems such as food, water, oxygen and propellant, but also the various problems faced by astronauts flying in orbit for long periods of time

It has been billions of years since life appeared on earth, and although there are seven planets in our solar system in addition to earth, as well as a number of dwarf planets, moons and other relatively large bodies, so far we have not found alien life on any other planet in our solar system for the time being. Even mars, another earth-like planet in the habitable zone of our solar system, has not found a single sign of life. Could it be that life on earth is really unique and no other planet is allowed to have life?

In the past days, scientists have been working on the study of meteorites, and as the research continues, there is more and more evidence that life should originate from outer space

According to some scientists, the earth itself did not exist billions of years ago, but about 4.6 billion years ago, a giant interstellar molecular cloud gravitationally collapsed to form the solar system. Some dwarf planets, moons, asteroids and other bodies that are somewhat smaller in size than the planets. This is how our home on earth was formed, but in the early days of its formation the earth was not as beautiful as it is today, the newly born earth was shown to be made up of magma, a boiling 'ocean' if you will.

Intelligent life is rare in the universe, or perhaps it is just wishful thinking on our part. As mentioned earlier, just in the galaxy, there are hundreds of millions of planets that have the natural conditions to nurture life, so a reasonable speculation is that life has evolved on many planets, and even a number of planets have evolved intelligent life.