"earth"

In this 5.5 million-year-old cave, not only is there no sunlight, but the environment is also very harsh

According to our knowledge of known life, liquid water is essential for life. In other words, if there is liquid water on a planet, there is a possibility of life, and it is for this reason that scientists always consider liquid water as the first requirement when assessing the possibility of life on a planet.

The modern Earth's atmosphere is so rich in oxygen that the vast majority of this hydrogen will be re-oxidized to water without escaping from the Earth's top atmosphere

If we dig up all the sand in the Sahara Desert, then we can see the "bedrock" of this desert

This satellite is the communications satellite LES-1. In the 1960s and 1970s, the United States launched several such communications satellites, from LES-1 to LES-9, which were relatively small, weighing only about 32 kg, each with a horn antenna and an x-band transponder, as well as a 237 MHz signal transmitter, which were powered mainly by solar panels

The universe is so big, but man's range is so small that the furthest man has been so far is the moon, which is only 380,000 km away from earth on average. Of course, humans have also launched all kinds of probes, and if you include them, the range of human activities is much larger.

The climate patterns on Earth will then become chaotic, and humans will lose the ability to control and drive the Earth's climate to remain stable and conducive to the habitability of humans and the Earth's biosphere as a whole

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.

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.

Since the discovery of the first exoplanet in the 1990s, scientists have found more than 4,000 exoplanets, some like the giant gas planets of our solar system, and others like earth-like planets. Some exoplanets may have very harsh environments, perhaps as hot as venus or mercury, or as extremely cold as other planets. Of course there are also exoplanets that may have relatively suitable temperatures, may be located in the habitable zone of a star system, are a potentially habitable planet, and may even be a living planet.