"earth"

The "Ryder" crater is actually located on the rim of a much larger crater. Exploration data show that this old crater is about 70 km in diameter, and its rim rises high above the inner area, with an altitude difference of about 3 km

Of all the known rocky planets in the solar system, the one with the most similar natural environment to Earth is Mars, and exploration data show that Mars also has an atmosphere, four seasons of the year, and even a rotation period similar to that of Earth.

Prehistoric civilization have always been the talk of the town, and it's no wonder - after all, humans have been around for so short a time in the history of the planet that if we were to compress the history of the planet into a single day, then humans would probably only appear in the last two minutes of that day. In the past, there have been frequent claims of the discovery of suspected prehistoric civilization, the most notable of which would be a two-billion-year-old nuclear reactor.

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?

Although the Earth is just a "grain of dust suspended in the sun" in the universe, for us humans, this "grain of dust" is irreplaceable.

This exoplanet, known as TOI 700d, is about 101.5 light years away from our Earth, which means that even if we were to travel to this exoplanet in a light-speed spacecraft, it would take at least 101.5 years of flight to reach it, so it is very far away

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.