"earth"

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

Since there are many lakes in China, many of them have the title of "largest".

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

The 500 trillion ton comet was discovered in 2010 by astronomers Pedro Bernardinelli and Gary Bernstein

The earth's water resistance comes from the high temperature, pressure and density of its interior

A rigorous discussion of the unknown is not possible, so it is necessary to narrow down the universe we are discussing to only the universe we can see

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

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.

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

The earth was born more than 4 billion years ago, when it was very different from the earth of today, one of which is that the environment of cosmic space is more different.