"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

NASA's Jet Propulsion Laboratory's Near Earth Object Research Center has such a database, which is called the "Fireball Database."

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

Nowadays, Mars is obviously unsuitable for direct human habitation, because the environment of Mars is very different from that of Earth, such as Mars is unusually arid, desolate and without a trace of life. Despite this, scientists are still keen to explore Mars

Earth is the only home we have in the universe and the only planet we know of so far that has life on it, and because of this, we usually think of it as a perfect planet.

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.

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

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 legendary prehistoric civilization is not the only one "Atlantis", then this mysterious "yellow brick road" could be the remains of some other prehistoric civilization left behind?

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