"earth"

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.

Titan is the largest moon of Saturn and the second largest in our solar system, even a little larger than Mercury, one of the eight planets. Due to tidal locking, Titan's rotation period and revolution period are the same, similar to our Moon

The energy released by the sun's nuclear fusion reaction, in addition to making the sun shine and heat, there is an important role, that is, to resist its own gravity

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?

The Big Dipper is located in the constellation Ursa Major, and under good observing conditions, we can find them almost every day in the night sky of the Northern Hemisphere. These seven shining stars form a unique spoon shape that is very easy to recognize.

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

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.

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

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.

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