Science

Everything we can see in the universe has an internal structure and they are all made up of smaller matter, so what is the smallest matter in the universe?

In essence, sound is actually a wave generated by the vibration of the object, the sound waves in the air is actually a "longitudinal wave"

Earthquakes are a common natural phenomenon. On average, millions of earthquakes occur on Earth every year, except that most of them are so mild that they are largely imperceptible to humans.

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

The solar system is a system of celestial bodies kept in motion by the sun's gravity, which means that all bodies within the effective range of the sun's gravity are part of the solar system, so by this definition, how large is the solar system?

The "four great beasts" of physics actually exist only in thought experiments, and their proposal helps to develop and improve the relevant theories

If mankind can master the method of extracting uranium from seawater in large quantities in the future, there will be enough uranium on the earth to last for tens of thousands of years, even hundreds of thousands of years!

In the evolutionary history of human beings, the gradual increase in brain volume is an important marker

The reason we don't see time travelers is actually because they are not in our timeline

The more "nucleons" an atomic nucleus contains, the greater its mass, but scientists have found that the average mass of the "nucleons" of different elements is different