Science

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"

In the past days, scientists have been working on the study of meteorites, and as the research continues, there is more and more evidence that life should originate from outer space

There is a view that the reason why the Earth looks round is because of the role of the Earth's oceans, which simply means that a large amount of seawater has "filled in" the undulations of the Earth's surface.

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 make the space station in space into a ring and let it rotate, then the humans in it will also feel the "centrifugal force" to "push" themselves towards the outer wall of the space station

In the macroscopic world, the solar system is a system of celestial bodies centred on the sun, in which the vast majority of mass is concentrated and the major planets orbit the sun, while in the microscopic world, an atom is a microscopic system centred on the nucleus of an atom, in which the vast majority of mass is concentrated and electrons orbit the nucleus.

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

Theoretically, life can take many different forms, such as silicon-based life, sulphur-based life, carbon-based life, amino-life, hydrogen-based life, etc. However, so far we only know that life exists on earth, and all known life, including us humans, is carbon-based.

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

Since gravity is actually a manifestation of gravity, and the magnitude of gravity is proportional to mass, for those objects with smaller masses, their own gravity is smaller