"universe"

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

For humans, the universe is too dimensional for us to see the details of its depths for the time being

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 theory, when a civilization develops into a civilization that can cross the stars, there is basically no risk of extinction

It has long been discovered in practice that the phenomenon of "gravitational time dilation" does exist

Although the Earth is just a "grain of dust suspended in the sun" in the universe, for us humans, this "grain of dust" is irreplaceable.

There are many rumors that Pluto is a terrible world, where the temperature is so low that no life can survive, and even if there is life, it may be some extreme virus, so how terrible and unusual is Pluto?

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

Proxima, a slightly smaller red dwarf than Ross 508, has been frequently observed by astronomers as a giant flare in the past.

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?