Science

Although ultra-pure water does not exist in nature, humans can prepare it themselves

The Arecibo Radio Telescope in the United States used to be the largest radio telescope in the world, with a diameter of 350 meters. As the most powerful radio telescope ever built, scientists have achieved many scientific results with the radio Arecibo radio telescope in the past decades

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

Prehistoric civilization have always been the talk of the town, and it's no wonder - after all, humans have been around for so short a time in the history of the planet that if we were to compress the history of the planet into a single day, then humans would probably only appear in the last two minutes of that day. In the past, there have been frequent claims of the discovery of suspected prehistoric civilization, the most notable of which would be a two-billion-year-old nuclear reactor.

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

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.

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

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

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

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