3 knowledge from the baby thought the truth, but ... not very true

Our understanding of the surrounding world is really still too humble, even with just the closest things.

Thanks to the continuous advancement of science and technology, people are increasingly studying more about everything around them. And sometimes, many people feel that there is not much secret in the world.

However, knowledge is always infinite, only human beings are finite. The more you learn, you will find that even things that seem to be true that we think about, turn out to be "wrong".

1. Planets in the Solar System orbiting the center are the Sun.

Today, when we look back on the past, we can find it funny for those who believe in "geocentric theory" that the Earth is the center of the universe, and every celestial body including the Sun revolves around the Earth.

Thanks to the scientists' demonstration efforts, in which Copernicus and Galileo stand out in the 16-17th century, now it seems that only a small number of people still think the Earth is the most cosmic. In fact, the Sun is the center, and the seven planets revolve around it.

The popular Solar System model we know.

However, this conclusion is still wrong because the Sun is not a giant sphere lying in the center of the system. By contrast, the Sun itself rotates - albeit very slowly, and all revolve around the "barycenter" between the Sun and each planet.

Imagine the dance between the Sun and the planet like motion in the weightlifting. When athletes swing dumbbells, not dumbbells around athletes but both of them revolve around a central focus, and because the body mass is many times larger than dumbbells, the focus will be near More towards the athlete.

And this is the real "dance" between the Sun and the planets.

Because the mass of the Sun is very large compared to the Earth, it is possible to "temporarily" recognize the Earth around it. But actually, the center of rotation is not in the center of the Sun. In addition, when the Earth turns, the Sun only wobbles a little.

However, with giant planets such as Saturn or Jupiter, the Sun's rotation around the center will be much clearer.

2. Gravity is zero when we go out into space

The common figure in space fiction films is the astronauts hovering over the gravityless environment.

Gravity always exists everywhere in the universe.

Images are not wrong. The thing is, it is wrong to call this "gravityless" environment. Because gravity always exists everywhere in the universe. That is to say, it must be called a "micro-gravity" environment.

Without gravity, the Earth could not hold the Moon in orbit, or distant astronomical objects such as Pluto had long since flown away from the Solar System.

The feeling of "gravity " that astronauts experience can be compared to the case of people skydiving when they leave the plane. Although the effect of gravity on the dancer does not diminish, but the time of free fall before sprung, even though that effect has been offset by the fall, causing the total force to be 0. And the astronaut turns orbit around the Earth is a never-ending free-fall process.

Without gravity, the Earth could not keep the Moon in orbit.

3. Definition of life

At present, the most " brain " brains of mankind are actively seeking signs of extraterrestrial life by all means, from using giant telescopes to scouring the universe to launching planet exploration robots. other.

The search for enthusiasm is so, but there is a paradox that people are searching for something that they themselves do not understand: "What is life"?

Life?Can I eat it?

Simply think that the cat, the tree, the friend you just met is "alive" . And the stone, the chair you sit in is "not alive".

But things are not so simple, the more they learn, the more scientists see the boundary between "living" and "not living" things not clear, sometimes intertwined.

For example, viruses are entities that do not eat or breathe, do not structure cells, only nucleic acids encased in protein shells. By biological definition, they do not live, but when they enter a living cell, they can replicate themselves, and they can evolve to resist the host's resistance.

Viruses cause great controversy in the scientific world about their "survival".

Even simpler than viruses is the viroid - consisting of only one strand of RNA , or prion - a protein molecule . However, they are still "acting impulsively" in the bodies of much higher organisms such as rhizomes that cause rhizomes in potatoes, and prions that cause mad cow disease.

On the opposite side, with clearly defined "living" objects such as buffaloes, ant colonies or even a group of people, the movement is like a completely inanimate stream of inanimate water.

The entity is clearly seen as "living" as ant colonies, the movement is like a completely senseless flow of senseless water.

So is your other point with a stone that you are living . But what is "life" after all?