7 truths are extremely unbelievable about the world, but you are not sure

Knowledge changes over time, only the truth is always lasting. And historically, there have been facts that have been there for a long time and we still don't know.

Even when science has found and proven, not many people understand. And below are some of these facts, compiled from a number of reports produced by National Geographic.

1. What does the top of a pyramid look like?

Egypt currently has more than 100 large and small pyramids discovered. In it, the largest is the pharaoh Khufu's tomb. But have you ever wondered what the top of the pyramid looked like? If you wonder, the answer is the rock in the picture above.

Pyramid peaks often have a rock called "Benben". On Benben there are some motifs engraved, usually ancient Egyptian characters representing reincarnation and praying for the king's soul.

2. Give a canary to chili, it will turn orange-red

Everyone thought that canaries should be yellow - like their name. But no! Canary's body has pigments concentrated in the wing area, allowing the ability to change color depending on the environment and diet.

A bird's nest with a lot of sun exposure will have shiny yellow fur. But if you feed him a lot of chili, the fur will turn to orange red.

And be assured, spicy chili peppers but not harmful to this bird. In contrast, it is also an extremely nutritious vitamin source.

3. There are seas like Photoshop

In fact, this phenomenon is not mysterious, it's not too rare, it's just that we don't know. That is the sea intersection - cross sea , occurs when two waves of waves move towards each other at an oblique angle. And if the angle is close to 90 degrees, we will have a block of squares like this.

Typically, the phenomenon will occur when waves in a weather system encounter waves of another system.

This phenomenon usually occurs in large seas, in areas far away from 2 weather systems and is quite a dangerous phenomenon. Because when they intersect, they form very dangerous areas that can sink boats.

4. King Tutankhamun's beard

You may not know, the mask of the face with the face and the beard below is one of the symbols of Egyptian pharaoh. It was even included in the top 10 icons of world civilization. Many of the later works on ancient Egypt were inspired by this mask.

However, the mask was no longer the same. Discovered in 1922, there was nothing to go through many battles. Yet in 2014, the beard was broken by negligence of the staff at the Egyptian museum.

The group then tried to hide it by re-attaching the beard to the glue, but ended up causing more damage to the entire mask. Things broke down in 2016, and the whole group had to stand trial.

5. There are no rainbow colors

Not every rainbow has to be colored. There are cases where rainbows have no color at all, and they are called.

White rainbow is a very rare phenomenon. It only appears when there is fog (not rain like a normal rainbow), but more importantly the dewdrops must have a very small radius, maximum of 0.05mm.

Interestingly, the white rainbow can also appear at night, at the time of the full moon.

6. GPS is not free as you think

We still use GPS technology in a comfortable way to locate the route on the map. Completely free, as long as there is a network available.

But know what, GPS is a navigation system of 24 giant satellites. And to operate and maintain them, every year the US government has to spend 750 million USD, equivalent to 2 million dollars per day.

No company or individual benefits from GPS. However, according to experts, the benefits of GPS are reflected in the fact that it reduces the consequences of natural disasters for the economy.

7. The Sahara used to be a clear green forest

Today's Sahara is hot, dry and deadly. But according to experts, only 6,000 years ago, the entire desert is still lush, lush, grass-like meadows like forests today.

The reason is because of the climate change process! And according to experts, every 23,000 years, switch once: from dense forest to desert and vice versa.

In other words, according to the rules, 18,000 years later we will have "Sahara forest", instead of the desert today.