How big would a piece of paper become if it was folded in half 105 times?

A piece of paper with a thickness of 0.1 mm, which is large enough, is folded 105 times thick, which is 4.6 times the diameter of the currently observable universe! But this does not mean that the universe cannot hold it, because humans do not know how big the universe is!

In this article, let’s use our imagination to explore what will happen if we fold a piece of paper 105 times. How thick can it be? Will it be able to hold even the universe?

We assume that the thickness of this piece of paper is 0.1mm (the thickness of an A4 printing paper is 0.104mm), and that it is large enough to be folded 105 times. We ignore other factors here.

1. Let's start folding this piece of paper and see what happens:

Fold once - 0.2mm

Fold in half 3 times - 0.8mm

Folded 10 times - 102.4mm

If we convert the unit to meters, it is 0.1024 meters. There is no obvious feeling here, it is just a little over 10 centimeters, let's continue to fold it in half:

Fold in half 15 times - 3.2768 meters: This is the height of a one-story building;

Fold in half 20 times - 104.8576 meters: This is the height of the third largest pyramid in Egypt, the Red Pyramid;

Fold in half 25 times - 3355.4432 meters: This is 300 meters higher than the height of Mount Wutai;

Folded 30 times - 107374.1824 meters: The thickness of this piece of paper has reached the top of the Earth's atmosphere, the troposphere. Folded twice more, it will exceed the height of the Chinese space station's orbit;

Fold in half 42 times - 439804651.1104 meters: This is more than the 380,000 kilometers between the Earth and the Moon. If someone asks you a similar question, you can answer him directly;

Folded 50 times - 112589990684.262 meters. The closest distance between the Earth and Mars is 55 million kilometers. A piece of paper folded 50 times can go back and forth between the Earth and Mars.

Fold in half 60 times - about 115.2 billion kilometers: this is the distance that light travels in about four and a half days...

The scale of further folding can only be measured in light years, which is beyond our imagination. Let's directly post a picture and you can check the thickness corresponding to the number of folding times:

At the bottom of this picture, we list the diameter of the observable universe, which is the well-known 93 billion light-years. To give you an idea of ​​this data, let's convert it into meters to get a feel for it:

The thickness of a piece of paper after being folded 105 times is (in meters):

4056481920730330000000000000

The diameter of the observable universe is (unit: meter):

879847933950014000000000000

In other words, the thickness of a piece of paper folded 105 times is about 4.6 times the diameter of the observable universe!

This number is beyond our imagination, but if you ask an astronomer: Does this thickness exceed the scope of the entire universe? Can it reach the boundary of the universe? I am afraid he cannot give you an answer, because humans cannot confirm the size of the universe, and it is possible that they will never be able to determine how big the universe is!

Next, let’s take a look at how big the universe is and why humans cannot currently determine the size of the universe.

2. How big is the universe?

We have mentioned at the beginning of the article that the diameter of the observable universe of human beings is 93 billion light years. The word to pay attention to here is "observable universe", which means that this is not the size of the universe, but only the size of the universe that humans can detect. Beyond this distance, it is not the boundary of the universe.

So how big is the universe? My answer is: I don’t know! Why do I say I don’t know? There are several reasons:

(1) The universe is really big

In astronomy, there is a word called "isotropy", which is used to describe "big". It means that when humans start from the earth and observe the universe in any direction, the observed scene is exactly the same.

Imagine, under what circumstances will the same situation appear in any direction? The answer is that this situation will only appear in the center of a certain space.

However, the earth is not the center of the universe, and "isotropy" also occurs. Then there is only one possible explanation, that is, the universe is too large, so large that we cannot confirm the location of the earth at all.

(2) 93 billion light years is only the diameter of the observable universe

The diameter of the observable universe is 93 billion light-years and the radius is 46.5 billion light-years, which means that humans can observe things 46.5 billion light-years away from the Earth.

But in fact, the celestial bodies that humans can see are only 30 billion light-years away from the earth. The farther distance is calculated through gravitational waves, and the measurement limit is 46.5 billion light-years.

We cannot observe places farther away, not because human technology is not advanced enough, but because light from farther away has not yet reached the earth. This is due to the limitations of the universe itself.

(3) The existence of “recession velocity” means that we may never be able to determine the size of the universe.

Have you ever thought that in the universe, some things change faster than the speed of light? Here we need to introduce a concept: recession speed.

In astronomy, the speed at which a celestial body moves away from us due to the expansion of the universe is called the recession velocity. Of course, it must be emphasized here that the recession velocity is not the speed of movement of the celestial body, but the change of the universe, which is allowed to exceed the speed of light.

The recession speed is not only related to the expansion rate of the universe, but also to the distance. For the same expansion rate of the universe, the farther away from us, the faster the recession speed will be.

If a celestial body is very far away from us, so far that its recession speed exceeds the speed of light, then any information sent by this celestial body will never be able to reach the earth.

What is this distance? According to scientific calculations, when a celestial body is more than 62 billion light years away from the Earth, its recession speed will exceed the speed of light.

That is to say, if the radius of the universe with the earth as the center is greater than 62 billion light-years (the diameter is more than 124 billion light-years), then humans will never be able to know the size of the universe!

So, if a piece of paper is folded in half 105 times, can the universe really not hold it?

The thickness of a piece of paper folded in half 105 times is 4.6 times the diameter of the observable universe, but this does not mean that the universe cannot accommodate it.

Since we don't know how big the universe is, the answer to this question is:

have no idea!

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