# Your Daily Life Becomes Fantastic!!”A TRAVELER” by Hideki Yukawa

Hello, guys! It’s me! Warotan!

Japanese version

This time I introduce “A TRAVELER” by Hideki Yukawa to you.
For the beginnig, I’m not intended to comment on the details but focunsing on

How my daily life has changed by reading it.

### Who is Hideki Yukawa?

For scientific people ( Especially Japanese), the name should give you courage and guts.
This part gives some information of him to people who don’t know.

Dr. Yukawa is the person who played an active role in Nuclear Physics.
Nuclear Physics? It sounds like a difficult and somehow dangerous field, doesn’t it?

However, you might have heard the word “atoms“.
As you may know, we now think that atoms compose all things around us.
Some small balls moving around a large one, yes that’s it.

The center-placed large ball is called nucleus.
You can easily imagine, right?
The Nuclear Physics is the field studying the ball.

By the way, can you imagin how tiny the ball is?
It’s about 0.0000000001 meters! VERY SMALL!!

To help you think of it, let’s take a 1-cent from your wallet and equally divide it into 10 billion parts.
The one of the parts is approximately the same size of nuclues.
It’s a really tiny world!!
That’s why we can observe strange phenomena. ( I’ll talk about the details if I remember )

At that time, there were two well-known facts. One is that there exists minus-charged particles called “electron” and the is that atoms are electrically neutral.
So, we should cancel the minus.
After many experiences done, there seemed to be plus-charged particles in the center of the atoms.

Here, one question risen.

Why can so many plus be gathered in such a narrow place?

You know the same kind of charged particles interact repulsively, right?
It’s impossible that the plus particles are centralized in such a tiny region.
The commonly known image of atoms is acutually really strange.
In fact, in the past, there was a model called “raisin bread model” which says that

atoms are constructed by minus particles and cloudly-spread plus electricity.

Simply speaking,

raisin = minus particles

This idea was the mainstream in Europe.
If the idea were correct, we could avoid thinking such a strange thing that the plus particles are gathered in one place.

However, an experimentalist Rutherford stroke alpha particles on gold atoms and found that there seemed to be some kind of mass centered at the atom.
This is really bothering, but fact is fact.
We have to design a model which can explain the fact.
Another model called “Nagaoka model” can explain it and this is the image you might think now.
The experiments showed the model is correct.

However, here is one remaining question.

Why can the plus particles be placed in such a small region?

There were so many people who studied this problem and Dr. Yukawa was one of them.
Excepting details, but he showed theoretically that if there is some kind of bonding agents affecting very short-range and strongly, then it is possible.
The theory is called $$\pi$$ meson ( or pion) theory.
Dr. Yukawa is the person who solved a large mistery of nucleus

### “A TRAVELER”~My favorite scene~

This book is a life story of Dr. Yukawa’s who won the first novel physics prize among Japanese people.
The period is from his childfood to about 30 years old.

I think it is really important for us to know what kind of life he spent because I think it is a good way to become a historical person.
In other words, what is important is to take some pieces of their thoughts.
That’s why I started to read their life stories (I will talk about Shinichirou Tomonaga some day ).

My favorite seen is his playing tag in shrines or somewhere when he was a little boy.
The book says that he lay on the ground because he got tired.
His heart was grabbed curiously by the picture of the sunlight filtering through trees.

And it says, when the idea ( pion theory ) occured to me, this image happend to cross my mind.
The situation of the sunlight is similar to that of the image I showed you some minutes ago. Certainly true.
Like this, I think physics can give us impression that

unexpected things are similar to each other at unexpected timing.

I also think that he is a really great writer because we can learn that from him.

In my daily life, I regard the sunlight as nuclues, like,
this is pion and that is proton…
I’m sick.

But it’s very fun because the sunlight is everywhere!
Whenever I see it, I’m impressed!
It’s totally fantastic!
That’s why I decided to go to a grad school and it’s like a place infested with demons.

### Summary

Now, that’s all I wanted to write, what do you think?
First, I introduced Hideki Yukawa and Nuclear Physics.
Second, I wrote about my favorite seen.

The book contains some stories that Dr. Yukawa struggled to get his results, so if you think of going to a grad school, I recommend you to read this at least one time.
I personally hope this blog can spread how splendid the physics world is all over the world.

Next time, I will introduce “Physics in mirror” by Shinichirou Tomonaga.