Preface
About 13.5 billion years ago, after the Big Bang, the substances, energy and space built the current thing what we called- the universe. All the fundamental existence and rule of how they work, we called it- Physics.
Then after about three hundred thousand years, those fundamental existences and energy started forming complicated structures called- Atoms. The study combinations of atoms is what we called- Chemistry.
In the further step, the combinations of these atoms, which are molecules, keep combining each other to create the first type of organism- monocell. They split with trembling, keep copy and paste themselves with exponential speed to form other organisms which are more complicated. The study of these organisms is what we called- Biology.
At the meantime, an insignificant planet called Earth was born. At that time, mountains could rise up for thousands of meters high and drop down in a few minutes. After the Earth cooled down, the ground, which is the crust of the Earth become harder, become stronger, become more appropriate for lives to live on. The study of the physical feathers on Earth, the life activities on Earth and the interactions between artificial objects and the nature is what we called -Geography.
Briefly about forty five thousand million years after the Earth was born, a kind of life form which just like other species, human appeared. They invented rock axes, figured how to control fire, built up kingdoms and countries, issued money and cheques and even further, we invented the Voyager, we invented the Boeing 747, we invented the quantum computer and we invented the Hadron Collider. All the stories in this stream of humans is what we called- History.
From” A Brief History of Humankind” by Yuval Noah Harari.
------------------------------------------------------------------------------------------------------------
Hi guys, it’s nice to be up here again. Today I am going to force you to listen to my speech because Mrs Rao is right there. Don’t you dare to make a move! Before I start I would like to mention and thanks Ashely for her idea about making an excellent series called the ”SA”, as well as her supportive.
Have you ever looked at the sky at night and wondered about, what these dots are, what supernova is, what impulse star is and what is a blackhole? Well luckily I have got this book called ”What Is Space” that could solve most of you questions about the space except for these frontier questions.
I’ll begin by talking about the cover of this book. As you see, the whole cover is filled with dark colour and in the middle of the page, there is a supernova named the “Crab Nebula” M1NGC1952 is exposed to our eyes. This is the nebula which was created by a star named SN 1054, at 964 years ago. In the middle of the nebula, there is an impulse star that self-spin 30 times per second and it is 6500 lightyears away from us. Now let’s move on to the left-top corner and you will see the famous telescope- the “Hubble” and the bottom right corner is the closest companion star to our Earth so figure it yourself.
Now, enough for the cover, let’s move on to the content of the book. This book mainly talk about the story and the information about the impulse stars, the blackholes, the nebulas,asteroids, comets, planets, stars and the stories of pioneers in astrophysics, the myth about the space as well as the equipment and the observatories all around the world.I won’t tell you that I just copied these words from the index. Anyway, if you are really interested in astrophysics, this book is really the write choice.
Well, what’s next? Oh! My favorite part of this book. It is my favourite part of the book so it might not be yours, but whether you like it or not, it is compulsory. Let’s get back to the prize. My favourite part is the biography of a Star, which is the timeline of a Star.
So firstly, when the density of hydrogen atoms went up to above 60000 per cubic centimeter in space because normally it is 1 per cubic centimeter, the matter outside the cubic centimeter will fall to the centre of the it which makes the homogeneous gas become a group of hydrogen atoms which has extremely high density at one single point and surround by rarefies but thick”atmosphere” on the outside. This will results more and more hydrogen atoms been pulled into the “singularity” with faster and faster speed. The process could last for about one hundred thousand years and until it’s singularity is getting denser and denser, bigger and bigger, hotter and hotter, after the hydrogen atoms all move fiercely, after the hydrogen atoms lost all their electrons, after the singularity achieved ten million degrees, an epic that last for ten billion years begins.
An extremely bright light appears, the whole universe seems to changed from black to white, with the γ ray, β ray, α ray, with different sorts of electronic magnetic wave and gravitational wave, a young star appears. This star unscrupulously shows the universe it’s unimaginable power by nuclear fusion reaction in the centre of itself.
During the next few billions of years, this star keeps fighting with its own gravitational pressure by using the radiation repulsive force which was produced by the huge amount of energy that was lost during the nuclear fusion. At this stage, this star is well balanced with the radiation repulsive force and the gravitational pressure so it is calm and comfortable because it has plenty of hydrogen as reactant to react.
Everything has a beginning and an ending. Including the universe, stars also die. As soon as the hydrogen runs out, the calm period ends. The balance between the radiation repulsive force and the gravitational pressure will soon be broken. The star will soon dim down and collapse under its own gravity. Aye, but not yet to die! Because of the collapse, the core got pressurized therefore the temperature increase in a instant, it lit up the helium for its nuclear fusion power and expand quickly again just as it was born. This is what we called- the helium flash. Under the unimaginable gravitational pressurization and ten million degrees, helium atoms start grabbing other two helium atoms to form carbon atoms. Then the carbon atom will grab another helium atom to form oxygen. These reactions are not as gentle as hydrogen fusion reaction, they shine and react in a sudden which is what we called- the helium flash.This will make the helium in the core burnt out first so the it has to burn the helium with is outside the core. This will results to the big expansion of the star that makes the star expands about one billion times bigger and because it expands, the temperature drops fast that make it changes from bright yellow to red. This is what we called- the Red giant star. But because of the size expanded, it still looks extremely bright with low temperature so the brightest star in the night sky are mostly red giant star.
After millions of year, after the reactive elements run out, after the iron appears, the efficiency of nuclear fusion drops fast and finally, the end of the epic appears. There are four possible endings for a star and they are:
1) To become a White drawf.
2) To become a Supernova.
3) To become a Neutron star.
4) To become a Blackhole.
网友评论