Why are planets suspended in space?

Perhaps many people in their youth looked up at the sky and saw the shining stars, they thought: Will they fall one day? What if it fell and hit the Earth?

Curiosity is the first step in human progress, scientists also conduct research through such questions and the answer to this question is: it will not fall! But what is the principle?

Planets will not fall.

"Big Bang Cosmology"

To understand the mystery of planetary hovering, we must first understand how planets are born. There has always been a lot of debate about the birth of the universe and what is recognized by most scientists as the 'Big Bang' cosmology.

In March 1949, British astronomer Fred Hoyle came up with the idea, the discovery of cosmic microwave background radiation in 1964 that later became important evidence in support of the big bang.

According to observations made by the Planck satellite in 2015, the Big Bang exploded about 13.8 billion years ago, then continued to expand to reach the state of the universe as we know it today.

According to the origin and proof of the big bang model, the early universe was composed of homogeneous and isotropic high-temperature and high-pressure matter, and very rapid expansion and cooling occurred during the early phase. the beginning.

You can imagine the explosion process like a pressure cooker filled with water and rice, blocking the steam outlet of the pressure cooker, causing the gas to expand without any place to escape, the pressure is constantly increasing. , the pot couldn't stand it and eventually exploded.

At the end, elementary particles are born, with extreme cooling, the first planets, stars, galaxies and even life are born.

Birth of planets.

Most of the stars that we can see with the naked eye in everyday life are stars. Stars are formed when high-density regions of molecular clouds collapse into spherical plasmas, all of which are inseparable from the Big Bang.

This is the process of the first birth of stars.

Maybe the stars you see when you look up are five years old, they've been shining for billions of years. When you grow up, you look up at the sky again, some of the stars from your childhood may have disappeared. This is a miracle of nature, making people amazed and fascinated by it.

Exploring "Cosmic Gravity"

In 1687, Isaac Newton first published the law of universal gravitation in "Principles of Mathematics of Natural Philosophy", which could well explain the interaction between bodies, a part of ancient mechanics. dictionary.

The reason why stars can be suspended in the air cannot be separated from the effects of gravity.

But what exactly is gravity?

 
Gravity keeps the stars from falling.

If we use the definition given by Newton, universal gravitation refers to the force that attracts two particles to each other, which is proportional to the product of their masses and inversely proportional to the square of the distance between them.

The simple summary of this sentence is: the greater the mass, the greater the gravitational force, the farther the distance, the smaller the gravitational force. In daily life, we can see many things that exist due to gravity, such as the more vegetables we buy, the heavier they are, the flow from high to low, apples falling from top to bottom.

Some people will ask, does gravity also exist on our human body? Why are there no thrills in everyday life?

This is because the mass of the person is too small, and the gravitational force between the person and the object is too weak to be ignored. But the gravitational force between Earth and humans is very strong, we humans have adapted and used to it in the long process of evolution, so there is usually no particularly strong feeling.

To prove it, there is a very simple example, in our life we ​​have never seen anyone jump on foot and fly straight into space, right? Have you ever seen anyone fly directly from the South Pole to the North Pole? It is because of the existence of gravity that we are drawn to the surface of the Earth, allowing us to live normally.

Why don't the stars fall?

So what is the relationship between gravity and the planets?

Each planet is affected not only by the gravitational force exerted by a planet, but also by forces from all directions, which work together to keep the planet in a constant state of motion but relatively balanced.

The stars we can see when looking up are very massive, but they are actually very far away from Earth.

In 1915, Scottish astronomer Robert Innes discovered Proxima Centauri in South Africa, which is the closest star to the sun and it is 4.22 light-years from Earth.

A light year is the distance that light travels in a vacuum in a year. 1 light year is about 9.46 trillion km. If the Earth's equator is used as a benchmark, this means that 1 light year can orbit the Earth's equator 236.5 million times, if you go at 120km/h, you it takes 9 million years to travel in 1 light year!

In general, stars are difficult to fall due to Earth's gravity, so they remain suspended in space. 

So what are the meteorites that we see? Are they falling planets?

Meteor refers to a meteorite that runs through interstellar space, usually consisting of space matter such as cosmic dust and solid masses. As it approaches Earth, it is attracted to Earth's gravity, thus entering Earth's atmosphere and rubbing against the atmosphere to ignite the trailing light. The color will vary depending on the degree of its burning.

It should be noted that meteorites are not planets, let alone falling planets. If you look up and see a shooting star, don't worry about the falling star but enjoy its brilliance and maybe grant a wish like in the legend.

Meteors fall to Earth.

Conclusion: The journey to explore the universe is endless

From time immemorial, mankind has always had curiosity and a desire to explore the infinite sky and universe. In the Ming Dynasty, Tao Chengdao, known as Wanhu, once built 47 rockets and tied them to a chair, then sat on the chair himself, igniting the rocket, wishing to fly to the sky.

Today, with the continuous development and progress of science and technology, people have built spaceships, international space stations, space suits, . and people are increasingly understanding. deeper into the mysteries of the universe.

With a constant depth of understanding, when we look up at the sky, we are freed from the fear of the unknown in primitive times.

Now that the pace of exploration continues, man-made space probes are all over the moon and even Mars, the mysteries of the universe are still quietly waiting to be discovered.