The lava produced by the impact splashed thousands of kilometers away in a short time, and the very high temperature burned the forests in most places. The impact produced a lot of smoke and dust, which dispersed into the sky and blocked the sunlight.
This situation lasted for many years, and the earth also entered the "nuclear winter" period.
Dinosaurs died out because they didn't master this skill?
Fly to deep space, where is our destination?
How many methods have humans used to fly?
During this "nuclear winter", 75% of the living things quickly perished. As one of the representatives of land reptiles, dinosaurs survived, but some flying dinosaurs gradually adapted to the environment and finally became familiar birds.
Through the extinction of dinosaurs, we can see that although it is sometimes very powerful, it can't get rid of the gravity of the earth, and it is not a very long-term viability. Only the flying man is more adaptable.
But the extinction of dinosaurs brought some good news, that is, the extinction of dinosaurs made some new species appear on the earth. Mammals gradually flourished after dinosaurs.
Compared with other species, human beings were born much later.
We know that life appeared on the earth about 4 billion years ago, but the earliest human beings appeared 5 million years ago, the earliest modern homo sapiens appeared about 300 thousand years ago, and modern civilization appeared even later.
However, it is such a short-lived human that has evolved from a race worried about being attacked by wild animals into a seemingly omnipotent race in the development process of hundreds of thousands of years.
History repeats itself on this planet. Some people with a sense of urgency began to doubt whether human beings would experience the situation faced by dinosaurs 66 million years ago.
Although it is possible to have a very similar impact event every 1 100 million years, there are other factors that will affect human survival.
In recent years, science fiction movies have told different disasters faced by mankind.
Interstellar told the story of the epidemic diseases faced by human beings, and The Wandering Earth, who was very popular last year, told the story that the sun expanded and flooded the whole earth.
These things seem very far away from our reality, but there are some other factors that we can't ignore. That is, with the increase of global temperature, Antarctic icebergs have melted rapidly in the past many years.
According to some scientists' estimates, in about 10,000 years, the whole earth will not be suitable for human habitation.
Some people are even more pessimistic. Stephen Hawking, a British physicist, once predicted that if human beings do not pay attention to protecting the current energy, the temperature of the earth will rise sharply in a few hundred years, which is not suitable for human habitation.
Therefore, the future of mankind is a problem that needs our urgent consideration: for our own future, mankind must learn to get rid of the gravity of the earth, and only those who can fly have a future.
From ancient times to the present, we know that countless human beings have worked hard to achieve the goal of flying. Many of the aerospace technologies we have now are actually the results of countless people.
In China, thousands of families flew into the sky in the Ming Dynasty, and the final result was failure.
1903, the Wright brothers kept the plane flying in the sky for 12 seconds, which opened the first step for human beings to go to heaven.
1926, the first liquid rocket was successfully launched. Although it only lasted 2.5 seconds and flew to the height of 12 meters, it laid the foundation for modern rocket launch.
Thirty years later 1957, the first artificial satellite was successfully launched, which opened the history of human exploration of space.
Four years later, at 196 1, astronaut yuri gagarin went into space.
Eight years later,1July 20th, 969, American astronauts completed the moon landing program. Armstrong said a classic sentence on the moon. His small step is a giant leap for mankind, which is the proudest moment in human history.
Of course, the brilliant achievements we have seen in the history of space are the result of the space competition between the United States and the Soviet Union in the 1950s and 1960s. However, it is their competition that promotes the development of space science and technology. With the help of these technologies, humans began to explore space and other planets in the solar system.
Mars is a planet that human beings have been longing for for for a long time. Since the 1960s, human beings have been exploring and finally successfully flew over Mars on Mariner IV in 1964.
Today, more than 40 projects have been launched around Mars.
This year, the United Arab Emirates, China and the United States launched three different mission to mars.
In 202 1 year, humans will fly on Mars for the first time. Its significance is no less than 1903 Wright brothers' test flight.
Everything we do is to make mankind realize the so-called interstellar travel in the future. Besides, we need to do two things:
Have we found the right planet?
1609, Italian scientist Galileo aimed his telescope at the sky, thus opening a new journey for human beings to explore the universe.
With the telescope getting bigger and bigger, with the help of the most advanced telescope, we know that the universe is actually more vast than our milky way.
Under the observation of Hubble telescope, we know that there are at least 2 trillion galaxies in the whole universe, and each galaxy contains at least 1000 billion stars.
Therefore, in our entire visible universe, there are almost 100 trillion stars. This number is more than100000 times the number of grains of sand on our whole earth.
The existing theory shows that there may be a planet around almost every star. How to find the planets around these stars is a difficult problem for astronomers.
What role does our earth play in the whole universe?
This photo was taken by Voyager 1 after 1990 and 13 left the earth for 6 billion kilometers.
Originally, the protagonist of this photo was the earth, but if we don't look carefully, it is difficult for us to find the shadow of the earth. The earth is hidden in a ray of light, just a small white dot, so small.
6 billion kilometers seems far away for the earth, but 6 billion kilometers is only half the size of the solar system, so from the whole universe, our earth is so small. So if we want to detect very small planets, we need very cutting-edge technology.
Finally, in the 1990s, when astronomical technology was relatively mature, we began to explore some planets outside our solar system.
1990, we discovered two planets around neutron stars for the first time.
1995, we found a planet orbiting the sun in Pegasus, which is about dozens of light years away from the earth, thus opening the curtain for our exploration of exoplanets.
Today, we have discovered more than 4000 exoplanets. Among these exoplanets suitable for human habitation, astronomers put forward the view that life is suitable for habitation based on their research on the earth.
These planets are located in areas that cannot be too close to or too far from the central star. Too close will be too hot, too far will be too cold.
Therefore, among the more than 4,000 planets, we finally found 12 ring planets which are very suitable for living, and the nearest one is proxima centauri, which we are very familiar with.
This proxima centauri, if you have seen the wandering earth, you will know that it is also the ultimate wandering place of the earth.
After finding the ideal planets, do we have the ability to fly to them? Is our spaceship fast enough?
The wandering earth tried to accelerate the earth to 5‰ of the speed of light. 5‰ is about per second 1500 km.
This is very difficult for the current space technology, at least under the existing technology, it is difficult for us to achieve such a high speed.
We know that in movies, even this fast speed will take 2500 years to reach. It takes a hundred generations, not a generation.
But interstellar shows another way, that is wormholes.
A wormhole is a high-dimensional channel that allows us to reach tens of billions of light-years away in a short time.
So this wormhole seems to be a very effective way, but after all, these are science fiction movies. What kind of technology do we have in reality?
The Apollo moon landing program 50 years ago can be said to be a bright moment in the history of human space. The rocket carrying two astronauts to the moon at that time was Saturn V.
Of all the rockets, Saturn V is still in service. It is the rocket with the highest thrust.
Of course, the next-generation American space launch system, as well as the large rocket of Space Exploration Technology Company or the large Falcon rocket, are all more thrust than the previous Saturn V, but from this comparison, we can see that their thrust has not changed particularly.
Why? This is because the energy sources of rockets currently used are all chemical energy, and if their size does not change much, their thrust will not change much.
So in addition, astronauts are still trying to develop some new rocket launching mechanisms, such as ion engines, nuclear fusion engines, antimatter engines, and even through the so-called space-time bending, which we call curvature flight.
I hope that in the near future, new technologies can make breakthroughs and help us achieve the goal of reaching distant planets quickly.
Only when there is a new breakthrough in rocket technology can human beings hope for interstellar travel.
In nearly 100 years, the development of rocket technology is very slow, and some people are very pessimistic. Liu mentioned in a speech that the future of mankind without space navigation is bleak, so those who can't fly have no hope.
Man must learn to fly fast.
In this decade, we have also seen some happy places. The aerospace industry is showing a thriving side. In addition to state power, more private enterprises have joined the aerospace industry, such as Space Exploration Technology Company and Blue Origin of Amazon. Some people call the present stage the space 2.0 era.
Although the development of our space technology is very slow, once the space technology is started, with the continuous efforts of mankind, we will definitely achieve the ultimate goal of space navigation.
If one day, human beings encounter similar experiences and disasters on earth, we can rely on future rocket technology to send future human beings to distant planets and realize the establishment of a new species across the Milky Way or the whole universe, as Asimov said in his novel "Base".
Let our future human beings survive in the sea of stars.
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Edit | Wang Lu