Mars, between science and fantasy

In this galaxy with hundreds of billions of stars, the Milky Way, a star on the inner edge of the galaxy, is called “the sun”. It is a common “yellow dwarf” in the galaxy. This kind of star has a life span of about 10 billion years. After burning fuel, it will eventually evolve into a white dwarf under the influence of its own gravity. The sun has burned for about 4.6 billion years and is currently in the middle of life, warm and stable.

A more detailed observation of the sun reveals that under its gravitational force, the celestial system formed around it hides mystery. There are eight major planets orbiting the sun. The inner four planets, mainly composed of metal and rock, are called “earth-like planets”. The surface of the third-blue azure planet is mainly covered by liquid water. It is wrapped in a dense atmosphere; the fourth planet looks different from the previous one – its surface is covered by red dust, only some white dry ice in the polar regions, the atmosphere is sparse, but And because of the seasonal changes, there will be a violent flow, and dust storms all over the world will occur.

The third and fourth planets that orbit the sun, the time, process, and even their appearance are quite similar. But in the subsequent evolution of more than 4 billion years, the two planets have embarked on a different path. The third planet, called “Earth”, has always maintained a dense atmosphere and a vast ocean. With its warm and humid environment, it has produced the greatest miracle in the universe, the phenomenon of life. Life multiplies and evolves on Earth until there is a highly intelligent human being.

Mars, between science and fantasy
Mars’ “Sailor Canyon” stretches for 4,000 kilometers and is the largest canyon ever discovered in the solar system.

At this time, the human beings on Earth are looking at the fourth planet named “Mars” with curiosity and confusion. What is the reason for this planet, which may have been as warm and humid as the earth, has become a red dust The dry and desolate barren land covered? In the history of more than 4 billion years, has Mars also derived life like the earth? Are Mars life similar to Earth’s life, and what kind of traces will they leave on Mars? Can humans study and explore Mars more deeply understand the meaning of life and the mystery of the evolution of the solar system? What lessons can humans learn from the changes in Mars? In the future, if human civilization has the opportunity to expand into the entire solar system and the entire universe, can Mars become the next stop and transit station for mankind?

Humans are not only using telescopes to observe Mars from Earth, but various detectors from Earth have already flown over tens of millions of kilometers to reach Mars. They are conducting various surveys on the orbit and ground of Mars, returning data about the other planet to the Earth. With the development of human science, the significance of detecting Mars seems self-evident – ​​whether it is studying the evolutionary history of the solar system, analyzing the process of planet formation, or even finding the next place for humans, Mars is an extremely important research. Object.

But whenever we look at Mars in the night sky, we will understand that this red planet is far more scientific than humans. It has fascinated mankind for thousands of years, and it also entrusts humanity. Some deep emotions map the most profound loneliness in the human heart.

Mars is particularly bright in the night sky, and has a distinctive red color. The ancient Chinese described it as “ying Yingyinghuo”. Standing on the earth, Mars’ moving trajectory and brightness are unpredictable, hence the name “Flaming”. Because in the midst of feeling that this planet is related to the human world, the ancient Chinese will divination on the ground through the position and dynamics of “Flaming”. For similar reasons, the traversing orbit of the planet in the sky makes the other civilizations feel elusive and even disgusted. 4000 years ago, the ancient Egyptians called Mars “Her Desher”, the Babylonians called it “Star of Death”, and the Romans followed the ancient Greeks, named Mars “Mars” “.

So what does Mars mean for humans in the 21st century? Why do humans must go to Mars? It can be said that the important reason now is to find life.

Mars, between science and fantasy
In April 2015, NASA released a Mars surface image from a Mars Reconnaissance high-resolution imaging device.

Looking for Mars life
Finding Mars life is not only a scientific issue, but also a topic that will excite the entire human society – it is about the dimensions of human society: What is the nature of life? Is humanity alone? Is there more possibilities for life? But in the face of such an adjacent planet that is homologous to the Earth and whose current environment is very different, where should humans start looking for traces of Martian life?

To find traces of life on Mars, it first involves how humans understand the phenomenon of life itself. The problem is that the Earth is the only planet in the universe known to humans that produces life phenomena. Going to aliens to find life can only start from the understanding of human life on earth. The existence of life depends on the cooperation of various conditions, then what is the most critical factor? From the human understanding of the earth, it is necessary to prove that an environment can breed a high standard of life – there needs to be water, there are essential elements that make up life (such as carbon), and there must be a stable source of energy, and these conditions It needs to be fully satisfied in the same geological period. In an environment, even if all of these conditions are met, human scientists need to evaluate them specifically, and then define what type of organisms will be produced under certain conditions.

Among all the factors that support the existence of life, water is the most important. “Following the trail of water” is the primary criterion for human planetary scientists to find signs of extraterrestrial life. Water is the source of life. Water can profoundly change the environment of a planet, and it can also give birth to life. Mars contains a lot of water, and this conclusion has been confirmed, no doubt. But is the water stored by Mars able, or has it been able to create an environment suitable for life in Mars? Further discussion, if Mars has produced life phenomena similar to Earth in the history of more than 4 billion years, especially when the natural environment has not become as bad as it is now, what kind of they may leave on Mars trace?

Studying the existence and changing processes of water on Mars is the key to understanding Mars and finding life on Mars. It is not that as long as there is liquid water, it can give birth to life. The water should be fresh and not contain too much salt. In a high salinity environment, the osmotic pressure of the cells is too large to survive. In addition, the acidity of water is also important. Although in some extreme environments on Earth, humans have discovered organisms that can survive in an acidic environment, it is obvious that more life forms can occur in relatively neutral waters, and there is a greater likelihood that they will evolve. Complex living body. Moreover, based on the Earth’s environmental analogy, the liquid water of the planet is preferably present on the surface, with stable water and water flows, such as stable lakes or rivers that are most suitable for the generation and reproduction of life phenomena.

At present, human exploration of Mars shows that in its long history of more than 4 billion years, perhaps millions of years, there have been rivers formed by liquid water on the surface. This length of time, although only a short moment compared to the history of billions of years of planets, may also have derived Mars life during this period. Taking the Earth as an example, the existence of a life phenomenon requires carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur to form an essential element of life in addition to moisture. In contrast, nitrogen and carbon are special. They need to be present in the soil, but they cannot be too tightly bound to the minerals in the soil, making it impossible for microbes to collect and use. These substances need to be soluble in water and easily absorbed by microorganisms – these conditions are likely to be met by Mars.

Mars, between science and fantasy
Photo of the Korolyf crater published by the European Space Agency in December 2018

In the long history of Mars, has there ever been a very short period of time, and all the conditions of life phenomena have been met at the same time? This will require further research on the rocks and soils of Mars. The Phoenix detector, which arrived in Mars in 2008, detected a slightly alkaline Martian soil with a pH of 7.7. Martian soil contains magnesium, sodium, potassium and chlorine, which are essential for planting plants, but also contain 0.6% perchlorate. Scientists believe that in the Martian soil of ancient times, the nitrogen may be easily taken by organisms, and other substances, such as phosphorus, need further detection. If human detectors are able to find some relatively concentrated deposits of nitrogen and phosphorus in Martian soil, there is considerable potential that these materials were once soluble in water and may have been absorbed by Martian microbes. , involved in the metabolic process of microorganisms.

In the Martian atmosphere, especially in the ancient Martian atmosphere, there is a lot of carbon dioxide. The Curiosity Detector, which arrived in Mars in 2012, also found a large amount of carbon on a dry “lake bottom” on Mars. Some organisms may be able to extract carbon from carbon dioxide directly through metabolic processes and build cellular tissue through carbon dioxide dissolved in water. “Curious” found pyrite, magnetite and pyrite in Martian soil, which may also be of great significance because these minerals may provide a source of energy for a particular organism – this is currently “ Curiosity is still looking for Chemolithotrophs, the ability to get the energy needed for life through the compounds that exist in rocks.

If there have been Martian creatures similar to Earth creatures, then after billions of years of change, and the Martian climate has changed dramatically, human probes on the surface of Mars will be launched, and even Mars will be explored in the future. How should human astronauts find and judge the traces left by Mars life? This in turn involves the possible existence of how Mars life is preserved and how to change the Martian soil. In this regard, humans need to understand the process of biodegradation, deduce the state in which the remains of paleontology have survived, and give the answer with the Earth as a reference.

Even on Earth, humans rarely find evidence of life that existed billions of years ago. Different types of living things live in different environments, and the traces of life they can leave in the environment vary. In the first two billion years of the Earth’s history, the forms of life produced are almost single-celled. If there is a life of Mars, it is very likely that it will start with a single-celled creature. Looking for evidence that they have existed on Mars requires not only that these creatures leave enough traces in the soil and rocks of Mars, but that these traces can not be completely destroyed by cosmic rays for billions of years.

A living organism composed of organic matter will degrade after death, and the remains of the creature are converted into sediments, which are then converted into rocks. These substances are deposited layer by layer, exposed to lithification in the liquid, gradually changing from a wet paste to a hard rock. The water flow over and over again will take away some of the chemical substances in the biological remains. The chemical composition of the biological remains in the soil will change, some substances will oxidize and become gas spills, and the organic carbon will gradually be converted into inorganic carbon. From this perspective, the rich water resources on Mars may not be conducive to the preservation of biological remains.

Even without experiencing these complex lithification processes, the remains of the surface of Mars may be destroyed by cosmic rays. So, if there have been life phenomena on the surface of Mars, are they still likely to leave clear traces? Bombardment from cosmic rays is unlikely to completely eliminate all organic molecules on the surface of Mars – humans still find organic molecules on some meteorites with billions of years of history – that is, if they do exist on the surface of Mars Some organisms left behind by organisms, and so far, there may still be some traces left waiting for humans to discover. Scientists have calculated that organic molecules on the surface of Mars, such as amino acids, are only one thousandth of every 650 million years under the radiation of cosmic rays. Calculated by this ratio, even if there are some organic molecules from the ancient Martian life on the surface of Mars, there must be little left. Humans want to find a lot of evidence and may need to go deep into the land of Mars.

In July and August 2020, the relative position of the Earth and Mars will be appropriate, and then human detectors will fly to Mars. NASA’s “Mars 2020” mission will launch a rover to look for traces of Mars’ life and to find existing Martian microbes. The European Space Agency’s (ESA) “ExoMars Mission 2020” also plans to launch a Mars probe in July 2020, including a Mars rover and a Mars science platform. The main goal of the European Space Agency’s Mars Exploration Program is to find traces of Mars’ life. The Mars rover that it launches can not only walk around, but also carry a drill bit that can drill down to two meters below the surface of Mars to find traces of organic molecules.

No matter what hopes humans have for looking for Martian life, one must face the reality that humans still know little about Mars, and the possible state and experience of Mars life can only be studied through the study of life on Earth. analogy. It is precisely because of this that perhaps a discovery may change the overall situation.

The Mars Express satellite once detected ammonia in the Martian atmosphere, possibly from Mars or Mars volcanoes; and the ExoMars Trace Gas Orbiter Also found in the atmosphere of Mars, a small amount of methane, which also stimulated the imagination of the existence of microbes on Mars; “Curious” Rover has tried to analyze the isotope contained in the atmosphere of Mars, hope to judge these Whether the gas is released by the organism or another, the results show that these gases are unlikely to originate from Martian creatures, even from the Martian creatures, in the deepest position below the surface, human detectors are currently inaccessible.

The biggest surprise may still come from the revelation of water. The Mars Express satellite has been conducting geological exploration of Mars since 2003, and the satellite is also equipped with a science called Mars Advanced Radar for Subsurface and Ionosphere Sounding. The instrument can be surveyed below the surface of Mars. After the software upgrade, after more than three years of exploration and analysis, the scientists found that there is a large amount of liquid water under the ice layer in the area of ​​the Martian Plateau Australe.

According to a paper published by scientists in the July 2018 issue of Science, there may be a large amount of liquid water 20 km wide and about tens of centimeters deep below 1.5 km of glacier surface in this area. There is long doubt that liquid water may be present under the surface of Mars, but this is the most reliable evidence of human detection to date. In addition, considering that the current radar is only surveying the Martian region of the Antarctic plateau, this discovery has been made. Once this speculation is confirmed, scientists have reason to speculate that there may be a large amount of liquid water stored below the surface of the surface of Mars. .

This unconfirmed discovery is hard to reminiscent of humans’ similar experiences on Earth. It was not until the second half of the 20th century that humans discovered Lake Vostok, one of the world’s largest freshwater lakes, beneath the ice near the Earth’s South Pole. The 230-kilometer-long, 50-kilometer-wide, 800-meter-deep freshwater lake is buried deep under about 3.7 km of ice. Before the humans discovered it, the freshwater lake had been isolated for at least 15 million years. In such extreme conditions that there is no sunlight and temperatures below 0 degrees Celsius, scientists still find traces of many microorganisms from the lake.

Under the surface of Mars, is there really a Martian lake or an underground ocean with a huge water content? In such an environment, it is safe from cosmic rays, but will the salt content of the water be too high? If humans really have the opportunity to detect the underground lake of Mars, will a new world be discovered? These questions require future generations of Mars probes, as well as human astronauts who visit Mars in person to give answers.

Mars, between science and fantasy
On May 30, 2017, NASA released a conceptual picture of the new rover

Explore the dream of Mars
“Because it is there.” – When asked why he must climb Mount Everest, George Mallory replied. The British explorer eventually died in 1924 with his companion Andrew Irving during the climb to Everest. Regarding whether they have achieved their lifelong ideals before the death, they have successfully reached the summit of Mount Everest. People have been arguing for nearly 100 years, and still have no answer.

“Because it is there.” In this simple answer, there is the strongest passion of mankind. This passion is not driven by fame and fortune, nor is it obstructed by difficulties and dangers. The desire to reach and conquer because of seeing is the unique emotion of human beings as a life of wisdom. This kind of emotion drives human beings to travel around the earth and turn their eyes to the universe. Desire to embark on Mars and explore Mars. This dream is not only for scientific progress, it is based on science and reason, and transcends science and reason, and it also contains a sublime human being.

In the history of human civilization for thousands of years, most of the time, Mars, like other stars in the night sky, is just another world that is out of reach. People standing on the ground watched the movement and brightness of Mars, hoping to predict the good and bad of the world. Humans have had records of observing Mars more than 4,000 years ago. In the 28th century, the ancient kingdom of Egypt, more than 3,600 years ago, because of the observation of the movement of Mars, the ancient Egyptians called Mars “Horus of the Horizon” (Horus of the Horizon) ) China also recorded Mars as early as the Zhou Dynasty and the Qin Dynasty. By the 4th century BC, the ancient Greek philosopher Aristotle judged that Mars was higher in the sky than the moon because it was observed that the moon covered Mars.

Mars, between science and fantasy
In 1972, the same size model as the “Mars 3” detector was exhibited at the Soviet Economic Achievements Exhibition in Moscow.

Although it is difficult for modern people to imagine standing on the surface of the earth, it is possible to obtain groundbreaking astronomical discoveries by observing with the naked eye. In fact, before the telescope was invented, humans obtained groundbreaking observations by visually observing celestial bodies including Mars. Discovery, and thus promoted the development of science. In the second half of the 16th century, the Danish astronomer Tycho Brahe spent exactly 20 years on the Observatory on the island of Wen, observing the trajectory of the celestial body with the naked eye and taking a lot of notes. These notes were later studied in detail by his assistant, Johannes Kepler, who finally calculated the elliptical orbit of Mars for the first time in history and eventually came up with the “Kepler’s Three Laws” – This great discovery also inspired Newton to establish classical mechanics to some extent.

The first person to use a telescope to observe Mars is most likely the Italian physicist Galileo. In 1609, Galileo, who was visiting Venice, was inspired by the Dutch optician to create the first human telescope. Galileo used a self-made telescope to observe many celestial bodies in the solar system, including Mars. With the continuous improvement of human-made telescope technology, humans have more and more understanding of this red planet. They have observed the ice cover in the polar region of Mars and began to measure the length of a Martian day and its distance from the Earth. In 1698, Dutch astronomer Christiaan Huygens even published a monograph discussing the existence of life on Mars.

In the 17th century, it is possible to explore the possibility of the existence of Martian life. It may be too early for modern people to be full of mistakes and subjective speculation. In the 18th century, British astronomer William Herschel’s speech on Mars at the Royal Society was mostly based on actual observations and rational judgments. He believed that there might be an atmosphere on the surface of Mars, and it was observed through observation. The dark and dark changes in certain areas of Mars are most likely caused by clouds and water vapor in the atmosphere, so the life of Mars and the life of Earth may be similar.

In the 19th century, the Italian astronomer Giovanni Schiaparelli drew the first detailed map of the surface of Mars in 1877. On this map, there were some similar “ditches”. Form, which has led to a richer and longer-lasting association of human life about Mars. American astronomer Asaph Hall discovered two natural moons of Mars in the same year.

Mars, between science and fantasy
On December 4, 2006, the US “Phoenix” Mars probe was tested in a hot vacuum container to simulate the Mars landing environment.

Humans have a deeper understanding of Mars, but it was still an unrealistic dream to launch a probe to Mars for direct observation until the early 20th century. From discovering the elusive red celestial body in the sky to studying its orbital period and judging its natural environment, it took thousands of years for humans to send probes to Mars.

Humans began to launch Mars probes at no cost, starting with the shadows and stimuli of the Cold War. Since the early 1960s, the Soviet Union has launched five Mars probes in succession, all failing; NASA launched the Mariner 3 Mars probe in November 1964, hoping to fly to Mars. The same harvest has failed. The first successful Mars exploration of the human detector was the “Sailor 4” Mars probe launched with “Sailor 3”. It was only 9846 kilometers from Mars in the process of flying to Mars. The detector took the opportunity to take a picture of the surface of Mars and send it back to Earth. This is the first time humans have seen a picture of the surface of another planet. This kind of ruin, ridiculous and dead scene makes many people beautiful for Mars. The disillusionment has opened up a new era.

In the 1970s, the “Sailor 9” probe that reached the orbit of Mars in November 1971 captured a surprising picture of Mars, the first time humans have seen the Martian dust storms that have spread across the globe. Immediately thereafter, the Soviet “Mars 2” probe also reached Mars orbit, but the accompanying “Mars 2” lander crashed on the surface of Mars. In 1975, NASA launched “Viking 1” and “Viking 2”. They consisted of a Mars orbiter and a Mars lander, and all completed the mission as planned. The “Viking 1” and “Viking 2” landers operated 2,245 and 1,281 Martian days on the surface of Mars, respectively.

Although between the United States and the Soviet Union, in the shadow of the Cold War, the detectors were launched to Mars for the purpose of competition by big powers. Objectively speaking, under such a competitive state, human detectors arrived for another time for the first time. A planet of great significance to humanity has left a strong and colorful stroke in the history of human civilization.

After the end of the Cold War, human detection of Mars did not stop. More and more detectors flew to Mars, doing their part, collecting various information about Mars for humans. The more humans know about Mars, the more questions they have – the planets of the Earth and Mars are in the solar system. Why is the difference so great? What are the factors that determine the fate of the planet? What secrets about the solar system are hidden in Mars?

Red brother of blue planet
Although there is still debate about the causes and processes of the formation of stars and galaxies, the current mainstream theory holds that there were only a large amount of gas and dust particles circulating in the universe in the solar system today, about 4.6 billion years ago. At one point, these gas and dust particles were somehow disturbed—perhaps affected by nearby supernova explosions—and they began to gather under the influence of gravity. In the central area, the sun is mainly formed by hydrogen accumulation. This huge newly born star occupies 99.86% of the mass of the entire solar system. Around the sun, the remaining dust, gas and ice gather together and form a terrestrial planet with a melting metal as the core and a mantle and crust.

If you make an analogy, in the planetary system of the solar system, Earth and Mars are like a pair of brothers who are similar at an early age, but whose situation is completely different (Mars may be formed earlier than Earth). In contrast, Mars is farther away from the Sun, 1.52 times the distance between the Earth and the Sun, and the received sunlight is 43% of the Earth. Even so, the surface condition of Mars in the early stages of formation is likely to be similar to Earth. At the beginning of the formation, Mars also has active volcanic activity, and the gas composition emitted may also be similar to Earth, which gives Mars a dense atmosphere sufficient to maintain its surface liquid water resources.

Mars and the Earth are also quite similar in composition. Both planets have a hot, melted metal core, and because these metals flow in the core to create a global magnetic field; outside the core, both planets have mantle and crustal structures, all of which have Active volcanic activity is also covered with a large amount of liquid water on the surface, and the dense atmosphere can keep the water from evaporating into the universe.

Mars, between science and fantasy
NASA’s “Viking 1” Mars probe was shot in Mars in 1978, “Olympus Volcano”

In all the planets of the solar system, the season of Mars is also similar to that of the Earth. This is because the inclination of the two planets is similar, and the cycle of Mars revolution is about twice that of the Earth—the length of a Martian day and an Earth Day are about the same. But a Martian year is about two Earth years, and the Martian season is about twice as long as Earth. The surface temperature of Mars is lower than that of the Earth. In winter, the lowest temperature can reach 135 degrees Celsius, while in summer, the equatorial temperature can reach 35 degrees Celsius.

Mars, like Mercury, Venus, and earth-like planets on the inner side of the Earth’s solar system, are shaped by volcanic eruptions, dust in the atmosphere, and impact from other celestial bodies inside the solar system. In the early days of the formation of the solar system, a period of between 4.1 billion and 3.8 billion years ago, the so-called “late heavy bombardment”, Mars and many other solar systems inside the celestial body experienced many meteorites and The bombardment of an asteroid. The impact from space left a lot of craters on the surface of Mars, and thus formed a huge plain – this looks like the scars of Mars, but people can also judge the formation time of various areas on the surface of Mars.

Mars’ Arsia Mons had a violent outbreak every 1 million to 3 million years during the active period, spraying a lot of magma, but its most recent eruption was 50 million years ago. Since then, Mars’ volcanic activity has gradually calmed down – that is the time when the dinosaurs on Earth were mass extinct. Although humans have not observed the outbreak of the Martian volcano, the exploration shows that there are still volcanic activities on Mars 100,000 years ago, and everything has not yet completely fallen to silence.

Today, the third planet in the solar system is still blue, but the fourth planet has become a red planet covered by desert. Unlike the blue of the ocean, where the Earth’s surface is encased by the atmosphere, the red color of Mars comes from the large amount of iron oxide contained in its surface soil, making it clearly recognizable in the night sky of the Earth. It’s just that in the thousands of years of human history, the vast majority of people who once looked up at the stars and stared at Mars would not think of what they saw in their eyes. They were in a place where they were in the early stages of formation. . They parted ways in the next few billion years, so that through relative colors they can show the opposite fate.

What is the appearance of Mars in the early days? Similar to speculating the initial global environment, people can only guess and restore through clues. The most important aspect of the many similarities between Mars and the Earth at the beginning of the formation is that both planets are surrounded by a dense atmosphere with liquid water on the surface. More than 4 billion years ago, the Earth’s atmosphere was rich in methane, ammonia, and hydrogen ejected from volcanoes, as well as some carbon dioxide and sulfur dioxide that were not soluble in water. Then, after billions of years of conversion of the Earth’s microbes, the Earth’s atmosphere now contains nitrogen, oxygen, carbon dioxide and water vapor. The original atmosphere of Mars may be similar to that of the Earth’s original atmosphere, and currently contains 96% of carbon dioxide, 1.93% of argon, 1.89% of nitrogen, a small amount of oxygen, and iron oxide-rich in the thin atmosphere of Mars. A large amount of dust is suspended, which makes the surface of Mars appear yellowish brown from a distance, and in the dusty weather, the atmosphere will show a little pink.

Mars, between science and fantasy
a global dust storm sweeping the surface of Mars

Because of the existence of liquid water on the surface, and other factors, it has created a rich landscape on the surface of Mars. The surface of Mars is not flat. The surface of Mars is nearly 4,000 kilometers long. The deepest canyon is 7 kilometers. The Valles Marineris is the deepest canyon in the solar system. The Olympus Mons, which has a shield-like Martian volcano, reaches the diameter. More than 600 kilometers and 25 kilometers high, it is the largest volcano in the solar system. Some seemingly uniform trenches on the surface of Mars are likely to be washed as liquid water melted by ice on the surface of Mars. There are very few traces of craters on some ditches, suggesting that this may have been formed in the last few million years (some people suspect that these ditches are shaped by liquid carbon dioxide on the surface of Mars and global sandstorms).

NASA launched several Mars landers and detectors to reach the surface of Mars for on-the-spot detection and analysis of the composition of Martian soil. In 2004, the Opportunity detector discovered the jarosite component in the Martian soil, and the formation of this material required the participation of acidic water; it discovered gypsum again in 2011, which also requires water participation. — There are indications that there are many undercurrents that may have existed below the shallows of Martian soil. These undercurrents flow in the summer of Mars. They not only shape the landscape of Mars, but also determine the composition of Martian soil.

It is believed that by understanding the history of water on Mars, one can understand the history of the Martian climate and understand the evolution of the planet, and even the entire solar system. It was discovered that Mars had experienced the largest flood in the solar system about 3.5 billion years ago. Where did the water come from and how long did it last? In fact, Mars still contains a lot of water, but most of it is in the form of ice. In the polar regions of Mars, there are huge white ice caps, which contain a lot of solid carbon dioxide, which also contains a lot of water.

Mars, between science and fantasy
The effect of the “Insight” Mars probe that landed in November 2018

There is also a large amount of ice stored in the soil of Mars. The “Phoenix” probe detected the presence of water at its landing site, and the “Curious” detector detected water in the Martian soil through its own sample analysis device (Sample Analysis at Mars). presence. Scientists estimate that on the surface of Mars, each cubic meter of soil may contain more than 30 liters of water, which is sufficient for future humans to reach Mars to establish a scientific base or permanent residence.

On the other hand, the large amount of water that Mars once owned has indeed been lost, and it has entered the space in the form of water vapor. The most important reason for the loss of Mars water is that Mars gradually loses its own dense atmosphere, which makes Mars unable to maintain its surface temperature and atmospheric pressure, liquid water no longer exists, and the appearance and state of the earth gradually become fundamental. Change and become a red planet that looks bare.

What caused Mars to lose its atmosphere? How does the earth preserve its own atmosphere? Perhaps it is the extremely subtle difference between the two planets that determines their respective fates.

Mars, between science and fantasy
Two NASA engineers measure the “work space” of the Mars lander at the Jet Propulsion Laboratory in Pasadena, California.

Disappearing magnetic field
Mars is only about half the size of the Earth and is about 15% of the Earth’s size. The density of Mars is also slightly smaller than that of the Earth, so its mass is only about 11% of the Earth, and its surface gravity is naturally less than that of the Earth, which is about 38% of the gravitational pull of the Earth’s surface. Because the gravitational effect is weak, Mars’ atmosphere thickness is 11.1 kilometers, which is thicker than the Earth’s 8 km atmosphere, but its temperature is lower and the average molecular weight is lower. When it comes to density, the Martian atmosphere is far less dense than the Earth’s atmosphere and cannot function to regulate temperature and protect the planet’s surface water resources.

At present, the atmosphere of Mars is very sparse (this makes the human Mars probe very difficult to land on the Martian ground), and the surface pressure of Mars is less than 1% of the Earth. As the second smallest planet in the solar system, Mars has a relatively weak gravitational effect and cannot have a dense atmosphere. But further research shows that the gap with the Earth’s gravity may not be the main reason why Mars eventually loses most of its atmosphere. The early atmosphere of Mars may be much denser than the current atmosphere, and the root cause of its change is the direct effect of the Martian atmosphere and the solar wind.

The so-called “solar wind” refers to the flow of high-energy charged particles from the outer layer of the sun. The speed of the solar wind can reach 1.6 million kilometers per hour, blowing to the entire solar system. The high-energy particles of the solar wind reach Mars and interact with the particles in the Martian atmosphere, allowing the particles in the Martian atmosphere to gain enormous energy and are no longer constrained by Mars gravity. The Mars Atmosphere and Volatile Evolution Mission (MAVEN) launched by NASA reached Mars orbit in 2014 to detect the atmospheric conditions of Mars. This detector directly observed the interaction between the Martian atmosphere and the solar wind. These high-energy particles from the sun give the particles at the top of the Martian atmosphere tremendous energy, leaving the Mars and eventually leaving the solar system.

Direct observation of the interaction between the Martian atmosphere and the solar wind has an important role in understanding the history of Mars and even understanding the development of the Earth, and also helps people predict the future of Mars. Based on the observations made by the MAVEN detector, scientists estimate that the Earth’s atmosphere will lose about 100 grams of molecules per second into space. The inclusion of oxygen, carbon dioxide and hydrogen in these losses are important substances that make up life. At the beginning of the formation of the solar system, the intensity of the solar wind is much higher than it is now, so Mars will lose its atmospheric molecules faster than it is now. It has been invaded by the solar wind for billions of years, leaving Mars with the outermost layer and the most important atmospheric protection, allowing most of the moisture on the surface of Mars to enter space in the form of water vapor. Through direct detection of the Martian atmosphere, scientists have also learned that the current sparse atmosphere of Mars is still sufficient to withstand the high-energy charged particles of the solar wind directly attacking the Martian ground – this is for the astronauts to explore the Mars in person, and even establish permanent The human base of Mars is a good thing.

The solar wind has destroyed the atmosphere of Mars to a great extent, and the fundamental changes have taken place in the Martian environment. Will such a tragedy occur on Earth as well?

At least for now, humans need not worry about it. Fundamentally, the earth has been alive for billions of years, and the dense atmosphere is not attacked by the solar wind because the earth’s core area is mainly composed of liquid metal under high pressure. The flow of liquid metal in the earth’s core forms a global magnetic field. This area covered by a strong magnetic field is called the magnetosphere. The Earth’s magnetosphere is like a strong protective shield, so that the gas molecules at the top of the Earth’s atmosphere do not have to interact directly with the high-energy particles in the solar wind. Therefore, the loss of molecules in the Earth’s atmosphere is far less than that of the Martian atmosphere, which makes the Earth in dozens of times. For hundreds of millions of years, it has been wrapped in a dense atmosphere to regulate the ground temperature and protect the earth’s water resources. As long as the core of the earth does not cool, the earth’s global magnetic field does not disappear, and humans will not lose the powerful magnetic layer, and there is no need to worry about losing the earth’s atmosphere.

From this result, it is conceivable that in the early days of Mars formation, its natural environment may be similar to Earth, suitable for the existence of life. Scientists speculate that Mars once had a global ocean about 4.3 billion years ago, and its water volume may be larger than that of the Earth’s Arctic Ocean. As the Martian atmosphere weakens, most of the water in Mars’ oceans gradually diminishes. It is water vapor and disappears into space.

So, has Mars once again had a global magnetic field like Earth? According to the probe, although the current Mars does not have a global magnetic field, a part of the Martian crust is magnetized. This shows that before Mars had a global magnetic field and the magnetic field had undergone a magnetic pole change. It is quite possible that Mars lost its global magnetic field protection about 4 billion years ago. How Mars lost its global magnetic field, there is no definitive answer yet. This may be due to the impact of asteroids, and scientists suspect that because the core of Mars is no longer filled with molten metal like the core, but gradually cooled, lost fluidity, resulting in the disappearance of global magnetic fields.

At present, humans do not know much about the internal structure of Mars. What we already know is that metal elements such as iron and nickel, as well as some sulfur, form the core of Mars with a diameter of 1,800 kilometers. The mantle portion of Mars is rich in silicon and oxygen, and the average thickness of the crust is 50 kilometers. The thickest place can reach 125 kilometers – compared to the average thickness of the Earth’s crust is only 40 kilometers. There are still many questions to answer: Is the solid metal stored in the core of Mars still in a liquid state or a solid metal that has gradually cooled? Is Mars similar to Earth, and there are plate movements that allow the resources of the entire planet to circulate, thus promoting the generation and reproduction of life phenomena? Still relatively static, there is no violent collision between the plates?

Human exploration of the internal structure of Mars is underway. NASA’s Mars Inspector (InSight) successfully landed on Mars in November 2018. It carries an extremely sophisticated seismograph to detect and collect seismic waves from Mars. This is the understanding of Mars internal structure. The most direct and accurate way. Similar to the method of detecting the Earth, the most accurate way to understand the internal structure of a planet is to listen to its heart and understand the structure of the entire planet by collecting seismic waves from its interior and throughout the planet.

What is the current state of Mars’ core, is it similar to the Earth’s plate activity, and will there be active volcanic activity? In the days of Mars, these are the most important issues to be solved by the “Insight”. After experiencing a thrilling Mars landing in November 2018, the “Insight” has begun to arrange various scientific instruments on the surface of Mars. It places a high-precision seismograph on the surface of Mars and a semi-circular copper cover on it to protect the seismograph from the atmospheric motion of the surrounding Mars. At present, the seismograph, which is called “The Seismic Experiment for Interior Structure”, has begun to collect seismic signals from Mars.

In addition to seismographs, a scientific device called The Rotation and Interior Structure Experiment will also detect its internal structure by accurately measuring the rotation of Mars. In late January 2019, the “Insights” will begin to arrange another scientific instrument, a thermal sensing probe called “The Heat Flow and Physical Properties Package,” which will be from Mars. The surface of the surface drills down a hole as deep as 5 meters, and probes the temperature change of the surface soil of Mars through a probe to study the heat transfer inside Mars and understand the structure of Mars from another aspect.

The intersection of science and fantasies
For this nearby planet, which is 54.6 million kilometers away from the Earth, with a maximum distance of 401 million kilometers and an average distance of 225 million kilometers, humans have already launched several landers, rover or satellites to inspect. Some of them work on the orbit of Mars, some on the surface of Mars, and some on the surface of Mars. At present, there are eight artificial satellites such as “2001 Mars Odyssey”, “Mars Express”, Mars Reconnaissance Orbiting Satellite, Mars Atmosphere and Volatile Evolution Mission, Mars Orbiter and Mars Trace Gas Mission Satellite, which are detected on Mars orbit. There are also “Curious” rover and “Insight” detectors for on-the-spot detection on the surface of Mars. The Opportunity Mars once encountered a sandstorm on the surface of Mars. Because of the lack of electricity, it entered a dormant state, but the staff on Earth still hope that it will wake up one day.

These achievements are great, but for Mars, human beings still have an ambition that has not yet been realized. That is to let human astronauts fly from the earth, leap over tens of millions of kilometers of the universe, set foot on Mars, and step out of the history of human civilization. step. When will humans be able to board Mars, when will they build a base on Mars and open up another home for humans like the scenes in the movie? Is it possible for humans to exploit the minerals of Mars and achieve interstellar trade between Earth and Mars? These imaginations about Mars are not only scientific but also about human madness and ambition. In the face of Mars, human beings seem to have come to another era of great voyages – the danger of death and the infinite possibility of coexistence. In the face of such a situation, fearless ambitions, ambiguous madness, or perhaps can reach the point of reason beyond reason.

With regard to Mars exploration, NASA has been working step by step for decades and has achieved its goals step by step in accordance with established plans. After launching Mars satellites and detectors, they are currently preparing to send human astronauts to Mars in the 1930s. From the Earth to Mars, human beings need a complete set of reliable life support systems. The surface of Mars is thin and the spacecraft needs to consume a lot of energy to slow down. The difficulty is far more than the launch of unmanned Mars. A nine-month trip in space, away from the Earth’s homeland, is also a great psychological test for astronauts. Given these factors, scientists and engineers need to be extra cautious.

On the other hand, SpaceX’s plan to explore Mars is far ahead of NASA, and company CEO Elon Musk is often amazed. Musk once released his words, to send 1 million people to Mars in this century, to build a human Mars base and even a permanent Mars city. Considering the existing technology of mankind and the results of detecting Mars, such words are tantamount to idiotic dreams. But as a world-renowned entrepreneur, Musk has also often achieved unexpected success – his fearless attitude to explore Mars is also likely to make a breakthrough in unexpected ways.

In early January 2019, Musk displayed an aircraft called “Satrship” on his “Twitter” account to replace the “Great Falcon Rocket” that was previously planned to fly to Mars. Falcon Rocket). From the big Falcon rocket to the starship, the aircraft will change from shape to material, which will inevitably delay the time, and will also make the observers feel that space exploration technology company is not enough to fly to Mars. But the starship is not just a concept empty shell – the starship used for testing has been assembled and entered the experimental phase – which is enough to make people feel the determination of Musk. Even though Musk himself later admitted that it would take at least 100 years for humans to establish a permanent base on Mars, he still believes that his space exploration technology company can send human astronauts in the 2020s. On Mars. When asked if he was also ready to board Mars, he gave a probabilistic answer: the probability is 70%.

Is a pioneering exploration of a planet full of unknowns based on the power of a government, step-by-step, step-by-step, or a bold attempt by a private company that is often unexpectedly more likely to succeed? Only time will give us the answer.

If we look farther into the future, in the farther future, is it possible for humans to build their homes on Mars and get wealth on Mars? If humans want to immigrate to Mars in the future, they need to be able to create a natural environment similar to Earth on Mars. Is this possible? There is still much controversy.

Is it possible to recreate the atmosphere of Mars? At the time of the interview, Musk had an amazing story. He believed that the quickest way to recreate the Martian atmosphere was to heat up the surface of Mars and turn the solid carbon dioxide stored in the polar regions of Mars into a gaseous state, allowing the Martian atmosphere to quickly fill up— – The most direct way to achieve this goal is to drop a nuclear bomb in the polar region of Mars, use the high temperature of the nuclear bomb to heat the surface of Mars, and then rebuild the atmosphere of Mars.

If you don’t use too extreme means, but you are eager to seek success, according to research, humans do have the possibility to gradually change the Martian environment. Maybe you can start by having Mars own a magnetic layer. Humans now have research on micro-man-made magnetosphere to protect astronauts and spacecraft. In theory, it is also possible for humans to create an artificial magnetic layer covering Mars to protect it from the solar wind. NASA scientists have shown through computer simulations that under the protection of artificial magnetosphere, the gas pressure in the Martian atmosphere will gradually increase, and the solid carbon dioxide stored on the surface of Mars will enter the atmosphere, producing a greenhouse effect, and then further enhancing the surface of Mars. The temperature, which eventually melts the water ice on the surface of Mars, may create an environment in which humans can survive. If this can be achieved, then perhaps in the distant future, humans can transform a cold, barren land of acidic substances into a warm environment suitable for human habitation.

There are even people who imagine that guiding small objects in the solar system to strike Mars to raise the surface temperature of Mars – even if the plan is implemented, thousands of impacts will be needed to achieve effective warming. The surface of Mars will be riddled with holes. Whether it’s a nuclear bomb madness or a computer simulation, considering the issue of Mars’ permanent life and even large-scale immigration to Mars when humans have not yet set foot on Mars, it is still too far away to be practical.

Considering the current state of mankind, Mars in the night sky is too far away, and humans’ current desire for Mars is still mostly between science and fantasy. Then, if we look at Mars in a more practical way, we will naturally ask, what resources are there on Mars? Can humans create wealth through Mars?

The volcanic landscape of Mars is similar to the Large Igneous Provinces on Earth. In this area, a large amount of magma emerged from the ground, which contained a lot of metal elements such as nickel, copper, titanium, iron and platinum. , palladium and chromium. In addition to the igneous rock area, near the crater on the surface of Mars, because of the impact of meteorites, some of the deep minerals in the crust are exposed. As the water in the impacted area melts and evaporates, some of the components in the rock are filtered out and condensed into pieces. In some similar areas of the earth, humans have discovered some precious rare metals. If similar to the situation in the Earth, the “Curious” that is currently being explored near the Martian crater will be able to detect the rare minerals found on Mars.

Contrary to the plot in most science fiction movies, if we measure Mars from a commercial perspective, I am afraid there is not much attention on this red planet. Whether it is precious metals or rare minerals, considering the cost of transportation, it does not seem worthwhile for humans to travel and transport hundreds of millions of kilometers to and from the universe. Musk also said that if you want to make money through Mars, you can only hope to make a breakthrough in the research process and get rich through intellectual property.

No matter how far away, Mars is the most suitable planet in the solar system for human exploration and immigration, because it has the potential to make humans self-sufficient on it—although it may require millions of people to support it. Until then, the Mars base will still need the support of the Earth. It is conceivable that if human beings are really capable of establishing research bases on Mars and even immigrant tribes in the future, the resources contained on Mars will be used by others. The rich clay in Martian soil can be used to make pottery and porcelain, and a large amount of silica can be used to make fiberglass. Various metal materials can be used to make houses and tools, and then get energy through nuclear reactors and solar panels.

In the thousands of years of human history, Mars has been a bright and unreachable star in the night sky for most of the time. Only when human beings use the power of science to look at the universe can they understand that Mars is the brother and neighbor of the earth. In a few billion years, a blue, a fiery red. By studying Mars, humans will understand that the emergence of life is a real miracle, and life is so fragile.