Main Blue Chimera

Gavriil Adrianovich Tikhov

Is there life on other planets?

Basic properties of the main planets of the solar system

There is a young new Soviet science – astrobiology.
The word “astrobiology” consists of three Greek words: astron – luminary, bios – life and logos – teaching.
Therefore, astrobiology is the science of life on the luminaries (it means – on the heavenly bodies).
An integral part of astrobiology is the science of astrobotany, that is, the science of plants on other planets.
– Excuse me! – The reader will say. – What planets are you going to talk about? Introduce them first.
Yes, the reader is right.
We will talk about the planets of our solar system and introduce the reader to their basic properties. There is the Sun at the center of our solar system. The planets – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto – are moving around it.
The first five planets, except, of course, the Earth, were already known in ancient times. The ancient Romans named them after their gods.
The planet Mercury orbits the Sun in just 88 days. Therefore, the Romans named her after the god Mercury; as a messenger of other gods, he must “quickly carry out the tasks given to him”.
The second planet was named after Venus, the goddess of beauty. This planet is brighter and more beautiful than all other planets and stars. It can be seen in the east before sunrise and in the west after sunset. That’s why people call it the morning or evening star.
For the orange color, somewhat resembling the color of fires and blood, the planet Mars was named after the Roman god of war.
The next planet was named by the Romans in honor of the chief god – Jupiter. It is second in brightness only to Venus and makes its way around the Sun in 12 years.
The last of the planets known in ancient times – Saturn – is named after the god of death for its dead greenish color.
In the XVIII, XIX and XX centuries, three more planets became known, also named after the gods of the Romans: Uranus (god of the sky), Neptune (god of the sea) and Pluto (god of the underworld).
All the planets (except Pluto, which is still very poorly known) are sharply divided into two groups by diameter, mass and density. Mercury, Venus and Mars differ little from Earth. They are called earth-like ones. Jupiter, Saturn, Uranus and Neptune are giant planets. They are very large, have large masses and low density.
The time of rotation around the axis of giant planets is much shorter than that of Earth-like planets. In addition, Jupiter and Saturn rotate not like a solid body, but in accordance with the zones: the farther away from the equator, the slower the rotation. Therefore, from Earth we observe not the solid surface of Jupiter and Saturn, but their atmospheres.
The masses of the giant planets are many times greater than the mass of the Earth: the mass of Uranus is almost 15 times, Neptune is 17 times, Saturn is 95 times, Jupiter is 318 times greater.
Jupiter has a powerful gravitational force and can hold even very light gases around it.
The density of the giant planets is only slightly greater than the density of water, and Saturn has even lesser one. The outer layers of giant planets are gaseous or consist of very light substances. Their atmospheres reach an enormous thickness, tens of thousands of kilometers.
People may ask, how do the physical and chemical properties of atmospheres are studied?
Using the method of spectral analysis, you can find out these properties. What is spectral analysis?
Take a glass prism and let the light of the Sun pass through it. The light will decompose into its component parts in the form of a color band called a spectrum. In its structure, the spectrum is similar to a rainbow with more clearly separated colors.
The Sun’s rays coming from the observed planet, for example, from Mercury, before entering the observer’s eye, pass through its atmosphere twice: falling on the planet and then reflecting off the surface. The atmosphere partially absorbs some of the sun rays. Each of the gases that make up the planet’s atmosphere absorbs only certain rays. This is expressed by dark lines in the corresponding places of the spectrum. Dark lines are used to judge the nature of gas.
So, using the spectrum, you can find out which gases the light of the Sun and planets passed through, find out what gases their atmosphere consists of.
To photograph the spectrum, a special device is used – a spectrograph. It makes it possible to determine which rays were absorbed by the atmosphere. Photography allows you to capture light weaker than the one that is captured by the eye, and also infrared and ultraviolet rays that are not visible to the eye.
We observe planets through the Earth’s atmosphere, but not outside it. The light of the Sun, passing through the Earth’s atmosphere, loses in it those parts of the spectrum that are absorbed by the gases of the Earth’s atmosphere.
Imagine that you were able to observe the planets from outside the earth’s atmosphere. Then, in the spectrum of a planet with oxygen in its atmosphere, you would see absorption lines of this gas. But when observed through the Earth’s atmosphere, which has a lot of its own oxygen, giving dark lines in the spectrum, the planetary oxygen lines sink in the lines of terrestrial oxygen, and they are very difficult to distinguish.
Here is another example. There is no doubt that there is water on Mars. Meanwhile, spectral analysis does not detect water vapor in the Martian atmosphere. Why so? Because the Martian water vapor lines sink into the water vapor lines in the Earth’s atmosphere.
Mercury is two and a half times closer to the Sun than the Earth. Therefore, the temperature on it is much higher than on our planet. In addition, Mercury is always facing the Sun with one side. On this sunny side of Mercury, the temperature reaches 340 degrees above zero, that is, almost the melting point of lead. And on the opposite side of Mercury, eternal darkness and cold prevail.
With the high temperature of the solar side and the low gravity on Mercury, the atmosphere could not hold in any significant amount. Observations reveal barely noticeable traces of the atmosphere on Mercury.
But the planet Venus is surrounded by a dense atmosphere, discovered by M. V. Lomonosov in 1761. The solid surface of this planet is not yet observable, and we know little about the atmosphere of Venus. Basically, its atmosphere consists of a huge amount of carbon dioxide. There is 500 times more of it there than in the Earth’s atmosphere.
With the great similarity of Venus with the Earth (in size, mass and density), no water vapor and oxygen were found in its atmosphere.
The absence of water vapor in the atmosphere of Venus is not difficult to explain. The Earth’s atmosphere contains 1.2 percent of water vapor at ocean level, and only 0.01 percent at an altitude of 11 kilometers. Suppose that the height of the clouds above the surface of Venus is 11 kilometers. Then the water vapor content above them should be too negligible to be detected by spectral analysis.
Why there is no oxygen found in the atmosphere of Venus – we will tell it to you further, but for now we will move on to Mars.
Carbon dioxide has been detected in the atmosphere of Mars and, moreover, in an amount twice as large as in the Earth’s atmosphere. As for water and oxygen vapors, they are beyond the limits available to observation from Earth. Meanwhile, science has established that there is water on Mars. Therefore, there must be its vapors in the atmosphere of Mars. Why doesn’t spectral analysis detect them? Probably because spectral analysis in this case cannot overcome the masking influence of water vapor and oxygen of the Earth’s atmosphere.
One can think that there is a significant amount of nitrogen in the atmosphere of Mars. But it has not yet been possible to detect it either, since nitrogen has no absorption lines in the observable parts of the spectrum.
Soviet astronomers have received accurate data on the pressure of the atmosphere on Mars. Its density is the same as at an altitude of 10-15 kilometers above the Earth’s surface.
In the atmospheres of the giant planets (Jupiter, Saturn, Uranus and Neptune), methane gas (a chemical compound of carbon with hydrogen) is found in large amount.
At normal pressure and normal temperature, the thickness of methane in the atmosphere of Jupiter is 150 meters, of Saturn – 350, of Uranus – 1500, of Neptune – 2500 meters. The amount of methane from Jupiter to Neptune is greatly increasing. But this increase is largely apparent. It is explained by the presence of ammonia.
In the atmospheres of Jupiter and Saturn, ammonia is in a gaseous, drop-liquid and solid state. Probably, the clouds floating in their atmospheres consist of droplets and crystals of ammonia, as well as other substances unknown to us so far. Blocking the underlying layers of the atmosphere from us, clouds reduce the influence of methane on the spectrum of Jupiter and Saturn.
Uranus and Neptune are of a different matter. The temperature in the upper layers of the atmospheres of these planets is already so low that all the ammonia has turned into crystals that have settled into deeper, denser layers. The methane atmosphere is visible here in its entire thickness, the light of the Sun penetrates far into the depths, passes back the same way and gets to Earth into the astronomer’s instruments.
Thus, the increase in methane content in the atmospheres of giant planets from Jupiter to Neptune may not be a real phenomenon, but only apparent one. We will need this thought when considering the possibility of life on giant planets.
Let us recall the history of the question of life on other planets.

Life is widespread in the universe.

Many people believe that the Earth is the only carrier of life. By the way, that’s what religion says.
After all: is life possible on other planets?
The idea of life on planets other than Earth has a very long history. Even millennia before people learned about the true place of the Earth in the solar system, about the true structure of the universe, the idea of the existence of life on other planets interested philosophers and scientists. One can count 110 names of philosophers, scientists, writers, starting from ancient times and almost up to our time, who spoke out for the fact that life is not limited to our planet, but is widespread in the universe.
The most ancient books known to mankind are the Hindu Vedas. They express the idea that, besides the Earth, there are other celestial bodies and that there “human souls are reincarnated”. The Hindu Vedas thus allowed for possible conditions for life on other planets.
Ancient Greek and Roman scientists believed that the Earth is not the only body in the universe on which life exists.
Thus, Metrodorus of Lampsacus wrote that to consider the Earth the only inhabited world in infinite space would be as unreasonable as to believe that only one ear of wheat grows in a huge field.
The Roman philosopher Lucretius wrote that the entire visible world cannot be the only one in nature and we must believe that there are other earths, other beings and other people in other places of the universe.
The belief that the Earth is not the only body in the universe on which life exists was especially strengthened after the great Polish astronomer Nicolaus Copernicus proved that the Earth is not in the center of the solar system, but moves, like other planets, around the Sun. The famous book outlining this discovery was published in 1543 (the year of Copernicus’ death).
And here are the names of some great medieval scientists who lived after Copernicus and believed that the Earth is not the only carrier of life in the universe. In France these people are Descartes and Pascal, in Italy – Giordano Bruno and Galileo, in Germany – Kepler and Leibniz, and in England – Newton.
In the XVIII century, the idea of a multitude of inhabited worlds was expressed by such scientists as Lambert and Laplace in France, Baudet in Germany and by the first Russian scientist M. V. Lomonosov.
In his poem “Evening Reflections” M. V. Lomonosov wrote in 1743:

Before us gapes a well of stars –
Stars infinite, well fathomless…
The mouths of wise men call to us:
A multitude of worlds dwell there,
Among them burning suns untold,
And peoples, and the wheel of time:
There, all of nature’s strength
Exists God’s glory to proclaim"

Showing his brilliant scientific foresight, M. V. Lomonosov wrote more than two centuries ago that on other worlds “all of nature’s strength”.
We, materialists, think that life is the highest stage of the development of matter, and it should arise wherever there are conditions for it. Consequently, life exists not only on Earth, but also on countless other bodies of the universe. Science proves it. Scientists proceed from the fact that the properties of life in the Universe are essentially the same, but different in form and manifestation, and that the adaptability of life to environmental conditions is very great.
The idea that the laws of life in the universe are essentially the same, is expressed by M. V. Lomonosov in the words “all of nature’s strength”.
The main elements that make up living matter are everywhere carbon, nitrogen, oxygen and hydrogen. However, the form in which the chemical compounds of these elements are clothed can and should be extremely diverse depending on the physical and chemical properties of the environment. At the same time, the performances of the vital processes of both an individual organism and the whole species and genus, etc., are extremely diverse.
In recent decades, the study of the question of life in the universe has been much advanced. The study of life in the depths of the ocean, which seemed inaccessible previously, as well as Soviet research in the Arctic have expanded our understanding of the limiting properties of the environment in which plant and animal life is possible. The research of S. N. Vinogradsky, V. I. Vernadsky, L. S. Berg and other Russian and Soviet scientists has shown the amazing adaptability of living organisms to the most exceptional environmental conditions.
Currently, science has some important information about the physical and chemical conditions on the planets of our solar system. Based on modern scientific achievements, it is possible to draw certain conclusions about the existence of life on other planets.
Anyone with knowledge of the structure of the universe cannot be opposed to the idea of the existence of life on other planets.
However, even today there are people who deny the possibility of life on those planets that are very close to Earth on an astronomical scale. These planets orbiting the Sun are more or less similar to the Earth in some properties. Some scientists are also skeptics. “If we pull the rug out from under the feet of those who are looking for life on the planets of the solar system” – these scientists probably argue – “then we won’t have to talk about life in the big Universe. It is unlikely, they say, that in any foreseeable time it will be possible to get to the observation of such phenomena in the big Universe that would give indications of life”.
These scientists have come up with a disguise and are trying, as in the time of M. V. Lomonosov, to refute life outside the Earth. But then the ardent opponent of the idea of life outside the Earth was mainly religion.
For example, the English astronomer Jeans in his book “The Movement of the Worlds” writes: “Life existing on our earth is the only life in the solar system… We must consider life as a disease that matter begins to suffer from in its old age. The universe is actively hostile to life...”*

* Translator needs help in identifying the name of the book and the original author’s phrase.

We hold the opposite point of view. We are convinced that if the existence of life on at least one planet of the solar system other than Earth is proved, then this will confirm the correctness of the dialectical view of the widespread prevalence of life in the Universe.
Below we will tell you why Soviet science paid close attention to Mars. And now we will only briefly express the idea: if there is vegetation on Mars and it is largely proven, then such a discovery testifies to a lot of things. The question of vegetation on Mars is an integral part of the general problem of the existence of life in the universe.

What scientific observations have revealed on the planet Mars

Mars is one and a half times farther from the Sun than the Earth, and makes a complete revolution around the Sun in 687 Earth days. Mars is surrounded by a fairly transparent atmosphere. On its surface, more or less dark spots are visible through the astronomical tube, according to which it was determined that Mars rotates around its axis in 24 hours and 37 minutes. The axis of rotation of Mars is tilted in the plane of its path around the Sun at an angle of 65 degrees, that is, almost like the Earth, whose corresponding angle is 66.5 degrees.
As you know, the seasons change from the inclination of the earth’s axis to the plane of its orbit. Therefore, on Mars, in each of its hemispheres, there is a change of seasons. Since the year of Mars is almost twice as long as that of Earth, the seasons on it are almost twice as long as those on Earth. As on Earth, the seasons on Mars are opposite in the two hemispheres. For example, if it is spring in the northern hemisphere, then autumn in the southern hemisphere, etc.
It has long been noticed that when autumn ends in one or the other hemisphere of Mars and winter comes, a bright white cap forms around the corresponding pole. With the onset of spring, this cap gradually disappears from the side of the equator, and by the middle of summer, only a small spot remains from it, the color of which turns into green-blue.
I was interested in the question of plant life on the planet Mars in 1909, when there was the so-called near approach of Mars, during which it comes especially close to the Earth. However, this proximity is purely astronomical. The distance from Mars to Earth is then still 56 million kilometers. Such an approach of Mars happens once every 15 or 17 years. With the least favorable opposition coming in about 81/2 years (after the near approach), the distance between Mars and Earth is 99 million kilometers.
Take a look at the diagram, which shows the orbit of the Earth and the orbit of Mars, indicating the oppositions of Mars in the period from 1939 to 1956.

The closest approach happens when Mars crosses the line on which the word “Perihelium”, which means the closest distance from the Sun, is written. In recent decades, the closest to the perihelium opposition of Mars was in 1939, and the next occurred in 1956.
It is during the closest approaches of Mars that astronomers can study its nature with the greatest success.
In 1909, when there was one of the great oppositions of Mars, I worked at the Pulkovo Observatory, studying mainly the optical properties of interstellar space. However, such a relatively rare astronomical phenomenon as the great opposition of Mars made me want to photograph Mars with the help of a huge Pulkovo refractor, the lens of which had 75 centimeters in diameter and a focal length of 14 meters. Despite this, it formed the diameter of Mars of only 1.5 millimeters on the photographic plate.
N. N. Kalitin, a student of St. Petersburg University, who later became an outstanding researcher of solar radiation, helped me in the observations of Mars.
Our goal was to study the physical properties of Mars and, in particular, the possibility of vegetation on it.
And how to achieve this? It was necessary to start with the study of the color of various places on Mars. So, it was necessary to photograph the planet in rays of different colors.
We have made light filters – dark red, light red, yellow and green.
The observations were made in August, when it was the end of summer in the southern hemisphere of Mars. We caught Mars through the slightest gap in the clouds, through any enlightenment in the fog, which quite often covered the sky.
The most steady images of Mars were on foggy nights. Each exposure time of the Mars photograph lasted only a few seconds. We managed to get about a thousand two-color images. Some of them allowed us to make a number of completely new scientific conclusions.
It turned out that on Mars, the polar cap at the end of the melting acquired a greenish color, and before that it was white. Having discovered this, we photographed a large block of ice and snow on the Earth in the same way. We made sure that the color of the polar cap of Mars at the end of its melting is the same as that of ice on Earth. So, on Mars, the polar caps consist of the same snow and ice as on Earth. When these caps melt on Mars, water and water vapor are obtained. But after all, water is one of the basic substances necessary for life. The presence of water on Mars reinforces the idea that life is possible on it.
By the way, in 1948, one astronomer in the United States of America confirmed with a completely different observation that the polar caps of Mars consist of snow.
Observations have refuted the misconceptions that the polar caps of Mars consist of frozen carbon dioxide or even salt mottles.
According to its physical properties, Mars is more similar to Earth than all other planets.
Our observations in 1909 established that the famous “channels” of Mars have the same color as the “seas” of Mars, which are considered areas of vegetation. We have discovered the similarity of the optical properties of the Martian atmosphere with the optical properties of the Earth’s atmosphere.

Mars according to drawings (through light filters) by G. A. Tikhov. Photographing was carried out in Pulkovo through a 15-inch refractor on May 13, 1920. In the northern hemisphere it is midsummer, and in the southern hemisphere it is midwinter.

The spectrum of the Sun and the spectrum of the green plant.

Exploring the question of the possibility of a plant world on Mars, we can say that we descended from Mars to Earth to study the optical properties of terrestrial vegetation, so that we could then transfer back to Mars and draw conclusions to which kind of green plants the vegetation cover of a particular section of the “seas” of Mars is most suitable.

Drawing of Mars through a red light filter, according to observations through the Pulkovo 15-inch refractor on April 23, 1918.

In 1909, we were interested in a section of the solar spectrum in red rays, which is strongly absorbed by chlorophyll, the green substance of the plant. After all, chlorophyll is of great importance for plant life. With its help, they form the first organic substances (sugar, starch, cellulose) from carbon dioxide absorbed from the air and water, and the released oxygen at the same time is released into the atmosphere. Due to this, the air on the Earth contains oxygen, which is necessary for the respiration of animals and plants themselves.

Drawing of Mars through a red light filter, according to observations through the Pulkovo 15-inch refractor on April 24, 1918.

However, in 1909 we had not yet discovered the absorption by chlorophyll of red rays falling on the plant on Mars. After all, the research was just beginning. However, what we discovered in 1909 testified to the possible conditions of life on Mars.
In 1918 and 1920, I again observed Mars at the Pulkovo Observatory. Then, in the Martian areas, where vegetation can be assumed to exist, I was looking for special properties in their light inherent in terrestrial vegetation. But the search at that time did not yield results.
The mystery remained unsolved for a number of years.
In 1939, at the Tashkent Astronomical Observatory, an expedition of Leningrad University, led by Professor V. V. Sharonov, found that in the infrared rays “seas” of Mars, which are considered vegetation, come out not light, but dark, unlike terrestrial vegetation. There was a riddle again.
And when people are faced with a riddle, someof them are not averse to making the wrong conclusions. On Mars, they say, the climate is very harsh, there is little water, oxygen, and there is no ozone in the atmosphere that absorbs short-wave rays that are disastrous for life, and then the “seas” of Mars come out very dark in infrared rays – it means there is no vegetation on Mars!
This idea was also supported by the fact that Martian vegetation, unlike terrestrial vegetation, is not green, but cyan, blue and even purple.
You, the reader, are used to seeing green plants on the Earth. And someone tells you that there are plants on Mars too, but they are cyan, blue or purple in color. Maybe you’ll even say, “How is it that the plants are of cyan or purple color?”
Maybe you’ll consider it a joke or a fairy tale.
Let’s see how science solved the riddle.
In 1945, in Alma-Ata, during a lecture on the possibility of life on other planets, I said that one of the main objections to the existence of vegetation on Mars is the lack of reflection of infrared rays by its vegetation covers.
After the lecture, agrometeorologist A. P. Kutyreva asked me:
– Isn’t this feature a consequence of the harsh climate of Mars, since infrared rays carry almost half of the sun’s heat, and Martian plants must absorb these rays for warming?
Agrometeorologist A. P. Kutyreva explained her question with very important considerations. Martian plants could change their properties in relation to terrestrial ones in the process of adapting to the harsh Martian climate. Consequently, the optical properties of the Martian vegetation must be very different from the optical properties of the vegetation of the Earth.
I was interested in these conclusions.
Back in the early 30s, E. L. Krinov and I worked at the Institute of Aerial Photography in Leningrad. He collected a wealth of material related to the study of brightness of plants of different climatic zones in different rays. E. L. Krinov’s materials made it possible to compare the optical properties of polar and Central Russian plants, as well as summer-green and coniferous plants. It turned out that polar and winter-green plants are closer to Martian plants in their optical properties than deciduous plants.
Maybe you, the reader, have not studied botany and physics. Therefore, we will try to give a detailed explaination here.
We have already talked about the spectrum. With the help of a prism made of glass or other transparent substance, as well as with the help of special devices, it is possible to split the light of any source, for example the Sun, into component parts, giving together the so-called spectrum.
Our eye sees red, orange, yellow, green, cyan, blue and purple colors in the spectrum. But before the red rays there are infrared, or trans-red rays invisible to our eye, and the violet rays are followed by ultraviolet rays, also not visible to the eye.
The infrared rays of the Sun carry almost half of the heat, red, orange, yellow and green rays – one third, and cyan, blue, violet and ultraviolet rays – one sixth of it. Therefore, red, orange, yellow and green rays are sometimes called warm rays, and cyan, blue and purple rays are cold.
How do ordinary plants act in relation to especially warm infrared rays?
Take a photo of a green plant using an ordinary photographic plate, which, as you know, is most sensitive to blue rays. If the tree is projected onto the sky, then on the positive the sky will turn white, and the tree will turn dark.
Then take a photo of the tree in infrared rays. Then, on the positive, the sky will come out dark, and the tree is completely white, as if covered with a thick layer of snow.
Meanwhile, there is no such phenomenon on Mars. On the contrary, the vegetation of Mars, when photographed in infrared rays, comes out especially dark.
To solve the riddle, we decided to photograph the spectrum of sunlight scattered by the foliage of summer-green and coniferous plants living in the harsh climate of high mountains and the Subarctic. We organized expeditions to study the spectral properties of plants in harsh climatic conditions.

On the way to the Cold desert of the Central Tien Shan. August 1949.

It has been found that many of these plants look in infrared rays exactly like Martian plants.
By the way, coniferous plants, when photographed in infrared rays, look twice as bright in summer as in winter. This means that in summer these plants emit warm infrared rays twice as much as in winter. Consequently, in summer, infrared rays give the plant too much heat, and the plant gets rid of them to a large extent.
Let’s take two pairs of plants: the first is green oats and polar juniper, the second is birch and spruce. The reflection of infrared rays in coniferous plants – spruce and juniper – is 3 times less than in birch and green oats. This means that summer-green plants do not need infrared rays, so they are reflected. For polar juniper, which lives in a harsh climate, and for spruce, which does not lose its greenery in winter, infrared rays are necessary for warming, and therefore they are reflected weakly.
The Tien Shan spruce reflects less infrared rays the higher it grows in the mountains.
It became clear to us that in the very harsh Martian climate, plants should treat infrared rays extremely carefully and absorb them into themselves, instead of reflecting them.
This conclusion was the first achievement of science, born in Alma-Ata 10 years ago and called astrobotany, from a combination of the words “astronomy” and “botany”.
The development of astrobotany moved so fast that already at the end of 1947, the Presidium of the Academy of Sciences of the Kazakh SSR approved the first sector of astrobotany in the world with researchers and graduate students.
Let us now turn to other riddles that the question of plant life on Mars has encountered.
When studying the spectrum of sunlight reflected by a green plant, a dark band is noticeable in the edge red rays, resulting from the absorption of these rays by a green substance that gives its color to the plant and is called chlorophyll, which in Russian means “leaf green”.
The Russian scientist K. A. Timiryazev showed with his long-term research that the life of a plant in the sense of using sunlight mainly depends on the absorption of that part of the spectrum where the absorption band of chlorophyll is located.
It seemed natural to expect that Martian plants should also have a chlorophyll absorption band. K. A. Timiryazev also thought about this. He asked the American astronomer Lowell, if he had observed chlorophyll bands on Mars?
The answer was that for 14 years Lowell and his staff have been looking for this band on Mars, but they have not found it. Lowell explained it by technical difficulties arising from the fact that the image of Mars in the focus of the tube is very small, and the places where vegetation can be assumed occupy a small part of the planet’s surface, therefore it has not yet been possible to solve such a difficult question.
We searched for the same strip on Mars in 1918 and 1920 and did not encounter any technical difficulties. But the stripes were still not found.
We had to accept as a fact that there is no chlorophyll absorption band on Mars.
“But if there is no absorption band of chlorophyll, then is there no vegetation on Mars?” the reader will ask.
Do not rush to such a conclusion. Remember that Mars has an extremely harsh climate.
Back in 1946, we came to the conclusion that the reason for the absence of a chlorophyll absorption band on Mars is again the harsh climate of this planet.
In fact, if in the mild climate of the temperate zones of the Earth it is enough for the vital needs of a plant to absorb a relatively narrow section of the solar spectrum in warm rays, then this is not enough for plants in a harsh climate. The plant should also absorb other warm rays, that is, rays adjacent to the chlorophyll band – orange, yellow and green. As a result, the chlorophyll band becomes barely noticeable or completely invisible.
This theoretical conclusion has also been tested on plants of harsh climate and confirmed. It turned out that many plants of the high mountains and the Subarctic do not have a noticeable band of chlorophyll.
What’s going on here? It is possible that chlorophyll itself does not change its optical properties, but it is surrounded by other coloring substances – pigments that help the plant to absorb rays adjacent to the chlorophyll band.
This phenomenon also made it possible to explain another difficulty in assumption about the vegetation on Mars. Observers of Mars agree to say and write that the Martian vegetation is not green, but cyan, blue and even purple. If the plant noticeably absorbs warm, that is, red, orange, yellow and green rays, then cold rays – cyan, blue and purple – gain preponderance in the light reflected by the plant. Consequently, the plant acquires the appropriate color.
This conclusion has also been tested on terrestrial plants living in harsh climatic conditions. Of coniferous plants, the white spruce, whose homeland is harsh Canada, is especially characteristic. On the Tuyuk-Su moraine, near Alma-Ata, at an altitude of 3.400 meters, squat cushions of the locoweed grow, the leaves of which have a pronounced bluish bloom.
But especially interesting results were brought from the Pamirs by agrometeorologist A. P. Kutyreva, who visited this place in the summer in 1950 and 1951.
Before the hiking up the Altai Ridge of Pamir in the river valleys, large expanses of floodplain meadows, as well as high and dry places of the river valley have a brownish-purple or entirely bluish-purple hue. This involuntarily causes comparison with the coloring of those parts of the surface of Mars where there are areas of vegetation.

The cold desert of the Central Tien Shan, in the vicinity of the high-altitude observatory, altitude 3.800 meters. August 1949.

At an altitude of about 4 kilometers in the Pamirs, the great burnet plant, locally known as karabash, grows. Its spikelets are similar to barley spikelets, but they are definitely purple in color. Even more interesting is that if you sow seeds of some varieties of barley there, brought from lower places, then the ears of ordinary green color appear in the first summer. If you gather the seeds of this barley and sow them for the next summer, then the spikelets of already purple color are formed. That’s how quickly the plant adapts to environmental conditions.
So, astrobotany quite naturally explained three seemingly insurmountable difficulties in the optical properties of the plants of Mars. Before the foundation of astrobotany, scientists compared the optical properties of Martian plants with the properties of terrestrial plants living in temperate and hot climates. That’s why there were huge differences.
These differences disappeared when we investigated the optical properties of plants living in a climate close to the harsh climate of Mars in both low temperature and dryness.
There is water on Mars. However, there is very little of it there. There are no large open reservoirs. Dark spots are, as we believe, moist places covered with vegetation. These spots occupy approximately 1/6 of the surface of Mars. The rest of the surface has a pinkish-yellow color, reminiscent of the color of some terrestrial deserts, and therefore it is considered a desert by all researchers.
There are still small dark spots on the Martian deserts, and some of them are arranged as if in chains. This, when observed through an astronomical tube of medium strength or with unsteady images originating from the disturbance of our atmosphere, gives the impression of continuous lines, as if wide channels. It is possible to think that along these chains the conditions for vegetation are more favorable and that vegetation exists on them.
In any case, our observations have shown that the color of these lades, or, as they are called, “channels”, is the same as the color of large dark spots that have long been called “seas”.
However, there is little amount of water on Mars, and there are no seas in the earthly sense. Both the “seas” of Mars and the “channels” are almost certainly places covered with vegetation.
What allows us to make such a conclusion?
The first reason for such a conclusion was that the color of these formations changes with the Martian seasons very similar to seasonal changes in the color of earthly deciduous plants.
As for the “channels”, they must be several tens of kilometers wide in order to be visible from the Earth through astronomical tubes. It is possible that in the middle of these “channels” water spreads on the soil or under the soil, which contributes to the manifestation of plant life. A small amount of moisture explains why the “channels” in very good observation conditions break up into separate sections, and the “channel” gets the appearance of a chain.
There was another difficulty for the hypothesis of plant life on Mars. The point is as follows. From the water in the leaves, when exposed to sunlight (with the action of chlorophyll), the first organic substances – sugar and starch – are formed. In this process, called photosynthesis, into the atmosphere oxygen is released, which animals, and at night the plants themselves, breathe.
However, for respiration, the plant consumes significantly less oxygen than it releases during the day. Meanwhile, there is about twice as much carbon dioxide in the atmosphere of Mars as in the Earth’s atmosphere. The presence of oxygen on Mars has not yet been detected with certainty.
The question arises: where does the oxygen from the atmosphere of Mars go if there is vegetation on it?
This can be answered as follows.
Martian plants release oxygen not into the air, but through the roots into the soil. Therefore, the soil of Mars has a pinkish-yellow color, somewhat resembling the color of oxidized substances (for example, rust). For respiration, plants receive oxygen from the soil through the roots.
Another explanation is that bodies of Martian plants are permeated with air-bearing chambers like terrestrial plants that live partially in water – for example, water lilies, reeds, etc.
Surely there are other possible features of adaptation of Martian plants to environmental conditions.

Plants in harsh conditions of existence

Mars is one and a half times farther from the Sun than Earth, and receives two and a half times less heat. The climate of Mars is much harsher than that of Earth. In the polar regions of Mars in winter frosts reach 70-80 degrees.
At the equator at noon, the temperature sometimes rises to +10 and +15 degrees, but by sunset it drops to zero and continues to decrease during the night, reaching -45 degrees by dawn.
Huge daily temperature fluctuations even at the equator are also explained by the rarefaction of the Martian atmosphere.
The average annual temperature of Mars is significantly below zero, whereas on Earth it is +15 degrees Celsius.

Asian spruce trees in the valley of Lesser Alma-Atinka river.

However, the harsh climate of Mars is not terrible for plants.
On the Earth in the Yakut ASSR, in the region of Verkhoyansk and Oymyakon, the climate is also no less severe. Meanwhile, about 200 species of plants live there.
The adaptability of plants to low temperatures is very high. For example, the white-flowered hellebore plant blooms in winter, often under snow. The unopened buds of the spoonwort on the Siberian shores of the Arctic Ocean endure winter frosts up to -46 degrees, sometimes without snow, and bloom with the onset of next summer.
Sharp fluctuations in temperature on Mars from sunrise to noon are comparable to fluctuations in the Pamirs. Here, the daily fluctuations on the soil surface reach up to 60 degrees. The average annual temperature in the Pamir valleys is negative and is equal to -0.9 degrees for Murghab. Nevertheless, the Pamir vegetation is very diverse.
A sharp change in the temperature of the day and night, most of all affecting the biology of the plant, is the main reason for an expressed increase in the frost resistance of the plant in high-altitude conditions. A constant hardening of plants takes place.
It would be possible to give many examples of plants’ adaptability to low temperatures.
The insignificant amount of water and, consequently, the low humidity of the Martian atmosphere also resemble the climatic conditions of the Pamir – a high-altitude desert. Passing over the highest ridges surrounding the high-altitude desert from all sides, the air currents dry up, leaving moisture in the form of grandiose glaciers and snowfields. The air currents come to the Pamir valleys already with negligible moisture content. During the summer noon hours, when the temperature is at its highest, the relative humidity does not exceed 9-45 percent. To understand the meaning of these figures, it is enough to indicate that a drop in relative humidity below 50 percent already affects a human adversely.
Wild plants in the Pamirs have passed a long way of development and are adapted to the harsh conditions of the highlands. In the Pamirs, the cultivated plant finds itself in a completely new environment, which it does not meet anywhere else in the agricultural zones of the globe. However, for the development of a cultivated plant, all extremes of climate are not insurmountable obstacles.
Pamir hardening gives the plant ample opportunities to endure ground frosts. It makes even potato, which is absolutely nonpersistent to frost, able to tolerate negative temperatures of 7-8 degrees. Spring two-rowed barley with low frost resistance also becomes resistant to frost.
The peculiar atmosphere of the Pamirs transforms plants that normally have high rates of moisture evaporation into plants that evaporate little moisture.
Hence, the extreme dryness of the Martian atmosphere cannot prevent the existence of plants.
Oxygen starvation on Mars also cannot hinder the development of plants. Underwater and swamp plants on Earth have adapted to a reduced amount of oxygen; they have significant reserves of air inside their bodies in the form of wide intercellulars, respiratory roots and other adaptations.
The same can happen on Mars. For photosynthesis, the plant uses carbon dioxide, and there is twice as much of it in the atmosphere of Mars as in the Earth. During photosynthesis, the plant releases oxygen, which is formed by the decomposition of water. Since oxygen is necessary for the plant to breathe, during photosynthesis it can not only release it into the atmosphere, but also store it in various parts, for example in the roots.
In the Earth’s atmosphere, ozone plays the role of a filter that absorbs life-threatening short-wave ultraviolet rays. There is no ozone in the atmosphere of Mars. But the absence of ozone cannot be a reason for denying life on Mars. For many hundreds of millions of years, plants could adapt to the conditions of existence, in particular, to the action of short-wave ultraviolet rays. The origin and development of life on other planets can go its own ways, different from those on Earth.

Asian spruce trees at an altitude of 2400 meters, taken in infrared rays.

After all, life is a natural phenomenon. It is the result of the evolution of matter. If ozone had not appeared in the Earth’s atmosphere, then life would still exist, having adapted to short-wave ultraviolet rays.
We can talk about the disastrous effect of short-wave ultraviolet rays on bacteria, but only on modern ones, not on ones of the oldest geological periods.
Microorganisms were the pioneers of life on Earth. Much later, plants appeared, and oxygen was a result of their vital activity. Oxygen formed that layer of ozone 3 millimeters thick (at normal pressure), which absorbs ultraviolet rays, fatal to modern terrestrial bacteria and other organisms.
We are not yet aware of other absorbers of ultraviolet rays in the ancient Earth’s atmosphere. Whether they were there or not is not the point. The fact is that the pioneers of life on Earth were not afraid of ultraviolet rays.
In Nalchik in 1950, Professor S. M. Tokmachev conducted very interesting research. Two experiments were made. Six corn seeds were taken on wet absorbent paper and placed under the bell jar of an air pump with a volume of 5.5 liters and, for control, near the bell jar. The temperature during the experiments in the bell was kept in the range of 20-22.5 degrees day and night. This corresponds to the summer Martian temperature in the zone of the non-setting Sun. The air pressure was maintained as on the surface of Mars.
In the first experiment, the air in the bell was changed twice a day and the plants were kept under pressure from 20 to 70 millimeters of mercury for three days.

Tien Shan fir trees at an altitude of 2.400 meters, photographed simultaneously in blue rays.

The sprouts at the beginning of leaf development had definitely better development than in the control seeds.
In the second experiment, the same germinated seeds were transferred to conditions of non-changing air dilution within 18-22 millimeters of pressure and kept without air exchange for five days. The development of the leaves slowed down in comparison with the development of the leaves of the control seeds, but the sprouts retained a fresh appearance. There were no signs of wilting.
Two conclusions can be drawn from the experiments. The first is that corn seeds would germinate well before the development of leaves if they were planted on Mars. The second is that in an ordinary greenhouse, corn seeds could germinate before the development of leaves at altitudes up to 25 kilometers in the conditions of the Earth.
So, life on Mars is possible. Vegetation exists on Mars. What are its characteristics?
Vegetation on Mars is generally very rare, except in places where there is relatively more moisture. Vegetation on Mars is low, pressing against the soil, growing in cushions. The color of vegetation is “cold” – cyan, blue and even purple.
In places especially cold, such as, for example, at the Acidalia “sea”, located at northern Martian latitudes from 40 to 60 degrees, the color of vegetation is very dark, almost black, like the color of lichens on high mountains and in Antarctica.
Vegetation on Mars is chlorophyll-bearing, but it does not have an absorption band, and absorbs the entire “warm” part of the solar spectrum.
On Mars there is vegetation both deciduous and coniferous. Deciduous vegetation changes its color with the seasons of the Martian year, like terrestrial deciduous plants of the temperate zone.

On the ancestors of plants on Mars

Some persons say that because the climate on Mars is very harsh, life cannot originate there. This is true only in the sense that currently life cannot originate on Mars. And life is hardly emerging on the Earth at the present time.
According to the generally accepted opinion, a very high temperature is necessary for the origin of life. Maybe life now originates only in hot springs with a temperature of 60 degrees.
However, in the question of the origin of life both on Earth and on Mars, it is incorrect to come from their current state, but it is necessary to look deep into the centuries.
In ancient times, the climate on Earth was much warmer and wetter than the modern one.
Note the color of the first leaves of oak, maple, apple and other trees. This color is not green, but “warm” brownish-red. Then, as the leaves grow, this color, a “tan”, gradually disappears, and the leaf acquires its usual green color. In the early spring (in April and early May) of 1951, in the vicinity of Minsk, near the biostation of the University, S. N. Sredinsky observed a predominance of reddish color in vegetation. There was no grass yet, but liverworts and other plants were very widely represented. All of them had a reddish, red-yellow and red-brown color. Only clubmoss – an evergreen plant of forests near peat bogs – was green.
Later, the general reddish hue of the shrubby thickets attracted attention. Branches, buds, unopened leaves had red, pink, red-brown color.
As further development progressed, everything turned green. What does it mean?
There is a very important biological, vital law. It consists of the following. Young animals and plants reproduce some of the properties of their ancient adult ancestors.
As applied to these plants, we can therefore say that their oldest adult ancestors (about 100 million years before our time) had leaves not of green, but of a “warm” brown-red color.
On the other hand, both theoretical reasoning and practice show that the leaves of plants have a “warm” brown-red color in a very hot climate.
It follows that in ancient times the climate on Earth was very hot. Then life, in particular, plant life, could have originated.
Now let’s move on to Mars.
In ancient (in the geological sense) times, vegetation on Mars was of “warm” colors, that is, with a predominance of red and yellow rays, and the climate on Mars was mild. There was more water on it than now, the atmosphere was denser, with greater water vapor and carbon dioxide content and significant cloud cover.
That’s when plant life on Mars could have originated.
It is interesting to note the following here. Ivan Vladimirovich Michurin established the influence of warm and humid conditions on the cultivation of roses with yellow flowers. Biology data has indisputably proved that in ancient times (the Carboniferous period) the climate on Earth was twilight, humid and warm. It can therefore be assumed that the organs of plant reproduction then had a yellowish color. By the way, currently the color of the reproductive organs of tropical plants is predominantly yellow. These plants are the heirs of the vegetation of the tertiary era of the Earth.
Based on the above, it is possible to imagine vegetation in the wettest polar regions of Mars, covered with snow and ice in winter.
Probably, evergreen plants live there, like our mosses, clubmosses and hard-leaved squat plants like cowberry, cranberry and fen-berry. Stunted trees can live there, similar to terrestrial dwarf birches and willows.
In early spring, young leaves of cranberries, cranberries and cloudberries have a brown-red color. In dwarf birches and willows, shoots acquire this color. Then this coloring disappears.
The French researcher of Mars Baldet testifies that plants like mosses and clubmosses on Mars, as well as on Earth, retain a greenish-bluish color even under snow. With the beginning of spring, in places freed from snow, plants such as mosses and squat hard-leaved bushes acquire a red-brown color. Trees like dwarf birches and willows produce shoots of red-brown color. All this gives the gradually developing band around the southern polar cap a brown-chestnut color close to this color.
The reason why the circumpolar vegetation of Mars acquires a lighter brownish-chestnut color as spring progresses is explained by the fact that the colors of the leaves gradually turn to yellow tones that precede the summer color, as is observed in spring and in some terrestrial plants.
Closer to the equator, the plants have a brown-purple or brown-purple usual Martian color. This is because summer has come there, and the plants have acquired their summer color.
If we take into account that there are many similarities between the climate of Mars and the Pamirs, then the similarity between the color of vegetation on Mars and the color of vegetation on the Pamirs can no longer be considered an accident.
This gives us a reason to compare the spring phenomena of vegetation on Earth and Mars.
Scientific assumptions show what should be paid attention to in further studies of the existence of life on Mars, as well as on other planets, in particular, on Venus.
Due to the hot climate of the planet Venus, the vegetation on it should be yellow or orange. In relation to Venus, we can say that the climate there is now the same as it was on Earth and on Mars hundreds of millions of years ago.

The role of self-emission in plant life

Plants not only adapt to environmental conditions – whether on Earth or on other planets, but also adapt the environment for their vital needs.
Having studied the optical properties of foliage and needles of plants, we began to study the optical properties of flowers.
Soon we noticed an interesting new phenomenon. It turned out that the flowers emit red and infrared rays.
This property in the green parts of plants was known before. As for the flowers, it is discovered by astrobotanics. Previously, such a property of flowers was not known.
We photographed the spectrum of flowers illuminated by the Sun, and then the spectrum of compressed barite powder, which is considered to be the substance of the greatest whiteness, on the same photographic plate.
After special measurements of these spectra, it turned out that in the infrared and far-red rays, some flowers are brighter than barite. Why so? How can it be that the flowers are brighter than the whitest object illuminated by the Sun?

Self-illumination of the leaves and flowers of the orange daisy (Erigeron aurantiacus in Latin). The leaves glow much stronger than the flowers, and therefore the latter came out as silhouettes against the background of light leaves.

Studies have shown that flowers not only scatter sunlight, but also have the property of self-illumination, or self-emission.

Studying the self-illumination of trees at temperatures from -40 to +20 degrees, we found that it increases with increasing air temperature. Self-illumination of plants in red and infrared rays provides plants with another opportunity to get rid of excess heat.
We remind readers that the first possibility is that the plant reflects warm rays of the Sun. This process gives the plant a yellow color. The addition of red rays to the yellow color gives the plant an orange color.
This conclusion was tested on the color of algae living in the Pamir hot springs.
In the area of Jelanda, in the eastern Pamirs, the temperature of the hottest spring is +71 degrees. In the hottest place, the first traces of the appearance of mainly red algae and a small amount of cyanobacteria were noted. The main signs of the location of hot springs are reddish-orange algae, visible from afar and growing in the water.
These are the theoretical arguments and observational data that allowed us to say above that in a very hot climate plants should have a “warm” color.
Now we can say something about the probable vegetation on Venus. Since the climate on this planet is hot, the vegetation on it should be yellow or red. Some observations of Kharkov astronomers show that places of the clouds of Venus, where the sun’s rays reflected by its surface fall, reveal in their light some excess of red and yellow rays.
We have already said that the self-illumination of plants increases with the temperature rising. However, the self-illumination of plants does not disappear even at a temperature of -40 degrees.

Self-illumination of the fern in infrared rays. A plaster plate is in the middle.

How can this be explained? Self-illumination of plants plays a double role in their life. At high temperatures, it allows the plant to emit an excess heat, and at low temperatures, the plant warms the surrounding air with its heat, creates a warmer atmosphere around itself, melts the snow lying above it in early spring and goes out into the open sky. This is, for example, the property of snowdrops, snowbell and other plants.
Examples of such self-heating of plants were observed during wintering at the Tien Shan High-altitude Observatory in 1931-1932, when a field of subglacial vegetation was discovered – a kind of natural greenhouses.
Under the ice of almost a meter thick, there were free spaces with an area of up to 400 square meters, where plants of the Alpine zone grew and bloomed. Domed glaciers provided a kind of greenhouse effect. Accumulating solar energy, they protected plants from frost. The plants obviously made themselves a greenhouse by their own radiation.
In Altai, in the mountain Shoria in early spring, when the air temperature is still significantly below zero, blue anemone flowers come out from under the snow 10-15 centimeters thick.
Thus, plants not only adapt to the conditions of the environment, but also adapt it for themselves.
Here is another confirmation of this ability of life, taken from the observations of the French physicist Becquerel.
Algae and mosses multiply in a sealed tube filled with water vapor of sterilized mineral solutions, which lack dissolved oxygen. These organisms live at first without air, producing carbonic acid. Then, restoring photosynthesis, they create a new, oxygen atmosphere. Oscillaria (a genus of filamentous cyanobacteria) lived in this way for eight years in an atmosphere created by itself, until its nutrient medium was depleted.
All this makes it possible to better understand that on other planets there is life adapted to specific conditions, in its various forms.

Is animal life possible on Mars and Venus?

We can assume that plant life on Mars is almost proven and there is a possibility of its existence on Venus.
You can be sure that there are microorganisms on these planets that are able to live and reproduce in the most seemingly incredible conditions.
The highest temperature that some creatures, such as spores of fungi or bacteria, can withstand is approaching 140 degrees Celsius. Even greater is the resistance of organisms at low temperature.
In the shell of the Earth’s crust, along with inorganic matter, there is living matter.
If you put mosses, lichens and algae for several weeks in liquid air with a temperature of 190 degrees, then when they are warmed in hot water, they come to life.
The French physicist Becquerel revived lichens – common orange lichen (Xanthoria) – with rotifers and tardigrades living on them after six years of drying and immersion in liquid air. The scientist also did experiments at the lowest temperatures (helium – 271 degrees) available. Dehydrated spores of bacteria, algae, fungi, mosses, ferns, peeled seeds exposed to this temperature in the vacuum gave normal offspring after defrosting.
Many species of bacteria and fungi live without free oxygen. They are called anaerobic (living without free oxygen) ones.
We have given above an example with algae and mosses that propagated in a sealed tube filled with water vapor of sterilized mineral solutions devoid of dissolved oxygen.
The adaptive capacity of unicellular creatures is inexhaustible. Cold, salinity, toxic substances – all this does not interfere with the life of some microbes.
In hot springs, with temperatures up to 92 degrees, peculiar organisms adapted to these conditions – bacteria and algae – were found.
I remind that the temperature limit of life for the vast majority of animals and plants is limited to the moment of protein coagulation. This limit for egg white, for example, lies close to +75 degrees. Bacteria and algae from hot springs have a special heat-resistant protein. In such exceptional temperature conditions, this protein was created in the process of evolutionary adaptation of bacteria and algae to life.
An expedition of microbiologists in 1946 discovered life even in the barren, waterless soils of the Sahara Desert. The ground surface there resembles a hot frying pan. There is no water. And under these conditions, up to 100 thousand microbes were found in a gram of sand.
Desert microbes turned out to be very sophisticated chemists. Their water-sucking power is higher than any rates known for vegetation in arid areas.
Special devices recorded the “breathing” of the soil. Consequently, these microbes are viable. Glass plates buried in the studied soil turned out to be covered with mold fungi and bacteria after two weeks.
Even more inhabited are the “black sands” – the Kara-Kum desert. There are more than half a million different types of microorganisms in a thimble-sized lump of soil. There is only a glimmer of life in microbes, though. But there is a huge hidden power in these creatures, which manifests itself as soon as the conditions become suitable.
It means that our usual ideas about the boundaries of life are very limited. You cannot judge life by seeing only cattle, poultry, fish in the river, etc. Look through a microscope and you will see more life, something that is not visible to the simple eye. And if the microscope is more advanced, it will expand our understanding of life even more.
Mold fungi, bacteria, yeast can withstand pressure up to 3 thousand atmospheres without any visible change in their properties.
Obviously, there may be organisms that can withstand very high temperatures and pressures.
The critical temperature is directly dependent on the pressure. Deep-sea dredges lifted numerous animals from the bottom of the deepest depressions of the ocean – from a depth of over 8 thousand meters, where they lived under a pressure of 800 atmospheres (during the immersion in water, the pressure increases by one atmosphere for every 10 meters).
Soviet microbiologists found live bacteria in oil wells at a depth of 1000 meters. Academician V. I. Vernadsky believes that living organisms can occur underground at a depth of 4 thousand meters.
Laboratory studies have established that yeast fungi can withstand a pressure of 8 thousand atmospheres.
Hidden life forms – seeds or spores – can persist for a long time in an “airless” space, that is, at pressures equal to thousandths of the atmosphere.
At an altitude of 7 thousand meters and at a pressure of about 225 millimeters of mercury, human loses consciousness. But after all, large mountain birds – condors – soar near the highest mountain peaks, for example, at Mount Everest in the Himalayas with a height of 8,882 meters. Aphids, flies are found in the air at an altitude of 8200 meters. The scientific balloon brings spores of bacteria and mold fungi from a height of 33 thousand meters – from the regions of the atmosphere bove the clouds, permeated by powerful cosmic radiation.
The area of chemical changes that life can withstand is also huge. Spores and grains can stay indefinitely without any harm in an environment free of gases and water, that is, completely dry.
The chemical environments in which life can exist are extremely diverse. Bacillus boracicola, living in the hot boric springs of Tuscany, freely withstands a 10% solution of sulfuric acid at normal temperature and a 0.3% solution of sulema. Some bacteria and infusoria can withstand even concentrated solutions of sulema. Yeast lives in solutions of sodium fluoride. The larvae of some flies survive in a 10% formalin solution.
Science has proven the existence of living beings lack chlorophyll, but extracting their nutrition from inorganic substances. These invisible creatures – bacteria – live in soils, in the upper layers of the Earth’s crust, penetrate deep into the ocean. To maintain their vital activity, they use the chemical energy of minerals rich in oxygen, so they do not depend on other organisms and sunlight.
The number of species of such bacteria is insignificant. It does not exceed a hundred. Meanwhile, up to 180 thousand species of green plants are known.

The leaves of the snowdrop in early spring broke out from under the snow.

Snowbell breaks through a thick layer of snow.

But one bacterium can produce several trillion individuals in one day. And one unicellular green alga, which reproduces the fastest of all plants, gives only a few individuals in the same period of time, and for the most part about one individual in two or three days.
Despite its microscopic size, due to the amazing power of reproduction, the importance of bacteria in nature is enormous.
So you, the reader, think now about whether microorganisms exist or do not exist on other planets, in particular, on Mars and Venus. Or, to put it another way: does life exist on planets?
We have introduced you to the physical and chemical properties of the planets of the solar system, to the enormous adaptability of plants and microorganisms to environmental conditions.
Let go of the usual ideas about life, look deeper into the essence of the question – and you will see that life exists on other planets. In any case, we are talking with confidence about the existence of microorganisms on Mars and Venus.
Is it possible to say the same about the giant planets – Jupiter, Saturn, Uranus and Neptune?
Yes, you can, and that is why.
The atmospheres of giant planets are filled with gases – methane (aka mine, or swamp gas) and ammonia. Microorganisms can live in these gases. By the way, methane and ammonia gases mainly come from the decomposition of overage organisms.
According to some data, it can be assumed that with the deepening into the atmospheres of the giant planets, the temperature gradually rises and at some depth becomes zero and positive. It is interesting to note that when comparing the spectrum of methane from a gaslight of organic origin with the spectra of giant planets, a complete similarity was obtained, whereas a difference was found between the spectra of these planets and synthetic ammonia of laboratory origin. Consequently, microorganisms can exist in the conditions of giant planets.
Can there exist higher animals on Mars, whose properties we know incomparably better than the properties of Venus?
It is necessary to say openly that here we are entering an extremely dark area. On Earth, plants and higher animals are in the closest relationship – plants emit oxygen, which animals breathe, and animals emit carbon dioxide, which provides air nutrition to plants. In the atmosphere of Mars, as mentioned above, the presence of oxygen is not detected. However, the presence of water vapor in its atmosphere is also not detected, although there is no doubt that there is water on Mars, and therefore there are water vapors in the air.
There is no doubt that spectral analysis as applied to the atmosphere of Mars has not yet talk its last. Further exploration of Mars with the help of powerful astronomical instruments and the development of some physics issues will make it possible to expand knowledge about life on this planet.
As we can see, astrobotany has already developed into the science of extraterrestrial life in a broader sense, that is, into astrobiology. Powerful astronomical instruments will allow us to explore the light of the planets, penetrating as far as possible into the infrared rays.
The close connection of astrobiology with astronomy, physics, chemistry, biology will unite the efforts of researchers. All this will give science a unified set of knowledge about life on Earth and other planets.

What do foreign scientists write about the possibility of life on other planets

It is impossible to imagine the case as if all foreign scientists hold an opinion about the exclusivity of earthly life. We mentioned an English astronomer Jeans, who is trying to deny the prevalence of life in the universe. There are, of course, other astronomers like him. But there are also scientists who believe that life exists on other planets.
Interest in exploring the possibility of life on other planets has greatly increased in all countries.
In recent years, many articles about the possibility of life on other planets have been published in foreign magazines. Therefore, Soviet readers, whom we have introduced to our conclusions, would be interested to learn, what foreign scientists are writing on this issue.
The American astronomer Kuiper, a planetary researcher, published his book “The Atmospheres of the Earth and Planets” in 1952. The conclusions he came to are very important.
Kuiper writes that in those places on Mars where vegetation is assumed, there is a change in color with the seasons, apparently depending on relative humidity.
Green-blue areas, after being covered with sand and dust from the Martian deserts, have the ability to resume. Only plants can have this property. The mineral formations would have been buried under yellow dust a long time ago.
Carbon dioxide, water and probably nitrogen are present on Mars. The temperature limits, although large, are not excessive. Plants can get food on Mars from dust and ice crystals falling on plant-grown areas.
In previous periods, Mars had a milder and wetter climate. This planet had as much time for the evolution of life as Earth. Of course, the development of vegetation on Mars took place in a different way than on Earth.
If life exists on at least two planets of the solar system, Kuiper writes, it is very tempting to conclude that it can spontaneously originate after sufficient time wherever conditions allow. There are many planetary systems in the universe. There is no reason to believe that life is limited only by the Earth.
And here is the opinion of another representative of science – Strughold, a German professor of physiology, working in the USA.
Strughold writes that when considering the question of life on Mars, it is necessary to keep in mind the peculiarities of the environment, that is, temperature and oxygen. After all, the structure of every living body in the universe is based on the carbon atom and its chemical properties. Temperature, light, water, the chemical composition of soil and air impose some boundaries on life. Only within these boundaries can an active life exist and develop.
What do active manifestations of life mean? This is the growth and activity of muscles and nerves. Their active manifestations are possible only at a certain temperature. The temperature range starts a few degrees below the freezing point of water and ends at about 60 degrees. Only heat-loving bacteria are still viable at temperatures above 70 degrees. Bacteria, spores and some seeds can tolerate even a temperature of 120 degrees for several hours. Arctic plants tolerate temperatures of -60 degrees. Rapidly supercooled organisms, such as algae, bacteria, lichens and mosses, can survive for a week in liquid nitrogen, oxygen, hydrogen or helium at temperatures close to absolute zero. So, in this area, writes Strughold, life is possible – hidden or dormant. A very low temperature does not destroy life definitely, if the cold lasts temporarily.
Strughold writes that Mars and Venus, together with Earth, are the only planets that, in terms of temperature, have conditions for life in our understanding. Mars is a life-loving planet. The detection of the oxygen in the atmosphere of Mars failed, though, but there is anaerobic respiration that does not need oxygen.
A human needs at least 65 millimeters of oxygen pressure. This corresponds to an altitude of 7 thousand meters. Human adaptation to such a height is possible, which is confirmed by an expedition in the Himalayas. But a long human life is possible, at the very least, only at an altitude of up to 5 thousand meters. According to modern data, the oxygen pressure on Mars reaches at best a hundredth of the minimum oxygen pressure required for humans.
The lowest oxygen pressure required for other warm-blooded animals (cats, dogs, pigs, rats, etc.) corresponds to an altitude of 8 thousand to 12 thousand meters.
Plants that can resist cold and dryness can live in the Martian climate. These are plants like lichens and mosses.
Terrestrial plants have a mechanism that supports respiration. Martian vegetation has adapted to an environment poor in oxygen and water.
The active life of plants on Mars can only be on the day side of the planet. At night, plants are in a state of hidden life. This is an advantage. Terrestrial plants can breathe at night, as there is a huge supply of oxygen in the air for their needs. And in the Martian environment, poor in oxygen or completely devoid of it, the combination of darkness and cold is physiologically more favorable than the combination of darkness and heat. On cold Martian nights, plants completely rest. The oxygen problem therefore presents fewer difficulties than is usually considered.
Although there is no oxygen in the atmosphere of Mars, Strughold writes, but plant bodies may have their own oxygen layer, which always moves around the planet along with sunlight.
In his other book “The Green and Red Planet”, which was published in 1953, Professor Strughold points out that if the atmosphere of Mars consisted even of pure oxygen, an Earth person could not breathe it. Why? Because at a pressure of 70 millimeters of mercury on the surface of Mars, the lungs of an earthly human could not receive any oxygen, since they would be filled by water vapor and carbon dioxide at a pressure of up to 87 millimeters.
As a practical measure, an Earth human would have to have oxygen on Mars at a pressure approximately 3 times greater than the air on the surface of this planet, which corresponds to the total pressure in our atmosphere at an altitude of 9150 meters. Only then could he survive on Mars.
At a pressure of 70 millimeters on the surface of Mars, water should boil at a temperature of +43 degrees. But such a temperature on Mars is never reached even at noon in tropical areas in the middle of summer. The highest temperature on Mars does not exceed +31 degrees. Consequently, the water remains in a liquid state and does not turn into steam. Also, the liquids in our body will not boil on the surface of Mars. Boiling would only occur at a pressure of 47 millimeters. In the Earth’s atmosphere, this pressure is at an altitude of 19200 meters.
Organisms that can survive in the Earth’s atmosphere above 17 thousand meters could probably survive on Mars. Bacteria gathered in air samples at an altitude of 19800 meters and placed in a nutrient medium germinated. Consequently, they survived at such amazing heights.
It is highly improbable that we have found any creature on Mars that resembles an Earth man. Strughold writes that with small devices of the kind provided to pilots volplanning in the high layers of the Earth’s atmosphere, a human could survive on Mars for a considerable time without inconvenience. A researcher could find the environment on Mars no more difficult than, for example, in Antarctica.
On Mars, we would not find a fire that requires free oxygen. In the Earth’s atmosphere, a height of 20 thousand meters can be considered the limit beyond which the flame will not burn.
Lack of oxygen prevents the development of higher-order animal and plant life on Mars. There are good signs for a primitive type of plant life, similar to the lichens that live on our desert rocks and in the Arctic tundra. The possibility of life of the simply structured organisms on Mars is not excluded.
Professor Strughold noted that the flight to this planet will give an exhaustive answer about life on Mars. Then, perhaps, it will be discovered that life on Mars exists even in a highly organized state, adapted, of course, to Martian conditions.
Struchgold’s statements draw attention to many facts that elude some researchers’ attention. We consider these statements to be very thorough. But Strughold, when he wrote his book, was not yet aware of the work of the astrobotany sector of our Academy of Sciences. In particular, the discovery that the optical properties of Martian plants are comparable to those of higher terrestrial plants living in the harsh conditions of high mountains and the Subarctic is of significant importance. In addition, the lichens and mosses mentioned by Strughold do not change their color with the seasons, and there are places on Mars that change their color in full accordance with what is observed in terrestrial deciduous plants of the middle zones of the Earth.
In May 1953, journal of the British Interplanetary Society published an account of an interesting lecture by Professor Bernal entitled “The Evolution of life in the Universe”.
At the beginning of the lecture, Professor Bernal noted that the ancient Greek scientist Aristotle believed that every living species has always existed with its own special characteristics; also at the end of the XIX century, it was believed that 92 chemical elements were separated since the very beginning of things. But now we know that even chemical elements had their own history, just like all living things that evolved out of a simple start. The nature of matter can be studied only when its history is studied at the same time. The same is applicable to the study of life.
What was the Earth like before life appeared on it? – Professor Bernal asks. Then there was no soil, since soil is a complex organic body and makes up the main mass of living matter on Earth. Science has learned what the air, water and oceans were like at the beginning of life.
Professor Bernal talks about two theories of the origin of the Earth. The rough division of these theories is “hot” and “cold”.
The “hot” theory is that the Earth was initially a small piece of the Sun. The “cold” theory is that the Earth was formed from the coalescence of dust. Professor Bernal thinks that all these theories are wrong so far. In his opinion, to give a satisfactory theory, one must be a mechanic, an electrodynamicist, a thermodynamicist, a physical chemist, a space mineralogist and an expert in many other things. It is necessary that all these scientists work together. Only by putting all these heads together can you get some semblance of an answer.
Soviet scientists founded the Department of cosmobiology to study the indicators of biological activity on other planets. This biology is not limited to our planet alone, but studies the nature of cosmobiology in the universe.
There may be planets of different stages of development in the Galaxy. And this must always be borne in mind in order to establish scientific truth.
In the English newspaper “Daily Worker” in 1954, an article by Donald Michie entitled “Life is green on Mars when the snow thaws” was published, where it was emphasized that the spectral properties of places on Mars differ from the typical spectral properties of chlorophyll and that this was proved by the Institute of Astrobotany, which is located in Alma-Ata (USSR). Due to the harsh Martian climate, green plants on this planet can resemble subarctic and high-altitude plants of the Earth. The author of the article also makes reference to the American astronomer Kuiper, who found that lichens have Mars-like spectral properties, which are very hardy terrestrial plants capable of resisting almost any climatic extremes.
In the French popular science “L’ Astronomie” magazine in 1954, the Lille astronomer Kurganov briefly outlined the achievements of Soviet astrobiology. He emphasized our thesis that the properties of life in the universe are essentially the same, but can take different forms and manifest themselves in different ways, that life adapts widely to environmental conditions, so none of the scientific facts currently contradicts the idea of life on Mars.
Interest in Soviet astrobotany is also shown in Italy, in particular, by readers of the magazine “Coelum” (Latin for “sky”). The astronomical Observatory in the USA, founded at the end of the XIX century by the Mars exploration enthusiast Lowell, expressed a desire to undertake a research on life on other planets using the method of our astrobotany sector.
Our article, published in 1955 in Journal of the British Astronomical Association, aroused the interest of the American astrophysicist Harlow Shapley. At Harvard University in December 1955, he gave a lecture on the achievements of our sector of astrobotany.
In Paris in December 1955, “Horizons” magazine published an article entitled “A new science was born – an astrobotany”. The article says that the time is near when Earth explorers will land on the planet Mars. There they will meet a world different from ours, with its own atmosphere, with its own climate, and, perhaps, with its own life – animal and plant one. The author of the article undertook a journey of more than 7 thousand kilometers to Alma-Ata, where astrobotany was born. He described in detail the essence of the work of our astrobotany sector. In No. 55 of the magazine “In Defense of Peace” for 1955, the article was translated into Russian.
As you can see, foreign scientists are showing great interest in astrobotany. It is already developing into a broader science of life outside the Earth, that is, into astrobiology.
The Soviet Union should be a pioneer in the creation of the Institute of Astrobiology. It should employ scientists of a wide variety of specialties – astronomers, physicists, chemists, botanists, zoologists, microbiologists, meteorologists and others. With the help of a special-purpose astronomical observatory equipped with the most accurate instruments, they will solve an important problem about life in the Universe.

General biological significance of astrobotanical studies [1]

Known to man and so far the only means of communication in the world space, the messenger of events that occurred in the Universe over a period of time over one billion years, is a light beam. To one degree or another, it is absorbed and reflected by qualitatively different surfaces.
For a human – an Earth dweller – a comprehensive study of the reflectivity of various living and dead terrestrial surfaces is quite accessible. The observational technique in astrophysics allows people to study the reflective properties of other planets. The application of the optical method allowed us not only to confirm the presence of vegetation on Mars, but also to establish a number of its properties.
Astrobotanical studies have a general biological significance. They are so far the only experimental basis for the development of the problem of life in the universe.
Everything we have said about the peculiarities of vegetation on Mars expands the scope of botany. Until now, botanists have mainly had purely morphological data indicating how certain groups of plants have adapted to exist in extreme environmental conditions (lack of water, high temperatures of soil and air, etc.). Although a wealth of material has been accumulated in plant biochemistry, proving that plants change their chemical composition in the process of adapting to environmental conditions, but the results of biochemical studies are difficult to project to a living plant.
The available astronomical data on the adaptation of plants to the changing light and heat conditions on Earth and other planets help morphologist botanists to deepen a number of concepts related to the problem of the evolution of the plant world. For example, it is possible to come closer to the knowledge of the principles of plant cell life, of such phenomena as frost resistance and drought resistance.
Discoveries in the field of astrobotany are of great practical importance when creating new economically valuable cultivars and species of plants by purposeful raising of experimental forms at different temperature and light conditions. The application of the latter method was developed by I. V. Michurin.
I. V. Michurin’s conclusion about the effect of temperature on the future color of rose petals is based on a deep knowledge of plant life. However, his insufficiently complete explanation of the appearance of yellow color not only by the action of high temperature, but also by the influence of increased intensity and amount of light is being refined and deepened by modern astrobotanical studies.
In our opinion, it is currently impossible to study Darwinism and general biology without the involvement of agrobotanical material. To understand the general biological patterns, it is important to know the materials of astrobotanical studies.
The Department of Botany of the Alma-Ata Pedagogical Institute attracts astrobotany data. And that’s right. The Department of Plant Physiology and Microbiology of the Kazakh State University does the same. The main conclusions of astrobotany are studied by students also in Michurin scientific circles.
The scientific community of the Soviet Union organized meetings to discuss the work of the astrobotany sector and its conclusions. The first such meeting was held in 1952. Up to 400 people were present. The participants of the scientific discussion emphasized that astrobotany is essentially an astrobiology that correctly publicizes the facts. Based on the generality of the laws of nature, astrobotany predicted a number of optical properties of plants based on observations of Mars, and then discovered these properties in those terrestrial plants that are in climatic conditions close to Martian ones. With these discoveries, astrobotany has significantly advanced the problem of life on other planets and removed some of the main objections to the existence of vegetation on Mars.
The methods of studying the optical properties of plants developed by the astrobotany sector open up possibilities for solving practical problems facing agriculture.
The participants of the discussion also noted that astrobotany, putting the question of the possibility of life on Mars to scientific ground, serves as a sharp weapon in the fight against the anti-scientific, idealistic, religious worldview declaring that only the Earth is the carrier of life.
In 1953, a second meeting on the possibility of life on other planets was held. It was organized on the initiative of the Leningrad branch of the All-Union Astronomical and Geodetic Society and the Leningrad House of Scientists.
The participants of the second scientific discussion emphasized that the discoveries of astrobiology confirm the correctness of the materialistic view of life as a natural stage in the development of matter, which occurs wherever favorable conditions develop. Soviet astrobiology has convincingly shown that, despite the harsher conditions of existence than on Earth, there is organic life on the neighboring planet Mars.
The results of astrobiological studies, as noted by the meeting, acquire serious practical significance in agrobiology – in the study of the radiation regime of cultivated plants, in the study of the qualitative features of the stage development of plants, in the directed change of plant heredity, etc.
The work of the astrobotany sector was discussed repeatedly at the sessions of the Astronomical Council of the USSR Academy of Sciences, and the last session was held at the Pulkovo Observatory in February 1956. The decisions of this session are important for the further development of astrobotany and astrobiology.
So, the production of a 70-centimeter planetary telescope has already been ordered. This telescope will expand the technical base of the astrobotany sector. Planetary science will take on an even greater scale in the USSR.
The time will come, and the workers of Soviet science will tell the people about many more things that happen on other planets, especially on Mars.
We have opened the veil of secrecy. What was once a mystery is known now.
There are no unknowable things. Today it is unknown, and tomorrow it will become known. Science does not stand still. Maybe now, when we finish writing this book, someone from the researchers of our solar system has already made a new contribution to the science of life on other planets.
The most difficult thing is the beginning of any work. And the beginning is done. Now it is impossible to say that only the Earth is the carrier of life.
Wherever there are suitable conditions, life arises and adapts to the environment.



H. S. Bayda and N. I. Suvorov. Proceedings of the Astrobotany Sector, volume I, 1953 The main provisions are taken by the author from these works.

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Translated by Pavel Volkov, 2021

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