Hayadan > Life on Mars - really?

Life on Mars - really?

On August 1996, XNUMX, the scientists of the American Aeronautics and Space Administration (NASA) announced in all media that signs of fossilized life forms may have been found on Mars

By: Yosef Zakbach

On the seventh of August 1996, the scientists of the American Aeronautics and Space Administration (NASA) announced in all media that signs of fossilized life forms may have been found on Mars. Some see the originators of the announcement as the most exciting discovery of the century, and some disapprove of it for many reasons.
This announcement was based on findings that were discovered inside a block of rock the size of a potato, weighing about two kilograms, which originated from Mars, and which hit Antarctica as a meteorite before
About 13000 years. This announcement was published as a summary of research that lasted more than two years, which was headed by NASA scientists. Their article was published (McKay) by David McKay on August 16, 1996 and caused great excitement in the "Science" newspaper, in the public and among scientists, and on the other hand - a lively polemic. This discovery, in which it was apparently discovered that in the past tiny bacteria-like creatures lived on Mars and they remained as micro-fossils inside the meteorite, once again raises the question about life outside
to the earth This event has a consequence regarding the way of life on Earth.

About 20 years ago, the American spacecraft "Viking" landed on Mars. The landing was intended for the month of July, 1976 in honor of the 200th anniversary of the declaration of independence of the United States of America. The spacecraft's precision instruments, which examined samples from the planet's upper soil layer, found no traces of organic activity or life forms of any kind. However, this fact does not put an end to the hope of finding life on the red planet. The age of the ancient meteorite in question is estimated at 4.5 billion years, and it was discovered in 1984 in the layer of snow and ice in Antarctica. The scientists believe that it originates from Mars, like the eleven other meteorites discovered and identified in the area since 1982 (the age of these is lower than the stone in question and estimated at less than 1.3 billion years). It should be emphasized that this is an opinion - no one can be absolutely sure of this.
The research in the last decade has convinced many scientists that these dozen meteorite rocks arrived on Earth after a body such as an asteroid or a giant comet hit Mars about 15 million years ago. The impact caused the mining of a huge crater and the removal of rock blocks from the face of the planet. For millions of years, these lumps floated and wandered in space, until they came close to the Earth and were attracted to it by the force of gravity. The "wandering" rock in question landed in an ice field in the South Pole region, at a site called "Allan Hills" as mentioned in 1984 and from its reference number ALH84001.

The rock is porous, and inside the holes in its depth were found spherical bodies with a yellow-orange shade of calcium carbonate. This compound is rare in meteorites, but the carbon (carbonate) detected in it is the same as the compounds in the limestones on Earth. It is known that the chemical creation of limestone requires liquid water and carbon dioxide, but today there is no liquid water on the surface of Mars. Planetary scientists believe that about three and a half billion years ago (when the planet was a billion years old) Mars had a high content of liquid water. The temperature was higher than now, and bodies of water covered a large part of its surface. The water and carbon dioxide in it formed minerals
and coals, and these crystallized in holes in rocks. It also had volcanic activities of the volcanoes, landslides and wind and water drift.
The best proof of the "wet age" on Mars comes from the images sent to Israel in the 70s from the "Mariner" spacecraft, which hovered around it. The photographs showed a kind of dry and winding river channels, huge canyons and doors carved by flowing water over three billion years ago. As a result, it may have had mild and comfortable conditions for poor life, some of which took shelter in rock crevices. The team of researchers led by McKee believe that the spherical bodies of calcium carbonate inside formed on Mars during the early wet era. Around each globule there are spots of compounds of iron oxide (magnetite) and iron sulfide ((4)O(3)Fe
Their shape and composition are similar to those of grains formed by activity. (FeS)

It is possible that this is a biological configuration familiar to us, of anaerobic bacteria (that do not consume oxygen for their respiration), and of other microscopic creatures. The size of the spherules is less than a quarter of a millimeter (between 50 and 250 thousandths of a mm), and their age is estimated at 3.6 billion years - an era that also corresponds to the beginning of life on Earth. Next to these carbonated globules, orange compounds were found, containing a group of organic molecules known as polycyclic aromatic hydrocarbons (PHAs).

These are aromatic polycyclic compounds of hydrocarbons. On Earth, these compounds are formed in the smoke of a candle flame, or as a result of grilling meat over hot coals. the compounds
These multirings, found inside the meteorite stone, are also strikingly similar to compounds formed from the decay of common organic matter.

Some argue: maybe these compounds, which were detected in rock from Mars, are the result of terrestrial bacterial contamination? The answer to this is negative, and the explanation: the concentration of the compounds in the area of the shell is lower than inside it. If the stone was contaminated by an external pollution of
Bacteria, which originated in the Earth's atmosphere, was the opposite. In such a case, their concentration in the outer part of the stone was higher than their concentration inside it.

These discoveries are impressive on their own, but the most amazing findings and the ones that provoked the most controversy among the professionals are tiny and strange shapes, SEM, that are densely grouped next to each other. Some structures that have been discovered are in the figure
"egg" or "pancake", as well as in the form of "filamentous worms", which have partitions dividing them into segments and segments, similar to what is found in bacteria. The largest dimension of a body
This is less than one hundredth the diameter of a human hair. The size and shape of these "biological" structures resemble tiny fossil life (nanobacteria) from Earth
whose dimensions reach only a few tens of nanometers (these tiny bacteria are perhaps the "evolutionary bridge" or the intermediate forms that link viruses and bacteria). Whereas the age of the Martian fossils is 3.6 billion years, as the age of origin
Life on Earth, McKee and his colleagues believe that these forms are most likely primitive fossilized remains of single-celled Martian creatures.
British scientists, who tested the "biological" forms discovered in the meteorite with isotopic tests, claim that their findings are similar to those that characterize special bacteria that produce (CH4).

The opponents of the "biological" interpretation claim that it is possible that
These forms, which are ten times smaller than the smallest bacteria (ten thousandths of a millimeter long), are actually streaks of mud embedded in the meteorite rock. Some claim that these are crystals of the mineral magnetite.

According to NASA researchers, it is possible that the microorganisms evolved in a warm atmosphere that resulted from volcanic activity under the ice sheet, in the valleys of the Martian soil, and which was suitable for thermophilic (heat-loving) creatures. On Earth, poor creatures (from the archaea group) are known to live at the bottom of the oceans (at a depth of many kilometers) in water whose temperature is over 100 degrees Celsius, near volcanic underwater springs, to which sunlight does not reach at all.

On the planet Mars, life can exist (at least theoretically) even today under the surface. But it must be remembered that scientists currently do not have any conclusive and direct proof of the existence of primitive life on the surface of Mars. For such a test, it is necessary to carefully test many soil samples. The launch of the new series of spacecraft to explore Mars began in the fall of 1996: two American spacecraft were sent to Mars (one, on American Independence Day - July 4, 1997) and testers will be sent to it next year.
The operation to return soil samples from Mars by spacecraft to Earth is intended for the beginning of the XNUMXs. Only in later stages is it also possible to send astronauts to Mars - an operation Sha'al
It is estimated that it will cost about 100 billion dollars, a huge amount by all accounts...
If it turns out that fossils of living creatures have indeed been found on Mars, the main importance of the discovery will be that the Earth is not the sole source of life. If there were ever microorganisms on the surface of Mars, then life may have been created on other planets in the solar system and beyond.

The origin of life and extraterrestrial life

It is difficult to define what life is, but it is possible to describe the characteristic of every living being: the structure of the cell, chemical structures such as DNA molecules, RNA and proteins with enzymatic properties, the ability to breed, growth and metabolism, heredity, etc. There are different opinions
About the origin of life on earth. It is believed that life began in a "primitive soup" - lakes of chemical solutions. Atoms concentrated relatively densely in lake fluids
These reacted with each other creating more and more complex organic molecules (in a process sometimes called "chemical evolution"). With the help of many physical factors (ultraviolet rays, shock waves, high temperatures and electrical breakdowns in the atmosphere), the chemical reactants created compounds of complex biochemical "fuels" (such as glucose and its derivatives). The energy of these and similar sugars was then used by the most ancient cells, which were created in the process of "biological evolution". These cells were the pioneer before the camp of bacteria (called "prokaryotic"), which appeared billions of years before the other cells with cells and compartmentalized organelles ("eukaryotic"). It is believed that the first primitive cells - the first form of life - developed in several places about 3.6 billion years ago or even more, through diverse evolutionary mechanisms, in the "primitive soup", on clay surfaces or in various minerals, but only the most successful cells survived the process of natural selection .

To the question of where the buds of life appeared on Earth, three possible answers were given: a. Life was created only on Earth and developed here. It is possible that in the distant past there were collisions between celestial bodies, and planets "rocked" each other with meteorite rocks (some see this as a kind of "interplanetary mutual fertilization"). If indeed a heavy object from the heavenly bodies fell on the surface of the earth and caused rocks to be splashed towards space, and these reached the surface of Mars, then the forms suspected of being fossils (like the rock discovered in Antarctica) were actually of earthly origin and were transported to Mars and back.
B. Life was created in different places (on Earth and Mars, for example), where the physical and chemical conditions made it possible.
third. Life was created in various bodies outside the Earth, and was brought to it, for example, from a planet such as Mars.

Where to look for extraterrestrial life?

Among the possible sites for the existence of extraterrestrial life, Mars can be pointed out today, as mentioned. This planet is the most serious candidate for finding extraterrestrial life forms. A few dozen years ago it was speculated that planets like Jupiter or Venus might contain poor life forms. These hypotheses have been falsified in light of the new information concerning these celestial bodies. Today, they talk about "Europa", one of Jupiter's moons, as a place where life might be possible, as well as about other planets outside
to the solar system. The photographs of the "Galileo" spacecraft imply that there is ice or even liquid water on the surface of "Europa". Under these conditions a poor life can arise. It is understood that planets outside the solar system can have conditions that will and do constitute a substrate
for the development of forms of life.

Is there really "life" on Mars?

The answer depends on the questioner or his public relations. Some argue that even if NASA's findings about life on Mars are true, it is still more worthwhile to invest the huge financial means in cultivating life on Earth, instead of "throwing" huge fortunes into space. Those who oppose the above findings claim that NASA's sensational announcements are intended for public relations, to create a sympathetic public opinion for space research and to raise funding for it. Indeed, the publication was very successful, and the President of the United States recently announced the allocation of large resources to NASA. It should be remembered that the announcements were distributed after the American space agency was subject to a major crisis in its popularity in recent years. The opponents also claim that the publication was done on purpose, before the decisions of the administration and Congress on the NASA budget.

The question of the essence of life and the possibility of its origin outside the earth is exciting and fascinating. The question that preoccupies many, and that has preoccupied humanity in the past for hundreds of years, is whether we are alone in the universe or do we have living neighbors that we have not yet been able to meet. There are countless science fiction stories about extraterrestrial beings coming to visit us in the morning news. But does science have a "real story" about this time?
Extraterrestrial life? We will wait and see.

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