There are about 100 definitions of life. An alternative (but imperfect) approach describes life as "a self-contained chemical system capable of withstanding Darwinian evolution." This is enough for many cases. The lack of definition is a big problem when it comes to the search for life in space
By: Samantha Rolfe, Lecturer in Astrobiology and Technical Director at Byfordbury Observatory, University of Hertfordshire
Life is very easy to identify. They move, grow, eat, excrete, reproduce. simple. In biology, researchers often use the acronym "Mrsgren" to describe life: movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition.
But Helen Sherman, Britain's first astronaut and a chemist at Imperial College London, recently said that it is possible that unidentifiable alien life forms may be living among us. how is it possible?
While life is very easy to recognize when you see it, it is very difficult to define it. Scientists and philosophers have been debating this topic for centuries, if not thousands. For example, a XNUMXD printer can reproduce itself, but we wouldn't call it a living thing. On the other hand, the mule is barren, but we can never say that it is not a living being.
Since there is no consensus, there are about 100 definitions of life. An alternative (but imperfect) approach describes life as "a self-contained chemical system capable of withstanding Darwinian evolution." This is enough for many cases.
The lack of definition is a big problem when it comes to the search for life in space. Not being able to define more than "we'll know it when we see it" means we're really limiting ourselves to geocentrism, maybe even anthropocentrism, when we think about aliens. We often envision a humanoid (deformed but still recognizable) being but the intelligent life we seek does not have to be humanoid.
Sherman says she believes aliens exist. Moreover, she wonders: "Will they be like me and you, composed of carbon and nitrogen?" Maybe not, maybe they are there and we can't see them?
Such life can exist in a "shadow biosphere" where creatures exist, based on different biochemistry, and the meaning is that we cannot distinguish them because they are beyond our ability to understand. Assuming it exists, a shadow biosphere would likely be microscopic.
So why didn't we discover her? We have limited ways of studying the microscopic world and also, only a small percentage of bacteria are able to grow in the laboratory. This may mean that there are indeed many life forms that we have yet to locate. We now have the ability to sequence the DNA of bacterial strains, but we can only identify life as we know it - containing DNA. But if we find such a biosphere, it is not clear whether we would call it alien - and even if so, it depends on the question of whether we meant "alien origin" or simply "unknown"?
Silicon based life
A popular proposal for an alternative biochemistry is one based on silicon rather than carbon. It makes sense, even from a geocentric point of view. About 90% of Earth is made up of silicon, iron, magnesium, and oxygen, which means there's plenty of opportunity to build potential life.
Silicon is similar to carbon, it has four electrons available to form bonds with other atoms. But silicon is heavier and contains 14 protons compared to six in the carbon nucleus. While carbon can form strong double and triple bonds and reach long chains that are used for many properties such as building cell walls, it is much more difficult for silicon. Silicon has difficulty forming strong bonds, so long molecular chains will be much less stable.
Also, common silicon compounds, such as silicon dioxide (or silica), are usually solid at room temperatures and are insoluble in water unlike carbon dioxide. We see that carbon is more flexible and provides more possibilities for creating molecules.
Life on Earth is fundamentally different from Earth's soil composition. Another argument against the silicon-based shadow biosphere is that too much silicon is trapped in rocks. In fact, the chemical composition of life on Earth has a close correlation with the chemical composition of the Sun. 98% of the atoms used in biology are composed of hydrogen, carbon oxygen. Therefore if silicon-based life forms are discovered they may have evolved elsewhere.
There are arguments in favor of silicon-based life on Earth. A few years ago, scientists at Caltech succeeded in multiplying a bacterial protein that formed bonds with silicon - actually introducing silicon into the living system. So even though silicon is less flexible than carbon, maybe it can find ways to form living organisms in addition to carbon?
When it comes to other places in space, such as Saturn's moon Titan or planets outside the solar system, we cannot rule out the possibility of silicon-based life. To find them we need to somehow think outside the box of earthly biology and find ways to identify life forms that are fundamentally different from the carbon-based ones. Many experiments examine these alternative biochemicals, such as the experiment from Katlak.
Regardless of the widespread belief that life exists elsewhere in the universe, we have no evidence for it. That is why it is important to take into account that life is precious, no matter its size, quantity or location. Earth is the only known life-supporting body in the universe, so no matter what form life in the solar system or in the rest of the universe may take, we must make sure we protect it from harmful contamination, whether it be terrestrial or alien life.
Can aliens be among us? I do not believe that we have been visited by life forms equipped with technology that allows them to fly in the vastness of space. But we have evidence that the basis of life, carbon-based molecules came to Earth on meteorites, so the possibility that the aliens are similar to more familiar life forms should not be ruled out either.
26 תגובות
M. Yosef
I liked the direction.
I always claim that our senses and the technological means at our disposal are not enough to measure and sense everything that is really happening around us (here and in space).
It is very possible that there are materials or dimensions (or even right here that exist between us), which we are unable to distinguish. We already know that we are not able to distinguish all colors and all wavelengths.
I am sure that we are not able to absorb many other things with our senses and our technology.
All human-like creatures have only one source. Earth. The automatic assumption that aliens come from space is silly romance
The problem is that the initial assumption is that the aliens come from other planets. So if there are aliens, they can only come from one place. Earth. And believe me, it is possible to hide an entire continent on Earth under the ground or under the sea, at a depth of kilometers below the surface.
In my opinion, in the age of the Corona, the demonstrators, the worshipers, the ones who do mass weddings, sometimes wearing masks, are the aliens spreading disease, what more proof is needed?!
True?
Aliens exist and are in continuous contact with the USA. There is enough evidence that Americans have adopted alien technologies. For example: Bob Lazar says he worked on the propulsion system of flying saucers in the 51s in Area XNUMX. Ben Rich, who ran Lockheed's skunk works factory, claimed before his death that in his factory they built flying saucers using alien technology. There is evidence of pilots flying alien flying saucers.
@עלמוניע First of all, there is a mistake in your statement that life on Earth does not affect life on other planets at all. In addition, the chances of life in the stars are not 90%, they are much less. One star with life does not indicate life on other stars. Beyond that, space has an end, rather the universe has a simple end. It is possible to reach it especially if it is not so far from the earth, which is true that the universe is expanding, but there are still chances that besides our location there are thousands of other universes and there are even hypotheses that there are other parallel universes (just hypotheses).
The earth is nothing compared to all space!
Space has no end.
It is with earth that there is life, what are the chances that there is life on other planets?
Maybe something like 90 percent...
Hey
The Gemara and the Holy Books are bullshit. Whoever believes in them has no basic understanding of science. Angels, demons, and fairies exist only in the imaginations of believers. Just like God. It's interesting that you forgot that the Gemara says that lice come from the human race, that the sun revolves around us and as if we are the center of the universe, and what about a talking snake?
Stephen Hawking said: God is not necessary to explain the universe. And Einstein said: The Jewish counter is a reincarnation of man's childish beliefs.
this is stupid
Moses
At a close distance (50 light years) there are around 300 Earth-sized planets, within "good" range of their Sun.
Don't be pessimistic...
In my humble opinion - there is no extraterrestrial intelligence.
The reason is very simple: the necessary sequence of events (to create intelligence) is so rare that billions more universes are needed to get additional intelligence.
This is also true for life (but with a much higher probability).
The sequence is serial, meaning: if we remove a step from it (or disrupt it) there will be no life.
For example (from here): If the earth was in a place a little less quiet for the milk - we wouldn't be here.
If there weren't a succession of super novas (with the ingredients that are here and in the right dosage) - we wouldn't be here.
If there was no tilt of the earth against the sun...
If there was no moon...
I'll stop here as there are tens of thousands of lines that start with "If it wasn't for..."
I don't understand where the firm statement that "there is no way that aliens will be human" comes from?
The entire article is based on a hypothesis that has no proof or evidence, that there may be a shadow biosphere in the XNUMXth century, except for that study at Caltech, which also does not lead directly to the desired conclusion.
Maybe there are other biologies and maybe not, I don't know, but human intelligent beings I believe there are, as a result of the phenomenon of convergent evolution.
Many animals of different species in the past developed organs and physical characteristics similar to other species. The clearest examples are eyes that evolved separately 8 times in different species in the XNUMXth century, and wings also evolved in insects, birds, reptiles and mammals.
If a planet is found that is similar in characteristics to Earth (temperatures, atmosphere, water, etc.) it is not impossible to find there also productions that developed tools similar to those that were developed in Earth. And there will be species very similar to cats, dogs, birds, insects, etc.
Hence it is also very possible that intelligent creatures, if they develop on such a planet, will have human characteristics: one head, legs, hands, eyes, etc.
There may also be another planet that developed other forms, but the chance that humans evolved is greater according to the knowledge we have at this time.
Aliens will not visit us, for the same reason we will not visit them. It makes much more sense to send robots to explore distant planets.
Think - what will people do on Mars? They will turn on all kinds of devices and read what is written on the monitor. This can be done from here…
According to the Gemara there are many living realities around us. ….. very true
It is found in all the Holy Scriptures
From a scientific point of view, there is no proof, and because the world today is based on science... it does not mean that the science we know is fun and open-handed, I guess science has reached 0.0001% of the knowledge and understanding that exists in the universe.
If we go back to the holy books, God bless him, he created the angels, the devil, and Adam, and millions of other creations that we know and do not yet know.
If we go back to the 3 main productions: angels...light productions, Satan...fire productions, Adam...earth productions (intermediate production)
And because human production is limited in all its senses, then we are not able to see an atom because their molecular composition is based on a different biochemistry, which our senses do not perceive.
We think and interpret "reality" in relation to what we know. If there is a foreigner visiting us - it is possible that that foreigner is different in essence and purpose.
Even when I wrote that the suitor is different from us - I created a comparison with us, and this without noticing.
There may be abstract life forms, other than matter, that are seen or heard
which are not "received" by our senses and our technologies.
Millions say they have seen aliens. Billions have not. Is it possible that they want to be seen and sometimes not? Do they live in different wavelengths?
For those who want to read more
Mophone Israel group on Facebook
The largest and oldest organization in the world for the study of the phenomenon
If there are aliens, what do they have to look for in us, they are probably so developed, if they want, they can do what they want in us, beyond that, evolution has given birth to millions of creatures, who are we anyway..
I saw a few this week and there are absolutely no aliens to be seen. Perfect camouflage from the future, from another planet
People have been saying this since before science was born, but they were called crazy
As long as the aliens can't make me lunch, they don't exist as far as I'm concerned.
According to the Gemara there are many living realities around us. They are called "harmful" in the language of the Gemara and there is simply no need to see them. (just like the human eye is unable to see infrared or ultraviolet).
Likewise, there are also spiritual auras that have been proven useful at the Weizmann Institute of Science.
Are non-existent aliens seen among us?
Are non-existent aliens seen among us?