'Master plan' touches on the most basic questions in modern cosmology - and perhaps in science in general: Why does our universe exist? And if it already exists, why are the laws of nature in it the way they are, and not others?
Allow me, this time, to be a little superficial.
The book 'Av-Plan' (Yanshof Publishing) looks, from the outside, wonderful. The cover is hard, the pages are of high quality, the colorful illustrations are embedded within the text instead of being bundled somewhere in some remote corner of the book. Also the decision to choose Emanuel Lotem - one of the excellent translators - to translate the book, shows the investment in the small details.
It is no coincidence that on the cover of the book the name Stephen Hawking appears in larger letters than the name of the book itself: Professor Hawking's reputation ('a summary of the history of time') is a very strong marketing element and his name alone was probably enough to ensure adequate sales for the book. The name of the other writer, Leonard Melodinov, is more modest - but these are the facts of life and they are as sharp as a knife, as the poet's article
Maybe it's a little strange to refer to the exterior of a book in a review, and especially in a genre like popular science that sanctifies the main thing over the trivial, but I believe that the investment in the small details is always evidence of something deeper. The shape of the jug, in this case, indicates what is inside - but also tries to cover up its shortcomings.
'Master plan' touches on the most basic questions in modern cosmology - and perhaps in science in general: Why does our universe exist? And if it already exists, why are the laws of nature in it the way they are, and not others?
These are such deep and primary questions that at first glance it is difficult to see how modern science is able to answer them, and even more so that a science book aimed at the general public will be able to introduce real meaning into them. This is a challenge that the book honors.
Hawking and Mlodinov begin with an excellent explanation of how scientific theory determines our worldview. The analogy they give is instructive: imagine a goldfish living in an aquarium and looking out. The round glass distorts his observations, and any movement in a straight line in the outside world is seen by him as movement in curved lines. Nevertheless, a sufficiently sophisticated goldfish can develop a physical theory that will well explain his observations: it will not be easy to understand, and the mathematics behind it must be terribly complicated, but glass is just glass and after you eliminate the effects of its distortion, you can reach logical conclusions. In other words, the strange theory of the goldfish will describe the universe with the same degree of accuracy as our conventional theories.
This conclusion allows the reader to better digest the oddities presented later in the book, which are part of quantum mechanics. For example, let's take a small spherical molecule and shoot it onto a screen through a plate with two slits. Through which of them will you pass? Anyone who has ever heard of the 'double slit experiment' knows that the molecule will go through both slits at the same time, because it behaves like a wave in water. This fact is interesting in itself, but Hawking and Melodinov point out another fascinating fact. If we measure the position of the molecule just before it hit the wall, after it passed through the slits, the new measurement will cause the molecule to behave as a particle and not as a wave - then it will pass through only one slit.
There's something odd about the last sentence, isn't there? After all, we measured the position of the molecule after it passed through the slits! How could the measurement affect something that happened in the past?
This theory is indeed strange and non-intuitive, but it describes the observed world with a wonderful degree of accuracy - and is therefore completely acceptable as a theory about the behavior of the universe on a small scale. She is as strange to our eyes as the world is to the eyes of a goldfish in an aquarium, but she is real.
This is where the theory that may answer those basic and primary questions that I mentioned earlier, 'M-Theory', comes into the picture. The mother theory (the name of the book in Hebrew is surely a pun on its name) is a modern and as yet unproven theory, which may one day offer a satisfactory explanation for the peculiarities of quantum mechanics and more importantly - be the 'great unified theory' that will explain all the forces in nature at once. Hawking and Mlodinov claim that if the mother theory is correct (a matter that requires proof, still) it can also give satisfactory answers to the question of why a creature exists and why it is the way it is and not otherwise.
Hawking and Melodinov's explanations of the various quantum phenomena are excellent: I haven't come across such a readable book in a long time.
The book is very tight and polished, and I have no doubt that even people with no prior knowledge of physics will enjoy it. In almost every chapter you can find wonderful insights of the kind that other whole books have a hard time reaching.
I won't tell here why mother theory may give us the answers to the deep questions of life, the universe and everything else so as not to spoil the point of the book. I'm just saying that the point is the one that demonstrates the biggest problem with 'Master Plan': it's too short.
The entire book, cover to cover, is only 158 pages. Of these, barely 131 pages contain the text itself and the rest are an index, a glossary, etc. Although books are not bought by weight, in this case it is clear that this literary anorexia has really hurt the enjoyment of the book. The highlight of the book, the mother-theory explanation of these basic questions, is given in less than two pages! Precisely in the place where we need words most critically, they disappear and the reader is left with half his lust in his hand. So many questions remain unanswered, and I don't mean deep questions but rather basic questions: What does today's research say about mother theory? Where do we stand on the question of its correctness? What are her conclusions and predictions? One can argue about the need for more reasoned and detailed explanations even earlier in the book, but it is clear that the book ends too soon. Perhaps this thinness is the reason why the book is so invested externally.
In conclusion, 'Master Plan' is a wonderful book and highly recommended. Hawking and Melodinov manage to give the reader - even a polished reader like me - wonderful insights and deep insights into the universe and nature. Unfortunately, I doubt if the recommended price given on the cover, NIS 98, is the fair price for this book. If cost is not a critical consideration for you, I would grab the Master Plan off the shelf. If so - and I believe most of us are like that - you should wait a little longer and catch it on sale.
[Ran Levy is a science writer, and hosts the podcastMaking history!'- on science, technology and history.]
47 תגובות
Oren (V.H.)
I'm sorry for the late answer. The assumption underlying the variation of natural constants is that the laws of nature known to us are the laws of nature and the only game left to "produce" different universes is the input according to which the laws of nature operate. This input is the constants of nature. The constants of nature are obtained from measurement and not from theoretical considerations. Now let's assume that the constants of nature can change and thus we will get a different universe with the same laws of nature for which the input is different constants of nature. For example, the force of gravity depends on the universal gravitation constant, what would happen if its value was twice its value measured today. It is then possible to assess, for example, which solar systems will lose stability and which will collapse, what is the permissible distance of planets from suns, etc... In a teardrop manner under the change of other constants of nature it is possible to assess which structures (atoms, molecules,...) are stable and which are not. Physics is characterized by characteristic scales that can be derived from constants of nature, for example, a characteristic length of the atomic nucleus is Fermi, a characteristic energy for electronic energy levels in an atom is an electron volt, a characteristic radius of an atom is an angstrom, and so on. It is theoretically easy to estimate what will happen to these characteristic rocks under changing natural constants. This is the basis for the claim that there will be no stable molecules under the change of the constants of nature.
Oren and Ehud,
I agree with Oren's opinion. In my opinion, we have no way to guess what will happen under conditions where the constants of nature are different. It is clear that atoms and molecules like the ones we know will not exist under these conditions, but who knows what will be created? Perhaps even completely different elementary particles will be created than what we know will create other structures?
I think that because of the complexity and chaotic nature it is difficult for us to tap from the micro to the macro in many areas such as the effect of mutations on phenotype, etc. And here we are talking about a much more complex thing that there is no way to check.
Fan,
Isn't it possible that a universe with different conditions will allow the existence of stable molecules despite being different?
According to my understanding, a molecule is held in a chemical bond, and not nuclear like the atomic particles are held, so why wouldn't this be possible?
And it is possible to go deeper: perhaps the atom itself can appear in a different shape, which we did not think about, due to different conditions. Maybe it was composed differently under those different conditions?
What I'm trying to say is that the possibilities are so special and illusory, including this universe, whose very form and organization seems to us self-evident and logical, and others not, but maybe that's because we're used to thinking in terms of this universe, and seeing a completely different situation from the most basic level of The atom and its particles, it's just sublime among us? (Although I don't like this expression... but we can settle for - it's really, really hard for us to understand another situation, or to think about it)
As I said earlier, you and I still do not know how the fact that we live and breathe from simple molecules became possible, so I think that the claim that "it is not unreasonable to claim that life could not have formed in such a universe" is absurd in itself, isn't it?
If you could explain to me in more depth why you don't think molecules can be formed, I would appreciate an answer.
To whom
Indeed a trip that sounds lovely for those who love cycling
I know the countryside in Germany and it is really beautiful
Good Day
Yehuda
Yehuda:
Indeed, as I wrote before I left, I was on a bicycle trip along the Hauser River in Germany.
It was very nice and I already wrote something about that too.
What I have not yet mentioned is the fact that on the Airbus plane in which I flew back, Ada Yonat and Aharon Chachanover also returned to Israel
to whom
Were you on vacation? We haven't heard from you for many days and here you are back full of energy!
So tell us about your vacation instead of confronting
(:))
Look how I try to be nice
Good Day
Sabdarmish Yehuda
A. Ben-Ner:
Science deals with "why" questions all the time.
The questions that science does not deal with are "why" or "for what".
"Why" questions are about finding reasons and not about goals.
Therefore, the questions presented here are also of interest to science.
Of course, these are difficult questions, the answer to which cannot come from the laws of nature themselves (because they are the cause of them) but from principles that seem more fundamental (like mathematics).
See in this regard the articles of Marius Cohen:
https://www.hayadan.org.il/ground-problem-of-metaphysics-part-1-0204103/
https://www.hayadan.org.il/ground-problem-of-metaphysics-part-2-0704103/
Yehuda and all the other commenters dragged into the discussion of the anthropic principle:
First of all - I already explained to you that the correct transcription is "the anthropic principle".
Besides - the anthropic principle does not provide an answer to the fundamental problems discussed.
In our world there is rain and one of the results of the existence of the rain is the existence of streams.
Using the anthropic principle in its non-religious version (that is, the one that does not claim that there is a God who created everything to create man, but only that if everything did not exist we would not be asking the question) as an answer to the fundamental questions is similar to the claim that the rain falls because there are streams.
And as for response 22:
really?! Aren't you trying to confront me?!
After all, the very writing of these things indicates their falsity.
Pine,
If stable molecules cannot form in a certain universe, it is not unreasonable to claim that life could not form in such a universe. If the lifespan of a certain universe is several million years before it collapses again it is unreasonable to assume that life could have formed in it although here the claim already becomes less well founded.
Today, in a situation where I don't really know how life even began, I think it is excessive to declare that life would not be possible in a universe with different natural constants.
If we do not know at all how we were created, how do we know that under other conditions, life could not be created?
In a different way of course...
And in general, isn't our thinking too fixed on the things we know about ourselves?
A. Ben Ner
The attempt of science is to find the rules that do not fit either in space or time. If I define a law of nature valid only on the surface of the earth it will not be a fundamental law. If I find a rule valid only on Mondays, it will not be a fundamental law, and even if I find a rule or law that was only true at the beginning of the universe, it is not a law of nature.
A. Ben Ner,
I think that by definition natural constants do not change, they are like the axioms of nature. If they change, it means that what we thought was constant was actually derived from something else and affected by some process. The question of whether there are such constants of nature that do not change completely under any condition and at any time is open. This is similar to the question of elementary particles, are there any indivisible particles?
Dear Friends.
Are the "constants of nature" that "thanks to them we exist" really permanent?
Maybe the "constants" also change during the evolution of the universe?
Remember the measurement of the "constant" omega (w) which is an indication of the speed of expansion of space.
The discovery that omega varies with time led to the conclusion that the universe is inflationary.
It is possible that during the evolution of the universe other constants also change and it is possible that things
will be measured in the future.
What is true is that: a]. Not necessarily because at every stage of the evolution of the universe there will be life in it.
B]. The degree of change of the constants allows life and provided that the change is small enough.
R.H.
If I remember correctly, the claim was that even a small change of a fraction of a percent from the current state could not produce a universe in which there are stable molecules. The above estimates derive from a model of the formation of the universe, but as I wrote to Yehuda I believe that some of these estimates have changed.
sympathetic,
The path between the decay or stability energies of isotopes and the creation of macromolecules, living cells not to mention intelligent, is a very long one. Obviously, in the extreme case of a very strong or very weak magnetic force or a very different gravitational constant, everything would be so different and the non-existence of stable molecules could be predicted. But what would happen if the physical forces were a fraction of a percent different from the current state? In my opinion it is impossible to begin to guess.
R.H. dear
Happy and happy that it is possible that the constants are not a constant size over time.
So please delete my comment number 31
What a beautiful night!
Sabdarmish Yehuda
Yehuda,
You lean on the shoulders of giants. According to Wikipedia, already in 1937 Paul Dirac proposed the hypothesis that physical constants change over time.
http://en.wikipedia.org/wiki/Physical_constant
Do you want to complicate the situation a little?, have fun?
Well, what is our assurance that the constants are really constants?
I can easily visualize a universe where the constants change throughout history
For example the speed of light or the gravitational constant.
So the entropy principle will only work in the case of constants that change in a certain way throughout history.
But there may be a proof that the constants are really constants. Then please delete everything I wrote here
Good Day
and with a smile
Sabdarmish Yehuda
R.H.
The fact that conditions on Earth are suitable for life is fortuitous as is our location in the galaxy and universe. There is no scientific significance to the question of why the earth allows life, because the answer is banal. The conditions for the formation of life simply exist in it, the fact is that we are here. Is the answer to the question why the constants of nature are the way they are
It is also banal, i.e. the answer is like this by chance? There are infinite universes and we happen to be on one of them. From this relationship I find the answer of the anthropic principle as to why the laws of nature are as they are, simply like that, there is nothing to ask.
Regarding your claim that we cannot estimate what a world would look like with different constants of nature, I partially agree.
It is possible fiscally to estimate decay constants and binding energies of atoms, molecules and isotopes given different constants of nature, such an estimate gives us a measure of their stability. The problematic part is the assessment of which intelligent life could have formed in such universes, when the implicit assumption is that the prototype of intelligent life is us, i.e. carbon-based organic intelligent life.
sympathetic,
The entropic principle does not claim that we are the crown of creation. He says we live in a universe that makes our lives possible. That is, there may be countless possible universes, but we are here because somewhere else we simply would not have been created in the first place. That is, there are no coincidences here or some miracle that we live in a universe that suits us.
Equally one could ask how it is that the conditions on Earth are so suitable for us? After all, a little warmer or a little colder and we wouldn't be here. The answer is the entropic principle.
Beyond that, I don't think anyone has the ability to estimate what a world would look like with different constants of nature, and everything is an ignorant hypothesis that in the current situation there is no way to check.
Yehuda,
Does the extension of the anthropic principle to the realm of ideas state that if people believe in something then it must be so? Bringing the opinions of two scientists who claim that there is a fine-tuning of constants so that only they allow us to exist, there are other scientists quoted here in the science who claim otherwise, one of the names I remember is Dr. Gilad Perez from the Weizmann Institute.
Let's put for a moment the question of whether there is a factual basis for the anthropic principle. Have you thought for a moment what its philosophical meaning is? The basic claim is that we are the crown of creation, the universe was actually created for us... this has a return to the era before the Copernican revolution. It can of course be argued that infinite universes were created in which there was no life and therefore there was no one to explore them, but still the claim that our universe fits us like a glove seems to me to be the opposite of everything that science strives for in the new era.
For one who asks and is interested,
do you exist What universe are you in? There are countless puzzling questions that can be raised... In the discussion, we tried to focus on questions that are scientific, that is, they can be formulated and tested scientifically. our existence as living beings
Regardless of consciousness, the constants of nature in our models can be scientifically tested and measured. Theoretically, it is possible to examine models in which the constants of nature are different. It is therefore a collection of scientific questions. A problematic assumption in the anthropic principle is that it identifies intelligent life with our own life even though other possibilities may exist.
To Ehud and Yehuda note:
It is not at all certain that the constants of nature known to us today are indeed constant.
It is known that the constant "omega" (w) is a measure of the expansion rate of the universe
Measured in the history of the universe with slightly different values today and based on a discovery
This is what is known today as the "inflationary universe". It is not impossible that
Future measurements will indicate that other constants of nature have also undergone a change
during the evolution of the universe.
The discussion here forgets that the questions being asked are about consciousness.
Is there proof that the consciousness that questions and investigates reality is limited to just one universe?
Is there proof that consciousness dies with the body and is born with it? Is this really conceivable?
And maybe the universe exists for the purpose of the development of consciousness and when it exhausts it, it continues to create another kind of creation?
Perhaps humanity's consciousness explores the four basic forces of nature and learns to control them?
Maybe there is an existence beyond the universe and that's where these four forces come from and therefore there isn't one M theory??
You should open your mind and not stay locked in basic concepts.
to love
We don't agree
I bring you a quote from Wikipedia. Treat it however you want
The anthropic principle/ Wikipedia
.
Adherents of the anthropic principle claim that we live in a universe exquisitely tuned to make life possible. If even one of the physical conditions were even slightly different, life as we know it would not be possible. Other claims that have been made have been that the anthropic principle explains physical constants such as the fine structure constant and the number of dimensions of the universe as well as the cosmological constant.
According to John D. Bro and Frank J. Tiffler, there are a huge number of unbelievable coincidences in the universe, all of which seem to have come together to allow us to exist as we do, from the particular energy state of the electron to the exact level of the weak nuclear force. According to them, we live in a universe that depends on a number of independent variables, and there is only a slight chance that these will gather into a structure that allows life, and yet, there is life. End quote.
In my response I referred to such a situation
Shabbat Shalom
Sabdarmish Yehuda
Yehuda,
Unfortunately, I don't understand your arguments beyond the fact that it is possible to understand from them that the constants of nature were set this way only to allow you personally to exist?
You write: "I actually read that a small change in the physical constants would have already changed the development of life and would certainly have prevented the coming of man." So in our universe this must be the case.” The fact that in our universe the constants of nature are as they are is due to the fact that they were measured and found to be so and have nothing to do with our existence. The question of whether it is necessary for the constants of nature to have the measured values or whether it is a matter of chance may have something to do with our existence and this is where the anthropic consideration comes in.
You write" Can this be said about everything that exists in the present that is the reason for the existence of our universe? I think so, but I know that it is not necessarily agreed upon by everyone." Again irrelevant, the question is whether everything we see around us forces the laws of nature to be as they are or whether there is no connection between the observations and the laws of nature. Everything we see around us are indeed the characteristics of the universe, but in the fact that we contract them there is no necessity, the laws of nature could easily be the same laws of nature even in a universe where we would not conduct the above correspondence.
Regarding Einstein, it is better not to quote him out of context. His claim was specific about quantum theory and that, according to his view, natural laws should be deterministic and not random. Even Einstein would have agreed that there is randomness in the world and we can talk about probabilities that also appear in statistical physics which is classical (not quantum) in essence.
Finally, there are constants that you can change and still receive life so that the claim "I actually read that a small change in the physical constants would have already changed the development of life and would certainly have prevented the coming of man. ” is not correct. If I'm not mistaken, there were several articles about it, even in my knowledge.
It is not possible to classify comments by the author, but only by keywords. For example, I just had to add three more words together as a prohibited keyword - due to a free advertisement that someone cheeky tried to plant on the site. Of course I blocked him and offered him that I would come to his house and paint him an advertisement with graffiti on the wall in the living room.
Really dear Avi Blizovsky
Maybe you will already decide not to censor Yehuda's comments. You notice that I try not to confront Mr. M*kaL so don't put me in the category with those who need to be censored like the pans and the like.
True, I have a strange quality that I don't like the dark mass, but after eighty years I'm really not alone anymore.
At least tell me what the suspicious word is and promise not to use it
Happy holiday, my father
Sabdarmish Yehuda
You wrote a suspicious keyword. I let go.
Again Censorship and Ehud will have to wait until they approve my response number 19. How poor and inappropriate it is for this business science website.
patience
Yehuda
to love
I actually read that a small change in the physical constants would have already changed the development of life and would certainly have prevented the coming of man. So in our universe this must be the case.
I have no problem with the fact that there are other different universes in large quantities, even a million times. It interests me that my universe has these conditions. So I do not state that only an entropic universe can exist!
Can this be said about everything that exists in the present that is the reason for the existence of our universe? I think so, but I know that it is not necessarily agreed upon by everyone. Here we return to Einstein's statement: God does not play with dice, if the general state of the universe at one point in time determines only one future then. History until today was bound to be the way it is, the establishment of the State of Israel, the Holocaust, the anesthetization of my beloved dog, and the fact that I am now drinking coffee.
It seems to me that quantum theory is somewhat opposed to this
A good week and a happy holiday
And in appreciation for your challenging responses
Sabdarmish Yehuda
Yehuda,
It seems you did not understand my words. The question is to what extent does the entropic principle force the physical constants? What is the strength of the entropic constraint? Let's assume that according to the entropy principle, the charge of the electron (one of the constants of nature) can be changed so that it is up to 100 times larger and up to 1000 times smaller (this is not the case, but I am just giving it as an example). Was the entropic principle a constraint if in a universe where the electron constant is 100 times greater human life is also possible? I think not. Studies show that it is not clear that the entropic principle is a strong enough constraint to determine why the constants of nature are the way they are.
Is there a necessity in the fact that we live to determine that only the universe we live in is possible? I don't think so. It is possible that in another possible universe, human life based on carbon would not be possible, but life based on silicon or another element would be possible? Therefore it can be argued that the fact that we live is accidental and has no effect on the laws of nature. I will explain the last point in more detail. Does the fact that I am writing to you in Hebrew require that history should have been such that the State of Israel was established? In my opinion, the establishment of the state is not necessarily a historical event and one can easily think of reasonable historical scenarios in which the State of Israel would not have been established. Therefore, in terms of history, the establishment of the state is something that happened by chance and was not out of necessity. At the same time it can be argued that carbon-based life with natural constants that enable it is a coincidence.
As mentioned, there are two types of arguments that can be established as to why something happened in a certain way: it was necessary and it was not possible for things to happen otherwise or the event happened probabilistically and then it has to be shown that there was a very high probability that it would happen otherwise it's just a matter of chance.
sympathetic
It seems to me that you have a fundamental mistake
It is not necessary to show that our universe is the most probable,
What must be shown to be suitable for human development
The reason
If it turns out to be the best but is not suitable for human development, then what good does it do us? We won't even be there to discuss it!
But since we do discuss it, it means that it is suitable for the formation of a person.
in brief
The entropic principle
Good Day
Sabdarmish Yehuda
What is the possible answer to questions like:
“…why does our universe exist?…
..and if it already exists, why are the laws of nature in it the way they are, and not others?..”
One possible answer is the religious option which for a long time was the only answer to this question, the world is like this because that is how God created it. If we abandon this answer and try to give an answer to the question of what causes necessity in science and whether it is a scientific question, we will find that for a long time the answer to this question was in the field of philosophy. Today there are several attempts to give a scientific answer to this question due to the increased ability of science to answer questions that were previously philosophical. An example of this kind of success is the Big Bang Theory.
If you try to answer these questions in a scientific way, you must first formulate them in a scientific way. The scientific wording of the question is: in the scientific theories that describe the universe and everything in it, physical constants of a certain value exist. The question that science asks is is there a necessity because the value of the constants is as it is or could they have had a different value? Possible answers are: There is only a single set of constants that allows for such a stable universe that exists over time, therefore there is no freedom to change the constants of nature, therefore there is a necessity in the laws of nature as they are defined by the constants we have measured to date. This possibility seems to have been ruled out since it is possible to show that there is a range of constants that allows for a stable universe. A second possibility is that given the constants, our universe is just one of countless possible universes only that the value of the constants in it is the most statistically probable, a resident that is essentially probabilistic. As far as I know they have not yet succeeded in showing that our universe is the most probable.
More than physics, the book deals with philosophical hypotheses that are supposedly based on science. On the other hand, there is the claim that we are unable to see and notice due to being bound to our specific universe. Hence, our philosophy is also bound in the same way, which drops the ground under the basic human ability to understand the universes, their beginnings and their end. In other words, engaging in this philosophy is essentially futile.
A somewhat bleak thought, isn't it?
The whole "master plan" thing is the holy grail of science in my opinion, and not (!) in God's sense.
For example, today we know that complex molecules are built under certain conditions with other molecules to build the basis of life, because of the structures of the atoms in them. Electrons are at a certain distance from the nucleus due to nuclear forces. Gravity is the result of the curvature of space by mass... Everything has a pre-structured reason in physics, and if we manage to understand that the foundations of the various elements in physics could not be other than some structured reason (basic, embedded in physics or even in mathematics), then we can reach Theory of everything" (perhaps M theory).
It seems to me that these questions already have an answer
The universe exists in its current form because we exist and discuss this question. The discussion would not have taken place if the laws were different because then we would not exist
This is called the "entropic principle"
I have already shown in my article here "Evolution of theories" that the existence of the entropic principle is closely related to the possibility of the existence of a "theory of everything". There were days when articles were approved for me.
Whoever wants to read there.
Happy holiday
Sabdarmish Yehuda
Is there not a fundamental error in the formulation of the "fundamental questions" of science as follows:
“…why does our universe exist?…
..and if it already exists, why are the laws of nature in it the way they are, and not others?..”
As far as I understand, (so far), the question of "why" is outside the scope of science.
This, in my understanding, is a philosophical question. The answer to it may degenerate the discussion into districts
non-scientific.
Isn't it appropriate to leave science only in the "limited" field of researching the "what"? namely
What does the universe we observe contain, and what are the laws of nature at work?
Apparently, Ehud in his comment to Yehuda in response No. 5 describes the reality.
Everything he is trying to know is written in our Holy Torah in the Holy Book of Caution.
disappointing.
Extraordinary truths are expected from Hawking, certainly when he publishes a new book that should contain a comprehensive and philosophical theory.
After all, if the important information can contain only two pages, a press release can be issued, producing a book can only be for show (and the money, of course) so that some people can show off that they have Hawking's new book, even if it does not substantiate his theory.
If it were a stream of particles passing through two slits, we would get on the screen two spots with a Gaussian distribution around the center of each slit. On the other hand, in a quantum way, you get that in total all the hits on the screen create an image of a struggle consisting of many points. In this way, the atoms reach the screen at points where the probability of their arrival is minimal.
What behaves like a wave is the wave function that describes the particle, but with each measurement of the particle on the screen or on the way to it, the particle becomes a point on the screen or a signal in the measuring device. The physical description of this phenomenon is the collapse of the wave function.
So if you get one point from one particle, where is the conclusion that the electron went through both slots at the same time? Is it because the total distribution of the particles does not correspond to that expected from a stream of particles passing through two slits?
R.H.
First, on the screen you only get single points when each atom hitting the screen creates a single point of light. The interference picture is obtained from a collection of experiments, each of which is performed with a single atom. It turns out that the point
which in the end was depicted on the screen is determined from a probability distribution corresponding to a wrestling picture.
I return again from a single atom it is not possible to get an interference image, measuring an atom is always equivalent to a point on a screen or to a reading on a spatially located counter.
In order to obtain a particle image, it is necessary to measure whether the atom passed through crack A or B.
In such a case, after many experiments, a spot consisting of many points will appear in front of one of the cracks or in front of both, depending on whether the measurement of the particles near the cracks was always carried out near crack A or always near crack B or whether each time the crack to be measured was chosen at random.
Regarding your specific question, measuring an atom near the screen as you do claim with common sense (which sometimes works even when talking about quantum theory) differs little if at all from measuring it on the screen and such a measurement does not destroy the interference image that will be obtained from repeating the experiment many times each time with an atom Single.
sympathetic,
In my understanding, what is special about the above experiment (and correct me if I'm wrong) is that if you only use the screen, you will get interference with even one photon (as if it were a wave), but if you put a sensor in one of the slots, you will get one point, that is, a particle phenomenon. What the article added here is that if the sensor is also beyond the slits, then again a point will be obtained and not an interference, and it is as if the measurement "radiated" to a past time and "caused" the photon to pass through only one slit. What is not clear to me in this description, and I would appreciate an answer, is what is the fundamental difference between the measurement on the screen and the same sensor beyond the slits? Why does each of them show a different result?
R.H.
You are absolutely right in your question and indeed in any case in measuring a molecule a point is obtained. The interference image on the screen is not an image of the passage of a single molecule but is composed of the image obtained for a collection of molecules passing through the slits and hitting the screen. Each molecule by itself gives a point on the screen.
Yehuda,
The world belongs to young people especially in science. Stephen Hawking is indeed a respected and appreciated scientist due to his past achievements, but his scientific contribution today is negligible/marginal, perhaps that's why he devotes his time to writing science fiction.
Hi Ren. Love your podcasts.
Recommended for everyone.
In the "wall" experiment. It is not clear to me what the difference is between a measurement on the wall itself which gives a pattern of friction and between "a moment before" which gives a particle result. After all, both were carried out after passing through the grooves.
What does "in his condition" mean?
Stephen Hawking is disabled in his body but completely not in his mind and he is still fertile and can come up with new ideas
Good Day
Yehuda Sabdarmish
Is Stephen Hawking in his condition capable of learning new things or developing new theories or is he simply recycling what he knows in his various books..
Is there anything else to learn from him that he hasn't revealed to us yet?