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Hello, first off I would just like to say this isn't a homework thread, and I'm just looking for general answers for how things work regarding my questions. ^^
Alright, so we have 4 fundamental forces. Gravity, Electromagnetic force, Strong Interaction, and Weak Interaction. I'm going to exclude the weak interaction as frankly it doesn't appear too significant in what I'm curious about, and well, it's not well understood by the scientific community either.
Waves. Lets talk light, light gets weaker with a magnitude that is proportional to r^2. Therefore the intensity of light 1m from a light source will be 4x stronger than light 2m from a light source. The reason is associated with the expanding sphere shape that emitted things follow. The expanding sphere has a total surface area of 4pi*R^2, so when you do one divided by the other you are left with the ratio of R1^2/R2^2. Okay, cool. So that explains why light, sound, gravity, and electromagnetic radiation all behave in this way. Simple stuff so far.
Now! Strong interaction is a force between... Quarks. This force is huge, cool. It has to be huge to hold together quarks together so tightly that observing free quarks is pretty much impossible, and breaking a baryon or meson is also next to impossible. Everything logically makes sense. Now apparently, the strong interaction doesn't diminish in strength as distance increases? What how? How can that be, please somebody explain. The force will be as strong if they are 1m apart as if they are 1 angstrom apart? How?
Okay, well as I don't know the answer, let me continue. The way I understand it, is if you have a strong interaction, you cannot actually exist, because you will be too attracted to things, therefore free quarks don't exist, and if you somehow split a baryon, it'd combine again almost instantaneously. Okay, so the only way something can exist in this universe is if it has 0 strong force (for all intensive purposes). So just like how we can cancel out electric charges with the opposite sign, we can do the same with quark charges... However these charges are called colors, and instead of there being a positive and a negative, there are 3 colors.
It appears that the only way we can actually get 0 strong interaction is by a combination of 2 up quarks and 1 down quark creating a proton and a different combination of 3 quarks to create a neutron. Awesome! We are getting closer to reality! Each quark has a different property, and the sum of the properties of the 3 quarks gives us the property of the of the hadron. Properties can include the charge and the spin most notably, and other stuff like mass and dipole moment.
Alright, well the strong interaction is between quarks, but for some reason (please explain to me why), the strong interaction isn't exactly negated, and you are left with a little bit of strong interaction left, which we call the residual strong interaction. This is the force we associate with holding the atom together. Now here comes the interesting thing, the strong interaction doesn't decrease with distance, however the residual strong interaction does... It actually decreases really quickly, an exponential amount, an amount even higher than proportional to r^2. That's like having two linear lines, and subtracting them, and getting an exponential graph. In reality, this doesn't happen. So why is it when the two strong interactions cancel out, you get a new force with totally different properties?
Now I'll move to the next question. Again, I don't know why the strong interaction behaves in this way, but I'll go with it. The residual strong interaction is what holds atoms together. The 3 forces we are talking about: Gravity is very very weak, the strong force is really strong at a short distance, stronger than the electromagnetic force, but because it decreases exponentially with distance and the electromagnetic force decreases in a way thats proportional to r^2, eventually the electromagnetic force becomes stronger than the strong force.
Inside the atom, we know that the strong force attracts baryons together. When the size of the nucleus is small, the strong force keeps the baryon's together, however as the size on the nucleus gets larger and larger, more than about 82 protons, the distance between the nucleons is simply so great (even though it's percentages of a femtometer), that the repulsive electrostatic force exceeds the strong force, and hence it's impossible to make an even larger nucleus or it will decay like uranium or other heavy elements. Alright, cool beans. That all is pretty straightforward, but now the questions:
At short distances the strong force is super powerful, why don't the two protons collapse into each other, is there something I am not considering? If the strong force is the one doing the most work, why wouldn't the protons be infinitely close together? Is there something keeping them at a safe distance?
Next question. Why do you need neutrons and protons in a nucleus to make it stable? And in relatively even quantities. If I had 5 protons in a nucleus and no neutrons, wouldn't that mean the radius of the nucleus is smaller, and therefore it will hold better on it's own. So why do I need neutrons in a nucleus? How do they stabilize the nucleus? Continuing from that question, why can't I have a nucleus of only neutrons? Don't all baryons have a residual strong force? Why can't neutrons keep themselves together?
My assumption to the previous is because somehow the interaction between a proton and neutron intensifies or actually creates the residual strong force, this is just a guess, but it'd make sense because especially small elements have a relatively even amount of neutrons and protons. But why is this? Does a neutron have a different residual strong force than the proton? How? If so, why?
I think that's mostly everything I wanted to ask without making this excessively long. If any kind soul can help me answer these I'd greatly appreciate it. Thank you!
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I really wish I knew the answers to... all of this. It's cool stuff tho, even if I'm only in AP Physics
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Since no one is answering, I'll try to give an answer, which may or may not be extremely unsatisfactory since I'm not an expert at this.
The reason why protons and baryons in general don't collapse due to the residual strong force, is that the residual strong force is repulsive at extremely short distances. I've seen this property rationalized as something similar to Pauli's exclusion principle. Therefore they won't collapse together.
Neutrons are needed in the nucleus to keep it stable, because they serve to balance out the residual strong force and the electrostatic force. Since neutrons are neutral, they do not contribute to the electrostatic repulsion, but do contribute to the attractive residual strong force, which balances things out and stabilizes the nucleus.
As to why you can't have a nucleus of only neutrons... I'm not good enough at Physics to understand why, though I've seen explanations.
So, yeah, this is an extremely rough answer that you probably shouldn't rely on too much.
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Hmmmmmmmm, unless someone wants to write a 1000 pages reply u will never get your answer
To start off what science class have you finished at school ( or what level of books did u read on those subjects)
To deeply understand physics u must understand how the math works behind it, this covers everything from limits, differential, vectors spaces, matrix, continuous and non continuous function and BLALBLALLABLLBALQLBAL ( I could go on forever)
Physics uses model to try to explain different things and it uses math behind the models to make them solid and logical. Your description of light and wave formation is really barren (consider i have just finished an optic level class at university) to create a wave can be explained and represented in many different ways and complicated ways. The actual more solid proof of explaining wave theory is using differentials of maxwells equation and defining every derivative as its physical counterpart (this is extremely long tedious and complicated, also TL doesnt have a way to write equation so good luck with that )
For everything that has to do with neurons, protons and general cloud activity u have to understand organic chemistry, the solution u are in, the different ways molecules can break appart and reform themselves, size quantity, stochiometry and alot of other factors come into account for different molecules.
I hope this small explanation has proven to u how fucking complicated this can get. The best way to learn these things if u dont want to take classes is to use wikipedia as a guide and when u get into more complicated subject to download thesis from grad students at universities
Here is the wikipedia portal for physics http://en.wikipedia.org/wiki/Physics
U can also read review papers to depen knowleadge, the most famous paper internationnaly for sciences is called Nature, but u probably lack the fundamentals to understand any article in those papers so i wouldnt bother with it
TLDR: NO ANSWER POSSIBLE, READ MORE, GO TO CLASS
+ Show Spoiler +If you want to study some weird things that are cool, I would suggest digging into the fractal world and the geometry behind it, maybe reading a bit on matrixes and complex number would be a good way of getting into it
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Darken Im sorry but neutrons and protons have very little to do with organic chemistry (in the context of OP's questions), and OP didn't even ask about cloud activity as far as I can tell. And as far as I can tell that math you listed is babby math that OP probably already knows if he is studying mechE and Econ. Also, anybody can understand Nature if they can read scientific papers, it has very little to do with background and more to do with simply reading papers.
I am also very curious as to why neutrons do not just bunch up together on their own. I've never really thought of that before.
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I've always been bad at thinking about abstract and theoretical things including talking about physics in great detail
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On December 04 2013 13:42 Chocolate wrote:
Darken Im sorry but neutrons and protons have very little to do with organic chemistry (in the context of OP's questions), and OP didn't even ask about cloud activity as far as I can tell. And as far as I can tell that math you listed is babby math that OP probably already knows if he is studying mechE and Econ. Also, anybody can understand Nature if they can read scientific papers, it has very little to do with background and more to do with simply reading papers.
I am also very curious as to why neutrons do not just bunch up together on their own. I've never really thought of that before.
Rereading the question you are right it makes no sense given the context but im in my finals week indulge with me.
As for all that being baby math, yes its the fundamentals, but there is alot of stuff to learn and not everything is easely comprehend or applicable directly, try using lagrange multipliers with sec 5 math, i still have no clue what a geometric series reprensents in a physical problem for exemple.
As for reading Nature is as easy as reading a scientific paper i have to frankly disagree with u, unless u pass ur spare time reading scientific papers this is not an accessible journals by any means ( you have to have a very good understanding of the field to even understand what they are trying to do), here let me quote a bit of a random article and see how many people understand
CAAX proteins have essential roles in multiple signalling pathways, controlling processes such as proliferation, differentiation and carcinogenesis1. The ~120 mammalian CAAX proteins function at cellular membranes and include the Ras superfamily of small GTPases, nuclear lamins, the γ-subunit of heterotrimeric GTPases, and several protein kinases and phosphatases2. The proper localization of CAAX proteins to cell membranes is orchestrated by a series of post-translational modifications of the carboxy-terminal CAAX motifs3 (where C is cysteine, A is an aliphatic amino acid and X is any amino acid). These reactions involve prenylation of the cysteine residue, cleavage at the AAX tripeptide and methylation of the carboxyl-prenylated cysteine residue. The major CAAX protease activity is mediated by Rce1 (Ras and a-factor converting enzyme 1), an intramembrane protease (IMP) of the endoplasmic reticulum4, 5. Information on the architecture and proteolytic mechanism of Rce1 has been lacking. Here we report the crystal structure of a Methanococcus maripaludis homologue of Rce1, whose endopeptidase specificity for farnesylated peptides mimics that of eukaryotic Rce1. Its structure, comprising eight transmembrane α-helices, and catalytic site are distinct from those of other IMPs. The catalytic residues are located ~10 Å into the membrane and are exposed to the cytoplasm and membrane through a conical cavity that accommodates the prenylated CAAX substrate. We propose that the farnesyl lipid binds to a site at the opening of two transmembrane α-helices, which results in the scissile bond being positioned adjacent to a glutamate-activated nucleophilic water molecule. This study suggests that Rce1 is the founding member of a novel IMP family, the glutamate IMPs
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On December 04 2013 14:54 Darkren wrote:Show nested quote +On December 04 2013 13:42 Chocolate wrote:
Darken Im sorry but neutrons and protons have very little to do with organic chemistry (in the context of OP's questions), and OP didn't even ask about cloud activity as far as I can tell. And as far as I can tell that math you listed is babby math that OP probably already knows if he is studying mechE and Econ. Also, anybody can understand Nature if they can read scientific papers, it has very little to do with background and more to do with simply reading papers.
I am also very curious as to why neutrons do not just bunch up together on their own. I've never really thought of that before. Rereading the question you are right it makes no sense given the context but im in my finals week indulge with me. As for all that being baby math, yes its the fundamentals, but there is alot of stuff to learn and not everything is easely comprehend or applicable directly, try using lagrange multipliers with sec 5 math, i still have no clue what a geometric series reprensents in a physical problem for exemple. As for reading Nature is as easy as reading a scientific paper i have to frankly disagree with u, unless u pass ur spare time reading scientific papers this is not an accessible journals by any means ( you have to have a very good understanding of the field to even understand what they are trying to do), here let me quote a bit of a random article and see how many people understand Show nested quote +CAAX proteins have essential roles in multiple signalling pathways, controlling processes such as proliferation, differentiation and carcinogenesis1. The ~120 mammalian CAAX proteins function at cellular membranes and include the Ras superfamily of small GTPases, nuclear lamins, the γ-subunit of heterotrimeric GTPases, and several protein kinases and phosphatases2. The proper localization of CAAX proteins to cell membranes is orchestrated by a series of post-translational modifications of the carboxy-terminal CAAX motifs3 (where C is cysteine, A is an aliphatic amino acid and X is any amino acid). These reactions involve prenylation of the cysteine residue, cleavage at the AAX tripeptide and methylation of the carboxyl-prenylated cysteine residue. The major CAAX protease activity is mediated by Rce1 (Ras and a-factor converting enzyme 1), an intramembrane protease (IMP) of the endoplasmic reticulum4, 5. Information on the architecture and proteolytic mechanism of Rce1 has been lacking. Here we report the crystal structure of a Methanococcus maripaludis homologue of Rce1, whose endopeptidase specificity for farnesylated peptides mimics that of eukaryotic Rce1. Its structure, comprising eight transmembrane α-helices, and catalytic site are distinct from those of other IMPs. The catalytic residues are located ~10 Å into the membrane and are exposed to the cytoplasm and membrane through a conical cavity that accommodates the prenylated CAAX substrate. We propose that the farnesyl lipid binds to a site at the opening of two transmembrane α-helices, which results in the scissile bond being positioned adjacent to a glutamate-activated nucleophilic water molecule. This study suggests that Rce1 is the founding member of a novel IMP family, the glutamate IMPs
Anyone with a bachelors degree in a hard science can probably understand at least the gist of that paragraph.
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On December 04 2013 15:23 IgnE wrote:Hydrogen bro? Wat?
I'm sorry I wasn't clear. I meant nuclei consisting of more than a single particle, since we were discussing bound states. You can have a free neutron floating around, but it'll decay pretty fast.
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On December 04 2013 15:25 IgnE wrote:Show nested quote +On December 04 2013 14:54 Darkren wrote:On December 04 2013 13:42 Chocolate wrote:
Darken Im sorry but neutrons and protons have very little to do with organic chemistry (in the context of OP's questions), and OP didn't even ask about cloud activity as far as I can tell. And as far as I can tell that math you listed is babby math that OP probably already knows if he is studying mechE and Econ. Also, anybody can understand Nature if they can read scientific papers, it has very little to do with background and more to do with simply reading papers.
I am also very curious as to why neutrons do not just bunch up together on their own. I've never really thought of that before. Rereading the question you are right it makes no sense given the context but im in my finals week indulge with me. As for all that being baby math, yes its the fundamentals, but there is alot of stuff to learn and not everything is easely comprehend or applicable directly, try using lagrange multipliers with sec 5 math, i still have no clue what a geometric series reprensents in a physical problem for exemple. As for reading Nature is as easy as reading a scientific paper i have to frankly disagree with u, unless u pass ur spare time reading scientific papers this is not an accessible journals by any means ( you have to have a very good understanding of the field to even understand what they are trying to do), here let me quote a bit of a random article and see how many people understand CAAX proteins have essential roles in multiple signalling pathways, controlling processes such as proliferation, differentiation and carcinogenesis1. The ~120 mammalian CAAX proteins function at cellular membranes and include the Ras superfamily of small GTPases, nuclear lamins, the γ-subunit of heterotrimeric GTPases, and several protein kinases and phosphatases2. The proper localization of CAAX proteins to cell membranes is orchestrated by a series of post-translational modifications of the carboxy-terminal CAAX motifs3 (where C is cysteine, A is an aliphatic amino acid and X is any amino acid). These reactions involve prenylation of the cysteine residue, cleavage at the AAX tripeptide and methylation of the carboxyl-prenylated cysteine residue. The major CAAX protease activity is mediated by Rce1 (Ras and a-factor converting enzyme 1), an intramembrane protease (IMP) of the endoplasmic reticulum4, 5. Information on the architecture and proteolytic mechanism of Rce1 has been lacking. Here we report the crystal structure of a Methanococcus maripaludis homologue of Rce1, whose endopeptidase specificity for farnesylated peptides mimics that of eukaryotic Rce1. Its structure, comprising eight transmembrane α-helices, and catalytic site are distinct from those of other IMPs. The catalytic residues are located ~10 Å into the membrane and are exposed to the cytoplasm and membrane through a conical cavity that accommodates the prenylated CAAX substrate. We propose that the farnesyl lipid binds to a site at the opening of two transmembrane α-helices, which results in the scissile bond being positioned adjacent to a glutamate-activated nucleophilic water molecule. This study suggests that Rce1 is the founding member of a novel IMP family, the glutamate IMPs Anyone with a bachelors degree in a hard science can probably understand at least the gist of that paragraph.
So you need a bachelor degree in science..... that is not accessible by any stretch of the imagination
The first thing i asked is what classes or readings level the person finished to try to give a more educated answer
Its like me going to a high school math level class and start explaining complex numbers to students and being like hey dumbshit its fucking easy u take the conjugate number of this weird thing and that gives u an angle on a circle of radius one, then u just separate the real part and the imaginary part.
I mean even expert in the field have trouble explaining interaction in atoms, to just classify 4 general forces in this earth and try to explain interaction on subatomic level is just dumb, it will give you a wrong answer and it will just lead you to wrong assumptions.
From what some of my friends told me (I am not at that level yet), to even begin explaining how atoms work u must be able to work in R4 or R8 and have a solid understand of a vectorial space that is non-eucledian, i can testify that even people who have finished bachelor in sciences are not all able to do that
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Italy12246 Posts
Will try to provide a decent answer when i get back from uni.
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On December 04 2013 15:40 Darkren wrote:Show nested quote +On December 04 2013 15:25 IgnE wrote:On December 04 2013 14:54 Darkren wrote:On December 04 2013 13:42 Chocolate wrote:
Darken Im sorry but neutrons and protons have very little to do with organic chemistry (in the context of OP's questions), and OP didn't even ask about cloud activity as far as I can tell. And as far as I can tell that math you listed is babby math that OP probably already knows if he is studying mechE and Econ. Also, anybody can understand Nature if they can read scientific papers, it has very little to do with background and more to do with simply reading papers.
I am also very curious as to why neutrons do not just bunch up together on their own. I've never really thought of that before. Rereading the question you are right it makes no sense given the context but im in my finals week indulge with me. As for all that being baby math, yes its the fundamentals, but there is alot of stuff to learn and not everything is easely comprehend or applicable directly, try using lagrange multipliers with sec 5 math, i still have no clue what a geometric series reprensents in a physical problem for exemple. As for reading Nature is as easy as reading a scientific paper i have to frankly disagree with u, unless u pass ur spare time reading scientific papers this is not an accessible journals by any means ( you have to have a very good understanding of the field to even understand what they are trying to do), here let me quote a bit of a random article and see how many people understand CAAX proteins have essential roles in multiple signalling pathways, controlling processes such as proliferation, differentiation and carcinogenesis1. The ~120 mammalian CAAX proteins function at cellular membranes and include the Ras superfamily of small GTPases, nuclear lamins, the γ-subunit of heterotrimeric GTPases, and several protein kinases and phosphatases2. The proper localization of CAAX proteins to cell membranes is orchestrated by a series of post-translational modifications of the carboxy-terminal CAAX motifs3 (where C is cysteine, A is an aliphatic amino acid and X is any amino acid). These reactions involve prenylation of the cysteine residue, cleavage at the AAX tripeptide and methylation of the carboxyl-prenylated cysteine residue. The major CAAX protease activity is mediated by Rce1 (Ras and a-factor converting enzyme 1), an intramembrane protease (IMP) of the endoplasmic reticulum4, 5. Information on the architecture and proteolytic mechanism of Rce1 has been lacking. Here we report the crystal structure of a Methanococcus maripaludis homologue of Rce1, whose endopeptidase specificity for farnesylated peptides mimics that of eukaryotic Rce1. Its structure, comprising eight transmembrane α-helices, and catalytic site are distinct from those of other IMPs. The catalytic residues are located ~10 Å into the membrane and are exposed to the cytoplasm and membrane through a conical cavity that accommodates the prenylated CAAX substrate. We propose that the farnesyl lipid binds to a site at the opening of two transmembrane α-helices, which results in the scissile bond being positioned adjacent to a glutamate-activated nucleophilic water molecule. This study suggests that Rce1 is the founding member of a novel IMP family, the glutamate IMPs Anyone with a bachelors degree in a hard science can probably understand at least the gist of that paragraph. So you need a bachelor degree in science..... that is not accessible by any stretch of the imagination The first thing i asked is what classes or readings level the person finished to try to give a more educated answer Its like me going to a high school math level class and start explaining complex numbers to students and being like hey dumbshit its fucking easy u take the conjugate number of this weird thing and that gives u an angle on a circle of radius one, then u just separate the real part and the imaginary part. I mean even expert in the field have trouble explaining interaction in atoms, to just classify 4 general forces in this earth and try to explain interaction on subatomic level is just dumb, it will give you a wrong answer and it will just lead you to wrong assumptions. From what some of my friends told me (I am not at that level yet), to even begin explaining how atoms work u must be able to work in R4 or R8 and have a solid understand of a vectorial space that is non-eucledian, i can testify that even people who have finished bachelor in sciences are not all able to do that
University wise: 7 math classes (3 calc, 2 linear algebra, numerical methods, differential equations), 2 chem classes, 3 physics classes... And lots of engineering classes that introduces new science concepts... For example: Behavior of Liquids, Gases, and Solids or another example is thermodynamics. It's an engineering class, but lots of science concepts are involved. GPA wise also at the top of the pack, but that probably isn't too significant. Obviously though, this kind of physics has little application for us in engineering until we pick a master's in a field like this, and so it is not taught. That's why my knowledge is pretty poor in it.
Besides that, I have a passion for reading interesting chemistry and physics related stuff I stumble upon on the internet. It is true that understanding scientific papers gets a lot easier after you take these classes. I remember when I entered the program I couldn't understand the higher-level textbooks at all, but now I can make a lot more sense of them because I learned mainly all the tools engineers use to solve their problems.
Anyway, I do find physics like this rather interesting, and if anyone has any good readings or textbooks they can recommend about the Standard Model, and other topics it reaches out to, I'd really like to give it proper time to understand.
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On December 04 2013 16:04 FiWiFaKi wrote:Show nested quote +On December 04 2013 15:40 Darkren wrote:On December 04 2013 15:25 IgnE wrote:On December 04 2013 14:54 Darkren wrote:On December 04 2013 13:42 Chocolate wrote:
Darken Im sorry but neutrons and protons have very little to do with organic chemistry (in the context of OP's questions), and OP didn't even ask about cloud activity as far as I can tell. And as far as I can tell that math you listed is babby math that OP probably already knows if he is studying mechE and Econ. Also, anybody can understand Nature if they can read scientific papers, it has very little to do with background and more to do with simply reading papers.
I am also very curious as to why neutrons do not just bunch up together on their own. I've never really thought of that before. Rereading the question you are right it makes no sense given the context but im in my finals week indulge with me. As for all that being baby math, yes its the fundamentals, but there is alot of stuff to learn and not everything is easely comprehend or applicable directly, try using lagrange multipliers with sec 5 math, i still have no clue what a geometric series reprensents in a physical problem for exemple. As for reading Nature is as easy as reading a scientific paper i have to frankly disagree with u, unless u pass ur spare time reading scientific papers this is not an accessible journals by any means ( you have to have a very good understanding of the field to even understand what they are trying to do), here let me quote a bit of a random article and see how many people understand CAAX proteins have essential roles in multiple signalling pathways, controlling processes such as proliferation, differentiation and carcinogenesis1. The ~120 mammalian CAAX proteins function at cellular membranes and include the Ras superfamily of small GTPases, nuclear lamins, the γ-subunit of heterotrimeric GTPases, and several protein kinases and phosphatases2. The proper localization of CAAX proteins to cell membranes is orchestrated by a series of post-translational modifications of the carboxy-terminal CAAX motifs3 (where C is cysteine, A is an aliphatic amino acid and X is any amino acid). These reactions involve prenylation of the cysteine residue, cleavage at the AAX tripeptide and methylation of the carboxyl-prenylated cysteine residue. The major CAAX protease activity is mediated by Rce1 (Ras and a-factor converting enzyme 1), an intramembrane protease (IMP) of the endoplasmic reticulum4, 5. Information on the architecture and proteolytic mechanism of Rce1 has been lacking. Here we report the crystal structure of a Methanococcus maripaludis homologue of Rce1, whose endopeptidase specificity for farnesylated peptides mimics that of eukaryotic Rce1. Its structure, comprising eight transmembrane α-helices, and catalytic site are distinct from those of other IMPs. The catalytic residues are located ~10 Å into the membrane and are exposed to the cytoplasm and membrane through a conical cavity that accommodates the prenylated CAAX substrate. We propose that the farnesyl lipid binds to a site at the opening of two transmembrane α-helices, which results in the scissile bond being positioned adjacent to a glutamate-activated nucleophilic water molecule. This study suggests that Rce1 is the founding member of a novel IMP family, the glutamate IMPs Anyone with a bachelors degree in a hard science can probably understand at least the gist of that paragraph. So you need a bachelor degree in science..... that is not accessible by any stretch of the imagination The first thing i asked is what classes or readings level the person finished to try to give a more educated answer Its like me going to a high school math level class and start explaining complex numbers to students and being like hey dumbshit its fucking easy u take the conjugate number of this weird thing and that gives u an angle on a circle of radius one, then u just separate the real part and the imaginary part. I mean even expert in the field have trouble explaining interaction in atoms, to just classify 4 general forces in this earth and try to explain interaction on subatomic level is just dumb, it will give you a wrong answer and it will just lead you to wrong assumptions. From what some of my friends told me (I am not at that level yet), to even begin explaining how atoms work u must be able to work in R4 or R8 and have a solid understand of a vectorial space that is non-eucledian, i can testify that even people who have finished bachelor in sciences are not all able to do that University wise: 7 math classes (3 calc, 2 linear algebra, numerical methods, differential equations), 2 chem classes, 3 physics classes... And lots of engineering classes that introduces new science concepts... For example: Behavior of Liquids, Gases, and Solids or another example is thermodynamics. It's an engineering class, but lots of science concepts are involved. GPA wise also at the top of the pack, but that probably isn't too significant. Besides that, I have a passion for reading interesting chemistry and physics related stuff I stumble upon on the internet. It is true that understanding scientific papers gets a lot easier after you take these classes. I remember when I entered the program I couldn't understand the higher-level textbooks at all, but now I can make a lot more sense of them because I learned mainly all the tools engineers use to solve their problems.
That quite impressive, U took quantum mechanics by any chance? I think the models they use for sub atomic particles are all based on quantum mechanic models
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Nah, the classes seem really primitive by physics standards, the classes were:
Electricity and Magnetism for Engineers
Acoustics, Optics and Radiation
Classical Mechanics I & II (Combined as Mech Engineers take dynamics so we have some previous knowledge there).
I'm looking at all the possible first year physics courses, and it seems like we've covered it all in engineering. Second year we've probably covered 1/3-1/2 of the material. Including the physics classes that were required.
I wouldn't mind taking a physics class, but it's just it'd cost $600, and I have no space in my schedule as I'm taking two degrees simultaneously. I'd like to learn this on my own time instead of having to take classes, I feel like my background knowledge while isn't a lot, it should be enough to understand the principles I need to learn in order to understand the explanations.
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I'll give it a go:
The residual strong force is the strong analogue to electromagnetism's Van der Waal force. In the latter case, positive and negative charges cancel, and the cancellation seems perfect at far distances but imperfect at short distances since of course the charges aren't all in the same place.
It may seem odd to take the difference of two lines and get something exponential, but of course the forces don't add up this way. Light seems to add up in weird ways until you realize that you're supposed to be adding up the amplitudes not the intensities. The intensities are a function of the amplitudes like the nuclear force will be a function of the colour charges, and it's not surprising that I(a1+a2) != I(a1)+I(a2).
As for why nuclei have the number of protons and neutrons that they do, think of nuclei as having a lot of potential neutron and proton "states" that each have a particular energy and can be occupied or unoccupied. A nucleus with an occupied state that has a higher energy than an unoccupied state will be unstable and susceptible to beta decay.
Also as far as I know it's not that when you split mesons or baryons they recombine almost instantly, it's that in splitting them you've put in so much energy that you've created new quarks (remember E=mc^2), which of course bind to the quarks that you've just pulled apart.
On December 04 2013 15:40 Darkren wrote:
From what some of my friends told me (I am not at that level yet), to even begin explaining how atoms work u must be able to work in R4 or R8 and have a solid understand of a vectorial space that is non-eucledian, i can testify that even people who have finished bachelor in sciences are not all able to do that
Just depends what level you want to explain atoms to. From what I've heard, organic chemistry gets pretty far with a bunch empirical rules that work except for when they don't and nothing more than high-school maths. However for a more complete "first principle" description of how atoms work you'd have to delve into the details of QED where you could be applying (for example) results from algebraic topology.
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Topology looks like such a scary class....
Maybe just looking for higher level classes and downloading the books in pdf files would be the easiest way, or some phd thesis on quarks
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Particle physics isn't really my field of study currently, but I am doing a lot of quantum mechanics. Read into the Yukawa Interaction, and its formulation (math stuff). You will need to understand wave functions, probability amplitudes, general bra-ket notation stuff. Also understanding Feynmann path integral formulation and second quantization helps.
I know this is a bad explanation, but it is stuff you really need to know to better understand (at least mathematically) why things work the way they do.
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On December 04 2013 16:25 Wonders wrote:
Just depends what level you want to explain atoms to. From what I've heard, organic chemistry gets pretty far with a bunch empirical rules that work except for when they don't and nothing more than high-school maths. However for a more complete "first principle" description of how atoms work you'd have to delve into the details of QED where you could be applying (for example) results from algebraic topology.
Actually 99.99% of Organic chemsitry is nothing but empirical rules. O-chemists could not care less why a reaction happens they just care about how to make it happen. P-chem is where you actually learn about molecular orbitals and what actually makes a reaction go.
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Italy12246 Posts
My knowledge is limited to a couple of nuclear/particle physics classes, so this is fairly basic stuff. Others have answered the more specific stuff already, so i'll just add a couple of points:
1) Now apparently, the strong interaction doesn't diminish in strength as distance increases? What how? How can that be, please somebody explain. The force will be as strong if they are 1m apart as if they are 1 angstrom apart? How?
The quantum mechanics of the strong force are a bitch. Since you have taken classical mechanics 2, i will assume that you know what a Hamiltonian is, and what a phase diagram is. So here's the problem: we do not know a simple way to write the potential energy for the strong force. We can make simple aproximations, but you can't write the Hamiltonian and solve Shroedinger's equation for a nucleus the way you can for an atom. All we can do is use aproximation (for example, the strong force remains constant). It obviously isn't always true, but within certain limits it's a good enough aproximation. There's examples of this in classical physics too: an infinite plane with a uniform charge distrubution will generate an electric field that's constant; this aproximation in fact is used in real life in calculating the capacity of condensators for example.
2) The way I understand it, is if you have a strong interaction, you cannot actually exist, because you will be too attracted to things, therefore free quarks don't exist, and if you somehow split a baryon, it'd combine again almost instantaneously.
It's not that quarks don't exist on their own. Simply, to this day they have never been seen in a free state, unbound from other quarks. We haven't created an experiment capable of separating quarks, but they are there anyway. Imagine having an atom that for some odd reason can't be ionized. The electrons are there and you can measure things on them, they exist but they will always be in that atom.
3) I'm going to exclude the weak interaction as frankly it doesn't appear too significant in what I'm curious about, and well, it's not well understood by the scientific community either.
I'm not sure what you mean here. The weak interaction is just another kind of nuclear interaction, and in fact at short range it's stronger than the electromagnetic force (which is why it occurs at nuclear scales like the strong force, and not atomic scales). I'm not sure what you mean by not well understood by the scientific community, i'm not aware of any uncertainty on its origins or behaviour (even though it does wierd shit like violating symmetries and other things that an actual praticle physicist will be able to explain much better than me).
4) At short distances the strong force is super powerful, why don't the two protons collapse into each other, is there something I am not considering? If the strong force is the one doing the most work, why wouldn't the protons be infinitely close together? Is there something keeping them at a safe distance?
The force between nucleons includes a repulsive term that forces the nucleons to be separated. I'm not sure where this term comes from, but if you think about it the same exact thing happens with the electromagnetic force as well as gravitational force: there is something (in the case of em and gravitational forces, that's angular momentum) which keeps things apart and balances things out. Normally an attractive potential looks something like this:
+ Show Spoiler +
Two terms "fight" against each other, one being repulsive and one being attractive. Depending on the range you are at, one of the two will dominate. A good way of writing the Coulomb potential for electrons in a hydrogen atom, for instance, is -1/r + 1/r^2 (without constants). At short range the 1/r^2 term dominates and the two particles actually push each other away, at long range both go to zero, and in between there is a minimum of the function where the particle tends to stay (things like staying at the lowest possible potential energy of course).
5) Why do you need neutrons and protons in a nucleus to make it stable?
Going back to point 1), you can not write the EXACT potential energy for a nucleon in a nucleus (as far as i'm awae). At best, we come up with our own, more or less complicated, phenomenological potentials to explain the nuclear properties. These potentials need to predict what actually happens in nature, ie, that you need both protons and neutrons in a stable nucleus. Once you have found a satisfactory form for these potentials, you can then give them (sometimes) an interpretation that resembles what happens at a macroscopic scale (ie, our own world). In fact, often times the point to start writing these potentials is a real world effect or force that we can experience in every day life. Essentially, you build a theoretical model around the empirical data. The nice thing is, these potentials are also able to predict other properties of nuclear behaviour (like multipole momentums, magic numbers and whatnot).
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And as far as I can tell that math you listed is babby math that OP probably already knows if he is studying mechE and Econ. Also, anybody can understand Nature if they can read scientific papers
you maybe will understand the final statement someone explains in words, but you have no chance of understanding the underlying mechanics and causes without serious math.
For example you can understand what a tunneleffect is and why it is important for CPU manufacturers, but you need like 1 year of math framework (Hilbert space etc.) for the theoretical side and some training if differential equations to apply the theory and know what is going on.
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EPT![[image loading]](http://thynnine.github.io/pysic/plot_directive/inline/da638a9740.hires.png)
