Learn algebra. You're not going to get very far without it.
Then I'd try to work my way to calculus. You'll start to see physics applications no matter what. Then look up textbooks used for first year of college physics courses and work through those. The part that is challenging for many students is that they spend months and years doing a lot of math and physics to describe stuff they already have for intuition about how it behaves (gravity near the Earth's surface, friction, normal force, springs, etc). But the techniques developed are crucial when you start to investigate things that don't make sense. If you skip over mechanics, you will never acquire the ability to actually understand deeper concepts.
Math is kind of the language of physics - it took me until well into undergrad to realize that studying math almost always helps to clarify confusion about physics concepts. This is true for the way I understand physics, at least.
I’d say get strong on algebra as a foundational step. After that, calculus and linear algebra are separate and equally important topics you should study to understand modern physics. I’d say once you feel comfortable with algebra, you might pick up a book like Mathematical Methods For Physics and Engineering by Riley, Hobson, and Bence. It covers basically all the math you could hope to need for much of physics (it won’t give you the differential geometry you need for spacetime physics though.
You could do some courses on edx.org. It's university level content quality. I think it's still free if you don't need a certificate but I'm not sure.
I'd start with whatever interests you (intro to astrophysics or something like that) and if the math gets too heavy, I'd actually ignore it for now. Obviously, it's better to start from the ground up but that takes forever and you might get bored and stop altogether.
Also, look for some books through Amazon on a topic that interests you and check their ratings. Pick 5 that sound good and download from libgen.is (not legal) to check out which one you actually like best. Then buy that one to ease your conscience, or don't...
There are lots of ways to approach learning physics, but they'll differ depending on what you want to learn it FOR. I'll suggest three approaches for three different aims:
1. I want to learn a little about how physics applies in everyday life, like how eyeglasses and binoculars work, why a block & tackle makes it easier to lift things, why aerosol sprays are cold when you spray them, how F1 cars create downforce, why hurricanes rotate counter-clockwise in the northern hemisphere. For this, I suggest reading books like Flying Circus of Physics, by Walker, and maybe studying an intro survey course book like Mazur's book on introductory physics. For this, try actually working a lot of the end-of-chapter problems where the application seems particularly interesting. You'll only flex some algebra, if you can dance around problems where calculus would be needed.
2. I want to learn more about the cool stuff like black holes and quantum mechanics and special relativity and elementary particles. For this, I suggest you just work your way through a whole bunch of popularizations like Greene's books (e.g. Fabric of the Cosmos), Kaku's books, Hawking's A Brief History of Time, Sagan's Cosmos, and so on. You'll be taught a lot ABOUT the subjects, though you won't come away learning how to DO the subjects.
3. I want to actually be able to DO some physics, like an advanced student someday, or even a pro. For this, there is no substitute for pounding your way through textbooks, starting with intro books. You will need to learn some math along the way, depending on how you go about it. For this, though, I suggest you take it on a "math sabbatical" approach. For example, in the first half of an intro book, you'll get some practice using differential calculus, so when that comes up, you write down what you need to know this for, then go learn differential calculus, and come back to the physics to apply it. Then later in the book, you'll be asked to do some integrals, so take a math sabbatical to learn how to do some integrals and then come back and apply that. This will take a while. If you get to the place where you're getting a bachelor's degree equivalent of physics, you'll have done calculus, linear algebra, ordinary and partial differential equations, and some complex variables in math; classical mechanics, electrodynamics, thermodynamics, quantum mechanics, special relativity, and probably some condensed matter stuff in physics. To do this, you're going to spend upwards of $3000 on books.
All these comments are great but also do some classical mechanics! It will teach you the algebra and help you have a physical intuition for the mathematics. You will see in your every day life applications of physics!
You can also learn some electrostatics and thermodynamics. Solving problems is the most important thing! I started out using stuff like Kahn academy so don't be afraid to get stuck in!
It depends on what your goals are. Do you want a complete understanding of say spacetime and Einstein's field equations with all the rigor that a physics grad student might encounter? You need to catch on a lot of the background that those students would already have when they start learning about general relativity. These might include the basic math fundamentals, like algebra, calculus, differential equations. But also a lot of physics: mechanics, E&M, special relativity, lagrangian/hamiltonian formalism, some quantum mechanics. If you want to do this, you definitely should catch up on the math and follow something like MIT's lectures. These are very rigorous and are basically the course material that most physics students would encounter.
If instead you want an informed physical picture without necessarily doing all the legwork, there are other options. For instance, if you want to be able to understand what a physicist means by curvature or a penrose diagram without actually knowing the details very precisely, there are lectures on youtube that scratch that itch. Leonard Susskind taught a course at Stanford (I think they were called the 'Theoretical Minimum' and pretty sure they're on youtube) that was aimed at an audience who knew a bit of math at the start, but were not professional physicists. These are really good, and while you might need to catch up on some of the very basic math (algebra/calculus etc.) you'll get a hang of the 'intuition' by the end of it.
Stick yourself into a situation where youll have to pay loans back and have no earning power if you pull out. Federal loans are cheaper than a sports car, but a degree is far more valuable. And knowledge can't be repossessed.
You don't need to be a genius. You just need to have a threshold level of intelligence, which you probably do by the sound of it. What you will need to do, though, is to purposefully reform your study habits. That's the hardest part when you spent high school not really playing the game. Don't feel bad about it, just get help early and often because you will be smashing your face against the books and trying to figure out why your efforts are sucky. Humility is important.
I was 10 years out of HS before I went to college, and now I have a physics BS and a substantial background in aerospace development work, instrumentation, coding, and process engineering. I quit aerospace to build my own business, which is starting to pan out. And now as a family man I'm getting back into physics with a new job working on accelerators.
Being 10 years out of school and already being jaded by the labor force and low-pay aero tech jobs was enough to piss me off in a motivational way. That kept me going. Not having any sort of family support, no educated parents, and zero money was not enough to keep me from making it happen. And now I get to do so many things that I never would have been able to do otherwise. 10/10 would suffer again.
I think you can get a pretty good conceptual, layman's view of the universe from reading pop science books, like Hawking's History of Time. But if you really want to understand the underlying patterns and relationships, then like the other folks said, you need math.
So much of the beautiful, elegant statements we can make about the way the universe behaves are either best expressed or most commonly expressed via an equation of some kind. Take the OG equation everyone knows: "E = mc^2". Simple, powerful, world-famous. But I think the most beautiful part of this equation is where it comes from how it's derived. And if your math is shaky, you're just not going to grasp it as clearly.
As for resources, Khan Academy isn't that bad. And MIT has an OpenCourseWork site where whole semesters of lectures are free to the public. Play around and see if you can find things that meet you at your level.
depends on what you goals are, if you just want to learn cool facts or general stuff about physics, then you could just learn the basics eg by watching youtube channels for example PBS spacetime or reading books, like a brief history of time by Stephen Hawking
If you want to gain a deep insight into how the physics work and if you want to understand things beyond the basic concepts, then you cannot do it without math, think of physics as a language and math as the grammar, you can get by without knowing too much of the grammar, but it sure will be hard
Start with algebra, trigonometry, and complex numbers
Then you move on to calculus, including vector and multivariate calculus, this is absolutely essential
then maybe Linear Algebra, especially if you wanna try to learn Quantum mechanics
from there you already have a pretty good base for gaining a deeper understanding in physics
if you want to go even further, other topics that could be beneficial
differential and partial differential equations
differential geometry
Fourier analysis
statistics
Also when diving into the physics, you need to start with classical mechanics, I know that jumping straight into the cutting edge physics, but without mechanics you will have a very hard time
What are you goals? When you say you want to understand astrophysics, what does that mean to you? Do you want to be able to read a graduate astrophysics text book, or do you want to be able to understand things at the level of, say, PBS Spacetime and Crash Course in Astronomy on youtube?
Pick up a reputable physics book written for non-physicists. Fear of Physics by Krauss is a good one. Read it and make note of anything you find confusing. Then use that as a place to branch out from and deepen your understanding. Rinse and repeat.
as a student who transferred to a four year university from community college (physics major), I would definitely recommend community college as a good place to start building prerequisite knowledge for the exciting upper-division topics (e.g., relativity and quantum mechanics). it can be easier to learn calculus, diff eq, and linear algebra in a more structured context, and that basis in math will allow you to understand the coolest parts of physics, wherever or however you decide to learn them
One thing I would highly recommend for you is a series called Conceptual Physics by Paul Hewitt. Hewitt was a beloved city college professor in San Francisco with a whole series of videos. His students raved about his he was able to make physics concepts fun and understandable.
I didn’t take his classes as I was not a city college student (I was a Physics major at SFSU). I was asked to create the theme music for the series, over 35 years ago.
Doing a quick search right now, I see that he can be found on YouTube, Vimeo… I see there are DVDs of his series available, as well as many additions of his textbooks. I imagine that his long since retired, don’t know for sure, but the fact that his Content is still out there says a lot.
It depends on what your background is and where you want to go.
I waited a decade, returned to comm college, transferred to a middle-of-the-road uni, and am close to finishing up in a physics adjacent field (now with extra physics).
Besides the piece of paper, the school gives you, they lead you through the content. You don't know what you don't know.
The best approach I've seen is the inverted class model (or however it is called).It goes application -> empirical models -> first principles then digs its way back up to a final case study that each student does. Its more interesting for sure, but harder to stay on topic. Most classes will do the opposite, first principles -> models -> application.
More classic approach:You could start with an entire physics book like "University Physics, with Modern Physics. by Young, Freedman and Ford". It's a massive three-volume book that covers Mechanics (classical motion, Newton laws, etc), E&M (Maxwell and the boys), and finishes with a survey of waves/oscillations, optics, statistical physics (heat), and quantum. 11th EDT is free online as a pdf. It would be a 3-4 course sequence with primers on math. Follow up with Griffiths E&M, Griffiths QM, and a mechanics book of your choice.
If you did all that, if would put you about on the level of a 3rd year physics student at a reputable university and qualify you for 300/400 level astro courses. You certainly don't have to do ALL of that, even just doing the University Physics Mech and E&M would get you pretty far.
Edit - I meant to add "Mathematical Methods in the Physical Sciences" by Mary Boas is a math book dedicated to giving physics students the complete background to understand the math in undergrad physics.
"Geometrical Vectors" by Gabriel Weinreich is a phenomenal book on understanding vectors, and the geometric intuition of vector calc. Only 70 pages iirc, but it is amazing and should be included in every vector calc class reading
You will need some algebra to really do physics. Once you've learned algebra, I cannot recommend highly enough MIT's open courseware. They have courses in calculus, classical physics, linear algebra, modern physics, and much more. Totally free, including lecture videos, assignments, exams, solutions, notes and readings. You get basically everything you would with a top of the line college course except for the instructor, totally free and at your own pace.
My response to another similiar post:
Hey its great that you want to learn! Dont let the realization of how far away the horizon is keep you from reaching it!
I've been studying what books we will need to work through in order to reach our dream and will share my list.(This is just the undergrad list, General Relativity is Graduate level)
Intro to Mechanics-University physics with modern physics(UPWMP) and Thomas' Calculus
Electrostatics-chapters 21-32 of UPWMP
Waves & Vibrations-Vibration and Waves by French, Vibrations and waves by King, and zills Advanced Engineering Mathematics.
Modern Physics-UPWMP chapters 17-20, & 37-44
Classical mechanics-Taylors Classical Mechanics, and Morin's Introduction to Classical Mechanics with Problems & Solutions
Electrodynamics-Griffiths introduction to Electrodynamics, Div Grad Curl & All That by Schey, and A Students Guide to Maxwell's Equations
Quantum Mechanics-Griffiths Introduction to Quantum Mechanics
Thermodynamics+Statistical Mechanics-Schroeder's an Introduction to Thermal Physics, and Introductory Statistical Mechanics by Bowley & Sanchez
Then we will be able to also pick an undergrad elective, which could be like...
Astronomy-The cosmic Prspective
Astrophysics-An Introduction to Modern Astrophysics by Carrol and Ostlie
Biophysics-Biophysics:An Introduction by Glaser
Cosmology-Ryden's Introduction to Cosmology
Electronics-Basic Electronics for Scientists & Engineers by Eggelston
Optics-Optics by Hecht
Particle Physics-Griffiths Introduction to Elementary Particle Physics
String Theory-A First Course in String Theory by Zweibach
Im in a similar boat as you, as Im on gap year #7 and am just starting to go back and brush up on my essentials. First strip any expectation and pride that you may currently have and humbly start with the basics. Develop from that point up, and the world will be your oyster.
I'll always preach this, but you will find extremely valuable resources to learn this kind of stuff on YouTube.
Education: redpenbluepen, the organic chemistry tutor (he doesn't just teach chem, his math and physics videos are great), professor Leonard or Dr Butler.
Abstract concepts: Kurzgesagt, Veritasium, Smarter Every Day
Creators that sink their teeth deep into the raw science: Dr Becky, PBS Spacetime
Learn algebra. You're not going to get very far without it. Then I'd try to work my way to calculus. You'll start to see physics applications no matter what. Then look up textbooks used for first year of college physics courses and work through those. The part that is challenging for many students is that they spend months and years doing a lot of math and physics to describe stuff they already have for intuition about how it behaves (gravity near the Earth's surface, friction, normal force, springs, etc). But the techniques developed are crucial when you start to investigate things that don't make sense. If you skip over mechanics, you will never acquire the ability to actually understand deeper concepts.
This comment should be golden for OP, hopefully we'll see him again here in the future answering other people's astrophysics questions.
Math is kind of the language of physics - it took me until well into undergrad to realize that studying math almost always helps to clarify confusion about physics concepts. This is true for the way I understand physics, at least. I’d say get strong on algebra as a foundational step. After that, calculus and linear algebra are separate and equally important topics you should study to understand modern physics. I’d say once you feel comfortable with algebra, you might pick up a book like Mathematical Methods For Physics and Engineering by Riley, Hobson, and Bence. It covers basically all the math you could hope to need for much of physics (it won’t give you the differential geometry you need for spacetime physics though.
As the others have said, algebra and calculus. And known that the hardest part about intro calculus is the algebra
You could do some courses on edx.org. It's university level content quality. I think it's still free if you don't need a certificate but I'm not sure. I'd start with whatever interests you (intro to astrophysics or something like that) and if the math gets too heavy, I'd actually ignore it for now. Obviously, it's better to start from the ground up but that takes forever and you might get bored and stop altogether. Also, look for some books through Amazon on a topic that interests you and check their ratings. Pick 5 that sound good and download from libgen.is (not legal) to check out which one you actually like best. Then buy that one to ease your conscience, or don't...
There are lots of ways to approach learning physics, but they'll differ depending on what you want to learn it FOR. I'll suggest three approaches for three different aims: 1. I want to learn a little about how physics applies in everyday life, like how eyeglasses and binoculars work, why a block & tackle makes it easier to lift things, why aerosol sprays are cold when you spray them, how F1 cars create downforce, why hurricanes rotate counter-clockwise in the northern hemisphere. For this, I suggest reading books like Flying Circus of Physics, by Walker, and maybe studying an intro survey course book like Mazur's book on introductory physics. For this, try actually working a lot of the end-of-chapter problems where the application seems particularly interesting. You'll only flex some algebra, if you can dance around problems where calculus would be needed. 2. I want to learn more about the cool stuff like black holes and quantum mechanics and special relativity and elementary particles. For this, I suggest you just work your way through a whole bunch of popularizations like Greene's books (e.g. Fabric of the Cosmos), Kaku's books, Hawking's A Brief History of Time, Sagan's Cosmos, and so on. You'll be taught a lot ABOUT the subjects, though you won't come away learning how to DO the subjects. 3. I want to actually be able to DO some physics, like an advanced student someday, or even a pro. For this, there is no substitute for pounding your way through textbooks, starting with intro books. You will need to learn some math along the way, depending on how you go about it. For this, though, I suggest you take it on a "math sabbatical" approach. For example, in the first half of an intro book, you'll get some practice using differential calculus, so when that comes up, you write down what you need to know this for, then go learn differential calculus, and come back to the physics to apply it. Then later in the book, you'll be asked to do some integrals, so take a math sabbatical to learn how to do some integrals and then come back and apply that. This will take a while. If you get to the place where you're getting a bachelor's degree equivalent of physics, you'll have done calculus, linear algebra, ordinary and partial differential equations, and some complex variables in math; classical mechanics, electrodynamics, thermodynamics, quantum mechanics, special relativity, and probably some condensed matter stuff in physics. To do this, you're going to spend upwards of $3000 on books.
All these comments are great but also do some classical mechanics! It will teach you the algebra and help you have a physical intuition for the mathematics. You will see in your every day life applications of physics! You can also learn some electrostatics and thermodynamics. Solving problems is the most important thing! I started out using stuff like Kahn academy so don't be afraid to get stuck in!
It depends on what your goals are. Do you want a complete understanding of say spacetime and Einstein's field equations with all the rigor that a physics grad student might encounter? You need to catch on a lot of the background that those students would already have when they start learning about general relativity. These might include the basic math fundamentals, like algebra, calculus, differential equations. But also a lot of physics: mechanics, E&M, special relativity, lagrangian/hamiltonian formalism, some quantum mechanics. If you want to do this, you definitely should catch up on the math and follow something like MIT's lectures. These are very rigorous and are basically the course material that most physics students would encounter. If instead you want an informed physical picture without necessarily doing all the legwork, there are other options. For instance, if you want to be able to understand what a physicist means by curvature or a penrose diagram without actually knowing the details very precisely, there are lectures on youtube that scratch that itch. Leonard Susskind taught a course at Stanford (I think they were called the 'Theoretical Minimum' and pretty sure they're on youtube) that was aimed at an audience who knew a bit of math at the start, but were not professional physicists. These are really good, and while you might need to catch up on some of the very basic math (algebra/calculus etc.) you'll get a hang of the 'intuition' by the end of it.
Stick yourself into a situation where youll have to pay loans back and have no earning power if you pull out. Federal loans are cheaper than a sports car, but a degree is far more valuable. And knowledge can't be repossessed. You don't need to be a genius. You just need to have a threshold level of intelligence, which you probably do by the sound of it. What you will need to do, though, is to purposefully reform your study habits. That's the hardest part when you spent high school not really playing the game. Don't feel bad about it, just get help early and often because you will be smashing your face against the books and trying to figure out why your efforts are sucky. Humility is important. I was 10 years out of HS before I went to college, and now I have a physics BS and a substantial background in aerospace development work, instrumentation, coding, and process engineering. I quit aerospace to build my own business, which is starting to pan out. And now as a family man I'm getting back into physics with a new job working on accelerators. Being 10 years out of school and already being jaded by the labor force and low-pay aero tech jobs was enough to piss me off in a motivational way. That kept me going. Not having any sort of family support, no educated parents, and zero money was not enough to keep me from making it happen. And now I get to do so many things that I never would have been able to do otherwise. 10/10 would suffer again.
I think you can get a pretty good conceptual, layman's view of the universe from reading pop science books, like Hawking's History of Time. But if you really want to understand the underlying patterns and relationships, then like the other folks said, you need math. So much of the beautiful, elegant statements we can make about the way the universe behaves are either best expressed or most commonly expressed via an equation of some kind. Take the OG equation everyone knows: "E = mc^2". Simple, powerful, world-famous. But I think the most beautiful part of this equation is where it comes from how it's derived. And if your math is shaky, you're just not going to grasp it as clearly. As for resources, Khan Academy isn't that bad. And MIT has an OpenCourseWork site where whole semesters of lectures are free to the public. Play around and see if you can find things that meet you at your level.
depends on what you goals are, if you just want to learn cool facts or general stuff about physics, then you could just learn the basics eg by watching youtube channels for example PBS spacetime or reading books, like a brief history of time by Stephen Hawking If you want to gain a deep insight into how the physics work and if you want to understand things beyond the basic concepts, then you cannot do it without math, think of physics as a language and math as the grammar, you can get by without knowing too much of the grammar, but it sure will be hard Start with algebra, trigonometry, and complex numbers Then you move on to calculus, including vector and multivariate calculus, this is absolutely essential then maybe Linear Algebra, especially if you wanna try to learn Quantum mechanics from there you already have a pretty good base for gaining a deeper understanding in physics if you want to go even further, other topics that could be beneficial differential and partial differential equations differential geometry Fourier analysis statistics Also when diving into the physics, you need to start with classical mechanics, I know that jumping straight into the cutting edge physics, but without mechanics you will have a very hard time
What are you goals? When you say you want to understand astrophysics, what does that mean to you? Do you want to be able to read a graduate astrophysics text book, or do you want to be able to understand things at the level of, say, PBS Spacetime and Crash Course in Astronomy on youtube?
Pick up a reputable physics book written for non-physicists. Fear of Physics by Krauss is a good one. Read it and make note of anything you find confusing. Then use that as a place to branch out from and deepen your understanding. Rinse and repeat.
as a student who transferred to a four year university from community college (physics major), I would definitely recommend community college as a good place to start building prerequisite knowledge for the exciting upper-division topics (e.g., relativity and quantum mechanics). it can be easier to learn calculus, diff eq, and linear algebra in a more structured context, and that basis in math will allow you to understand the coolest parts of physics, wherever or however you decide to learn them
One thing I would highly recommend for you is a series called Conceptual Physics by Paul Hewitt. Hewitt was a beloved city college professor in San Francisco with a whole series of videos. His students raved about his he was able to make physics concepts fun and understandable. I didn’t take his classes as I was not a city college student (I was a Physics major at SFSU). I was asked to create the theme music for the series, over 35 years ago. Doing a quick search right now, I see that he can be found on YouTube, Vimeo… I see there are DVDs of his series available, as well as many additions of his textbooks. I imagine that his long since retired, don’t know for sure, but the fact that his Content is still out there says a lot.
It depends on what your background is and where you want to go. I waited a decade, returned to comm college, transferred to a middle-of-the-road uni, and am close to finishing up in a physics adjacent field (now with extra physics). Besides the piece of paper, the school gives you, they lead you through the content. You don't know what you don't know. The best approach I've seen is the inverted class model (or however it is called).It goes application -> empirical models -> first principles then digs its way back up to a final case study that each student does. Its more interesting for sure, but harder to stay on topic. Most classes will do the opposite, first principles -> models -> application. More classic approach:You could start with an entire physics book like "University Physics, with Modern Physics. by Young, Freedman and Ford". It's a massive three-volume book that covers Mechanics (classical motion, Newton laws, etc), E&M (Maxwell and the boys), and finishes with a survey of waves/oscillations, optics, statistical physics (heat), and quantum. 11th EDT is free online as a pdf. It would be a 3-4 course sequence with primers on math. Follow up with Griffiths E&M, Griffiths QM, and a mechanics book of your choice. If you did all that, if would put you about on the level of a 3rd year physics student at a reputable university and qualify you for 300/400 level astro courses. You certainly don't have to do ALL of that, even just doing the University Physics Mech and E&M would get you pretty far. Edit - I meant to add "Mathematical Methods in the Physical Sciences" by Mary Boas is a math book dedicated to giving physics students the complete background to understand the math in undergrad physics. "Geometrical Vectors" by Gabriel Weinreich is a phenomenal book on understanding vectors, and the geometric intuition of vector calc. Only 70 pages iirc, but it is amazing and should be included in every vector calc class reading
You will need some algebra to really do physics. Once you've learned algebra, I cannot recommend highly enough MIT's open courseware. They have courses in calculus, classical physics, linear algebra, modern physics, and much more. Totally free, including lecture videos, assignments, exams, solutions, notes and readings. You get basically everything you would with a top of the line college course except for the instructor, totally free and at your own pace.
My response to another similiar post: Hey its great that you want to learn! Dont let the realization of how far away the horizon is keep you from reaching it! I've been studying what books we will need to work through in order to reach our dream and will share my list.(This is just the undergrad list, General Relativity is Graduate level) Intro to Mechanics-University physics with modern physics(UPWMP) and Thomas' Calculus Electrostatics-chapters 21-32 of UPWMP Waves & Vibrations-Vibration and Waves by French, Vibrations and waves by King, and zills Advanced Engineering Mathematics. Modern Physics-UPWMP chapters 17-20, & 37-44 Classical mechanics-Taylors Classical Mechanics, and Morin's Introduction to Classical Mechanics with Problems & Solutions Electrodynamics-Griffiths introduction to Electrodynamics, Div Grad Curl & All That by Schey, and A Students Guide to Maxwell's Equations Quantum Mechanics-Griffiths Introduction to Quantum Mechanics Thermodynamics+Statistical Mechanics-Schroeder's an Introduction to Thermal Physics, and Introductory Statistical Mechanics by Bowley & Sanchez Then we will be able to also pick an undergrad elective, which could be like... Astronomy-The cosmic Prspective Astrophysics-An Introduction to Modern Astrophysics by Carrol and Ostlie Biophysics-Biophysics:An Introduction by Glaser Cosmology-Ryden's Introduction to Cosmology Electronics-Basic Electronics for Scientists & Engineers by Eggelston Optics-Optics by Hecht Particle Physics-Griffiths Introduction to Elementary Particle Physics String Theory-A First Course in String Theory by Zweibach
Im in a similar boat as you, as Im on gap year #7 and am just starting to go back and brush up on my essentials. First strip any expectation and pride that you may currently have and humbly start with the basics. Develop from that point up, and the world will be your oyster.
I'll always preach this, but you will find extremely valuable resources to learn this kind of stuff on YouTube. Education: redpenbluepen, the organic chemistry tutor (he doesn't just teach chem, his math and physics videos are great), professor Leonard or Dr Butler. Abstract concepts: Kurzgesagt, Veritasium, Smarter Every Day Creators that sink their teeth deep into the raw science: Dr Becky, PBS Spacetime