The Modern Physics Thread

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Joey D

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Alright so here's the deal, I'm taking very few summer classes this semester, just so I get some more credit hours under my belt. Anyways the class I'll be starting tomarrow night is a Modern Physics class. I can't remember the name of the course.

I've always been intrested in things like this, black holes, the shape of the universe, white dwarfs, etc. So I was wonder wheather or not anyone else was interested in Modern Physics or Metaphysics?

and if anyone has any neat info to share I'm always up for a read about this stuff.
 
read a brief history of time and the universe in a nutshell, they enlightened me a lot. plus, they are in laymen's terms.

i am very interested in this stuff (hence, my username). hopefully, we can get in a discussion with the other people in this board interested in this stuff (i know there are people who know about this)
 
Alright I'll have to read that.

But by far the coolest book I've read on this has to be the Hitchhikers Guide the Galaxy, yes I know its a sci fi book but still its really does make you think.
 
I know I need to get the other books, just a matter of finding time with work and school to find time.

Anyways one part about modern physics that I've been reading about for the past hour or so is the string theroy. I still don't understand it. How can a string prove there is 10 diamensions and that some of those diamensions are to small to see or to complex to understand.

Any of you guys know any more about the string theroy?
 
Originally posted by Event Horizon
read a brief history of time and the universe in a nutshell, they enlightened me a lot. plus, they are in laymen's terms.

i am very interested in this stuff (hence, my username). hopefully, we can get in a discussion with the other people in this board interested in this stuff (i know there are people who know about this)
is that book by stephen hawking?
 
I'd like to take such a class myself, because I've always been totally interested in space. Admittedly, I don't know very much though as of yet (I just learned Einstein's Theory of Relativity a few weeks ago [the one about how gravity "works"]). I'm taking Mechanical Physics next year, which won't be anywhere near as fun, but whatever.
 
Originally posted by 5LiterRiceEater
is that book by stephen hawking?
yes

i have the all 5 hitchhiker's guide to the galaxy series in one book. i read the first 2 until i stopped reading fiction. this was a while ago, so i was confused about it. i know the most about realativity and black holes/stars. i also have a few theories of my own about how light works and the big bang.
 
Yes I've come up with a few theories of my own, like how the universe is a giant tarus knot that expands and contracts. But I will become smarter on this through out the summer and may I'll change my mind.
 
I have a few theory's on black holes and stuff but I haven't done any uni stuff and I'm still in high school but I'm interested in Space.
 
I took all the physics I could in high school, but we never really touched much on the modern part of it. We did some in AP physics but other then that high school doesn't really teach it.
 
My highschool physics was based pretty much on all equation, which was fine because I found it alright. But on one occation in particular we had a substitute teacher who litterally stood at the front of the class and talked for the whole period about "modern physics" It was probably the most interesting class I have ever had.

Staying on topic, Im curious if there are any decent websites that address many modern physics theories???
 
Not really that I've found, I just go to the book store and buy books on the subject or to the libarary. Check google, and I'll look to. I've never really checked to much on the net for much stuff.
 
This site looks pretty good to check out. I'll try to find more and if anyone else gets soem good info post it.

Hyper Text Book

Anyways lets start our topic of discussion on black holes since that seems to becoming up a lot.
 
well, lemme get started. I will share my knowledge of Black Holes to those who don't know. i did my junior research paper on stephen hawking and i went in depth in my paper about black holes. I got an A, so as soon as i can access it, i will post the paragraph on them, plus add some tidbits
 
Well, unfortunately, I lost my paper in a format, so I will start form scratch

A star is made by numerous gases (mainly Hydrogen) being pulled together by gravity. As all of the gases get compacted together, they burn and release light. The Hydrogen then forms Helium, which gives off much radiation when it burns (because of the very strong bonds) and turns into heavier elements. Eventually, it turns to lead or iron (I cannot remember which) in the center of the star. Eventually, the energy of the exploding gases and the high gravity of the solid, non-combustible core cannot keep the star from collapsing. The star does not collapse when it is young because of the frequency and energy of the explosions. Since there is less fuel to burn, it collapses on itself. If the mass is low for a star, it forms a neutron star (which I do not know much about). If the mass is too high, it forms a Black Hole, an object with such high gravity that not even light can escape its surface.

Most of the matter of the star (minus the gases that were blown off in the supernova) is crushed into an infinitely small, infinitely dense point called a singularity. Black Holes can "eat" entire solar systems and eventually galaxies (there is a theory that I believe in that says that there is a black hole in the center of every galaxy that will eventually consume the entire galaxy, INCLUDING the Milky Way...). When a black hole feeds, the prey's gases swirls around the black hole, accelerating to infinity. (When it gets to infinity, it is said to leave space-time as we know it, I will get into that later). The gases heat up do to friction and release light, which is why we can "see" black Holes. A recent theory by Stephen Hawking shows that when a black hole is not feeding, energy (which is now called 'hawking radiation') does escape from the black hole, which will eventually cause it to evaporate. This is caused by a theoretic phenomenon.

At every instant in empty space, virtual particles are being created and destroyed at every moment. A virtual particle and anti-particle are created for the sole purpose of being destroyed. This does NOT violate the conservation of energy because they cancel each other out. If a virtual photon and anti-photon are created and one gets sucked into the black hole, the other has no purpose because its sole purpose was to be destroyed (it is a sad life for a virtual particle) so it becomes a real photon. I really do not understand too much about this.

Now, on to relativity. Gravity, as told by Einstein, is said to bend space-time, AKA the fabric of time, AKA the 4th dimension. Imagine a rubber sheet, which represents space-time. Place a heavy ball (represents a massive body, such as a star or planet) on the center. This bends the rubber sheet. The heavier the ball, the more it bends the sheet (the more gravity it has). Now, take a ball bearing (a "photon") and roll it on a straight line past the heavy ball. The ball bearing curves around it and eventually rolls into the Ball. Now, at the speed of light, that bearing will change course briefly and will not slow down and go into the Ball. This is relativity in a nutshell. Since gravity accelerates everything, no matter what, light has to be accelerated. But, the speed of light in a vacuum is constant. Since the definition of acceleration is a change in speed or direction, speed in this case cannot change. So gravity changes its direction, so it causes light to curve.

In the case of a black hole, it bends space time to infinity, so it puts a hole in space time. When a photon travels too close to a black hole, it curves around it. It curves so much that it gets closer to the center. When it passes the so-called "Event Horizon," the curvature of the path of the photon goes to infinity and is lost forever. This is like being flushed down the toilet. This is the end of time for anything that enters the black hole.

You can read much more in Stephen Hawking's Best-Sellers A Brief History of Time and/or The Universe in a Nutshell

Hope this has enlightened you, it took a while to type, so please do not copy it and take credit for it. Comments & Criticism welcome and encouraged, I would hope to discuss this further.
 
I totally love Einstein's Theory of Relativity concerning gravity, just because the analogy works so well and is just perfect. It's kinda weird though to think that these "indentations" in space are everywhere, and how they overlap each other (the Earth's indentation overlapping a building's indentation overlapping your body's indentation...).
 
they basically are indentations on the earth's indentaion.
 
That was a very intresting read, it put things in easier to understand terms.

Black Holes are some of the most intresting things I've ever read about. I wish they could actually prove there exsistance through pictures instead of math. Although I still do believe they exsist, I really think that they are in the center of the galaxy and a huge one at the center of the universe.
 
Ok I just got back from my class and wow what a experience. That things crazy, but so intresting. I was shocked how fast the time went. But my first assignment is to read A Brief History of Time by Steven Hawking also the Nature of Time and Space. So I'll be busy this week. I can't wait to dive into the books, they look fasinating.
 
I was reading about this stuff when I was in 8th grade. And what science are you in? Chemistry, physics, earth? There are many kinds.
 
Organic Chemistry was pretty neat stuff. It's kind of odd to know there are people out there that don't believe crude oil comes from dead animal and plant life. They claim nobody really knows the true origin of oil. One book I read, sorry I can't remember the title, was writen by a guy that believes oil came from meteorites. Neat stuff, indeed.
 
Originally posted by BlazinXtreme
Ok I just got back from my class and wow what a experience. That things crazy, but so intresting. I was shocked how fast the time went. But my first assignment is to read A Brief History of Time by Steven Hawking also the Nature of Time and Space. So I'll be busy this week. I can't wait to dive into the books, they look fasinating.

do you have to buy the book, or just rent it from the class? if you have to buy it, i would suggest getting the hardcover Illustrated brief history of time. the pictures really hep A LOT. the text is the same, except for the captions. I got Universe in a nutshell with that last easter. both hardcover. the pictures look cool and help you visualize the high-end stuff.

on an unlrelated note, my friend recently was bored and without previous knowlege, he used einstein's equation of relativity to derive E=MCsquared. einstein's equatiion shows that nothing can go faster than the speed of light the equation is time=(time of the observer)/(square root of(1-velocity squared/c squared)). if velocity is greater than c, you get a negative number under a square root which gives you an imaginary number, so it is impossible. he found E=MC squared without any proir knowlege of how einstein derived it. kind of interesting. (btw, c always equals the speed of light, or approx. 3x10^8 m/s). the kid is a genius. his IQ is around 190.
 
The class just gave it to me, I guess they had enough copies. There aren't to many people in my class. But both books are hard cover with pictures in it. I read about half of A Brief History of Time last night. I couldn't stop reading it and I plan to finish it today. My mind was really boggled after all of that though.
 
I am doing modern physics (2nd year at university) now... quantum mechanics, special relativity, particle physics, solid state physics, nuclear physics, general relativity.
 
Well then you should know this stuff pretty good, so jump in to our discussion. Right now we are on black holes. So fill us in on your theroys.
 
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