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79 Comments
- RetroRufio, on 10/12/2007, -1/+40A cool concept:
Since E=mc2, energy is in no way reliant upon the type of material, just the mass. Therefore, a kilogram of potato salad, has the same amount of energy as a kilogram of plutonium. Unfortunately, mankind knows much more about plutonium fission than the atomic capacity of potato salad :( - muggin, on 10/12/2007, -0/+35I'am a premium member to newscientist.com and there was an interesting article about space-time. I copied the text and put it into a simple webpage with an easy read backround (better on the eye's) and uploaded it to my site.
Enjoy
http://www.doomcrewinc.com/member_media/spacetime.htm - Djerrid, on 10/12/2007, -6/+28The concept that energy and matter are interchangeable has always been so compelling to me. They are just different forms of the same substance. Like ice and vapor are just other forms of water.
And it gets me thinking about the "Space-Time Continuum". Are space and time interchangeable also? Can one use space to "create" time and vice versa? Is there a simple formula that explains the "conversion rate"?
I don't know if anyone else has delved into this. If they had, let me know in a reply. - 350Zed, on 10/12/2007, -0/+13Let's call this "E=mc2 Explained POORLY"
- 350Zed, on 10/12/2007, -1/+12No digg.
This is full of inaccuracies. For example...
"Elements heavier than iron are unstable." - a) wrong... how about lead? b) what does weight (i.e., the effect of gravity) have on the subject? (*basic* physics teaches that "weight" and "mass oare not interchangeable)
"antimatter ... a substance composed of 'negative mass'." - negative mass??? huh??? there's no such thing! e.g., a proton and an anti-proton have the same mass
How does garbage like this end up on the front page here? - bogomill, on 10/12/2007, -0/+8It does read like a fifth grade report. I was looking forward to *how* Einstein came up with the equation, rather than an explanation of the equation.
- ohnnyj, on 10/12/2007, -0/+8This century or last century?
Technically I guess you could say most famous in the last one hundred years. - speedyrev, on 10/12/2007, -0/+7Why not just go to
http://en.wikipedia.org/wiki/E%3Dmc2 - inactive, on 10/12/2007, -1/+7I thought Hawking was the most famous from THIS century.
- foolonthehill, on 10/12/2007, -0/+5Stating that something has 'negative mass' is not even wrong.
An antiparticle has the same mass and the opposing energy to it's corresponding partcicle.
The rest of the article is OK - corser, on 10/12/2007, -0/+4Controlled nuclear fusion, with the intent of extracting useful energy is still a ways off. Blowing a hole in the world, pretty damn easy in comparison. Maybe it's the laws of thermodynamics, maybe it's just the priorities of man, but destroying ***** seems to be a whole lot easier doesn't it?
- billmania, on 10/12/2007, -0/+4"Unfortunately, mankind knows much more about plutonium fission than the atomic capacity of potato salad :("
Ron White can tell you all you want to know about the mass of potato salad as it's getting thrown out of a bar in New York City - Darrelc, on 10/12/2007, -1/+5I don't trust any site that has an animated .gif of albert einstein smoking.
- gp120, on 10/12/2007, -2/+6Explained by grade school kids.....did anyone notice the URL
- Nougat, on 10/12/2007, -0/+3My admittedly limited understanding of space-time is that, yes, future/past can be viewed as another dimension on the same par as left/right, up/down, back/forth, ana/kata. This was explained quite nicely in a book called "The Planiverse."
Consider two two-dimensional discs rolling toward one another, colliding, and recoiling. This 2D action through time can be represented by a static 3D object - two tubes bending towards each other in the middle. Extending that analogy, our 3D universe - from the beginning to the end of time - can be represented by a single, static, 4D object. - colinnwn, on 10/12/2007, -0/+3Hydrogen bombs are fusion devices
http://en.wikipedia.org/wiki/Nuclear_weapon - dignation, on 10/12/2007, -0/+3Its just easier to create a bomb than to harness its power. Just like its easier to burn stuff with fire than to get electricity out of it.
- Eeqmcsq, on 10/12/2007, -0/+2"The concept that energy and matter are interchangeable has always been so compelling to me." - This, and my great respect for Einstein, is the reason why I chose such a nick for myself on Digg. :) I have studied some the concepts of relativity, and here are my comments on your thoughts about "space" and "time":
According to the Gen. Theory, mass causes space to curve. Objects within this curvature will appear to move slower to objects far away from the curvature. The deeper an object falls into the curvature, the slower it appears to you. If it were a clock, the ticking would appear to slow down more and more to you. If it were a person speaking, his lips would appear to move slower and slower.
So for now, mass causes space to curve. This curvature causes objects in that curvature to move slower (like in slow motion). Thus, their time is slower than your time. - gnilrets, on 10/12/2007, -2/+4This reads like a fifth grade report. Anyone else notice that it's lead, not iron, which is the heaviest of the (standard) stable atoms?
- idonthack, on 10/12/2007, -2/+4No. They are unstable, they're just not very unstable.
- Lingur, on 10/12/2007, -0/+2*head explodes*
- Daiken, on 10/12/2007, -2/+4There are people who didn't know what it means?
JK, there will always be such people, but come on Digg people are more educated...right? - proidiot, on 10/12/2007, -0/+2@doodbun:
who wants to define motion w/o time?
he said energy, not motion - doodbun, on 10/12/2007, -0/+2ok, so you're playing way to much with words here. in the current, established theory of the standard model, particle/anti-particles do have the same mass. period. the standard model doesn't include gravity. so what you're saying is not even wrong. a theory encompassing all of this would probably not even relate to particles/anti-particles, new concepts will come into play. they will probably be recovered as a flat space-time limit of equations from that theory.
so yes, according to current theory, there is no ambiguity as in, yes we are sure it has positive mass. and don't use the word "theoretically" to mean "hypothetically". the standard model is well established and has been severely verified to be in accord with experiments. - sven007, on 10/12/2007, -1/+3dig for other people who have no idea what this is. id just like to add, its the speed of light in a vacuum, not in air or other matter
- inactive, on 10/12/2007, -1/+3all matter is energy, space is the absence of perceivable energy and time is the brians perception of energy in motion.
get it got it good. u are now releived of your stupidity. - axiomata, on 10/12/2007, -0/+2I remember when digg used to have interesting physics articles.
- corser, on 10/12/2007, -0/+2Actually c is precisely 299,792,458 m/s They sort of redefined it in such a way that it is now an exactly number.
- darkpulsaromega, on 10/12/2007, -0/+2I've thought about the concept of E = mc2. Mostly about converting energy back into matter. The amount of energy required to make a small amount of matter...it would be huge. Think about a nuclear bomb and the energy it releases. Reverse the process. That's an equally dangerous situation.
- Necoras, on 10/12/2007, -0/+2The actual formula is quite drawn out... C itself isn't exactly 3.00*10^8mps, it's closer to 2.97*10^8mps. However, the formula is remarkably close to E= mC^2. Odd how so many of the fundamental truths of nature write themselves so simply :)
- doodbun, on 10/12/2007, -0/+2basically, no. a photon is its own anti-particle. in fact, anti-photons do not really exist. particles/anti-particles are defined using creation/annihilation operators for the Dirac field, which is used to describe fermions. photons are bosons, and thus do not have anti counterparts. the electromagnetic field also has creation/annihilation operators. you can create/annihilate photons with a certain polarity, but you cannot create/annihilate an anti-photon.
as for the interaction of light with matter, it is hard to think about it in term of virtual particles, like a photon emitted by the nucleus or stuff. electron around a nucleus are in bounded states. virtual particles are only defined around the concept of perturbation theory. unfortunately, perturbation theory breaks down when you try to apply it to bounded states. too bad, you would have to turn to highly correlated electrons theory and stuff, which is a tad more difficult. - corser, on 10/12/2007, -0/+2I stopped reading at precisely that point.
Antimatter has been observed in the lab, in fact positrons are used every day in P.E.T scans in hospital, and not once have I ever read anything about it having negative mass. Negative mass would imply negative energy, causing total annihilation to result in the energy being destroyed.
I don't know much about the life time of a positrons or antiprotons but under the correct circumstances I can see an antihydrogen atom being created - XStatic, on 10/12/2007, -0/+2Even simpler, antimatter is a fundamental particle of regular matter with its electrical charge reversed. The common proton has an antimatter counterpart called the antiproton. It has the same mass but an opposite charge. The electron's counterpart is called a positron.
- Topfuel, on 10/12/2007, -0/+1Hi all,
Check out the book The Complete Idiots Guide to Quantum Physics. It has a great explanation of everything starting from Greek Mythology to present day theories and facts. Fascinating talk about how they discovered that light acts like both a wave and a particle at the same time.
There is also Einstein for Dummies but I have not read it. - NerdyNinja, on 10/12/2007, -0/+1"I've thought about the concept of E = mc2. Mostly about converting energy back into matter. The amount of energy required to make a small amount of matter...it would be huge." - darkpulse
Very true in all respects - but here's another question... assuming we figured out how to turn energy back into matter and pulled enough energy together to actually do it... how would it be possible to pick which element the energy coalesced into? Would it always end up being a single proton, Hydrogen, or would it be several protons? Maybe in order to create matter, we need to have enough energy to create an unstable element - and all other matter just decays from that element. I don't know enough about the ratios of the elements in the universe, and I don't think anyone REALLY knows how old the universe is, as they keep on pushing the date back - so this is purely speculation on my part. Makes you wonder if the big bang was simply a very large-scale nuclear fission reaction, and if the universe expands and then shrinks back into a single point again - well, it would stand to reason that the particles would accelerate as they get closer to that point - sounds kind of like a complicated version of nuclear fusion to me. And if you want to take a dive into the realm of ungrounded assertions and the like, what if the secret that gives life to organisms is that same sort of radioactive principle, and we die when whatever radioactive-ism can't decay any futher. That's not to say that I think life requires a radioactive element in every organism, just something that operates on the same princple - although I'm sure we could keep fusing protons together to create new elements nobody's imagined, so maybe THAT'S life-element I don't know - I've never really understood how life could come to be just from base elements - especially after a violent reaction like the big bang and the forming of planets.
But who knows - I'm probably way off, just a stream of consciousness (well, kind of out loud) about an interesting topic. Digg me down, those who aren't interested in my rampant ponderings. - Rickler, on 10/12/2007, -1/+2"The only way for ALL this energy to be released is for the kilogram of water to be totally annhilated."
Umm.. what?
Law of conservation of matter 101.
The law of conservation of energy states that energy cannot be created or destroyed, but can change its form.
The law of conservation of mass (the Lomonosov-Lavoisier law) states that mass cannot be created or destroyed, but can change its form. - NomenNescio, on 10/12/2007, -1/+2This doesn't expain E=mc2, this article just says what E = mc2 means, not why it is right :/
- 350Zed, on 10/12/2007, -0/+1You're comparing the strength of forces (e.g., strong, weak, gravity) to the absolute energy potential of matter itself. The forces acting on matter, even when combined, are miniscule in comparison, so temperature, quantum orbital state, and other forces become mere rounding errors.
- tominabox1, on 10/12/2007, -1/+2I thought E=mc2 had something to do with the rotary girder....
- hackwrench, on 10/12/2007, -1/+2So when light causes an electron to raise a level does it collide with an anti-photon emitted from the nucleus of the atom?
- proidiot, on 10/12/2007, -2/+3if hawking is correct, wouldn't that make him the most famous scientist of the past century, and einstein the most famous of the next?
- trollick, on 10/12/2007, -0/+1antimatter ... a substance composed of 'negative mass'?????????????????????????????
And this is not buried as inaccurate? WTF? - foolonthehill, on 10/12/2007, -0/+1"An antiparticle has the same mass and the opposing energy to it's corresponding partcicle."
:S
That should be opposing _charge_. My bad. - 350Zed, on 10/12/2007, -0/+1Restated:
Mass is not dependent upon gravity. Gravity is dependent upon mass.
I am disputing this statement, which implies that the mass of antimatter is somehow related to mass-gravity interactions:
"...as are a lot of things, this is only theoretical. it is thought that this (mass-gravity interactions of antimatter)..." - Mousse, on 10/12/2007, -0/+1The law of conservation of matter is only useful in the sense that Newtonian physics are useful -- they give us approximations that are accurate up to a certain scale. For example, the conservation law is useful in chemistry where one can be sure that a chemical reaction hasn't changed the total mass in the system.
However, conservation of matter is fundamentally false. Matter-antimatter collisions do indeed annihilate. In fact, quantum physics predicts that in a vaccuum matter is constantly being created and destroyed in particle-antiparticle pairs.
Here, educate yourself:
http://en.wikipedia.org/wiki/Law_of_Conservation_of_Matter - Flooq, on 10/12/2007, -0/+1All hail the Brians, masters of our universe!
- J6stik, on 10/12/2007, -0/+1@muggin-
Thanks for the link! That looks like a good read as well! - pyrotherm, on 10/12/2007, -0/+1There is a great flash animation already posted to digg that explains the 10 dimensions of our universe in a very easy to understand, narrated animation!
http://digg.com/videos_animation/How_to_visualize_dimensions_1_10 - doodbun, on 10/12/2007, -1/+2"and time is the brains perception of energy in motion."
energy in motion seems like motion to me...
but yes, there is definitively something about motion in general which is deeply linked with our perception. - AceTracer, on 10/12/2007, -0/+1That's a pretty crappy explanation.
The best explanation I ever read of E=mc^2 and in fact of a lot of physics concepts were in Tony Rothman's book "Instant Physics". In about 250 pages he turns out a fun, readable, comprehensive guide to basic physics that is perfectly understandable to the layman.
(No I am not getting royalties for this) -
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