Slashdot Mirror
One Hundred Years of E=MC2
Eric Ward writes "To mark the one hundredth anniversary of Einstein's
famous equation, E=mc2, NOVA has gone live this month with a Web site that features exclusive content and podcasts from ten of the worlds top physicists. This once-in-a-lifetime gathering of top scientists such as S. James Gates, Jr., Brian Greene, Neil deGrasse Tyson and Nobel Laureate Sheldon Glashow simplify what the equation means to our world today and the effect it has had on their careers. NOVA online also details how Einstein grappled with the implications of his revolutionary theory of relativity and came to a startling conclusion: that mass and energy are one,
related by the formula E=mc2.
Viewers will also find lesson plans through the
award-winning NOVA Teacher's Guide and a special
library resource kit."
Its E=MC^2/(1-(V^2/C^2))
But m = \gamma m_0, where \gamma = 1/sqrt(1 - \beta^2), and, of course \beta = v/c.
I.e., E = mc^2 = m_0 c^2 / sqrt(1 - (v^2/c^2))
Oh, m_0 is rest mass, in case you didn't know that, and m is the relativistic mass.
Ben Hocking
Need a professional organizer?
Sadly, this comes just days after the anniversaries of the Hiroshima and Nagasaki bombings.
Even if it was plagiarism, the mere article itself made a much greater effect on the scientific community than did the other previous researchers. Sometimes it's not who thought of it but who pushed their point or got lucky who gets famous - that's just a fact of scientific research.
Newton's 3 laws survived 239 years, I wonder how long Einstein's will last?
Einstein's _theories_ will last until evidence no longer supports them (just like all science).
Newton's _laws_ were and still are wrongly named.
And another pedantic relativity thing. The E=MC^2 was part of the _Special_ Theory of Relativity which says that measurements of time and distance vary as anything moves relative to anything else. This is where the twins where one goes in a rocket near the speed of light and the rocket twin comes back still young and the stationary twin is old (I really hope I didn't embarrass myself by reversing this, but I think this is right).
The other theory of Relativity that Einstein came up with was the _General_ Theory of Relativity that came out in 1915. This is the space-time continuum being bent by gravity.
Einstein was a little upset that he was able to join the two theories into one, but then again that is the goal of many physicists today.
Einstein was a very interesting and good person from everything I have heard and read. RIP.
Hm. I call bullshit. The same site appears to also support UFOs and some sort of secret Nazi base in Antartica?
Seems like a scientist's National Enquirer.
"For years, I struggled with reality... but I'm happy to say I finally won out over it." -- Elwood P. Dowd
Ummm - a good visual example? Ever seen photographs of the ruins of Hiroshima? I don't think it gets much more visual then that! A few grams of matter (Ok, not sure exactly how much) converted to enough energy to level a city.
But I have a few nagging question about this famous equation. People just tend to explain c^2 by saying something like "a little matter represents a lot of energy, and c is a big number and so c squared is even bigger". Well, that certainly is true if c is measured in meters per second or any other common unit. But it's all about the units. If c is expressed in light-seconds/second rather than meters per second, or worse yet light-years/second then the "logic" of that argument is exposed as just hype. So the real issue comes down not to the equation e=mc^2 itself, but the selection of the units that e, m and c are expressed in. Use a different unit and, as I try to show above, the whole thing breaks down.
Al himself made a pretty famous point of saying that c was a constant. So c^2 is also a constant. So the equation boils down to expressing an important relation between e and m. But it all depends on the units of measure. So here's the question:
Is there some science behind the selection of the units involved that allows this equation to be so simple, or are we to believe that some serendipitous magic just allows this to be an exact equation and the units somehow just happen to match up? After all, I certainly don't know of any reason why a meter is any more of a valid unit to do this calculation with than a furlong, or a foot, or a parsec. And I am under the impression that the units of both mass and energy were determined before the equation, not as a result of it. So should I believe that this equation is just a serendipitous chance match up of units, that Einstein made some sort of deal with God, or that the equation just might be a bit over simplified?
If a meter were and inch shorter or an inch larger, there would still be an equation that could show the relation between e and m, but a conversion number would have to be added to the equation to make up for the slight difference in the size of the meter. How is it that this equation works out with the current rather arbitrary length of a meter to such whole numbers?
I'm an American. I love this country and the freedoms that we used to have.
We already know they don't hold under all circumstaces; they have trouble dealing with quantum effects. We have other theories that work there, but they don't work very well on the macro scale.
Which is like Newton's equations. They had known for quite a while that the orbit of Mercury couldn't be accuratly described by his theories, but they were the best avalible.
Einstein's are the best avalible now, for non-quantum events. Someday someone will come up with something that handles both. Then they'll be the genious hailed as the greatest.
'Sensible' is a curse word.
Einstein noticed that there's a discrepancy between Newton's laws and Maxwell's laws of electricity and magnetism (E&M). To patch this, most physicists assumed special treatments for E&M like ether. Einstein went backwards and decided Newton must be wrong.
The most amazing conclusion he reached was that the speed of light is a constant in any reference frame. ANY reference frame. Even if you were moving at 1,000 million miles per hour, the light will still travel at the same speed to you as if you weren't moving.
To me, to have the audacity and creativitiy to challenge Newton and come up with absolutely mind boggling conclusion like the constantcy of the speed light are the most amazing thing about the special relativity.
Plenty of things travel at the speed of light. Just no things with mass != 0.
I don't know if I fully believe that energy equals mass... To take mass, and BANG, the mass is gone and there is energy, does not ring true to me.
And Newton's first law of motion didn't ring true to Aristotle—clearly objects in motion tend to come to a stop if nothing is pushing them. Our intuition about how the universe works is based on our limited experience of medium-sized objects moving at low speeds on the earth's surface, with the result that all physics post-Aristotle is more or less counterintuitive. The fact that you can't imagine it doesn't mean it isn't so.
They aren't laws. They are observations. They don't tell us WHY things happen they way they do, they merely model the interactions.
-everphilski-
> However, Einstein certainly deserved a Nobel
> for one reason or another and another excuse was chosen.
While I agree that awarding the Brownian motion paper was an excuse, proving the existance of atoms logically at a time when the atomic hypothesis of matter was not settled is definitely not chopped liver.
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
From the sound of it, it seems that De Pretto wrote the equation and had no idea what it meant. I'm a total layman when it comes to physics, but it seems entirely possible to come up with something profound and not have a clue if it's true or not.
So Einstein might not have written the equation, but he obviously figured out what it meant and that's really more important, isn't it?
When I talk to "scientists" (I'm not one either), and even hint that Einstein's theory might be wrong, it's as if I've shouted out a stream of profanities at church.
it's not because they thought you shouted profanities in church, it's because you're showing remarkable lack of understanding of the scientific method and how science is done. if you want to be taken serious, propose your model, show how it explains an observable fact that current theories don't.
being a physicist, i can't believe your post. do you really believe what you say? more importantly, does anyone else? not only is your 'discourse' lacking in supporting evidence, but it's clear you don't know how science is conducted.
one does not simply accept something that's published because it's published. yes, it makes a difference what journal, but that is what references are for- a paper which doesn't give enough details to be reproduced is useless.
have you heard of tenure? it's very hard to get fired if a professor has tenure regardless if he puts forth crackpot theories. to suggest scientists are priests and are afraid of dogma is unfounded and completely false. it's hard to disprove a standard theory simply because the standard theories are the cumulative sum of all of mankind understanding.
physics always consider alternatives. how else do you advance understanding? it's the willowing of all these alternatives that have given us relativity, quantum mechanics, statistical mechanics, electromagnetism, etc.
really, the natural sciences are not a religion. it has to do something, everytime. "objectivity" not "clinging to tradition" is what insures your computer works, electricity is on, gets a probe to Mars, etc.
i do hope you are simply a troll...
Actually this is not consistent with special relativity. Special relativity allows me to convert mass into energy so suppose I start with a neutral pion. This can be travelling at a constant velocity when it decays into two photons. Suddenly I have now have no mass and my speed is that of light...and no external forces acted. Ooops!
Newton's Second Law: that the change in motion is proportional its change in momentum
First that is NOT Newton's second law since Newton actually defined momentum as "motion" and the above is just that definition - no physics involved. The correct law is:
The rate of change of momentum of a body is proportional to the external force applied.
This is only correct if you use the 4-vector definitions for force and momentum and not Newton's. Thus, the law as Newton wrote it is wrong.
Newton's Third law, Every reaction is met by an equal and opposite reaction is simply conservation of energy and is not violated in any classical theory, of which relativity both General and Special are.
Ok lets fix this one...first a minor point: relativity is NOT classical physics. Now consider trying to stop a relativistic cricket ball (or baseball for you Canadians out there). The distance moved by the ball while you stop it will vary depending on whether you look at it from the balls point of view or the cricket pitch's point of view. Since, as you point out energy is force times distance the ball and the catcher will both observe different forces. Thus NIII is not correct either...unless you use 4-vector definitions for force.
What Newton was wrong about (and it's not really fair to call him wrong since ......)....and the nature of light as a particle.
Oh boy this is so utterly wrong it is even funny! One of Newton's most amazing ideas that turned out to be CORRECT was the particle nature of light, although the lacked the means to prove it. What is so ironic about your statement is that Einstein was the one who showed that light behaved as a particle in the same year as his relativity paper. Thus the one time you would be correct in saying that Einstein showed Newton to be correct you instead say he is wrong!
As for calling Newton wrong I think you have got confused between cause and effect. Newton was wrong BECAUSE he lacked the means to discover relativity. This does not make him any less wrong. His achievements were amazing given his resources and the previous state of physics and no amount of time will alter that...but he is still wrong! Even at everyday energies Newton's laws are only approximatations and are not correct. However they are such good approximations and so much simpler to understand that we still teach them to school kids. Newton was an amazing genius, arguably even more so that Einstein: he also made huge contributions to maths [~invented calculus] and anti-counterfeiting measures [as master of the royal mint]. His contributions to physics were incredible, but still in the end his laws were proven wrong just, as I am sure, we will find a lot of our current understanding will not quite be correct in a hundred years from now.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."