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."

Comments

It is E=mc^2

[benhocking]

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.

Timing

[burtdub]

Sadly, this comes just days after the anniversaries of the Hiroshima and Nagasaki bombings.

Re:What if E = mc^2.0000000001?

[hackstraw]

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.

Re:Plagiarist?

[double-oh three]

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.

serious question

[frovingslosh]

I, of course, learned this famous equation back in grade school. And I understand the relationship between matter and energy (at least as well as most physics students do and better than most lay people, if anyone really understands it).

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?

Re:What if E = mc^2.0000000001?

[Daniel_Staal]

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.

Re:What did E=MC2 give us the past 100 years?

[Kafir]

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.

Re:E=MC^2 roadblock

[parker9]

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...