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

Time for a physics limerick

[utopianfiat]

There once was a fencer named frisk,
whose movement exceedingly brisk
so quick was his action
the Fitzgerald Contraction
reduced his rapier to a disc

Re:Time for a physics limerick

[Rei]

Q: Why did the chicken cross the road?

A1: To actualize its potential

A2: Unknown; the fact is, most of the poultry in the universe seem to be missing

A3: It didn't. It simply moved its legs standing still, while the road passed underneath.

A4: It didn't cross the road - it simply returned to where it started, but was momentarily moving backward in time.

A5: There exist numerous parallel universes in which the same chicken is in differing stages of crossing the road. Only when one of the chickens has concluded crossing the road do their wave functions coalesce.

A6: Chickens at rest tend to stay tend to stay at rest, and chickens in motion tend to cross the road. Given an equal and opposite reaction, clearly, it was pushed onto the road by another chicken who consequently moved away from the road.

A7: The chicken never actually crossed the road (a task impossible for a chicken of it's energy level). Instead, through uncertainties in its position, it found itself tightly clustered in with other chickens inside a coop just beyond the road, and unable to escape and return to its starting side.

Happy 100th

[Robotron23]

In response to this momentous occasion...I can only quote the great MC Hawking. :)

"I explode like a bomb. No-one is spared. My power is my mass times the speed of light squared."

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.

Re:It is E=mc^2

[John Seminal]

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.

Do you get laid much? I can just imagine the bar talk.

So, ladies, did you know that if. wait. I need my blackboard. Would you mind pushing the pints down a little, I need more space to show you this. Screw it, lets just go back to my TA office. I sure hope professor Greennuts is not there. He steals all my women with his theory of relativity- they're not related to him. bada-boom-bang.

I admit it, I am crazy and my mind entertains me.

BTW, I am shocked you would put a link on slashdot to your picture. You will have to let us know if this has brought you any nerd on nerd love?

Albert Einstein's performance review, 1905

[alispguru]

By Peter Norvig.

Don't miss the rest of his site while you're there.

If Einstein Was So Smart...

[Anonymous Coward]

"If Einstein was so smart how come people only call you 'Einstein' when you do something really stupid?" - Brian Regan

Re:Plagiarist?

[Frymaster]

my question is, then, why aren't we celebrating another famous 1905 paper by a. einstein? i am, of course, talking about his work on brownian motion.

einstein was awarded the nobel prize for his brownian paper. relativity, published the same year, was all but ignored.

source:
http://www.bun.kyoto-u.ac.jp/~suchii/einsteinBM.ht ml

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.

Einstein was so wrong

[__aamcgs2220]

As my mass has gone up, my energy has gone down. What more proof do you need?

Re:serious question

[RealityProphet]

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.

I think you are making the mistake that, for example, a 4-slice pizza is smaller than an 8-slice pizza, because, as everyone knows, 4 is less than 8. However, the pizzas are exactly the same size, it is just that the slices are larger in a 4-slice pizza.

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?

Yes, there is a very challenging derivation of this simple relationship. It is just math, and it is not magic. I won't do the derivation, but I will show that the units do, indeed, make sense:

Energy is a force acting through a distance: F x d
Force is a mass undergoing an acceleration: F = m x a
Acceleration is a change in velocity over a change in time: A = deltaV/deltaT, whose units are length/time x 1/time. Let's use metric. That would be m/s x 1/s.
Substituting the units back into the general energy equation, we get:
E = F x d = m x A x d = kg x (m/s x 1/s) x m. If we pair the 1/s with the meter from "Force acting over a distance" The units are:
E = kg x (m/s) x (m/s), which are the same units as Einstein's famous relation. So, yes, the units do make sense, it is not serendipitous that this works out, and the reason it is so famous is because it is so simple.

Re:One Hundred Years of E=MC2

[Shazow]

So what was E equal to in 1904?

e = 2.71828 18284 59045 23536 02874 7135...

Or are we being case-sensitive? :D

- shazow