that it isn't the whole story. It just describes objects that have mass and that aren't moving.

它不是全部的故事。它只是描述了有品質的物體，而這些物體並沒有移動。

The full equation is E, squared, equals m c squared, squared, plus p times c, squared,

全式為E，平方，等於m c平方，平方，加上p乘以c，平方。

where p represents the momentum of the object in question. This might all seem a bit confusing,

其中p代表有關物體的動量。這似乎有點令人困惑。

but in fact you can draw it as a right triangle with sides E, m c squared, and p times c - and

但其實你可以把它畫成邊長為E、m c平方、p乘以c的直角三角形--而

just use the pythagorean theorem (a squared plus b squared equals c squared) to give you

只需用畢達哥拉斯定理（a平方加b平方等於c平方）就可以得到。

the equation.

等式。

Also, from here it's clear to see that for an object that isn't moving and thus doesn't

另外，從這裡可以清楚地看到，對於一個不移動的對象，是以不'。

have any momentum and thus p is zero, we get back our good ole' friend E=mc2. On the other

有任何動量，是以p為零，我們又回到了我們的好朋友E=mc2。另一方面

hand, if the particle in question is massless (like light), then mass is zero and we get

手，如果有關粒子是無品質的（如光），那麼品質為零，我們得到

E equals p times c. This tells us that the energy of a massless particle (like a photon

E等於p乘以c。

of light) is the same as its momentum (up to a factor of the speed of light).

的光）與它的動量相同（最多為光速的一個係數）。

In fact, the closer the energy of something is to p times c, the closer that something

事實上，某物的能量越接近p乘以c，該物就越接近

is to behaving like light (I mean, look here, this tiny little bit of mass is hardly mass

是表現得像光一樣（我的意思是，看這裡，這一點點的品質幾乎不是品質

at all).

根本沒有）。)

Anyway, as an example, an object's velocity is equal to the speed of light times the ratio

總之，舉個例子，一個物體的速度等於光速乘以比例。

of the object's momentum to energy - or pc over E. If your momentum increases, p times

物體的動量與能量的比值--或pc超過E，如果你的動量增加，p乘以

c gets closer and closer to equaling your energy, so their ratio gets closer and closer

c越來越接近等於你的能量，所以他們的比例越來越接近。

to being one, and your speed gets closer and closer to light speed. But because of that

到成為一個，你的速度越來越接近光速。但正因為如此

tiny little bit of mass, the momentum side of the triangle will always be a little bit

一點點的品質，三角形的動量邊總會有一點點的

smaller than the energy side. No matter how hard you try to increase your momentum, it

小於能量方面。無論你如何努力地增加你的動力，它

never quite gets to the point where p times c equals your energy, and thus your velocity

永遠不會達到p乘以c等於你的能量，從而等於你的速度的地步。

can never quite reach the speed of light, all because the hypotenuse of a right triangle

永遠也達不到光速，這都是因為直角三角形的斜邊

is longer than its legs.

是比它的腿長。