An excerpt from "Why does E=mc2?"

One of my more recent reads was this enlightening book by Professors Brian Cox and Jeff Forshaw, both from Manchester University. In it, they try to talk through the theory of Einstein's famous equation and discuss topics like energy, mass, light, particle physics and the like in an accessible manner to help the lay-reader (like me!) understand the science behind this astonishingly simple and, to physicists, beautiful equation.

I've reproduced a small passage below...

"If we could build a spaceship that could whisk us into space at speeds very close to light speed, then the distances to the stars would shrink, and the amount of shrinking would increase the closer to light speed we could travel. If we managed to travel at 99.99999999 percent of light speed, then we could travel out of the Milky Way galaxy and all the way to the neighbouring Andromeda galaxy, almost 3 million light years away, in a mere 50 years.

Admittedly, that looks like a tall order and indeed it is. The big obstacle is figuring out how to power a spaceship so that it could get up to such high speeds, but the point remains: With the warping of space and time, travel to distant parts of the universe becomes imaginable in a way it never was before.

If you were humanity's first Andromeda expedition, arriving in a new galaxy after a fifty year journey, your children born in space might wish to return to their home world and gaze upon the earth with their own eyes for the first time. For them, the Blue Planet would be nothing more than a bedtime space story.

Turning the spaceship around, and travelling back to Earth for fifty years, the entire journey to Andromeda and back would have taken one hundred years. By the time they arrived back in Earth orbit, however, a shocking 6 million years would have passed by for the inhabitants of the earth.

Would their progenitor civilization have even survived? Einstein has opened our eyes to a weird and wonderful world."


You'll need to concentrate when you read it - particularly for the optional worked mathematical examples - but I think it's a really enjoyable read: highly recommended.