Why does e mc2 review

And Why Should We Care? July Da Capo Press. News U. Politics Joe Biden Congress Extremism. Special Projects Highline. HuffPost Personal Video Horoscopes. Follow Us. Terms Privacy Policy. The example he gives is that if we go fast enough, we can get to the Andromeda galaxy, which is three million light years away, in fifty years of our time.

Are we going faster than light? No, my spoiled princess, remember that is only how it appears to you. How it looks to the people who sent you is coming up next. According to the equation, light, which goes the speed of light, takes no time at all to reach its destination. It suggests that a photon traveling between you and Andromeda is everywhere on its path simultaneously. Does this not mess with causality?

Is there any connection with wave nature of particles in quantum mechanics? The Imaginary Single Speed in Minkowski Space-time I was aware that travelling in space means that you also travel in time, and nothing can go faster than light. But the introduction of Minkowski space-time was a revelation.

It begins with the observation we just made that distance in space changes depending on the relative motion of the observer. This violates causality, which means this model does not work. But, of course, he knows the answer in advance. He then constructs a hyperbolic curve to demonstrate this relationship. It solves the causality problem, but visually the arithmetic is clearly false.

Squaring it gives a negative number, hence the minus sign. Now it makes mathematical sense, but why did he not explain this?

Anyway, the amazing result is that the speed of light is not just a limit, it is the only possible speed! When we think we are standing still, we are zooming through the time dimension at the speed of light. When we move in space we have to slow down our movement through time to compensate. The Mystery of the Time Travelling Twins I think the twin paradox is the key mystery in special relativity. One twin takes a round trip to Andromeda on a fast spaceship while his sister remains behind on Earth.

When the travelling twin returns, he thinks it took one hundred years, but the Earth, including his sister, is now six million years older. After all the work we have done, I thought I was finally going to understand it. But at the end we are told the whole calculation fails because it does not take into account the acceleration required to turn the spaceship around.

How can he do this to me? Lets jump ahead to the final chapter on General Relativity. We learn that acceleration and gravitational attraction are equivalent. We also learn that clocks run faster in weaker gravitational fields. This must mean that clocks run slower under higher acceleration. Then why did he not make the connection? Well, lets go ask Mr. Yikes, you would think this would have been figured out by now, but apparently not.

The most common view is that, contrary to this book, the acceleration is irrelevant. Apparently the special relativity formula is correct, and there are ways to explain it with simple math. It would have been nice if he did this for us. So then, why do the effects of General Relativity make no additional difference?

Ah, forget it, nobody answers my dumb questions. So wow, we can go anywhere in space as quickly as we want, and travel far into the future! The problem is that we are not photons — we have mass. Why does he not mention that it takes an ever increasing amount of energy to accelerate mass?

Near the speed of light the energy required becomes infinite. Lose some weight first like all of it. Then we realize that a momentum vector in space does not work in relativity, so we must find an equivalent in space-time. The now familiar distance vector in space-time is transformed into a momentum vector, which is mass times velocity.

To get there, we multiply by mass and by the velocity of light, then divide out the distance. Figuring this out from the text took a lot of work on my part. By trying to simplify, he actually made it a lot more difficult than it needed to be. Now he makes an approximation for the Lorentz factor, which is reasonably accurate at low speeds. At zero velocity, we still have energy in the mass. We have just achieved the stated goal of the book.

So far I have been feeling sorry for the scientifically challenged trying to read this book, but now I experienced being one of them. The verbal description made sense, but without knowing what the symbols or operators mean, constantly referring back to the equation just got in the way.

I think this book could have been better if they accepted they are writing for two different levels of knowledge. The equations could then be presented properly in a text box, accompanied by a text description of what they mean, followed by a philosophical summary for the non-mathematical reader. Better still, they could provide supplementary material on the web to answer my questions. I suppose this review is really a long confession of ignorance. I learned a lot from this book, and more from the research to make sense of it.

Actual Rating: 3. The writing of science books is a difficult task. On one hand, you have a ready market of science nerds that will instantly pick up your book an easy sale , but they want hard facts, maths and challenging concepts. On the other hand you have a large mass market audience wanting desperately to learn more about science but if you dive in with the hard facts, maths and challenging concepts you are possibly going to lose some of them along the way and turn them off scienc Actual Rating: 3.

On the other hand you have a large mass market audience wanting desperately to learn more about science but if you dive in with the hard facts, maths and challenging concepts you are possibly going to lose some of them along the way and turn them off science. So what do you do? Brian Cox has made a living on bring science to the masses and having heard him speak a few times now when he has been in Australia it is always such a delight to see the diverse crowds that rock up to see him talk.

If any-one was able to please both groups - I would put money on it being him. While I found this book to be a really solid read and will definitely read it a second time , I unfortunately think the audience of the book is unclear. The book starts out quite gently with some very easy to get your head around concepts about space and time, the speed of light and special theory. I was speeding through these chapters feeling pretty confident with everything I was reading and coming up with a few good examples to incorporate into my work.

Then there is a sudden switch to spacetime momentum vectors that had me trying to recall study from years ago and wishing desperately that I had a pen and paper note: next time bring pen and paper.

So just when you go "yes The jumping back and forth between baby steps and elephant steps just made me feel a little confused and dizzy. I also wonder if the authors solo wrote specific chapters as the voice way of explaining did seem to change throughout and that also mixed up my rhythm with the book a little and added to the dizzy. So hats off to them both. So if you are a hard-core physics geek, maybe skip the book and grab a textbook.

If you are totally new to this field If you are in the middle, bring pen and paper and enjoy the bumps. He is incredibly intelligent to state the obvious , but gets across ideas in an accessible and easily understood way, and has a great sense of humour to boot. Probably a book I'll read again to try to cement my understandings. Very much enjoyed it. May 10, Ana rated it it was amazing Shelves: science.

Omg I had no idea how shallow my understanding of relativity was!! A bit difficult to follow at times and I still have a few technical questions that I'll need to look-up myself, but I still learned a lot! While the progress we've made is astounding, I can't help but feel a bit of despair at the thought of how this progress was achieved sometimes see the Minkowski spacetime "why not try Pythagora's theorem with a minus sign???

Jun 17, Carlos Martinez rated it really liked it Shelves: science. An entertaining and not-entirely-impossible guide to Einstein's physics. I enjoyed reading it, but it'll take me at least one more go to master the main concepts. It has been 12 years since I read this book and I thought I would try it again to see if I better understood it than the last time.

Although I have a HNC in physical sciences I have always found the maths of the subject challenging and this was the case of this book. I found it frustrating to constantly having to re-read and re-look at diagrams to digest what was being said.

The authors do make a commendable job of trying to explain things in lay man's terms and I did enjoy the sections of the boo It has been 12 years since I read this book and I thought I would try it again to see if I better understood it than the last time.

The authors do make a commendable job of trying to explain things in lay man's terms and I did enjoy the sections of the book which looked at the subject of physics in a historical context. The explanation of why nothing can travel faster than the speed of light, and the chapter on gravity and space-time were particularly well done. One of those books due to the nature of change in scientific theories and discoveries, may in another 12 years be out of date.

View 2 comments. Plan on going back to this, and crunching the numbers. View all 3 comments. Aug 28, Eduardo Barroso rated it it was amazing. Physics is often neglected by many people for its deep connections to math.

In this book, the authors expose the main concepts behind modern physics using only Pythagoras theorem. They make you realize that the genius of heros like Einstein comes out of pondering the trivial implications of our universe rather than solving crazy equations. From to he was a Lecturer at Harvard. He is a board member of the Lifeboat Foundation. Apart from his scientific work, Rothman is the author of nine books.

Doubt and Certainty was chosen by the "A-List" as one of the most notable books of Rothman was the scientific editor for Sakharov's memoirs Knopf, Follow Tony Rothman on Twitter. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue.

See Subscription Options. Go Paperless with Digital. Read more from this special report: General Relativity at Don't feel it? Don't worry, no one else did either until Albert Einstein redefined the substance of reality at the start of the 20th century. Neither Galileo, Michael Faraday, James Clerk Maxwell or Isaac Newton knew about the speed of light thing, despite laying the foundations for the insights that the Austrian patent-clerk-turned-physicist would eventually have.

Let me clarify. We are all moving at a speed "c" that happens to correspond with the speed of light as it moves through a vacuum in normal space. Except that our movement is through a 4D co-ordinate system called spacetime. Unlike 3D space, which allows you to measure the position of an object, spacetime allows you to measure events where and when.

Even if you are sitting still in 3D space not moving in any direction , you will nevertheless be moving in 4D spacetime in other words, no movement in the three space dimensions but moving in the "time" direction. Knowing that mass and energy are equivalent has given us, for better or worse, the mushroom cloud and nuclear power stations, but none of these applications were on Einstein's mind as he explored the fabric of space and time. His formulation of what became known as special relativity tore apart the classical view of the clockwork universe that Newton and his colleagues had developed in the 18th and 19th centuries.

Einstein started with a conundrum, the niggling problem that the ideas of Galileo and Maxwell seemed to be at odds. Galileo had shown how there was no such thing as absolute motion, that you can only define movement relative to something else.