17 October 2012

Time Travel and Warp Drives by Everett and Roman

Scientists are very interested in time and the possibilities of time travel but are very cautious with how they approach the matter. A recent example was the news in 2011 that Neutrinos could travel faster than light. The Opera group at the Gran Sasso shocked the world with their announcement that contradicted Einstein’s light-speed limit. In March of 2012 when two flaws were found in their calculations, the leader of the science team Antonio Ereditato was made to resign.

The internet and the media are full of pseudo science and sensationalists news, videos discussing machines and alien technologies making it hard to discern between what is scientific and what are imaginative personal theories.

In this book the authors explain that they only interested in measures of time that do not depend on the variations and vagaries of human perceptions. The emphasis is on what modern astronomy and especially modern physics have learned about the subject of time.

The vastness of space is bewildering, the nearest star Proxima Centauri, is about 4 light-years away. With our present technology it would take over 10,000 years to send a probe there. On an even larger scale , the distance across our milky way is 100,000 light-years and our nearby neighbour galaxy, Andromeda, is about 2,000,000 light-years away.  It is no wonder that we should seek “shortcuts” between the stars involving travel faster than the speed of light.

And what about time? Why is the past different from the future? Why can we remember the past and not the future? Is it possible that past and future are “places” that can be visited.

This book examines the possibility of time travel and of space travel exceeding the speed of light from the purely scientific point of view.

Science fiction often mentions warp drives but there is one problem, superluminal travel seems to involve a violation of the known laws of physics, in this case the “light barrier” in Einstein’s special theory of relativity.  Science fiction writers describe “what” technological developments might occur in the future and scientists describe “how” they might actually work. When Carl Sagan was writing “Contact”, later made into a movie with Jodie Foster, he wanted a believable way for his characters to travel across the galaxy through space-time shortcuts. His discussions with his physicist friend Kip Thorne got the latter to develop theories that today allow us to understand “how” a traversable Wormhole might work.

The curiosity and enthusiasm of scientists is why we built particle accelerators at CERN in search of the “god particle”, experiment with entangled particles and explore how we could build a quantum computer. The Nobel prize for physics this year was in fact assigned to two scientists, Haroche and Wineland, who’s work will lead to incredibly accurate optical clocks and are a first step towards the quantum computers (super fast computers that will work with each bit having 3 states as opposed to today’s binary, 1s and 0s computers).

This book is great in telling us what scientists have achieved as far as 2012. I found it to be a very interesting read though the conclusion is a little disappointing, as of today scientists believe no object can travel faster than the speed of light. In fact even the experiments on entangled particles which show that when the spin of one particle is observed the other distant one will be observed to always have the opposite spin, doesn’t  prove superluminal travel. The measurement of one doesn’t cause what happens to the other. When the observers get together and compare notes after the experiment they will find a correlation every time. So no time machines or warp drives yet!

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