Here is something I did not know before I started reading Brian Greene's 'Fabric of the Cosmos'.
(i) Time is not absolute. It is relative, your clock (even the body clock) runs depending on how fast you are moving. Thus, faster you travel slower you age! If you can tavel at the speed of light you will never age! (So you can safely throw away your Botox injections)
(ii) Time at moon moves faster than time at earth, because moon has smaller gravity. So, if you ever have a choice to live on moon, don't, you will live longer.
(iii) The actions you take "now" can effect what happened billions of years ago, light years away from earth or so it seems!
(iv) Universe at scales billions of times smaller than a centimeter, behaves in fundamentally different way to what we experience in our day to day lives. For example, particles at those small sizes(like electrons or protons) seemingly have no definite position or speed , in fact, they don't have a definite anything. The reality at those scales is subsumed in a cloud of uncertainty.
(v) Universe probably started out as a lump of matter weighing a meagre 20 pounds!! That lump of matter gave rise to billions of galaxies and billions of stars in each one of them. The universe at Big-Bang did not weigh more than Brian Greene's dog!
(vi) Gravity can create waves in the fabric of space & time. These gravitational waves can stretch or compress space around you and yourself. Thus, we may get flatten or ballooned if a strong enough gravitaional waves from a distant supernova happens to pass by. Not a great way to get in 'shape':)
Well, Thanks to Greene that era of darkness is over and finally there is light;). Now, I know all that I mentioned above and a lot more.
Brian Greene's wonderful book takes us to a journey called 'Man's understanding of the Nature'. During this journey, we encounter startling discoveries which forever changed the way we (or at least the physicists) look at the universe. All along this journey, Greene is carefully holding our hands, making sure we don't get lost trying to understand the daunting complexities of nature. He is a very kind & gentle explicator, explaining the concepts in a colloquial language with liberal use of metaphors and analogies. His enthusiasm for Physics shines through every page of the book. However, even with a guide as good as Greene, this journey is not an easy one to undertake. Some of the concepts (like Entanglement in Quantum Physics) are so counterintuitive and cause such an upheaval to our intuition towards the world that it takes a great deal of faith, provided in no small measure by staggeringly accurate experiments, to believe in those. However, it does help to know that even as great a scientist as Einstein had a lot of trouble accepting the notions of reality as envisaged in Quantum Theory (Infact, he never accepted Quantum Theory as it is ) .
There are many places in the book where one can't help but get deeply intrigued. For example, during the discussion on the Flow of Time, Greene seems to assert that time does not pass by, it just seems to! Every moment in time is frozen for ever, every moment in time exists as it is, nothing is past & nothing is future, everything just is. This smacks of the concept of Fate, a design which is already in place and all we do is just live through that design without changing it (matrix, anyone!). To me, this was deeply intriguing . It looks like believers in Fate have finally found scientific evidence for their beliefs! However, Greene is kind enough not to thrust his opinions to reader's face, and points out alternative viewpoints & more elaborate explanations at such controversial (and other) junctures.
The book ends with delightful discussions on topics which are more like Science Fiction than Science. Greene dwelves into the topics of Teleportation and Time-Travel. It is encouraging to know that theoretical physics has not ruled out time-travel, yet. So, as of know traveling to the past (traveling to the future is possible, thanks to special relativity) is still a possibility, albeit a highly unlikely one, but if you are thinking that this will give rise to mind-bending paradoxes then think again. The past you may be able to travel will exist in a universe different to what you currently reside in. So, nobody can go to the past and erase you(ala terminator) because that past will take place in a different universe. Thanks to Quantum Physics, teleportation (actually it is more like cloning) is already a reality, although at a much smaller scale. The day when we may have the capability to teleport humans or even small objects "exists"(if it does) somewhere far far into the "future".
Finishing up the book, one is sure to gasp at the wonder nature is. One also can't help but wonder at the distance we have traveled since the dawn of civilization. The distance we have traveled from the days of Copernicus , Galileo or even Newton is surely impressive. Not too long ago, people just used to look at the sky and theorized about what lies out there. Now, we have giant telescopes which can look almost at the edge of the universe. We know that we are part of a solar system which is only one of hundreds of millions in the galaxy milky way, the galaxy we are part of is one of only a billions out there, and if current theories are right, the universe itself may be part of one of only infinitely many universes out there. All this, if it were not true, would have made great science fiction. Achievements like this make me think of the most wondrous thing in the nature , the human mind. The human intellect is the biggest marvel of nature. It is surely staggering to realize what pure thought combined with passionate curiosity can achieve. Physics's monumental achievements are a great proof of that.