With string theory the time scale before technology is advanced enough to test could be greater than the life of the universe. Extra dimensions require faith. They assume a fourth or fifth spatial dimension is as real as 3 dimensions without a physical way of seeing, feeling, testing or even imagining it.

What happens to the faint Hawking radiation that the black hole emits? My understanding is that it's already been more or less dismissed, and the Black Hole War, far from ending in a victory for Susskind's faction, is still going on. Consider, says Susskind, what happens to an astronaut who falls into a very large black hole. From the point of view of someone a long way from the black hole, the astronaut will be fried to a crisp as they get closer to the event horizon. Since the black hole is very large, tidal forces will not be strong at the event horizon, and the Principle of Equivalence means that they won't notice anything special happening. Susskind says he gets plenty of crank mail from people who write to tell him they have black hole paradoxes all figured out. I am reluctant to join this unhappy band, but there is an obvious point I'm surprised not to see highlighted, and it's not mentioned either on any of the pages I found when I googled "what happens when you fall into a black hole".

So after all these fun-filled years of grabbing all the popular science books by all the great names in physics today, I revel in all the conflicting theories and directions that they take. Susskind VS Hawking square-off about BLACK HOLES. Susskind always felt like he was on the losing side, but you know how those niggling doubts are. Well in the spaces of these years, we went from total loss of information and not just scrambled information (information being any kind of physical state in the universe) to a discovery of a cool little idea that states that if you add information (matter or energy) into a Singularity, it will either A: get bigger by at least a Plank or B: heat up. We must incorporate the little idea that the information of a holographic universe is contained on the SURFACE of any kind of container and not its volume.

The basic question at the heart of the book is whether information is lost as a particle is entrapped by the horizon of a black hole. On the one hand, Stephen Hawking and many other physicists claimed that information was, in fact, lost. Leonard Susskind was nonplussed by the nonchalant attitude of so many followers of Stephen Hawking, in believing that information conservation does not hold for black holes. However, since an observer cannot be both inside and outside the event horizon at the same time, there is no paradox.

Susskind was not at war with Hawking. Susskind does explain his theory of how information is not lost in a black hole very clearly in layman's terms. His description theory that information is stored and released with Hawkings radiation from the black hole.

The central physical question of the book, the black hole information paradox, is a very fascinating issue that has led to powerful new ideas (such as the holographic principle) and offered new insights into old ones (such as information and entropy).

That said, I would say this book is one of the few that classify still as not being technical (as I said before, you don't need to have a degree to read it), but still treats complex, high-level and current problems in physics. It might also be a good guide for refreshing some concepts, and think about them in different ways if you're taking a degree in Physics.

Chapter 1 - In 1981, Hawkings postulates that information is lost in black holes. Chapter 2 - Black holes and the horizon at the Shwartzchild radius described. Tidal forces are less at the horizon of large black holes. General Theory of Relativity states that objects move straight ahead through space-time. Einstein discovered (General Theory of Relativity) gravitational red shift where clocks slow down near a heavy mass. The Planck length, time and mass are the size, half-life and mass of the smallest possible black hole. Chapter 8 - John Wheeler stated that black holes have no hair, meaning the horizon was smooth. Adding one bit of information to a black hole increases its horizon by one square Planck length. Entropy of a black hole is proportional to the area of the horizon. Chapter 9 - Black holes have temperature which is inversely proportional to their size. Black holes emit photons and therefore evaporate. Hawking calculates that the entropy of a BH equals one quarter of the horizon area, measured in Planck units. Chapter 10 - Hawking states that when a BH evaporates, the trapped bits of information disappear from the universe. Chapter 16 - It requires increasingly short wavelength (high energy) photons to observe smaller particles. Chapter 19 - String Theory - We do not know whether this model actually represents the real world. The mathematical theory of quarks and gluons is Quantum Chromodynamics (QCD). Possibly, fundamental and QCD strings are the same objects at different scales. The string theory of gravity is not fully described but appears to be the best mathematical model of quantum gravity. Chapter 21 - Going up the mass scale beyond elementary particles, are conjectural collections called superpartners, grand unification partners and string excitations. T' Hooft speculates that the spectrum of particles extends beyond the Planck mass in the form of black holes. The entropy of a BH is proportional to the area of the horizon, and therefore the square of the mass. This is how small strings are formed at a horizon, producing Hawking radiation. These turn out to fill a large mathematical hole in String Theory. The use of D-5 branes for the extra dimensions, D-1 branes for the normal dimensions, and fundamental strings allowed the math to be developed for an extremal BH showing that the entropy = one quarter of the horizon area. The space time curvature in ADS creates a gravitational field that pulls objects back to the center even if there is nothing there. Chapter 23 - The Holographic Principle states that everything that takes place in ADS (4+1) is describable by a mathematical theory with fewer dimensions. The possibility is that fundamental particles and nuclear particles are really the same objects in different areas of space. Chapter 24 - It appears that the cosmological constant is non zero - 10 exp -123 in Planck units.

Thus, it is not "information" which gets or doesn't get lost when it enters a black hole, but rather an ensemble of physical particles in particular configurations. The book also mentions the holographic duality principle: wherein all the physical happenings on a particular chunk of space can be coded on any surface which surrounds said chunk of space. Using this principle, the author claims that the universe is a hologram, with the real physics going on at the boundary of space-time.

For 30 years Hawking and Susskind debated whether or not information disappears once it is sucked into a black hole. Once that black hole takes in more "information" (stuff) than it can hold, it begins to evaporate - as it sucks in more & more stuff - cuz the gravity won't quit.