LOG#212. Understanding gravity(II).

Hi, there! In the previous blog post and log, we introduced the high energy stringy part of the 4-point (particle!) tree approximation amplitude for the graviton scattering in type (II) superstrings (1)   This “simple” formula gives no negative probability … Continue reading

LOG#211. Understanding gravity (I).

Hi, everywhere! Have you missed me? A little short thread begins. This thread is based on some Nima’s talk on the understanding on gravity. Do we understand gravity? Classically, yes. Quantumly, it is not so easy. String theory is the … Continue reading

LOG#210. Weak gravity conjectures.

  Hi, everyone! I’m sorry again for the time lapse, but I required to. To secure my current job (as High School teacher), and well, to fight against doubts about my health. Thank you for your patience! Gravity is weak … Continue reading

LOG#209. A cosmic link with a non-trivial zeta zero?

Some weeks ago, the Riemann zeta function and the Riemann hypothesis were again in the news. Sir Michael Atiyah proposed a (wrong) failed proof of the Riemann hypothesis. My blog has an history of being controversial from time to time. … Continue reading

LOG#208. Monsters and LISA.

Black holes and other astrophysical objects are true monsters. Some interesting tools from web pages to learn about these free catalogues: WATCHDOG and BLACKCAT. Also, the blackhole.org page and the sounds of spacetime for gravitational waves are suitable for you. … Continue reading

LOG#207. Beck, Zeldovich and maximal acceleration: the vacuum.

Some time ago, Zeldovich derived the following expression for the vacuum energy density: (1)   or equivalently, with a link to Caianiello’s maximal acceleration formula, (2)   Remark: the above vacuum energy density is related to the cosmological constant via … Continue reading

LOG#206. Multitemporal theories.

Newton’s gravity reads:     In extra dimensions, , , it reads     For extra dimensions, if their size are much smaller than considered distances, , then by matching         So, gravitational is weak in our … Continue reading

LOG#205. Ether wind, SR and light clocks.

From the Michelson-Morley experiment, some clever experimentalist tried to derive the light speed through the “ether wind”. It is very similar to a river being rowing by sailors in a boat. The times for journey “upstream” and “downstream” are:   … Continue reading

LOG#204. Mechanics and light.

Gravitational or electrical forces are inverse squared laws:         Strikingly similar, they are both also conservative forces. For gravity:     and     for the electrical force. Defining the potentials , and , you get the … Continue reading

LOG#203. Action gym.

A challenge post! 😉 Quantum physics becomes important when the magnitude called action is of order of Planck constant (an action itself!). Action is quantized. It is a much more essential quantization than that of energy or angular momentum (action … Continue reading