LOG#182. Duality and gravity: extra thoughts.

In the previous post, I reviewed very naively and shallowly some of the relationships between duality and gravity, and that from electromagnetic duality. There are many other interesting points. This post is aimed to highlight some issues and works that … Continue reading

LOG#181. Duality and gravity: a short note.

The 2nd superstring revolution circled/circles about (electromagnetic) duality. In D=4 (or general space-time), duality transformations for the electromagnetic field strength read and for the dual field 2-curvature They are true symmetry for the Maxwell equations in vacuum, , and for … Continue reading

LOG#150. Bohr and Doctor Who: A=mc³.

The year 2013 is coming to its end…And I have a final gift for you. An impossible post! This year was the Bohr model 100th anniversary. I have talked about this subject already, here, here and here. The hydrogen spectrum is very important in Astronomy, … Continue reading

LOG#074. Dual units.

The last of my three posts tonight is a mysterious dual system of units developed my rival blog (in Spanish language mainly): http://tardigrados.wordpress.com/ His author launched an interesting but speculative dual system of units in which every physical quantity seems … Continue reading