We humans love to get close to these clever, cute and cuddly sea-creatures, but do you know how they treat their women in the world of dolphin debauchery? Do you really want to?
One of my planned projects will involved tracing points, by hand, from one piece of paper to another. I cannot use proper tracing paper, so I built a light tracing box to help me:
When times are tough, successful leaders must not only be liked. They must also be feared. No one fears Obama, in part because he hasn’t faced anyone down, least of all the Congress that is now supreme emblem of everything the public thinks is wrong with the system.
Irish Class, February 22, 2010
Rang Gaeilge, 22ú lá mí Feabhra 2010
Einstein tells us that space and time are dynamical, and in particular that they can evolve with time. When the space through which particles move is changing, the total energy of those particles is not conserved.
Don’t look for a free lunch. There are still rules:
….energy and momentum evolve in a precisely specified way in response to the behavior of spacetime around them. If that spacetime is standing completely still, the total energy is constant; if it’s evolving, the energy changes in a completely unambiguous way.
This has been known since the 1920’s, and I learned about it when I first seriously studied GR at Stanford in 1973. However, scientists now need to pay more attention to it. In recent decades astronomical observations have have revealed many more situations where the effects of general relativity are significant.
Mathematical details at Is Energy Conserved in General Relativity?