The sum over all possibilities: The path integral formulation of quantum theory
A fundamental difference between classical physics and quantum theory is the fact that, in the quantum world, certain predictions can only be made in terms of probabilities A travelling particle As an example, take the question whether or not a particle ...
Einstein’s Nobel heritage
Einstein's theories of relativity are the foundation for much of modern physics - small wonder that there is a sizeable number of Nobel prizes related to relativity. Here's a list with brief descriptions of the most important ones: 1921 - Albert ...
Mass and more
There are a number of fundamental differences between Einstein's theory of gravity (general relativity) and the classical Newtonian description. Arguably the greatest difference is the role of geometry: In Einstein's theory, gravity is not a force; instead, ...
Inertial and Gravitational Mass
In classical physics, mass plays a curious double role, which is responsible for a peculiar difference between gravitation and all other forces. This difference, in turn, was Einstein's starting point in developing his theory of gravity, space and time: ...
The gravity of gravity
One reason why the physics of general relativity is much more difficult than that of Newton's theory of gravity or the theory of electrodynamics is a property called non-linearity. In short, gravity can beget further gravity - where gravitational systems are ...
The wave nature of simple gravitational waves
What makes a gravitational wave a wave? The standard illustrations (and animations) show the influence of a gravitational wave on a collection of particles floating in space: In this animation, the red spheres are the free particles, and we have ...
A subtle change in direction: Geodetic precession
In Einstein's general theory of relativity, gravity is directly associated with the geometry of space and time. In particular, spacetime around a massive body is curved - for instance, the geometry of space is different from the usual Euclidean geometry ...
Gravity: from weightlessness to curvature
What is gravity? Einstein's general theory of relativity has an unusual answer to that question which will be explored in this spotlight text. In part, gravity is an illusion. In part, it is associated with a quantity called "curvature". Overall, gravity is ...
