torus
A torus (pl. tori) is a surface shaped like that of a donut or bagel. It is possible to define analogous geometric objects, all of them finite in extent and closed in upon themselves, with more dimensions than two. These are also known as tori; whenever it ...
time
It is a fact of life that not all events in our universe happen concurrently - instead, there is a certain order. Defining a time coordinate or defining time, the way physicists do it, is to define a prescription to associate with each event a number so as to ...
time dilation
In special relativity: From the point of view of an observer (more precisely: an inertial observer), a moving clock goes slower than an identically built clock at rest. All other processes moving alongside the clock (for instance: everything happening aboard ...
tidal effects
Idealized situations apart, the gravitational influences acting on an object depend on the object's position. Take two small objects in the neighbourhood of a massive body: If one of them is closer to the massive body, it will be subject to a ...
thermodynamic equilibrium
A physical system is in thermodynamic equilibrium if its energy is distributed evenly among all the different ways in which its components can move or vibrate - what physicists call the system's "degrees of freedom" - and there is no flow of energy within or ...
thermal radiation
In a narrow sense: synonym for infrared radiation. In a more general sense: The electromagnetic radiation emitted by every body with non-zero temperature due to the laws of thermodynamics. The properties of this radiation (in particular: its spectrum) ...
thermal motion
What we call heat in everday life corresponds to disordered motion of the microscopically small constituents of matter (say, atoms or molecules) - one example being the chaotic dance of the molecules making up a gas, another the oscillation of the molecules ...
thermal energy
The energy contained in the disordered motion of a body's constituents - for instance, the energy of the disorderly motion of the atoms or molecules of a gas, or their oscillation in a solid body. If one increases a body's thermal energy, one also raises its ...
