muon
An elementary particle which is a somewhat heavier version of the electron. Its electric charge is the same as that of the electron, and like that particle, it does not interact via the strong force. The muon's mass is about 207 times that of the ...
momentum
Physical quantity that is equal to a body's mass times its velocity (in special relativity: its relativistic mass times its velocity). What makes momentum a useful quantity is that it is conserved - if several bodies interact, the sum of their momenta ...
molecule
Composite object consisting of two or more atoms, bound together by electromagnetic
milli
"Milli" as a prefix denotes "one thousandth", making a millimetre a thousandth of a metre. ...
Milky Way
1. Our home galaxy - a spiral galaxy, a disk of stars with a diameter of roughly hundred thousand light-years and a thickness between three- and six thousand light-years, containing about 100 billions of stars. It also contains a supermassive black hole in ...
microwaves
Electromagnetic radiation with wave-lengths between a millimetre and 30 centimetres, corresponding to frequencies between some and some hundred billion oscillations per second. Looking up to the night sky, almost all energy that reaches us of the cosmic ...
microquasar
An astronomical object comparable in size to a star, which emits enormous amounts of energy; the processes responsible for the emission are similar to those which happen in quasars or other active galactic nuclei. The key component of a microquasar is a ...
