Physiological Effects from Exposure to a Vaccum

Vacuum doesn’t have a temperature of its own, so space is not really that cold. It’s a great insulator too, meaning that your core body heat doesn’t get sucked away. Without an atmosphere to transfer heat away, the risk of exposure is somewhat mitigated. The saliva on your tongue may boil off, as it’s not pressurized like your blood is, and you may get some frost on your skin. Sunburn from direct contact with the sun’s ultraviolet rays is a more immediate danger than perishing from ...

 M-Theory is a Map

M-theory is not a theory in the usual sense. It is a whole family of different theories, each of which is a good description of observations only in some range of physical situations. It is a bit like a map. As is weU known, one cannot show the whole of the earth's surface on a single map. The usual Mercator projection used for maps of the world makes areas appear larger and larger in the far north and south and doesn't cover the North and South Poles. To faithfully map the entire earth, one ...

 QED Explained

Feynman's graphical method provides a way of visualizing each term in the sum over histories. Those pictures, called Feynman diagrams, are one of the most important tools of modern physics. In QED the sum over all possible histories can be represented as a sum over Feynman diagrams like those below, which represent some of the ways it is possible for two electrons to scatter off each other through the electromagnetic force. In these diagrams the solid lines represent the electrons and the wav...