I just had an Idea and want to write it down before I forget. I was reading an article on dimensions, and circles/spheres and the such, which made me think of conic sections for some reason. I dont know why, but that got me to thinking about world lines (not wure this is it, it is that thing that looks like a conic section in Stephen Hawking's book.... Well anyways, since you can take a plane and intersect it with the conic section so that the plane is perfectly level, you get a circle. So... If you take a plane and intersect it with the World Line/Cone thingy, you would get a specefic point in time.. If you know what the hell I'm talking about, please respond.

tetra ... Like a 4d 'plane' intersecting a 4d 'sausage' resulting in a 3d sphere (the Universe) a la 'Flatland'? Hmmm ... time for lunch. Take care Please Register or Log in to view the hidden image!

Light cones The "y" axis is time and the "x" axis is space. The sides of a light cone are at an angle of 45<sup>o</sup>. This angle represents light, or information, propagating through space at c (the speed of light). If you cut it with a plane parallel to the x axis you have a particular point in time. An explanation http://musr.physics.ubc.ca/~jess/p200/str/str22.html

Small detail... Hi Boris2, ... just a small detail, but important if you want to continue reasoning in this fashion: the angle between the lightcone and the x-axis is not necessarily 45 degrees. It depends on the timescale (y axis) used. If you express something time on the y-axis in seconds or in days, you will find a different angle. The angle should be such that the derivative of the lightpath is exactly c, i.e. if you take 300.000 meters on the x-axis (length) and 1 second on the time access, then the line connecting the origin and the point (300.000 , 1) is one side of the lightcone. Bye! Crisp

Thank you Mr Crisp, clarification and correction are always welcome. I know little bits of a few topics and struggle with what fits where.Please Register or Log in to view the hidden image!