Just a small point about Black Holes. Yes, just a few years ago they were the stuff of science fiction but are now accepted as fact by mainstream science. As a Black Hole is basically a region of very high density, then surely it is the very OPPOSITE of a true vacuum? Andy.
> ---------- > From: geor...@lexmark.com[SMTP:geor...@lexmark.com] > Reply To: geor...@lexmark.com > Sent: 30 November 2000 22:10 > To: george_t...@dell.com > Cc: brian_ku...@leco.com; emc-p...@majordomo.ieee.org > Subject: RE: How does RF travel through outer space? > > > Geez, this question makes me feel like I'm on "Who want to be a millionaire"! > Brain should have provided multiple choices for his two questions. > > George, good anaolgy re the pumpkin. Here is some other stuff I remember > from my hated electric field classes some 40 years ago. If the radiator is a > point > source in space, and the energy is equally distributed in a spherical pattern, > the > energy at any point in space drops off as the cube of the distance from the > source. > If the radiator is an infinite line, the energy drops off as the square of the > distance > from the source. If the source is an infinite plane, the energy remains the > same > regardless of the distance from the plane. Are these right? > > Now to the tough part about RF travelling in space. Note that all energy we > receive from the sun comes in some form of electromagnetic energy, ranging > from frequncies which give us light, to infrared which gives us heat, in > addition > to all kinds of non-structered RF signals. > > Doesn't electromagnetic energy depend on the sequential exitation of electrons > from one adjacent molecule to another to "travel" anywhere? It is my > understanding > that space is not a vacuum, but merely a lower pressure than that here on > earth. > The > molecules may be further apart (less dense), but are still out there. The > only > TRUE > vacuum I know of is what they call a "black hole" in space, which literally > sucks all > nearby matter into it......but this is still a theory. > > Brain, the RF energy, or any other part of the EM spectrum, travels through > space > just as in the water you mentioned, only with different molecules, and spacing > of > same. > > These are my FINAL answers. Did I win anything, or must I go home a loser? > > George > > > > > george_tang%dell....@interlock.lexmark.com on 11/30/2000 03:56:59 PM > > Please respond to george_tang%dell....@interlock.lexmark.com > > To: brian_kunde%leco....@interlock.lexmark.com, > emc-pstc%majordomo.ieee....@interlock.lexmark.com > cc: (bcc: George Alspaugh/Lex/Lexmark) > Subject: RE: How does RF travel through outer space? > > > > > We all just carved pumpkins not too long ago. We can use pumpkins to > explain one of these questions. If you put a 5 watt light bulb at the > center of your carved pumpkin, then each square inch of the internal pumpkin > surface gets the amount of light energy given by the expression: > > 5W / (internal surface area of pumpkin) = light energy per square inch > > Now you move your light bulb to a bigger pumpkin and do the same > calculation. You find that each square inch of your bigger pumpkin gets > less light energy due to a bigger surface area. This is why RF signals drop > off at the rate of 1/distance squared, since the pumpkin surface area is > proportional to the square of the radius. Light is simply a higher > frequency emission than RF, but the same concept applies. > > As far as "How RF travel through vacuum," you can think of it this way: RF > is composed of electric field and magnetic field. Electric field is simply > the attraction force between the positive charges and the negative charges. > And magnetic field is the interaction between 2 current loops. It is not > hard to imagine that refrigerator magnets will work in vacuum or protons and > electrons will attract in outer space. RF is simply the electric and> > magnetic fields changing polarity at a very rapid rate. > > George > > > > -----Original Message----- > From: brian_kunde [mailto:brian_ku...@leco.com] > Sent: Thursday, November 30, 2000 12:51 PM > To: emc-pstc > Subject: How does RF travel through outer space? > > > > > > Hello, > > I'm sorry if this is too simple of question... "How does RF travel through > outer > space?". > > I will be teaching a class in which this question will come up. I want to be > prepared with all the basic science behind this principal. I need an > explaination that is simple and easy to understand. > > People seem to have no problem understanding how waves can travel through > mass > such as a body of water but can not understand how it can travel where there > is > no mass. I also understand that there is a lot of debate over how Light > travels > through space (photons and all). > > Also, I understand that RF signals degrade at a rate of 1/distance(squared). > What force is causing this attenuation? > > Try to keep it simple for my audience it not all that technical. Appreciate > the > help. Please forgive any improper punctuation or word misuse. > Brian > > > > > > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > > > > > > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > > > This e-mail and its contents may be confidential, privileged and protected by law. Access is only authorised by the intended recipient. The contents of this e-mail may not be disclosed to, or used by, anyone other than the intended recipient, or stored or copied in any medium. If you are not the intended recipient, please advise the sender immediately. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
