Recent content by AJH

I would re-cap what I have learned from this thread, seds.org and ned.caltech.edu as follows: 1) A measure of the velocity of a galaxy would depend on the point of reference (Sun, galaxy centre, group centre etc) of the observor as well as the object's activity within its own group - a galaxy...

Thanks very much for giving me a definitive answer on this. I have encountered contradictory suggestions in several guides and websites (as there also is regarding distances). I would be interested to know for certain if other binocular objects such as M51 and M101 were receding from us. All...

I have found M81 and M82 with my 10x50 binoculars. I understand that they are both part of the M81 group, separate from our own Local Group, and was under the impression that anything outside of our Local Group (including the Virgo cluster and other groups) was receding from us due to the...

Thoughts on the "caged birds in a plane" chestnut. Someone recently asked in the notes and queries section of a British newspaper, "would the weight of a plane flying at a constant altitude change if its cargo of birds in cages were all on their perches or flying about in their cages?". I have...

I have had some success with a recent question on electric fields where people kindly explained the nature of electric fields by analogies without recourse to mathematical terminology. I would be interested to pick up any guide on mainstream physics that would resolve all the obvious why and...

Time for a re-cap OK, let me try and organise logically what I've learned about electric fields from physicsforums.com and the terse responses I got from YahooAnswers... 1) Charge is a property of particles (connected to their "symmetry" within a particle system - not quite sure what this...

Thanks for the reply, 'frog. OK, I can deduce there can be no binding energy in a simple hydrogen atom. I had read about iron being the most stable atom (don't know where I got lead from in the previous post...) You're right, I was preoccupied with the notion of binding energy being somehow...

Hooray! This is the missing link between fields and EM radiation that I have been clumsily trying to understand since I started this thread - disturbance/movement in fields creates radiation; radiation propogates fields. I am happy to take this as gospel as I will never have the maths or...

Still struggling with hydrogen-to-helium fusion Ah, so the binding force in a hydrogen atom is between the proton and neutron. Thanks also for the staircase analogy. However... If the binding energy per nucleon INCREASES in atoms as atomic weight increases (up until lead) how can there be...

Encyclopedias and the like seem to explain the energy gain from nuclear fusion reactions (as in the sun) in the following manner: for elements with atomic weights less than iron, the HIGHER the weight of the atom the less binding energy needed to overcome electromagnetic repulsion in the...

Thanks for the message, Xezlec. I may be getting a bit confused because your answer seems to contradict the answers from JT and Deep Q. My understanding was that a field was local to a charge (maybe around a proton) and not being carried through space by radiation (which I thought was just...

Thanks for the rubber membrane analogy, Deep Q. When you say that an electric field is fundamental, a property of nature, are you inferring that it a property of space itself - similar to how matter bends space and creates gravity? Can the nuclear forces also be explained in this way? JT, I...

Thanks for the illustrations, Rob. I have has no science education and am trying to resolve something that has always mystified me. I guess the nub of my question was... when charges move from a source point through an electric field are they mediated by waves OF the source particle (eg...

I have read that an electric filed is a vector of electric charge and this explains its effects and boundaries. How, in practice, is the charge mediated across the field from the source charged particle so that the particle can interact with any other charged particles that come within the...