Some one mentioned the need for a FAQ. Last year I started compiling a FAQ and resources for uplink.space.com. So, I've copied the details to a new URL for all to see.

It can be found at http://physastro.mysite.freeserve.com

WARNING: It was put togehter in a hurry, is a first pass and needs vast amounts of work to be done on it. It is very a rough draft, I know that. If anyone wants to submit new articles, I'll post them with proper attribution. Error corrections and suggestions are welcome.

thed,

I read some of your FAQs (after I found them) and am pleased to see that they are written in simple terms that even a layman can understand.

However, in the Black Holes FAQ, you stated that "More technically, a black hole is a region of spacetime that is so highly curved the world lines are closed.". A few weeks ago, I asked a question on sciforums whether mass truly curves spacetime, and whether spacetime really exists. The response that I got from the more educated members was that there was no proof that spacetime curves, even though Einstein's field equations are mathematically valid. I think you should refrain from using terms like "curved spacetime" until it is proven that spacetime actually exists (and curves).

Note: On your main page, the link to sciforums.com is missing the "r".

Good luck with your FAQ.

I think that you should include the caveat:

"In the contemporary view...," or, "It is the concensus of physicists that...," or, better yet, "According to the ____ theory/theory of ____ ..."

This would resolve problems of the nature indicated by Pros.

Thanks, thed.

I will be starting an FAQ sticky thread as soon as I have a little more time, and I'll link your site into it.

thed,
When I clicked on the link, I was taken to a page that had a picture of a rocket on the left and some text in the middle. I have some non-technical suggestions:

- put some margin between the picture of the rocket and the text, so that it is easier on the eyes.

- put more emphasis on the link to the FAQ's.

- it is a bit distracting to here that clicking noise indicating a new page has been downloaded (or whatever sound one's computer is set to produce) every few minutes. I'm assuming that you have to display ads in order to support your site, but I'm wondering if there is a better way to do it. Not only is it annoying to hear, but if one sits and reads a particular FAQ page for a while, and then wishes to use the back button, then one must repeatedly click the back button to return to the main FAQ page.

Are you sure that you want to say the medium must be <i>inelastic</i> to prohibit loss? Also, if the medium is perfectly rigid, then, speaking in terms of Newtonian, wouldn't that imply an infinite speed of propogation in that medium?

I have the interferometry experiement was carried to conclusion (or actually lack thereof) in 1887. Also, it might be found interesting that Michelson was awarded a Nobel prize in 1907 for precision instrumentation.

Perhaps you should not mention any arbitrary medium, and just stick with empty space. Most people will probably have an easier time wrapping their minds around that.

Can you put some QM FAQ's on there?

The web host is a free service offered by my ISP, upto 5 sites of 30 Mbytes each. The rat bags wrap some Javascript around the index.html to display the ads. I get no revenue from them and don't want them but can't stop them either.

The idea was to use frames where the upper frame always returns you to the main page for a subject e.g. FAQ's. I can re-write the frames to change the menu though. Point noted about site navigation anyway. I suspect the ads go away if you register for a domain name.

QM FAQ's, now there's a good one. For some reason the majority of questions on most boards are about GR, Cosmology and Black Holes. QM hardly ever comes up, imo. I'm open to suggestions for topics though. Things like, the Copenhagen Interpretation, Wave-Particle duality, Heinsenberg's Uncertainty, Dirac Equation. The messier stuff requires maths really, hell, the previous is bad enough to explain without maths. Hmmm , explain CPT violations without maths? Tricky one. Lethe, any ideas.

A good starter though http://www.mtnmath.com/faq/meas-qm.html

A good one I found today, http://www.wikipedia.org/wiki/Michelson-Morley_experiment, more than you ever wanted to know.

Other suggestions noted. I'll try and action them at the weekend.

I've only looked through the black holes stuff, but it seems like a good site. Anyway, I just hadd one question about your answers; you said that the only force that can compress the star is a supernova. Surely a supernova is an explosion caused by the stars inability to fuse higher elements such as iron, and does not in fact compress the star at all.
What does compress the star is gravity.
Also, I think you should put a caveat saying that just because a star is over the Chandresakhr limit oes not mean it will become a black hole, as mass may be lost when the star goes nova.

I think that what was meant was that the supernova is the only <i>natural phenomenon</i> capable of producing a black hole (that scientists believe to have observed). Remember, the FAQ's are for <i>laymen</i> (and lay women).

Are you trying to tell me that gravity is an artificial phenomenon?
First I've heard about it.

No, though I don't think of gravity as a phenomenon, I think of it more as an ubiquitous natural consequence. Gravity is everywhere, but black holes are not. Thus, something more specific should be responsible for them.

OK then, the phenomen that causes black holes is having a mass above 1.44 solar, after fusion has ceased (and the star has gone nova) You can have a supernova without creating a black hole, and the supernova actually reduces the likelihood of any particular star forming a black hole, as it ejects some of the star's mass.

{pedantry}
Strictly speaking it is the core mass that has to exceed 1.44 M_solar.
{/pedantry}
Note to self, update FAQ on this.

The exact conditions under which a given star goes Supernovae depends on a huge number of circumstances. Binary stars can seriously effect each others evolution for one. There are of course several types of Supernova, I am talking predominantly about Type II.

As Prosoothus points out, the details are dumbed down for the Layperson[0]. A full analysis requires a lot more detail. My plan was to include a 'more details' section going into that detail but no maths. If I felt up to it, I could add the maths and proofs but I am not employed as a lecturer to do so. Want a laugh, read http://www.sartar.fsnet.co.uk/tutorial/index.html

Just a small final note on the whole supernovae/black holes thing.
If we're being pedantic, a star has to have a core mass greater than 10 M_solar I think (I'm sure I read that somewhere). So a star can become a black hole even after only going nova.
The only stellar phenomen I can think of caused by supernovae is the formation of stars inside gas clouds, due to the force of the nova compressing the gas enough to initiate fusion.

Anyway, back to the rest of your FAQ, I like the Cosmology section. Otherwise, just be carful with where/were in the relativity section.