h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Neutron stars - A853355
Author: Sovereign - U206089

Hi everyone

This is my first submitted entry. I have done my best to keep it as factual and concise as possible. It's very easy to add more detail to your work as you read it through each time. I had to try very hard resist this temptation because the first reason I visited this guide was to find out information quickly. Please, any comments and suggestions would be welcome. Thanks.

I like reading about neutron stars, but then again I have a degree in chemistry. When I first came across them the two things that first grabbed my attention were: how they were discovered and the fact that a teaspoon full of one would weigh a few thousand tons. I believe that neutron stars rotate so rhythmically that the signal they radiate is more accurate than any clock. So I would put in an introductory paragraph to set the scene. After all most people are interested in science but find the tech stuff too forbidding. You've managed to make it intelligible without being baffling. Don't think I'm having a dig, because I'm not, but most people would not understand escape velocity measured in g's. Maybe you could explain, but wouldn't the gravity be so intense that it would crush you so small you would end up as a nuclear explosion? All in all a very enjoyable piece

Hi third man.

Thankyou for your comments. No, I don't think you are having a dig becuase I know what you mean. I could add a footnote that explains escape velocity a little bit further. You are correct about the intensity of the gravity, it would crush a person in quite a horrible way. Explaining this would involve going into a lot of detail which is fine, I have an example that I can use for this. Since this is my first entry I have to learn as I go along as to how much detail is necessary for an entry like this. Chemistry is an interesting science, but I understand the basics that I have learned from school and reading books such as a Brief History of Time by Steven Hawking. I'm glad you enjoyed my work ,
- Sovereign

Hi Sovereign. Good first try. I think you resisted your temptation to expand some of your explanations a little bit too much. Some account of why neutron stars spin so fast, why the system as a whole has too much energy, and why the position of the magnetic poles gives rise to the "pulsing effect" would give the peice more depth.
Stylistically you seem to be wobbling between using present tense and past tense; I'd stick to the present tense. Thus (under composition) "....are compressed. This forces..."
Also "which is the reason why they are so dense" "density of more than" and "and this will result" will improve the flow of reading.
Just nitpicking a bit, but it's nice to have a pukka entry.

Best of luck

Noggin

Yeah this is really good for a first entry, I'd never have clocked it for a first attempt if you hadn't said so.

So much so that my comments are limited to a couple of suggestions for science fiction stories you could mention at the end as "further reading". Firstly there's Larry Niven's "Neutron Star", which is available in the short story collection... "Neutron Star" (!). And for something longer, and containing a lot more "real" science, there's Professor Robert L. Forward's excellent "Dragon's Egg", which is about the development of a civilisation of beings living on the surface of a neutron star (!) and contains more (accurate) technical details than you can shake a stick at. Both highly recommended anyway, but especially if you're interested in this subject at all.



H.

Hi Noggin.

Good comments. I am considering expanding the entry more to include some footnotes, links and more detail where it is needed. All input is really helpful and it helps to develop my writing skills.

Thanks for the support

Sovereign

Hi Hoovooloo.

Cheers for the complements .

Yes, that's a good idea to include some suggested reading. I'll have to check up on them myself .

Thanks

Sovereign

Update:

I have added some selected reading material at the end of the entry which includes both fiction and fact.

Also, I have changed references from the past tense to the present tense as necessary.

I am looking into adding more detail where I think it is required by adding footnotes, expanding the existing text and linking to other guide entries that already explain some of the terms used.

- Sovereign

Hi. Not bad... I am having prblems with the following passage though:

"Surprisingly they are not composed of gas but are mainly solid and liquid."

... Stars are not made of gas, they're made of plasma. I know I am being a bit pedantic, but there's a nice little piece on plasma which you could link to right here: A765047 Plasma - the Fourth State of Matter.

I wouldn't call a neutron star solid or liquid either. The solid state is something different from something being hard to touch. Maybe you could change this passage?

"[...] Surrounding the core is a layer of solid iron."

I doubt that. I guess the gravitational forces must be so high that what you have is not a solid iron mantle but probably tightly packed iron nuclei.

I am mentioning that because a lay reader might get the wrong impression, that a neutron star is a huge iron ball with liquid neutrons in it. I think that's too oversimplified. - But it's just my humble oppinion of course.

See you around, and don't get demotivated just because of my comments above.

HELL

Have a look at A357806. It's pretty relevant.

Sorry, that should have been A418637 (edited).

"Stars are not made of gas, they're made of plasma. I know I am being a bit pedantic, but there's a nice little piece on plasma which you could link to right here: A765047 Plasma - the Fourth State of Matter."

I just examined that info on Plasma and I agree 100%. The first thing that I have to comment on is that Plasma ( as indicated in the entry above ) is 'ionized gas etc' - which is a more exact explanation than what I gave. However I am correct in saying that Stars are made of gas 'in general', I'm just being abstract in my original article. I will update the entry to reflect the plasma explanation however plus a link to that entry you recommended .

"I wouldn't call a neutron star solid or liquid either. The solid state is something different from something being hard to touch. Maybe you could change this passage?"

Most of what I have learned and written was based on general information on Astronomy in the form of books, websites etc. Having checked my sources again they don't go into a lot of detail so I can only reflect on what I have read etc. I'm no expert on the workings of Stars, I just have a general interest them. You have to forgive me if I am not precise on my explanations, that will come from more reading on the subject in the future. Your comments are very welcome and it helps to polish the entry further - cheers !

Sovereign

I'll update the necessary parts of the entry the next chance I get - stay tuned !

"Have a look at A418637. It's pretty relevant."

It is I'll link to it in the next update.

Thanks

Sovereign

Excellent stuff, Soveriegn! A Scout has picked this now, so a final update from yourself should see this one go straight into the Edited Guide. I'm waiting to press the big red buton...

I'm going to ask the Scout that picked this to pick another. Don't worry though, Sovereign - your entry is assured its place in the EG; I'd just rather wait till you're ready to do that final update before accepting the recommendation, that's all.

So, it's still up for grabs, Scouts (but only after Sovereign replys, of course ).

Sorry for the delay guys. I've been out of action recently due to having the flu , but rest assured I'm better now !

Great news about the edited guide !

I'll get right onto those updates and polish it off .

- Sovereign

All updates are completed !

The entry is ready for submission .

- Sovereign

Hi Sovereign.

Looking a lot better . There's still one (IMO important) thing:

"The neutrons form the liquid core of the star, hence the name. Surrounding the core is a layer of solid iron."

I still think that might lead to the wrong impression. I guess the neutrons forming the core and the iron nuclei surrounding the core should not be called solid and liquid. TRy this instead:

"The neutrons form the [] core of the star, hence the name. Surrounding the core is a layer of [tightly packed] iron nuclei."

You could even add the following sentence after that section:

"It is as if the neutrons were a liquid surrounded by solid iron."

Hope it works,

HELL

I think it is misleading to say that the core of a Neutron Star is liquid or solid. These suggest that it is similar in some way to normal liquid or solid matter. In fact it is totally different. Normal solid matter consists of nuclei with electrons smeared around them. There is a large amount of space around the nuclei. Almost 100% of the atom is empty space. But neutron star matter is different. There are no electrons: there is only one big nucleus. So solid is something of an understatement!

Do let us know whether you want to make the changes please, I'm sure I'm sure there are other scouts with there eye on this