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

No, no, go ahead...

I've got time.

Now what I may have seen was the version just before you reposted it, so bear that in mind.

2nd sent: first first advances

'It can emit a positron (when? By?) converting a proton into a neutron. The positron (anti-matter) immediat(e)ly reacts with (to?)
the elctrons fo the surroundings (thus? By?) generating two gamma-photons.'

'There are also some forms of radiation, which are responsible for the radioactivity, going along with nuclear reactions'
could become
There are also some froms of radiation associated with nuclear reactions which are responsible for the signature radioactivity.

The dash in Neutron-Radiation
You had two radiations capitalized and two not.

the comma in the atomic clock sentence.

I have a few commments to make. In the second sentence you repeat the word first " when first first advances"

Also later in the paragraph, you say
"The materials investigated by the Curies showed a radiation similar to the recently discovered X-Rays but generated by an unknown process."

I am presuming that here we now know what this process is and this is this is what you are writing about. If this is true, then this should be "then unknown"

You talk about the H nucleus, in one sentence in the section about the Atomic Nucleus "excluding the 1H nucleus which consists of only one proton". Whilst some people might know that this is Hydrogen, the full name might be more understandable for people who don't. Also, even if you include this as H, the 1 superscript is probably not neccesary for naming elements.

You mention an "Anti-neutrino". This seems ambigious to me. Do you mean here the opposite of a neutrino, or an anti-particle, called a neutrino. I think this needs to be explained a bit more.

Also when talking about Electron capture, you say that this is like beta decay, but in beta decay, an "anti-neutrino" is produced. Is there an equilalent here?, with an "anti-netrino" being absorbed in the reaction.

Later on you say
"The rate at wich those elements undergo nuclear reactions" which is mispelled"

Later on we have
"All elements have at least one radioactive Isotope (e.g. Tritium alias 3H, Helium-3, Carbon-14 - the one used for the carbon dating method - etc..),"

The notation 3H(with 3 in superscript), is probably not very clear unless you know the notation. Even with the notation, wouln't the number be to the right, not the left?

Later in the paragraph you mention heavy nuclides. This is a term that might be confusing to someone who does know the terminology (like me).

In the section on the effects of Radiation, you use He rather than Helium, which might not be clear for someone who does not know the notation. You also say "Alpha radiation is responsible for the disruption of DNA in living cells, the main reason for the cancer cases after a nuclear fall-out" Surely Fallout is what happens after nuclear reaction , so after a nuclear fallout does not make very much sense. I don't think mentioning fallout is neccesary, as this tends to suggest disasters, and their aftermaths. This could be "the main cause of cancers resulting from radioactivity" or something similar.

Later you mention "ionization potential", another term that is probably not familiar to the layman.

In the penultimate paragraph, you say that ". In science radioactivity is still a widely used form of radiation: It is used for mutagenesis and molecular marking in biotechnology (e.g. in DNA-fingerprinting), for the synthesis of artificial elements to gain fundamental understanding, in archaeology in the famous radiocarbon dating method and many more."

Perhaps here, you could simply say that radioactivity is widely used. Mutagenesis, and molecular marking are also terms that may not be known generally. Perhaps you could explain what they mean, or leave them out, and just mention the examples.

That's all for the moment. I think that generally the entry is good, but there are improvements that could be made. Also another point I have just thought of is in relation to footnote 3. The reaction in a nucleur bomb is not contained, and is allowed to go out of control, however, this is not desirable in nucleur power, when systems exist to keep the reactions from spiraling out of control. You appear to have made some changes while I have been writting this, so some of this might have become moot anyway.

OK. Thanks for the suggestions. Most of them have been implemented.

OH... I see... I thought (When?) and (By?) were actually questions, and not suggestions for correcting the prepositions...

I think it should be like:

It can emit a positron by converting...
It reacts with an electron of the surroundings thus generating...

Thanks tonsil.

HELL

Okay. Bye.

Oops have not seen your post,Silverfish. I was answering tonsil's sorry.

OK you have some comments:

1 - Of course: 'then unknown'. Changing underways.
2 - OK: H - Hydrogen, I see your point
3- 'anti-neutrinos' are the inverse (but not opposite) of a neutrino, they are the anti-particles of neutrinos and are called 'anti-neutrino'. I don't think this needs to be explained more here, since there are many entries dealing with matter, sub-atomic particles and anti-matter. There a more detailed explanation can probably be found.
4 - The electron capture mechanism is a little more complicated than just simply the inverse of a beta decay, that's why I wrote 'LIKE', maybe I should stress this by writing 'almost like'.
5 - which... of course. I thought I have checked for typos. Sigh.
6 - The notation 3H is totally clear, and I do know the correct useage. You - I might add - obviously don't, yet you allow yourself a quite harsh tone here.
7 - I am sorry if you don't know what a nuclide is. But I think from the context one could figure out. If not I'll add a footnote.
8 - Helium instead of HE... OK
9 - I'd go for 'after a fallout' then, instead of 'nuclear fallout'. And, yes, it tends to suggest disasters and their aftermaths. I can see no problem with that.
10- ionization potential... Footnote?
11- If terms like mutagenesis and molecular marking are not generally recognized terms, then the lay-reader should ignore them and think to himself: 'OK there are many uses with complicated names'.

Well, thanks anyway for your comments Silverfish.

I'll just make a few comments again. Thanks for clearing up 3. Has an anti-neutrino got an name in its own right?

For 4, thanks for clearing that up. A bit more emphasis is needed to make it clear that they are not the same, as like can be a bit vague. Extra details problably aren't needed in that case.

For 6, I am sorry for doubting you knowledge, on that. Given that you give the more conventional name as well, I don't think having the technical notation as well is a problem.

For 7, from the context, I would probably be able to work out the meaning here.

9 I have reconsidered the fallout point. However, one possible problem is that fallout tends to refer to disasters, in particular nuclear meltdown, and atomic bombs, rather than more mundane causes of radiation.

For 10, I think a footnote might be useful here, like you say, although as I do not know how much detail is needed, seing as I do not know what ionization potential is.

11 You have a point there.

Another point worth considering is mentioning mutations as a result of radiation, as another possible effect of radioactivity.

Another cosmetic point is that some of the time you use dashes, when bullet points might look a bit better. For example, when talking about the kind of possible reactions of unstable nuclei

In the third of these, could disaggregate be replaced with split or divide? Also, according to one source, the neutrons lost are converted into energy(according to e=mc^2), which accounts for the energy produced in nuclear power, and nuclear bombs.

Finally, in regard to the above mentioned section, it might be worthwhile noting which of these are more likely for out of proportion nuclei, and which are more likely for heavy nuclei. According to one source, nucleur fission is more likely in the later case.

Anyway, that's all for know, but I'll be back at some point to have another look, at some point.

I seem to have misinterpreted by source when talking about neutrons turning into energy. It seems from other sources that is is the energy keeping things together that is converted, not the neutrons.

OK... More comments.

1 - yes anti-neutrinos have a name of their own.

2 - For 4, thanks for clearing that up. A bit more emphasis is needed to make it clear that they are not the same, as like can be a bit vague. Extra details problably aren't
needed in that case.

3 - It was not the doubting, it was the tone I did not like...

4 - I'm glad 7 is cleared up.

5 - Yes, fallout refers to disasters. This is the probably the only kind of situation, where people will get in closer contact to the hazardous effects of radioactivity. More mundane causes of radiation have a quite negligible effect on our everyday life.

6 - The footnote is there already.

7 - Thanks for accepting point 11.

8 - I mention mutations as a result of exposure to radiation indirectly in the passage where the alpha radiation reacts with DNA, and in the passage where cancer in mentioned. I also do that in the passage with the 'mutagenesis'. But maybe it's not clear enough.

9 - I'll leave the GuideML formatting to the sub-ed.

10- I do not see why disaggregate should be replaced by split. I think that disaggregating is more suitable, since the nucleus is not split by something else, it just stops sticking together.

11- The energy produced in a nuclear fission chain reaction is not subject of this entry. Anyways if you are interested: The total energy is not comming from lost neutrons that are turned into energy according to 'EMC2'. There is an observable loss of matter though, which is equivalent to 'EMC2' but only a very faint fraction of the mass is converted into energy every time a nucleus is split, not entire neutrons. The gross energy of a nuclear chain reaction comes from the kinetic energy of the nuclei and the radiation fying around. The force that holds the nucleus together is released and boosts the remaining parts at humongous speeds - That's the source of the energy.

12- I didn't get the following question: "Finally, in regard to the above mentioned section, it might be worthwhile noting which of these are more likely for out of proportion nuclei, and which are more likely for heavy nuclei."

13- Your source is right: Nuclear fission is more likely for heavy Elements.

Thanks for your comments, I hope I got things get cleared up now.

Bye

HELL

Oh yes.. I just saw your last post now...

Keep me busy Silverfish...

Bye,

HELL

Oh and point 2 in the long post above... I've changed the entry accordingly. Just forgot to erase your quote from the reply. Sorry for that.

HELL

Nice article.

Here's (just one) (non-technical) correction:

'...but generated by a by then an unknown process...'
changes to
'...but generated by a then unknown process...'

...mmmh...

Why didn't I see this?

Thanks S'pe;lug:x.

Hi

just a comment on a suggested revision from T Revenge in post 42 -

" 'There are also some forms of radiation, which are responsible for the radioactivity, going along with nuclear reactions'
could become
There are also some froms of radiation associated with nuclear reactions which are responsible for the signature radioactivity. "

IMHO the alternative given here is also rather ambiguous. Is it the 'forms of radiation' or the 'nuclear reactions' which are 'responsible for the signature radioactivity'?

Although I agree that the current formulation (the original phrase does not appear to have been changed) could perhaps be improved, I am not sure this is the way to do it. No doubt it seems obvious if you know something about the subject in advance, so perhaps it is just me.

Spiff

Hi Hell, back again.
I just re-read the entry, to be sure what I am talking about.

In the five ways.

alpha emission must leave two electrons somewhere, as you start with a neutral atom and subtract a positive alpha particle.

positron emission also emits a neutrino, for the same reasn as in electron emission.


Effect of radiation. Maybe you can first tell what damage is done, before separating in the different types of radiation.
And I stil think energy is here more important than momentum, for with every process creating damage there is always a minimum ENERGY in the centre of mass system involved before it can happen, no matter what particle causes it.
An interesting damaging process is capture of an alpha particle by a nucleus, creating another atom (possibly radioactive) and more gamma rays. This atom will not fit in its molecule.
Other processes are turning speed into heat (vibration), ionisation or breaking molucular bonds (both again requiring a minimum energy).
Neuton capture will always give extra gamma rays, as the new nucleus invariably will be in a highly exited state.

Enough for now. See what you can do with it.
Marijn

#54: I don't think the original sentence is totally wrong. What I want to say is: There are 3 forms of radiation. Radioactivity is a term used to denote the presence of one or more of these forms of radiation, but only if they are comming from nuclear reactions.

#55: a) After the alpha decay the 'new' element is doubly negative charged. So it leaves two electrons where they were... I didn't understand your argument Marijn. b) positron emmission and neutrino... I think I'll change the passage to 'four types of reaction' and merge the positron emmission to the beta decay (it's the beta plus (+) decay anyway). c) OK I'll cange momentum to energy. I think it's a concept more people can handle anyway. d) All nuclear reactions are accompanied by gamma ray emission.

Thanks.

HELL

Hell,
don't worry about not always understanding me.
I (used to) have a lot of knowledge about this stuff, so I have some trouble keeping apart what I take for granted, and what you or the entry should take for granted. In this case I saw a violation of charge-conservation in the entry, but knew it to be just your frasing.

Marijn

Does that mean you now like the entry?

I always liked it, we just differ on minor points.
There are still some points that mayby stated differently, but I will keep quiet now for some time to think about it (and to bring it upwards in peer-review again if needed).

BTW, there is a 'radiocative' in the uses-section.
Marijn

Hi, hell.
I'm subscribed. I just don't have anything more to contribute.
I like it.