studiot

They are not kept out, the full table is unweildy, the standard version includes the rare earths in a more compact way and appear in your table. There is a comprehensive discussion and link about this on Quora. https://www.quora.com/Why-are-lanthanides-and-actinides-are-kept-out-of-the-periodic-table which also offers the full table

Here is an interesting discussion about the effect of entry angle. It is intended for rocket capsules, but also discusses meteor(ites). https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/cami/library/online_libraries/aerospace_medicine/tutorial/media/iii.4.1.7_returning_from_space.pdf @Bazil_SW I see you are a new member of 7 hours standing. Welcome. Just to warn you that new members are allowed only 5 posts in the first 24 hours. This is nothing personal, just a very effective measure against spammers who try to flood sites like this with junk. After 24 hours the restriction ends. If you really need to say something before that the private message system can be used.

You were also asked for your definition of absolute. This is so we can distinguish an 'absolute singularity' from any other sort of singularity. Or are you just adding fancy but meaningless words for effect, rather like advertisers do ? My great grandchildren are non existent. I asked this because I was concerned that you had presented a circular argument or contradicted yourself. I see you have not done this because as I understand your meaning of 'exist' it can only be applied to material objects. However this argument is just as fallacious as I have already pointed out that the English language makes provision for material things as well as for immaterial things. And your argument seems to rest on the premise that no immaterial thing exists. So would you deny the existance of colour ? Is a shadow a material or immaterial thing ?

Not really. Firstly PHI asked you to define what you mean by 'absolute' and 'singularity'. You have not done so. Secondly I asked what you mean by unsubstantiated. All you have done is repeat it. And you made no reference to my comments about the use of language. One's use of language and in particular the use of negatives is crucial to discussions such as these. As a friendly note new members to this forum are limited to a total of five posts in their first 24 hours. This is nothing personal it is a very effective anti spam measure. You may have noticed some websites that do not do this are flooded with advertising and worse spam. After 24 hours you can post all you want - but remember the mods like one topic per thread and a rule of themb is that you need to post sufficient material on the forum for those who cannot look elsewhere to participate. If you make assertions you may post a link to a known authority (eg Stanford Encycloperia of Philosophy) to substantiate your assertion. Note I have used the verb to substantiate. This is why I asked about your use of 'unsubstantiated'. Do you mean asserted without support or do you mean non-corporeal or something else again ?

The language of this forum is English. I learned recently in another thread here that negatives are treated differently by (some) other languages. I have no idea what you mean by an unsubstantiated idea ? English allows two sorts of nouns (and their 'existence') - concrete nouns and abstact nouns Are you referring to something like this. You do seem to have introduced new undefined terms, additional to those already introduced in your opening post (op). I will leave it to the kind moderator to explain what link you may or may not post. Or you could just read the rules.

My great grandchildren are non existent. ?

Hello Jd1 and welcome. Yes that was the topic. The former member did not have enough Maths knowledge to appreciate the simple explanation, and you have not indicated your level of Maths. I can't see that the decimal - fraction converter in your link is any use either. Here is a simple correct Mathematics answer to the question, you may appreciate. Consider the whole number system : 0, 1, 2 ... That is all the numbers in the system are whole numbers. The system is sometimes called the counting numbers. In this number system there are no numbers between 0 and 1 or indeed between any adjacent two whole numbers. Now consider what we call the rational number system, which includes all possible fractions. That is all the numbers in the rational number system are fractions, so in this system the whole numbers appear as fractions where the denominator (bottom number) is 1. So in this system [math]0 = \frac{0}{1}[/math] and [math]1 = \frac{1}{1}[/math] One property of the rational number system is that between any two rational numbers there are more rational numbers. So the is nowhere where there are two numbers that do not have more fractions between them, no matter how finely you divide the gap up. We denote this property by saying that the rational numbers are dense. Further the rational number system is the simplest number system with this property. The counting numbers are not dense

Not exactly, no. The free atom does indeed possess the s an p orbitals. I already said that. When this free atom enter a bond it does not reorganise its orbitals into hybrid ones as a preparatory process. This a a theoretical and mathematical device for us to transform the s and p orbitals into the hybrid ones, just as you say is outlined in the text. But the text also has different hybridisation equations depending upon the environment as it shows with methane and ethylene. Nor does the carbon in methane deconstruct its hybrids to reform the s and p orbitals then form different hybrids when the methan molecule enter a chemical reaction where say one hydrogen is replaced by a chlorine. So you cannot get away from the environment ie the other atoms in the molecule. This is just as you cannot solve Schrodinger without the boundary conditions.

Thanks, I'll look it up. +1 Update. If I follow your link it goes to a page similar to the old popup. That page is headed as > Browse > online users If I click on that heading I get a differnt page showing different users. Sloppy programming IMHO.

Sorry If I gave the wrong impression. I did indeed refer to the first LED lights I had. This was some 10 years ago and they were complete celing fittings with the LEDs integrated within. These have been performing well for 10 years. These were installed on the new ceiling as part of an extension project to the house. They were however expensive, at £120 each. The project was discussed extensively, with photographs, in the old thread I referred to. The replacement bulbs were 'ony' £8 each (tungsten is aout £0.25) a couple of years ago. They have only been available fior 3 to 4 years.

I'm not sure I follow. I've barely had these bulbs a couple of years, yet they are starting to fail. Here is the package from one.

Thank you both for these answers. My original LED lights were fitted before almost 10 years ago and are still going strong. These were complete light fittings, not just plug in replacement bulbs, which are much more recent. My experience with the replacement type is that they do not live up to their promise and Zap's description is all too familiar. A further thought occure to me. Light bulbs of any description are not particularly high current devices. However LED types really need a much lower voltage than UK mains so perhaps the lower American mains voltage lead to a longer lifer in the voltage reduction circuitry ?

I note you have posted this in 'Relativity' What connection to relativity are you looking for ? And what do you mean by 'constrained' ? Yes there is are a collection of hypotheses (strictly - not theory) called the 'block universe'. I say collection because there are variants of the hypothesis. https://www.google.co.uk/search?q=block+universe&source=hp&ei=p7IfYY3OHNGE8gLou4_4AQ&iflsig=AINFCbYAAAAAYR_At-KaN5C9DL025ykI-HzjO5l0zHKu&oq=block+universe&gs_lcp=Cgdnd3Mtd2l6EAMyBQgAEIAEMgUIABCABDIFCAAQgAQyBQgAEIAEMgUIABCABDIFCAAQgAQyBQgAEIAEMgUIABCABDIFCAAQgAQyBQguEIAEOgsIABCABBCxAxCDAToRCC4QgAQQsQMQgwEQxwEQ0QM6DgguEIAEELEDEMcBEKMCOggIABCABBCxAzoOCC4QgAQQsQMQxwEQ0QM6CwguEIAEELEDEJMCOg4ILhCABBCxAxDHARCvAToICC4QgAQQsQM6CwguEIAEEMcBENEDOhEILhCABBCxAxCDARDHARCvAToLCC4QgAQQsQMQgwFQhhFYtihgslNoAHAAeACAAc4DiAGsGJIBCTUuMi4yLjIuM5gBAKABAQ&sclient=gws-wiz&ved=0ahUKEwjNva_e3r_yAhVRglwKHejdAx8Q4dUDCAg&uact=5

Good question at this time I don't know as previously I simply swopped them into place as old tungsten or CF bulbs failed. So I really only checked at the end of their life.

Can anyone tell me why the new update has change the way the list of members online is presented ? I didn't realise just how useful the popup of what they are looking at really is until now.

Does anyone have any experience in the failure modes and comparisons with the offered lifetime and real world time to failure of the replacement bulbs ? Since the introduction of LED replacement bayonet and screw fitting bulbs I have seen several fail prematurely. I have also noticed they run hotter than I expected, though not as hot as incandescent. I think I might start to dissamble any more that fail to find out what why they failed. Coupled with the hotter running I have noticed three that have started to flicker before failing, suggesting that it is not the LED that fials, but the driving electronics. Comments and experiences of others are welcome.

My post about the BBC article and some of my other material has really been to highlight that most, if not all, of these matters have been tried before, some of them long ago. Yet no one seems to be prepared to analyse and learn from past experience.

You are right it was my sloppy use of language. I should have said The set {1} is part of the partition set of S so is a subset of S but not a member of S. This difference between the use of 'partition' in the physical sciences and in mathematics strikes again.

I still say that hybrid orbitals only occur in bonds, not free atoms. And the actual hybrid varies depending upon the actual atoms concerned. Here are some simple examples of the maths.

It is you attitude which impedes progress. I said, "I think that........" I did not try to lay down the law. Your response could have been that you think you do understand set theory perfectly and so you wonder what I mean. Instead you tried to lay down the law. I agree with this first statement. But this second statement is inaccurate. This means that the set S must contain sets as members. Which is not a requirement of set theory. The issue of failure to distinguish between subsets and elements is further compounded by your sudden switch from elements to members. The number 1 is a member, but not a subset of your set S = {1,2,3,4} The partition {1} is a subset of S but not a member of S. I don't take kindly to the attitude that you know everything and no one else knows anything. Particularly as you are introducing mocking irrelevancies such as "byspel", which are no longer funny.

Oh dear. I really thought the new forum upgrade included a change from plain English to Runish. Is that not the case. Frightfully sorry.

I think you misunderstand the meaning of disjoint in set theory. This should be cleared up prior to any other consideration.

It's always useful to have an idea what the update is supposed to achieve. There are some very knowledgable members here in respect of It matters so their input can always be considered valuable. For my part there was a prefectly understandable update announcement early this afterennon, in place of the usual site itself. When the site returned I noted that the information about members online / offline had changed its presentation. I really hope that the various clocks and timers are now coordinated so that members are not still shown as online half an hour after they have left, and the timing of post nn longer suggests that replies occur before the question is asked.

The future's good. the future's rosy. So they said back in 1910 https://www.bbc.co.uk/news/business-56748346

Since you have heard of fission can you not answer my polite and simple question ?