User talk:Terra Novus/Archives/2010/October
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Physics Discussion about Skylon performance
So this aircraft needs a specially strengthened runway ?? It says so, twice. But if the aircraft has a takeoff mass only one tenth of a loaded Boeing 747, then why does it need a special runway ?Eregli bob (talk) 09:08, 21 September 2010 (UTC)
- Simple...Momentum is the product of mass times velocity, and the runway has to deal with that momentum. Though this craft is far lighter than a 747, its takeoff speed will be massive (Half the speed of sound), and will subject the runway to a proportionate amount of stress.--Novus Orator 09:08, 26 September 2010 (UTC)
- Well the 747 takes off at 290 km/hour. So "half the speed of sound" is double that. So if the skylon is one tenth of the mass, and double the speed, of the 747, then its momentum is only one fifth of that of the 747. So your rationale doesn't make sense at all.Eregli bob (talk) 13:16, 28 September 2010 (UTC)
- 747 442 tonnes Skylon 275 tonnes. Half speed of sound 615 km//hour. SO Skylon had 1.32 * the momentum, and 2.8 * the energy.--Kitchen Knife (talk) 14:34, 28 September 2010 (UTC)
- Well the 747 takes off at 290 km/hour. So "half the speed of sound" is double that. So if the skylon is one tenth of the mass, and double the speed, of the 747, then its momentum is only one fifth of that of the 747. So your rationale doesn't make sense at all.Eregli bob (talk) 13:16, 28 September 2010 (UTC)
- I'm not convinced this explanation is sound. Momentum, like velocity, is a vector quantity, and its largest component by far is parallel to the runway. So increasing a plane's takeoff or landing speed (i.e. its groundspeed) doesn't seem relevant to me. As I see it, what's relevant re the necessary strength of the runway is only the momentum that's normal (perpendicular) to the runway, i.e. whether a plane makes a "hard landing" or a "soft" one, and how heavy it is. The vertical component of the velocity at which the plane touches down should be about the same as that of a 747. It would correspond to a vertical airspeed of just a few feet per second, one would hope: anything more and you have a crash landing, anything less and you overshoot and don't leave enough runway for braking after you touch down. The aircraft's groundspeed shouldn't matter at all except as it affects takeoff and landing/braking distance. It's been a long time since college physics, though, so perhaps I've neglected some factor that y'all are aware of? – OhioStandard (talk) 02:36, 2 October 2010 (UTC)
- Yes, you are correct, my explanation was not clear. As far as I understand it, velocity and acceleration are vector quantities, and the acceleration vector of the landing aircraft is diagonal to the runway, e.g. it has a x-component and a y-component. The Force of Kinetic Friction is equal to the Normal Force (Weight) and the mu k (frictional constant), which contribute the additional stress that I am referring to. The y-component is smaller than the x-component, but the Normal Force caused by the aircraft/(in this case spaceplane)'s mass is a part of the frictional force equation (which is the friction the runway exerts on the spaceplane's wheels). The combination of the y-component of the acceleration vector (working down) and the Fk (working horizontally against the wheels) together is what puts the stress on the runway.
- I'm not convinced this explanation is sound. Momentum, like velocity, is a vector quantity, and its largest component by far is parallel to the runway. So increasing a plane's takeoff or landing speed (i.e. its groundspeed) doesn't seem relevant to me. As I see it, what's relevant re the necessary strength of the runway is only the momentum that's normal (perpendicular) to the runway, i.e. whether a plane makes a "hard landing" or a "soft" one, and how heavy it is. The vertical component of the velocity at which the plane touches down should be about the same as that of a 747. It would correspond to a vertical airspeed of just a few feet per second, one would hope: anything more and you have a crash landing, anything less and you overshoot and don't leave enough runway for braking after you touch down. The aircraft's groundspeed shouldn't matter at all except as it affects takeoff and landing/braking distance. It's been a long time since college physics, though, so perhaps I've neglected some factor that y'all are aware of? – OhioStandard (talk) 02:36, 2 October 2010 (UTC)
- To solve for the total linear force the runway must exert on the spaceplane (neglecting air resistance) is:
- (in x) (1.0) Frictional Force in x-dimension=(mu k)×(Normal Force)
- (in y) (1.1) Normal Force=mass × acceleration
- If you wanted to find the Momentum of the Spaceplane once on the runway, you would then take the x-component of the resulting Force in the following equation:
- (1.3) Momentum=[(Force of Thrust in x dimension)-(Frictional Force in x-dimension)]×(change in time)
- Which you could then relate to the horizontal velocity in the Momentum equation:
- (1.4) Momentum=mass×velocity
- Though this is a very interesting topic, I am reminded of the policy WP:NOTAFORUM and therefore I must end this discussion. It's great knowing that there are editors out there who love Physics as much as I do.. --Novus Orator 03:12, 2 October 2010 (UTC)
Reliable citations
Hi Forums and suchlike are nor reliable to support any content, please have a read of WP:RS Thanks. Off2riorob (talk) 15:13, 2 October 2010 (UTC)
ANI
Hello. This message is being sent to inform you that there currently is a discussion at Wikipedia:Administrators' noticeboard/Incidents regarding an issue with which you may have been involved. Thank you. Rd232 talk 13:47, 4 October 2010 (UTC)
- And again here. Toddst1 (talk) 07:01, 14 October 2010 (UTC)
- And again. Thread restored from archive for additional comment. – OhioStandard (talk) 16:14, 16 October 2010 (UTC)
Links to Heim theory
Please stop adding links to Heim theory to articles about mainstream science topics (as you did at dark matter and quantum gravity). Per discussions at WT:PHYS, and also at Talk:Heim theory with other editors, Heim theory is sufficiently far from mainstream that linking it from these articles violates WP:UNDUE. The only places links are appropriate are articles that are already discussing fringe or highly-speculative physics models, or articles discussing highly-speculative topics about which Heim theory has been mentioned in high-profile third-party press articles (which is why I left it in at faster than light, and removed it from intergalactic travel).
You seem to understand and acknowledge that Heim theory is far-fringe, so please accept that it won't be linked from the vast majority of physics and space related articles on Wikipedia any time soon. That's just one of the aspects of the way Wikipedia's science articles work (they follow well-established thought rather than pushing the boundaries). --Christopher Thomas (talk) 19:21, 21 October 2010 (UTC)
- That sounds totally fair. I will continue adding it to relevant articles, but I won't push it into articles that don't give reference to Heim theory's principles..--Novus Orator 04:34, 22 October 2010 (UTC)
Speedy deletion nomination of Category talk:Global warming skeptics
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Young-earth creationism edit to UDFy-38135539
Hi again. I reverted this edit for which you gave the edit summary, "fixed neutrality". The material you added was not supported by the source cited; it was, in fact, (yet another) POV-based misrepresentation of a source.
Look, you seem like a pleasant-enough person, but this kind of behavior simply has to stop. I understand your religious beliefs, and no one here wants you to change those beliefs. We just need you to follow the rules, which you know perfectly well by now. You can't insert your beliefs into articles if the sources don't support them, or if you can't introduce reliable-source cites to do so. I'm getting the impression that at least half your reason for participating here at all is to do just that, to put your religious beliefs into articles. Your choice of a new user name suggests that, of course, that one of your principal interests here is to champion young-earth creationism.
I imagine I can guess with some accuracy as to your particular denomination of Christianity, so let me ask you this: How would you respond to an editor who, despite many, many cautions and warnings (to cite just two), kept introducing edits supporting the view that the Roman Catholic Bishop of Rome was literally infallible in all his statements, even when not speaking ex cathedra? ( There are certainly people who believe that. ) This is how I see you, I'm afraid, and how many of your fellow editors appear to see you, as well. So tell me, please, how would you respond to such a person? Would you see him as a net asset to the encyclopedia, even if he contributed very well in other areas? Could you, in good conscience, permit such an editor to just continue to use Wikipedia as a platform to promote his belief?
As I said at ANI previously I don't want to see you subjected to a community ban. I also don't want the community to have to go through any more Sturm und Drang over your editing, either. But you're almost forcing your fellow editors to move in that direction, to move to have you permanently banned. I won't waste my time (or yours) asking you again to stick to the rules, but please don't make such an outcome necessary: I'm not trying to be dramatic in any way, but no more "slips" as you described edits like this, previously. I won't keep asking you follow the rules when you all you do is say nice things in response and keep up your familiar pattern of violating them.
Btw, in response to your Rensberger quotation about scientists on your user page: I know there are biased scientists, just like there are biased plumbers or accountants or politicians. I even know one (a scientist, not a plumber ;-) who I consider very biased, even though he's a friend. But most I've met or have known fairly well are doing their best to try to figure things out as honestly as they can. One, a pharmacology professor I know (and respect greatly) begins every lecture to a new group with this quotation, from Karl Popper: "Whenever a theory appears to you as the only possible one, take this as a sign that you have neither understood the theory nor the problem which it was intended to solve."
Likewise, I remember I loved the authors of my organic chemistry textbook in college for writing, in their preface, that the models (like the electron cloud model for how organic molecules are formed from atoms) they presented and used in their textbook were just that: models. They stressed that the models were representations, abstract ideas that were good for some purposes, not so good for others. Even Sir Issac Newton didn't write that the gravitational attraction between two objects varies inversely as the square of their distance apart; he wrote, as I understand, something like, "everthing we observe happens as if it so varied. This has been the attitude that I've found among almost all the scientists I've known. I'm not a scientist myself, btw, (just a very amateur student of mathematical philosophy when I can find the time) but it's my belief that they're not really so shabby a lot as you appear to think.
Anyway, I hope you don't mind the digression, and I do hope you'll (at last) stick to the rules here. I want you to be able to stay around. Best, – OhioStandard (talk) 07:29, 22 October 2010 (UTC)
- I agree, observational science is generally uncontroversial. The debate lies with interpretive science. I agree that most scientists are honestly researching and analyzing from their own perspective (and despite my disagreements with most of them, I think that when it comes to observational science there isn't a bad dog among them)-the question lies with how their pre-existing philosophical perspectives lead them to perceive evidence. In the case you mentioned above, I obviously slipped again. I agree that if I keep this up, the Wikipedia community will feel that they have no other alternative to banning me (I understand the realities of WP:Systemic bias) I will keep trying to avoid editing contentiously, and I appreciate the help from more experienced editors such as yourself.--Novus Orator 07:41, 22 October 2010 (UTC)
- In this diff [1], contrary to your edit summary, you did not add any new information. You hid some highly informative non-technical information on the timeliness of the discovery in a footnote. Your change was reverted by later editors. Please try to avoid making edits like this, as they are not helpful for readers. Thanks, Mathsci (talk) 13:06, 22 October 2010 (UTC)
- I agree, observational science is generally uncontroversial. The debate lies with interpretive science. I agree that most scientists are honestly researching and analyzing from their own perspective (and despite my disagreements with most of them, I think that when it comes to observational science there isn't a bad dog among them)-the question lies with how their pre-existing philosophical perspectives lead them to perceive evidence. In the case you mentioned above, I obviously slipped again. I agree that if I keep this up, the Wikipedia community will feel that they have no other alternative to banning me (I understand the realities of WP:Systemic bias) I will keep trying to avoid editing contentiously, and I appreciate the help from more experienced editors such as yourself.--Novus Orator 07:41, 22 October 2010 (UTC)
- My bad. I guess I thought it looked better as a footnote.--Novus Orator 03:49, 23 October 2010 (UTC)
DYK nomination of Interpretive science
Hello, your nomination of Interpretive science at DYK was reviewed and comments provided. --NortyNort (Holla) 10:31, 27 October 2010 (UTC)
October 2010
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Terra Novus, you have been warned three or four times now about how you edit, both on WP:ANI and on this user page. Each time you say you will reform. However, each time you lie low for a few days and then return with the identical problematic editing patterns. Various users have shown great patience with you, but you are now likely to incur a community ban or possibly even an indefinite block after your latest spell of edits (which will be reversed without yet another a discussion). Your post on my user page will be removed. At the moment what you are doing is exceedingly disruptive. There is an ongoing thread about you on WP:FTN by User:Cardamon. Mathsci (talk) 05:56, 29 October 2010 (UTC)
- I do not see how encouraging other editors to WP:Discuss instead of edit war is counter-productive...--Novus Orator 06:04, 29 October 2010 (UTC)
blocked
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{{unblock|Your reason here}}
, but you should read the guide to appealing blocks first. I have blocked this account from editing for a duration of 1 week, on account of repeated disruption of multiple articles and talk pages in relation to Heim theory. Several editors have complained about your activity, and you have promised to behave differently, but have not followed through. This has cost a great deal of time and annoyance to other editors. Because you have not kept your word in the past, I am not going to be prepared to unblock or reduce this block. If the same behavior resumes after the block expires, longer blocks will follow. Looie496 (talk) 18:31, 29 October 2010 (UTC)