Iggy

A l'impossible, nul n'est tenu. Nothing else can occupy that space-time coordinate. A coordinate in space-time is a specific spatial location at a specific time. "At the moon in 1969" is the space-time coordinate. "The moon landing" is the event. That is the event that goes with that coordinate. What "other physical body" would be there?

You seem to be asking how we can know about the moon landing if it isn't currently visible. Events inside your past light cone affect current events. Information, in other words, can travel less than c. Information about the moon landing can get from the moon 42 years ago to here and now by paths other than direct line of sight.

For almost 40 years the rate of expansion of the universe was believed to be constant. It is called the Hubble Constant. The Hubble constant isn't constant. It changes over time depending on the deceleration parameter. There were a few other basic misunderstandings about cosmology in your reply that make me wonder how you are using the word "theorist".

I don't know what that means. We don't dismiss events we can't see. We don't dismiss the moon landing just because we can't see it at the moment. Past events don't need to be on the surface of the light cone to cause present events.

Which physics model includes God?

Exactly. Each "spherical plane in 3-D space" is the surface of a sphere, and the light cone is in fact an expanding sphere around the observer. Agreed -- a past light cone contracts and a future cone expands, but agreed. I would draw exactly the same conclusion. Right. We don't hear Neil saying "one small step for man..." It's not on the surface of our current past light cone.

With all three spatial dimensions, it would be a 4 dimensional hypercone. One of the axis in the OP represents time and the other represents one of the spatial dimensions. Here is a fair description of a light cone.

Yeah, thinking about the brightness and frequency of the light is where the train goes off the rails for me.

Notice the source it gives for that (19)

But, we don't see it 9.1 Gly away. If we did then I'd agree the light travel time would be a much more natural unit of distance. The light took 9.1 gigayears to get to us, but the light's speed relative to us wasn't constant during that time so it doesn't translate directly into a distance. Let's say that the galaxy is named Merlin (my cat's name as it happens), and also pretend that Merlin and the Milky Way are at lest 9.1 billion years old. The Milky Way was 5.72 Gly from Merlin 9.1 billion years ago when it emits light towards the Milky Way. In other words, 5.72 billion observers, each with a ruler 1 lightyear long, would fit between the galaxies when the light is emitted (each observer moving with the expansion of the universe -- "comoving observers" they would be called). The light moves at c relative to its nearest observer throughout the trip. 9.1 Gyr later the light arrives in the Milky Way. By the time it arrives each observer would need a ruler 2.415 ly long because the universe has expanded 2.415 times its previous size. The 'proper distance' (as they call it) to Merlin has gone from 5.7 Gly (when light was emitted) to 13.8 Gly (when light was received). At some point in time Merlin had a proper distance of 9.1 Gly from the Milky Way, but it wasn't when the light was emitted or when it was received. It was some point between. I think light travel time is a fine measure of distance (no less correct than redshift, luminosity distance or any other definition of distance in cosmology), it just doesn't mean what a lot of people intuitively think it means. Quiz question for anybody: if a galaxy is currently 18 billion lightyears from us and we send it a message, will it ever be received (assuming the standard model is correct)?

The two links I can think on this are the following: http://www.astro.ucla.edu/~wright/cosmo_02.htm#MD http://www.astro.ucla.edu/~wright/Dltt_is_Dumb.html There is more than one definition for distance is cosmology. If you go to the cosmology calculator: http://www.astro.ucla.edu/~wright/CosmoCalc.html plug in z=1090 (that's the redshift of the cmb) and hit 'general' on the left it gives the distance to the cmb on the right, As you suspected, 45.6 Gly is the current distance. The distance, for example, from the milky way to another galaxy which is as old as the milky way. At the time of the CMB the two areas (they weren't galaxies yet) were roughly 42 million lightyears apart. The universe expanded 1091 times over since then so the two areas are currently 45.6 billion years apart. One of the areas turned into the milky way and the other turned into a galaxy at the edge of our visible universe. Because of the acceleration of expansion we will never see that galaxy. The CMB is the last glimpse we got of that mass.

I've worked with molten lead and pewter, but not aluminum so I couldn't say. I would trust John Cuthber about rather hot aluminum. By the way, how does anyone know the temperature of the fire? I saw a that said 980 C. I wonder where or how anyone got to that number

it is precisely because they have different properties that we are able to know what is entirely spatial separation for one is temporal and spatial separation for another. If space and time didn't have different properties then everything would just be one kind of separation. There would be no difference between proper distance and proper time. As it stands, there is. I'd echo everything Md said. When Neil said "one small step for man..." -- at that instant -- Houston was in his past light cone in the sense that the whole history of Houston was in his past light cone. All of the events that happened in Houston from the moment it was named up to nearly the present instant (1.3 seconds before the present instant) was in his past light cone. If that's what you mean then I agree We're only talking about things close enough to be observed... nothing outside the visible universe

Yeah, I tried to be concise and ended up not saying that very well. I'll try to articulate better... Both, yes. I believe the nature of a conspiracy theory is to add layers to the explanation of a situation (layers of people and events). It's like the video you mentioned of molten metal dripping from one of the towers. Speculating that it is melted aluminum from the plane wouldn't add any elements to the plot and wouldn't be conspiratorial. But, speculating that termite is responsible adds all the elements that come with a controlled demolition and makes it conspiratorial. It would add a covert demolition team, structural / chemical / mechanical engineers to design the demolition system, and of course the resources of big brother to keep everyone quite. It seems like the purpose of a conspiracy theory is to add elements like that. The method involves extrapolating small unexplained evidence into a large well-conceived machination. Conspiracy theories are mysterious to me, but that's how I perceive them. Trying to minimize the number of people in the 9-11 conspiracy sounded at cross purposes to me because it goes against that principle of adding layers to the explanation. I mean that it would be easier to support the notion that a plane hit the pentagon versus a missile. For the plane there are eyewitnesses, video, wreckage, and other evidence of that sort. To support the missile idea we not only have to find some positive evidence of a missile, we have to deal with all the evidence of the plane. To consider ways to cut down the number of people in the conspiracy like you said, saying "a plane hit the pentagon" or "building 7 failed from an uncontrolled fire" does that quickly. If there were positive evidence of a conspiracy -- for example, surveillance images of workers bringing hundreds of boxes of material into the buildings a few weeks before the event -- then there would be difficult constraints in limiting the size of the conspiracy. We would have to consider who these people were, who trained them, who paid them, who made the thermite devices in the boxes, etc. Without positive evidence nothing would prevent us from eliminating the whole lot of them from the equation. My point, I guess... If a person believed there was a conspiracy and wanted to see how small the conspiracy could be while still being consistent with the evidence, it could be arbitrarily small. It could be, the example I used, George Bush calling Bin Laden on the phone and saying "It would really help me out if you attacked". No limit to how small. Hopefully that makes sense. I wouldn't look at it like that. The official account of what happened may have holes in it (there are always unknowns in everything), but I wouldn't consider "the government could lie" and "people had access to the buildings" holes. As an analogy, I wouldn't consider "the government lies" a hole in the official moon landing account.

That all sounds correct to me.

But doesn't it seem like conspiracy theories are big and complicated by nature? It would be a lot easier to say that building 7 was an unintended consequence of the main event, just like it'd be easier to say that a plane hit the pentagon rather than a missile. But, once we start doing that it isn't long before we're left with Bush, Bin Laden, and a single phone call for the whole conspiracy. That's not the stuff conspiracy theories are made of.

After googling it, I suspect Mystery111 may not be wrong. His 2009 biography suggests he had undiagnosed autism. He was apparently famously socially inept. At Cambridge (according to wiki) they joked that a unit of Dirac was the smallest imaginable number of words that someone with the power of speech could utter in company, an average of one word an hour. The biography's cover has "pathologically reticent, strangely literal-minded and legendarily unable to communicate or empathize... hopelessly socially inept..." Kudos, Mystery, if you guessed aspergers without seeing it on wiki or somewhere.

How'd I know you were gonna say that? or the local light cone of an event, ok. Yes. yes, corresponding. The world lines are the collection of events in the history of the objects. Different world lines, different objects. right the properties of space are different from the properties of time because we measure one with a ruler and the other with a clock. Any indication that objects persist in time is an indication that objects persist along a world line. It's the same thing. No, the center line, for example, is the Milky Way. The top of the center line is the Milky Way today. A bit further down is the Milky Way a billion years ago -- further down, 2 billion years ago -- and so on. If you consider the Milky Way 12 billion years after the big bang to be the same object as the Milky Way 13 billion years after the big bang then it is the same object. I think that's spot on. Any event we see out there, like "star shines", has a history and a future. Draw the complete world line for any event on our past light cone and it can't really be an empty diagram.

I think the east penthouse collapses into the building about 5 seconds before the core goes... if that's what you mean.

The thing that's twisted and strange, but typical I suppose -- that blog was written in Feb. 2010. The first bit, Suzan Mazur apparently believed the science Gestapo was trying to silence Massimo Piattelli-Palmarini and keep him from publishing his book. Smash cut to three months later and Massimo Piatelli (a different person with an ironically similar name) wrote "Nonsense on Stilts: How to Tell Science from Bunk". The book mentions Suzan as, I would guess, some kind of trumpet for pseudo-science and conspiracy theories. Suzan tried straight away to get the publisher to remove the book from circulation.

Yeah, depending on how fast you drink and if you have a full stomach and things like that, but it returns to normal not long after your blood alcohol level stops rising would be a good benchmark. +1. It's actually the first thing the second link I gave says, Drinking alcohol, even pure grain alcohol, the body reacts as if you just drank a good deal of water. It thinks it needs to clear free water from the blood.

Right, that would have to make sense -- otherwise the camera would be over the water. It does seem to me then that the report is right about it progressing east to west. It does make sense to me that if the core went first it could help yank the perimeter down, at least briefly, and especially on the west side. I wouldn't want to say for sure how possible it is without knowing more, but it does seem reasonable to me. The thing for me though -- if I had doubts as far as the validity of the official explanation it wouldn't make me think controlled demolition or conspiracy. On the contrary, it would seem weird if such unique circumstances were completely explained and understood.

Like you say, If you follow the source wikipedia gives for that definition it actually nowhere says "an attempt to negate the truth of a claim" or anything like that. It gives these definitions which support what I said: Appealing to personal considerations rather than to logic or reason [American Heritage Dictionary] A term used in debate to denote an argument made personally against an opponent, instead of against the opponent's argument. [West's Encyclopedia of American Law] To the individual. Relating to the principles or preferences of a particular person, rather than to abstract truth. Often used to describe a personal attack on a person. [Latin Phrase] appealing to a person's feelings or prejudices rather than his intellect [Obscure Words] to the man; argument directed at man’s character, not his position [Random House Word Menu] Calling someone a hypocrite is implicitly (by definition) comparing their assertions to their actions and addressing the latter in place of the former which is what "ad hominem" is all about. That is surely why tu quoque is ad hominem. It would be hard to know about lost ideas. It is something that the OP talks about delayed scientific recognition and we've moved on to lost ideas. In the same vein, the title says "ridicule is not good science" and I think the point was recently made that ridicule is useful in stand-up comedy.

I've seen this said more and more over the last few years but it's actually not true. Ad hominems are a substitution for a valid point in a debate, but it isn't necessary that the "validity of an assertion is questioned". Poisoning the well, for example, happens before there is an assertion to refute and is a type of ad hominem. The type that iNow used is "tu quoque". Tu quoque is ad hominem. Ad hominem

Sorry, I'm playing catch up. I'm reading the wikipedia entry to get an idea... In November 2008, NIST released its final report on the causes of the collapse of 7 World Trade Center.[8] This followed their August 21, 2008 draft report which included a period for public comments.[35] In its investigation, NIST utilized ANSYS to model events leading up to collapse initiation and LS-DYNA models to simulate the global response to the initiating events.[44] NIST determined that diesel fuel did not play an important role, nor did the structural damage from the collapse of the twin towers, nor did the transfer elements (trusses, girders, and cantilever overhangs). But the lack of water to fight the fire was an important factor. The fires burned out of control during the afternoon, causing floor beams near Column 79 to expand and push a key girder off its seat, triggering the floors to fail around column 79 on Floors 8 to 14. With a loss of lateral support across nine floors, Column 79 soon buckled – pulling the East penthouse and nearby columns down with it. With the buckling of these critical columns, the collapse then progressed east-to-west across the core, ultimately overloading the perimeter support, which buckled between Floors 7 and 17, causing the entire building above to fall downward as a single unit. The fires, fueled by office contents, along with the lack of water, were the key reasons for the collapse. http://en.wikipedia.org/wiki/7_World_Trade_Center#9.2F11_and_collapse It sounds like the core went first. That would seem to support our deduction, but that's just going off a small wiki entry. I really know next to nothing about this topic. Here are a couple images: http://doujibar.ganriki.net/english/e-wtc7/wtc7-nist-diagram1.jpg http://cinemaelectronica.files.wordpress.com/2010/03/wtc7_column-79-collapse.jpg of column 79. If the collapse went east to west from that point I'm sure it would happen quite quickly. Can we figure out which side of the building the acceleration is measured in the video?