CPL.Luke

Mowgli the problem is that if we assume that the debris from the star is emitting radiation, we would be unable to define at present what that light will look like. according to the dopplar shift for an object coming towards us, the light should be shifted to an infinite frequency when the debris is coming at us at 1C let alone 2C. You can't just say that the light will have been shifted to the gamma ray range, because there are no physics to describe an observable faster than light object. In my mind the only way that it could work would be if there was a luminal boom that behaved almost exactly like a shockwave from a sonic boom, to my knowledge no one has ever worked on what a light shock wave would look like, so once again it seems like the only way to show that a superluminal object could exist would be to define real observables.

hmm, thanks all for the replies. I don't think I have the mathmatical know-how to tackle a physics book that includes anything like differential geometry, and it also seems like a knowledge of the basics is important before going on to that kinda thing. So I'll have to pick up a copy of goldsteins mechanics than. (also ajb I did have the equivalent of a freshman course in mechanics)

Mowgli, I think that your idea could mesh with astronomical observations of superluminal objects. IF you assume that there is some mechanism in the universe for changing the reference frames in such a way that an object can appear to be travelling faster than the speed of light in our frame and in its own corner of the universe it could be measeared to be travelling at a sub light velocity. I think this could be a possibility because you mentioned two objects that you believe are in fact one object traveling superluminally, are close to the galactic core, a place where there are some very large and complex gravitational and electromagnetic fields at work, and in my mind it is entirely possible that such a phenomena could exist. As for the idea that the electron and positron are one particle traveling superluminally. I'm curious to see what would happen if in your animation you had two superluminal particles that either A: intersect B:collide C: some combination there of. and then plotted our observer's observation of the points, it would be intersting to see if a collision between two superluminal particles would result in us seeing the "image" particles collide. EDIT: actually I think the core of this debate lies in how an EM wave would behave if it was observed coming off a superluminal object traveling in a straight line away from the observer, if there is a meaningful answer to this question then I would say that it is possible that there observable objects (like the ones mogli pointed out) that could be moving superluminally. I say that this is the core issue because the notion of every superluminal object in the universe being oriented such that it travels like the hypothetical dots in mowgli's animation is more than a bit ludicrous, and if there is a meaningful answer to what EM waves look like when they are moving superlimunally, then we would know that there are telltale signs that an object is superluminal, and just by my own intuition if there is a meaningful answer to the question than I wouldn't doubt that the universe displays it.

what do you guys think of tackling Goldstein's mechanics on one's own?

no, gravity and acceleration cannot cancel eachother, I know that in GR everyhthing is generalised to make the frame in a gravitational field inertial, but SR cannot do this.

When do students normally start to learn about QFT? is it traditionally done in grad school?

Mowgli it appears in the animation as if the two "image" dots are still moving with superluminal velocity, this would seem to give a mechanism for determining whether an two identical images in the sky are from 1 superluminal object or from gravitational lensing etc.

this is a continuation of a discussion that started in the thread faster than light -ve. The discussion seemed interesting enough to warrant a new thread and seemed to be heading in the direction of a proper scientific discussion, and so I created the thread here. Mowgli said that he had worked out some math showing what a superluminal object would look like to us. It sounded interesting so lets see it. although for simplicities sake lets consider a point first and then move onto

^I agree with demosthenes, you can never take what a person says when their drunk as a serious representation of how that person feels.

any thread can be started without the need to consult the moderators, and because it sounds like its going to be mathmatical and scientific in nature, I don't think it needs to go into the speculations forum

matrices are used in a large number of sciences, essentially they are used whenever a situation becomes very complex involving a large system of equations. probability theory uses matrices alot, so thats why QM uses them as well. also matrices are used in economics and engineering, GR and by extension of QM, QFT in all of its forms.

Mowgli I didnt see anything in the animation or the math to show that the two dots move with a subluminal velocity.

ENTP is there any statistic on how an average population should break down into the categories? EDIT: I found this http://www.geocities.com/lifexplore/stats.htm but don't know how reliable it is.

darn just when I was coming out of withdrawal, I find anouther fix. this is the second time in the past couple months SFN has been down for more than 12 hours, is there any reason for the recurrent shutdowns?

I remember my sister had to build a hovercraft in her 8th grade science class, all it was was a disc of styrofoam with the center cut out, then a small electric motor was placed in the center cut out with a fan attached to it, a piece of construction paper formed the skirt. The main idea of a hovercraft is to keep a bit of positive air pressure underneath the craft, in order to do this you need two things A: some sort of fan to push air underneath the craft B: you need some sort of "skirt" around the craft to keep the air underneath the craft and help build pressure (this also adds to the stability). if you want to stear the hovercraft you need an additional fan to provide thrust, along with either a rudder or some method of turning the fan. The latter method is far more efficient, albeit a bit more difficult to use.

but like was said before, those aren't inertial frames and you have to account for some other effects. Also leave the quoting to the social sciences, were physisists here show us the numbers

the same amount of mass has to exit the tube, but it would have to do so at a lower velocity (of course its pressure would increase to keep the mass flow constant) the key in the problem is that the turbine isn't drawing any power until you plug the tv into it, so the water doesn't lose any energy into it (at the point where you say the amount of water exiting the turbine has the same velocity and flow rate as the water entering). But then you plug in your TV and that starts drawing juice, so the water slows down a bit.

freedom fries weren't mandatory though

yeah and even in the event of a massive collapse in infrastructure and population its not that hard to make your own power. just take the starting motor out of a car and hook it up to a windmill, that could give you up to 12 hp or ~8400 watts. more than enough to run a computer and power a few lights. could even run the microwave and the stove off of that. I expect that even in the event of a catastrophic population collapse (95% of population dies off) that humans would be back up to our full capacity within a millenia

http://news.yahoo.com/s/ap/20060729/ap_on_re_mi_ea/iran_foreign_words The Iranian President issued a decree today banning foreign words that have crept into the language, among the 2000 words to be replaced pizza is being replaced with "elastic loaves". Apparently they are less sensitive to arabic words that have moved into the language as the koran is written in arabic. now if it isn't fascism when the government tries to control what words you can use I don't know what is.

allso its alot easier to remember and apply 100 different equations than it is to remember and apply 1 massive equation thats a composite of 100 equations. the key is that every memory has to have a purpose or you'll forget it very quickly.

While I agree that the current interpretation of islam is violent etc. its important to remember that there is a difference between the religion and the current interpretation of it. Like Walrusman said the Christianity had its slaughterfest during the middle ages, and then it stabalised and became "relatively" peaceful in the modern era (at least I'm sure none of us would call it a violent religion now). I'm sure that over the course of several hundred years and maybe a profit (or massive secularization) it will stabilize. I also think we need a new term other than islamofascism, I would be hesitant to seperate the two words entirely and just call it fascism because the regions fascist movements are based on islam to a large extent, with the leaders often creating a cult of personalaty proclaiming them as holy men. But islamo fascism has the ring of Fox news and shameless rhetoric.

Mowgli GR simplifies to SR in flat space. you just said that an earth observer's time is dilated with respewct to the sattelite observer, how can you possibly say that time dilation doesn't exist? not to mention all the oher results that you supplied on your own, which all say the same thing

hey gcol do you knokw where I could find the full version of that story, I'm interested in seeing the rest of it. I think that we have seen enough government's that have tried to put an end to hardship to know that it leads to a less productive, less motivated and less happy country. look at the USSR and the USA during the cold war. The USSR's GNP essentially stayed the same during the course of the cold war while the USA's increased dramatically eventually allowing president Reagan to invest far more money in the military than the Soviet Union could and thus leading to the end of the cold war. many writer's when talking about the soviet economy have mentioned the lack of motivation that faced the Soviet work force. essentially the cold war proved that a capatalist society where someone is allowed to sink or swim results in a far more productive work force. and personally I like knowing that my future is in my own hands and mine alone

mowgli the gps sattelites run their clocks something like 39 nanoseconds/ day faster than normal in order to have their clocks be in aggreement with earth clocks. if they didn't do this the gps reading would shift by several kilometers each day. ^note they run faster do to the combined effects of SR and GR (they experience less gravity) experiments have also been done where one plane flys an atomic clock at high speed for a few days and then compares their clock reading to a stationary clock (they measure a discrepancy that is exactly what SR predicts it should be) also if you refuse time dilation then things like gravitational lensing wouldn't occur anymore (these effects have been observed) do some research into the subject before you denounce it mowgli