Ceedee

This intrigued me from a forum I was reading A poster presented a screenshot with the following title "Mister, your time has gone." (Yes, he does mean that in past tense...) The following post seems to challenge this as follows.. "Strictly speaking, it's not a past tense: you couldn't say: "Yesterday, your time has gone" - it would be "your time had gone" Gone is the past form of to go but has is in the present tense. It's the same as when you say I have been playing tennis for two hours: it's the present. Right now you have been playing for 2 hours, if you see what I mean" Is this correct in terms of tense etc. i lack the nescessary skills in this area yet it seems to me that the first post could be correct when referring to time. Also can has and gone not be used in other tenses for example.. "when he has gone i will let you know" Looking for a simple answer here as i am not very clued up on this area.

http://www.theregister.co.uk/2006/02/23/quantum_computing/ it solved a problem without actually running i dont get it

excellent link tormod thank you. thats one of the few articles i have read that doesnt gloss over these unknowns and rather accepts and acknowledges that theres a lot of guesswork and estimates going on. These type of texts are what i like as they present a truer picture of what we know / dont know rather than claiming its all fact. This in turn prevents layman such as i from assuming we know more than we actually do, and ,in pointing out the "guesses" ,lets me decide for myself what validity this information can have when taken further down the line. i look forward to finding more articles such as that one.

"We can observe a remote galaxy well enough to make a pretty good estimation of the total number, mass, distribution, and motion of its stars. We can observe multiple galaxies with similar properties at different distances, showing us what similar galaxies look like at different times" This is where my problem arises. Can we extrapolate like this when as far as i can gather those basic facts are best guesses and not facts. We dont even know how our own galaxy works let alone another. We base mass on guestimates derived from luminosities and suchlike which are far from being facts. I understand that we have to pick something to work from but as i have said before we tend to extrapolate from these guesses to incredible extremes and then pronounce that we understand matters that we really dont. or maybe im missing something.

I am left wondering what validity any simiulation can have if it is based upon the same fudged data as we base everything else on. I assume logically that the simulation can not know more than we do ( it can only work it out quicker ) and as such it must be fed the same unknowns. Why are we surprised when simulation develops into something like what we see when it couldnt really develop into anything else. i do understand that the simulations are great and should we actually get real data to feed into them would be a marvelous tool.

Thanks DoctorDick for a very useful reply. I will take on board what you have said although i smiled when you assumed i was young. i am 42 years old. no science background but very curious since i was a child. interested and active in astronomy from a young age but never progressed beyond simple observing etc. i have followed astronomical and cosmological developements tho for over 30 years but could never claim to understand most of it but i try hard. i do i confess glean a fair amount of what i "know" from layman materials or things written with the layman in mind. books like stephen hawkins brief histories and bill brysons short history of everything etc. serious texts tend to lose me and as such i struggle. i have an 8 year old son whose mission in life seems to be to disturb me whenever i pick up a book or try to think about anything :lol: good point made about being too concerned with conclusions. will have to think on that for a bit. maybe i am uneasy about things that dont actually matter all that much. that is an angle i hadn't considered. sorry about the real life statement :) i think you knew what i meant though. will read your paper although on reading some of your other posts i believe it will be way over my head but im not ashamed to say it or to have a try... (edit because i re re read the post as i should have before i posted..) your remark about the klingons sort of slipped by me when i first answered but has just dawned on me. this is the kind of mistake i try so hard not to make but it makes me look like i dont think. the subtle difference between them saying dark matter "but we dont know what it is" (fudge) and me saying i know what it is, its klingons ( which i dont know at all), is such a good point. just thought i need to post a qualification there while i think more on how to post properly.

I appreciate your reply and will take some points on board. I am quite new to this and i apologise if i make what seems to be rash posts. I am not new to science but I am new to actually trying to put my thoughts down in writing in a way that makes sense. I will try harder to not make silly errors. I can not put my finger on any specific text that has caused me to feel this way and that as the main thrust of my initial post. I was reading a few things and watching a few documentaries where they where discussing big bang and m theory etc and felt a little out of my depth. So i worked backwards a bit and started to read between the lines and it was as if i suddenly noticed all these areas where fudge factors had been added to bolster theories. I then thought lets see how far back down the scale they go and traced back finding that most if not all theories and things i had assumed where solved where actually far from it. I'm not tryin to tear holes in things its just an uneasy feeling that i thought i would share in case it was just me that was feeling it. No offense taken. there is no room for offense in science i think. My point on the distance issue was the scale of the uncertainty. I accept that these are hard things to measure i just question the logic of basing huge designs on innaccurate data. Its hard for me to explain, but this one point is a major sticking point for me. if we dont actually know the distance to the nearest star say. how can we have faith in any measurements using that distance as a basis to infer from. Its like sayin 2 & 2 is 4, from that we can say 4 & 2 is 6 and from that we say 6 & 6 is 12 but then when we have gone on and on someone says oh by the way 2 isnt really 2 its between 1.5 and 4. I know its not the same thing exactly im just tryin to make an analogy to explain my gut feeling. I apologise for the galaxy and gravity mistake my error. What i meant to say was that galaxies do not behave as a solar system does. the outer edges of the galxies in question rotate at the same speed as the inner edges not faster. but this is strange because gravity weakens over distance so why dont the outer edges just fly off into space. The source for this was a documentary called horizon in which a woman discocvered this anomaly. i think it was called most of our universe is missing but i may be wrong. i agree cornerstone was a bad choice of words. I dont expect science to have all the answers. i do however expect science to be accurate with the answers it chooses to reveal. all my life i have it seems been under a mistaken idea that science was aa way of explaining what we observe in a manner that can be proven or at minimum be plausible by that i mean not easily disproven. an example of what i mean is in the missing mass debate. if i understand it correctly the latest news is that the universe is not only expanding but this is accellerating. This has led to fudge of grotesque proportions ie dark matter and dark energy. yes these 2 items fit the bill and let us explain it but my uneasiness raises its ugly head once more. would i be correct if i made an opposing theory which says the 20% or so dark matter and the 70% dark energy dont actually exist. the missing mass is actually billions of klingons in cloaked war birds. sorry for the inane analogy but is not one theory as good as any other in this respect.in fact a better analogy could be no dark matter or dark energy instead there is 90% invisble fudge. This theory is actually better than the dark energy / matter theory by virtue of occams razor and as such should it not be adopted. a clumsy way to make a point i know but has it any validity. totally aggree on your last points. i didnt mean to sound pessimistic rather was trying to appear cautionary. i am very excited about science still and now that i have discovered this forum i look forward to it even more as to be honest i dont get to discuss things like this in real life.

Thank you for the replies and all are valid points. I agree that it is nescessary to thoerise and build on possibly unsound facts in order to see where it takes us, this is human nature, however my concern is just how far these theories have progressed. they seem to me to have left the realms of science and wandered into the realm of hyperbole. Whilst there is nothing intrinsically wrong with this it appears that so much time and resources are being invested in these areas and the basic building blocks are mostly ignored with little time or energy devoted to them. The basic blocks i refer to are many and i will take the advice and research them in this forum, which i had overlooked to my shame. A few that spring to mind in the interim are as follows. Practically all cosmology theories i have looked into are based upon the fact that we know how big, how old, how far way everything is. Eg precise figures are given for distance to the nearest star, how bright it is and the same with galaxies etc. From this we extrapolate to the further stars and galaxies etc. My recent reading has led me to discover that far from being exact figures they are hazy. They say star X is 1.45 lightyears away when in reality the figure is given as between 0.8 and 2.6 light years. Thats a lot of fudge. once extrapolated it can go off the chart. ( this is purely for illustrative purposes and star X bears no resemblance to any star) Another is gravity. I know we dont understand gravity at all but if you listen to these theories it would appear that they think they do. I was convinced we had worked out gravity already barring the little things, but to my surprise i discovered that we dont even understand the big things. What led me to this was that gravity predictions all fit nicely in our solar system. The planets are where they should be, rotate around the sun at the speeds they should do and have corresponding masses that all fit neatly into how gravity should work. However recent discoveries suggest that something is very wrong with this view. galaxies dont follow this gravity. They rotate as if it where a solid entity with the outside edges of the galaxy going as fast as the inside. Another is redshift the cornerstone of cosmology. Everything more or less has been extrapolated from redshifts. But now serious misgivings are being raised about them and what causes the redshift.If infact some other mechanism is at work and it isnt purely a function of velocity that turns our whole universe map on its head. Basically then my concerns are that we should be devoting more effort towards these fundamental yardsticks that we use to measure our universe because without confidence in those what use are grand theories. I read that according to the latest information and theories we are now left with a situation where we have stars and galaxies in the universe that are older than the universe is itself. Science has lost its way a little and neads to do a bit more basic spadework instead of building theories which more rightly belong in a sci-fi film or novel. I will post back again after thoroughly reading through this forum and apologise if this ground has already been covered.

The more I learn the more i realise how much i don't know. Granted I haven't begun yet to explore the depths but I am stumbling at an early stage which disheartens me somewhat. From what i have gleaned so far, it seems to me that cosmology is putting the cart firmly before the horse and in fact is putting it so far in front that the poor horse has lost sight of the cart altogether. When i started gettin interested in cosmology I was impressed at first with how much we knew. So many people saying great things like we are close to the answer of everything ,unified theories etc etc. I was intrigued and dug deeper. Alas I had been hoodwinked. I started at the top, maybe a mistake, string theory, M theory etc wow. were we really that close and then reality check. Big holes everywhere and fudge factors bouying up all these nice theories. So i started to work my way back. Rolling back the theories one after another finding more fudge than a chocolatier could imagine until i finally eneded up back at the start. All these great ideas and theories masquerading to the layman as "facts" where in fact nothing of the kind. All these things based on other things taken for granted but not nescessarily understood or prooved in any way. "is this really science ?" I asked myself. I am now stuck in a hole and need some old fashoned kicking in the pants to re awaken my interest which i hope someone here can provide. I have waffled abit here and i apologise for that, but in a nutshell my main concern is this. Whilst i understand the need for theory and wild hypothesis, is it only me that is worried that we too easily jump to the next question without actually prooving the former. Most cosmology theories I have read seem to take for granted that we know certain things which we dont. Simple basic building blocks. For example. A lot of thoery is based on red shifts and standard star candles and such. What i have read so far tells me that these standard candles are by no means standard. We don't for sure know how bright they are or how far. These simple things are used to build huge theories on and yet these basic things are actually just guesses. How can anyone take seriously a theory as grand as M theory ( just one theory of many anyone of which will suffice ) when if you extrapolate back to its basic basic roots comes up with distances to stars and galaxies and such which are just guesses. I think the brakes must be applied so that the horse can catch up with the cart then maybe something meaningful might appear. Sorry for rambling a bit and if you bothered to read all this please dont judge me harshly. I in no way intend this to be a dig at anything.

I stumbled across this forum whilst looking up some answers to what i thought were "simple" questions for my 9 year old son. It was only when he started to question some of less than accurate answers i have given him that i realised how little i understand about most things. They are the usual suspects i suspect all parents encounter such as "why is the sky blue daddy?" , "Why doesnt the moon fly away or fall on us daddy" , "why does toast always fall jam(jelly) side down?" etc etc. Unfortunately for me or fortunately I am not sure which, I realised that my usual answers of "because it is" "because it doesnt" etc (these where kinda accepted in earlier years) suddenly wouldn't work anymore. Thus I decided to learn something, at least a small bit, in order to either answer his questions or point him to more knowledgable sources. However i became "hooked" and now i have a string of why does questions of my own as well as his. Scanning thru this forum shows me that there are people here on a completely different level then I, some posts making little or no sense to me, yet that somehow spurs me on to learn more. So thats a non to brief reason for me being here. A little about me I suppose well Im not uninversity educated, just a "normal" working guy. Im 42 years old and still want to learn something new and i look forward to doing just that if you will forgive any occasional layman posts I may make whilst on the way to a greater understanding of things and especially answering the toast question :cup: