When writing the Principia Mathematica, Isaac Newton declared his hand on most of the big questions in physics. He outlined the nature of space, explained the motions of the planets and conceived the operation of gravity. He also laid down the law on time declaring:
“Absolute, true, and mathematical time, of itself and from its own nature, flows equably without relation to anything external.”
For Newton time was absolute and set apart from the universe, but with the theories of Albert Einstein time became more complicated; it could be squeezed and distorted and was different in different places.
Time is integral to our experience of things but we find it very difficult to think about. It may not even exist and yet seems written into the existence of absolutely everything.
Contributors
Jim Al-Khalili, Professor of Theoretical Physics and Chair in the Public Engagement in Science at the University of Surrey
Monica Grady, Professor of Planetary and Space Sciences at the Open University
Ian Stewart, Professor of Mathematics at the University of Warwick
Audience reactions to this edition
The Physics of Time | M. A. Cherian
It has never been shown and there is no entity time to dilate any more than there are temperature, pressure, volume, height, weight as entities, which dilate. Any well-defined succession is a version of number and also a measure of time ii) It is self-contradictory to claim experimental evidence of time dilation (and hence time as an object or entity) based on the assumption of an absolute (c) or a constant speed of light, in 'empty space' or vacuum. Time dilation if it occurred makes the absolute or constant speed, the very basis of its derivation, a variable. Definitive experiments have to continuously monitor ‘c’ and the justification of the reified ‘second’ as a prefixed multiple of the period of the caesium oscillator. iii) An absolute value does not emerge as the ratio of two unequal real [infinite decimal] numbers, as measures of two heuristic concepts space and time, which are forms of sensibility to Kant. iv) Without an absolute time as an entity there cannot be relative times as entities. v) There is no absolute measured or measurable value with units of measurements attached. vi) Light as a form of energy has mass and is subject to gravitation. This is recognised in the equation e=mc^2. Thus gravitation, which affects the speed of light, should not be ignored, as is the practice, in the Special Theory. vii) There is no need in experimental science for the speed of light to be an absolute, only to be taken contextually as a constant and/or a limiting value. viii) Light travels at its assumed absolute speed only in the assumed ‘empty-space’. ‘If all bodies were destroyed and brought to nothing, what is left is absolute space. All its attributes are private and negative, mere nothing except its extension. In empty space extension too is mere nothing’, Berkeley. A vacuum is no firewall against macro- and micro-gravitation. ix) The alleged experiment to measure time dilation does no such thing, only shows the effect of acceleration (gravitational and others) on light. In ten-millionths of a second, light travels 3km at its nominal speed of 3x10^8 m/s. A few thousand orders of magnitude difference between the speed of light at which the elementary particles travel, and their velocity recordings absorbs the slack in their experimental measurements. x) It is theory which determines what is observed in experiments. Theories come with prior assumptions, they make assumptions, they assume their conclusions. xii) Cause-effect is not a logical (non-attributed) relation to make time the physical stuffing between them To Madhyamika Buddhists if effect is dependent on, continuous from, or necessarily (logically) follows from cause nothing new has come into being for lack of self-identity. If effect is different from cause, anything can produce anything. To Hume causality is synthetic not analytic, to Kant a necessary attribution of the mind.xiii) Einstein realised at the end of his life, “Considered logically, space, time and events are free creations of the human intelligence, tools of thought…’. This makes all theories involving space, time, events, e.g. relativity and string theories, and attempts to combine them open-ended, and accounts for the surprising results of quantum mechanics. xiii) Once the engineering has been got right the CERN LHC would confirm that there is no knowledge beyond interpretations of phenomena. xv). Science, religion and other philosophies are our ways of looking at phenomena. There is nothing unique or sacrosanct about any of them or our conclusions. xvi) "Not only science cannot teach us the nature of things; but nothing is capable of teaching it to us, and if any god knew he would not find words to express it". Poincaré. “At the basis of the whole modern view of the world lies the illusion that the so-called laws of nature are the explanations of natural phenomena”, Wittgenstein."...‘Nature’s conformity to law’, of which you physicists talk so proudly, ...why it exists only owing to your interpretation and bad ‘philology’”, Nietzsche. "... whether a being that was merely the result of natural
Matthew, re: The Physics of Time
Dear IOT,Whenever physicists talk about gravity on science programs, they use the Rubber Sheet Analogy. You know, pretend space-time is a rubber sheet, drop a big mass in the middle, space-time warps. I suppose I get it, but if I put a bowling ball on a rubber sheet, the sheet warps because of gravity. Marbles on the sheet go toward the bowling ball because of gravity, not because the sheet is warped. Without gravity, what makes the rubber sheet bend when the big mass is placed in the middle? And once space time is warped, what makes one body follow the warp toward another?
Peter S - The Physics of Time
This subject is very hard to summarise in 40 minutes but, as always, IOT makes a very good and worthy attempt within these restrictions. Although specialists may rightfully criticise the “dumbing-down” of the subject matter, I think that IOT are very correct to try to bring the subject into the listener’s ream of understanding and perception. More than any other, this particular subject forces a wedge between theory and everyday experience. It is great to hear again some of the models that are used to help us understand the theory such as the taught sheet of curved space-time. Although this model is an over-simplification in terms of the number of dimensions involved, it nonetheless serves a useful purpose. I am sure that IOT can uncover other useful models to help us mere mortals understand other difficult concepts in Physics.I would also like to see IOT extend it’s attempt to deal with the difficulties of putting human experience alongside the proposition that all of time (past and future) is pre-defined. And along with that the assertion that the arrow of time (and therefore our experience of it) is tied to the laws of thermodynamics.Lastly, I would like to see this discussion on the subject of time extended into the context of gravitation and the general theory of relativity (unless I have overlooked a previous programme).Thanks IOT.. Keep up the good work.Regards, Peter.
Francis Lloyd
I would have enjoyed a discussion on concepts such as Planck time, for example is time 'granular'?
Daniel F - The Physics of Time
Extremely interesting, however the 'boiling an egg' example of time moving forward is not a good one. The reason for this is that whether it is instantaneous or takes 2 years to boil an egg is immaterial. The important thing is the irreversible thermodynamic process associated with boiling an egg which is time independent, or if you like you could still boil an egg if time were reversed.
Joseph - TIme
It's "Lorentz Transformation" not "Lorentz Transform" but no worries.The Lorentz Transformation is brilliant visually and mathematically.However, the equation does not cover the full spectrum of fascinating historical developments, or mainstream scientific studies, or philosophical concepts surrounding the questions of how, what, why, and where is time.This is have your say, not the Journal Nature.I think there are some very interesting insights, both philosophical and scientific written here. Very interesting reading and the show was outstanding!Time Part Two Please. Merry Christmas!
Mike A - The Physics of Time
On the question of 'why base 60', presumably part of the answer is because it factorises nicely. You can easily divide it by 2, 3, 4, 5, 6, 10, 15, 20, 30. Base 10 is nowhere near so flexible. "I'll be there in 0.3333 recurring hours" is not quite so handy as "I'll be there in 20 minutes". Such things were important before calculators came along!
Mike A - The Physics of Time
Good effort at introducing some key questions, but sadly not enough time to dig very deep. For once on IOT I didn't really learn much I didn't already know. One problem is that it's virtually impossible to explain relativity without a diagram or two - if you can't picture the beautiful way the Lorentz transform distorts spacetime to allow motion whilst maintaining C then you'll never really understand even Special Relativity, let alone its bigger brother.Unsurprisingly there are a few posters on here with their own pet theories - none of which appears to have a shred of evidence behind it, or lead to any testable hypotheses, and therefore absolutely nothing to do with science whatsoever.
bill stewart Time.
Enjoyed the discussion and I find it most difficult to put a definition on time and the conception of it in a nutshell.However I find myself drawn more to the philosophical aspect of it.As humans we have found the need through our labours as a species to record events experienced,therefore the concept of time as a measurement came about.Perhaps as a Marxist this view comes to the fore....I think it would take quite a few similar programmes however to discuss the ongoing passage of HUMAN time linked to that of the universe its contents and their journey.
The physics of Time
For a rejection of the claim that astronomical data supports the thesis that the universe is explanding, look up Halton Arp, for his anomalous redshift. There is, online, also, Tom Van Flandern's Top 30 Problems with the Big Bang. For a definitive refutation of relativity, google Guy Burniston Brown's classic article What is Wrong with Relativity? (1967) and also check out the link there to the book by the late, great Prof. Herbert Dingle, Science at the Crossroads.
PHYSICS OF TIME
The skilled metrologist and inventor of the caesium clock, Louis Essen, recognised that if rate of atomic resonance (the basis of modern time measurement) changes, this is simply a change of units, not of the flow of time itself. Special relativity is replete with such logical errors; one that Essen points out is that Einstein starts off making a reference of 'clock B as viewed from A', then, at the end of a section, suddenly and without any reasoning ditches the 'as viewed from A' and continues with the derivation without making any further reference to it. Also, engineers working in cosmology have refuted such claims as that nothing can travel faster than light and that (when data is properly scrutinised) velocity causes time dilation. The SR logic is entirely circular in any case: velocity causes time dilation, but velocity is distance divided by time. The Newtonian state varibles of length and time are metaphysical - not toys for physicists to play with.
Time Roger D. Butters
The programme gave me to understand that the conception of a 'Block' universe arising out of Einstein's unification of Space and Time implies that action at any location and at any time was effectively (pre)ordained, fixed and unalterable. This conception of a static fixed state seems to rule out all change of any nature. In this case whst is the staus of Heisenberg's indetermincy principle ? For this to have significant meaning surely the possibility of change, even if unforecastable in detail, must remain conceiveable.
anna Time
Another analogy to show the illusion of time being linear.If your life is like a house--you enter by the front door and leave eventually by the back door.In the meantime you change from a baby to an old person,you change the furniture around,you knock walls down ,you live your Life in it.You change,you live,you die. The p oint is that the house always stays the same in the same place .There is no linear Time progression because there is no Time.Things simply change. It s a Western thing this obsession with progress ,getting from A to B,achieving a result--in the East,they are far more laid back with their religions and philosophies and Time is regarded in a completely different way especially the concept of it being circular rather than linear.I think we should train ourselves to think of things simply changing and that Time is a man made convenience to help us catch trains.
Peter Belcher - The Physics of Time
With regard to the question raised in the message by Michael Stewart, I would suggest that the Babylonians used base-60 as a division of 360 degrees because they might have perceived the orbit of the Earth as being a circle, and the rotation of the Earth being circular.
Peter Belcher - The Physics of Time
When the guest expert described the sun as being eight light-seconds away, I assume that she meant to say eight light-minutes.
anna Time
This is what I think about Time. For years now I have worked at de programming myself to think of Time as an ever rolling stream flowing forever onwards and bearing all it s sons away. It s hard work but really worth it when finally achieved as it gives one such a new sense of freedom of thought.I think that the only reason that Time is considered to be linear(or even to exist) is that a false conclusion has been universally accepted for hundreds of years whereby organic decay is seen as proof of Time passing.Why so ? Why should the fact that a new born baby or a newly sprouted acorn by simply growing bigger and then dryer,more crumbly and finally returning to the earth--why should that imply Time passing?It s simply organic change happening ,that s all.We ve been conditioned very hard to think of it as a linear process of decay.Everything in the universe is cyclical including clocks,the Earth,the orbit of the planets etc.We know the Life cycle of plants is cyclical and many religions believe the same applies to Humans.A straight line does not exist in Nature so why assume that Time is an exception to the rule? If you think of Time as being more like a lake than a stream ,then it s easier to see.In this way there is no Future.We are not driving along a road from point A to point B.There is no road.When you understand that there is no Future to worry about because it doesn t exist, then this gives one far more freedom to concentrate on the Now which is all there is, really ,from a practical point of view,Some of our Speakers were implying that Quantum Physics seems to support this view. In any discussion on Time,it seems to me that whatever is said nevertheless everyone is still thinking of linear Time presumably because this is the easiest way in which we can make it manageable to the human mind --hence the endless analogies to it with rivers,roads,lines,threads etc etc. It need not be like this!So once the yoke of the idea of linear Time has been thrown off--the possibilities are endless and will be discovered by anyone who wants to try it. Things change ( re Entropy) but that s all it is --change not a progression.The egg is boiled from soft to hard--that s all that happens..why should it be a problem that it cannot be reversed? Even that implies a progession along a line. Again,it s just change neither going forward or backwards.The seed sprouts and grows and dies i e it goes through a process of change which is not a linear one just a simple alteration of state. I really enjoy these times with Melvyn and friends and hope they continue for a long time to come...oops !!
Michael Moore, Time
Time is an illusion, an event horizon or our perception of change. There will never be a Doctor Who to travel through time because there is nothing to travel through. It is our concept not reality's.
Giles: More rigour less blather
I was really looking forward to the physics of time programme, but thought it was let down by some of the contributions.I know it's hard to keep a panel discussion coherent, but I did feel that the contributors and presenter tied themselves in knots, labouring over things that should have been dismissed very quickly such as the difference between time and clocks and the difference between actual time distortion and psychological time distortion.These points are about the psychology of time, not the physics of time.But these issues, along with Newtonian time (common sense but wrong), soaked up a lot of the programme.There were some really interesting areas for discussion we glossed over or ignored. In particular the nature of space-time and the fact that some physicists think time may not exist.Those are big, mind-blowing ideas and they're what makes science wonderful. Whereas meandering, woolly discussion is what makes science seem complicated.
Charlie
A truly fascinating discussion. I cannot pretend to have understood much od the subject but fascinating! Towards the end of the programme, one of the participants said words to the effect (assuming I understood correctly) that at the sub-atomic level, time did not appear to exist, instead it "appeared" at "larger" structural levels.Is it therefor correct to draw a conclusion that Time exerts its' influence over "large" distances, similar, in some respects, to Gravity?
Kim S: TIME
Very much enjoyed the programme. Especially intrigued by Ian Stewart's analogy between a pencil curve and a life being lived. Couple of thoughts overall: that time can only exist where there is change. Even colloquially, if we describe a setting as timeless, we imply that nothing ever happens there.The other thought was about trying to imagine four dimensions. I remember Carl Sagan's series Cosmos back in the 1970's where he made a very good attempt to help the audience visualise this, but in the end, it is something that we can't really do. Our brains are not equipped to imagine in more than three dimensions. That's where the maths comes in handy.
Alan Stone:Space/time
John Donne wrote in 1624;"No man is an Island, entire of itself; every man is a piece of the Continent, a part of the main;....any man's death diminishes me, because I am involved in Mankind;And therefore never send to know for whom the bell tolls; it tolls for thee."This famous passage fore-echoes Einstein's concept of space/time; Donne views humanity as connected in a medium in which every entity (persons) are linked; in a similar way all bodies with mass are linked by the medium of Einstein's space/time. A case of time-thought catching up with itself?
John Courtneidge - The Physics of Time*
Excellent, as usual - and nice to have the IOT e-news letters back again.Two thoughts:1) if time is hard for us to get our heads around (agreed - think about the confusion over 'changing the clocks' twice-yearly, to say nothing of phoning over different time zones), then two other topics - truth and money - are, at least, equally mind-scrambling. So, 'truth' and 'money' would make good programmes (example questions: 'does truth precede the start of the universe?', and 'how comes there's no money when we need it to alleviate/eradicate poverty, but there's always an abundance - miraculously?! - when a war is declared or banks have to be 'recapitalized'?', and 'what's the relationships between money, truth and time?')2) A pity that no chemists were on the panel - as an example, 'boiling' an egg is an example of a (non-reversible) chemical change - a chemical reality, barely understood by physicsts: whereas boiling the water is a physical (reversible) change at an initial level, but, when considered more deeply (at the level of bond-breaking), is another chemical reality . If only someone were at the table who could explain the concept and applicability of systems and Gibbs' Free Energy (a well-taught part of sixth-form chemistry courses). Keep up this good work! Best wishes to all for the new year (pun appreciated!)*ps These border interactions are enlightening!
The Physics ofTime - Gareth's question
Gareth was confused by talk of the finite speed of light shown in the few hundred years for us to see some supernova. That's 'special relativity'.Time and space are mixed in General Relativity via _accelerated_ motions. Monika Grady said we need a frame of reference (got chopped off)which is the big clue. The inertial frame of reference (harmonic coordinates of Fock) has to be chosen for a consistent formulation of gravitational waves, which points to advances on Einstein.Max Wallis, Cardiff University.
Time
Time is in the first place our imagination of our day. The sun and earth determine the cycle that propogates growth,food and our and other beings basic need for food,warmth,coldness etc. We then imagine all around us with our senses,including a sense of past, present and future. In my opinion we are just now, nothing more or less! But if there "are" in the sense of physics things outside of our senses,such as radio waves, why could there also not be "things" outside of our "now". I have been wondering why should there not be a "god" or "gods", follow that path for a while, trying to not think you are being illogical! People say that they are guided by something outside of themselves, maybe there is another mobile phone company transmitting on a frequency we do not acknowledge, because it could be illogical,is that a good enough reason not to consider the theory.
Max Wallis Nature of Time - what shoddy science!
Einstein's description of (light) cones of influence solves the problem of the future not being determinate, that Al-Khalili struggled with. As you move forward, influences from wider past parts of the cone reach you. You also send out signals in the forward cone - this cannot be reversed.The Laws of Physics have to be formulated to cover this - and they can be. The integral formulation (retarded potentials)does it for Maxwell's electromagnetic fields, something similar is need for gravitational fields.Gravitational fields fill space - we don't need a distorted space metric to explain action-at-a-distance. And changes are not "instantaneous" (Grady)but travel at the speed of gravitational waves (ie. speed of light).Einstein did get mixed up, in pressing the analogy of G-field equivalent to geometry change too far. He did believe in gravitational waves and psat/future light cones, so the programme did him a great disservice.Max WallisCardiff University
jenny Hayford
i THINK THAT TIME ISA DIMENSION LIKE YOU SAY BUT I ALSO THINK THAT mIND IS A DIMENSION, PERHAPS THE FIRST DIMENSION WHERE EVERYTHING REGISTERS... tHE CONSCIOUSNESS IF YOU LIKE OF HUMAN BEINGS.tHE PHYSICAL REALITY CAN THEN BE PERCEIVED - EVOLUTION, SPACE, TIME, UNIVERSE
Jim Conner: Time
I am a layman but like many people have pondered the concept of time.My theory of time is that it is a concept created my humans to 'chronotize' (my word) change.I believe that there is only the present. We only have memories and records of the past and expectations for the future.We have developed an illusionary concept of the passage of "time" to explain what is really happen which is the passage of change.If there is no change at the quantum level then "time" has not passed. We even say in conversation, "Time has stood still" as an idiom for situations where it appears 'nothing has changed.'My theory is totally consistent with everything that was said on the programme. It is also consistent with Einstein’s theory of relativity because according to my theory, time is also relative to each and every thing. Take another idiom, we say that a person "hasn't aged" when we refer to a person who, by appearance, 'hasn't changed' appearance relative to a comparative like group.How about another idiom, "Frozen in time" used to express our perception that something hasn't 'changed.' Our language is replete with examples of humans intellectually connecting "time" and "change." No wonder!
babylon numbers
Your correspondent is correct, 60 and twelve derive from having two hands with eight fingers and two thumbs. Sixty is the most that Babylonians could count on their hands as follows, (sorry but it is tedious to explain but easier to demonstrate)Step 1: Little finger of left hand raised counts as ONEStep 2: Little finger of left hand raised plus next finger counts TWOStep 3: Three fingers of left hand raised counts THREEStep 4: Four fingers of left hand raised counts FOUR.Step 5: Four fingers and thumb of left hand raised counts FIVEStep 6: Close left hand and raise little finger of right hand. This counts SIXStep 7: With little finger of right hand still raised, raise litle finger of left hand. This counts SEVENStep 8: Keeping little finger of right hand raised raise two fingers of left hand. This counts EIGHT.Steps 9,10,11: Continue raising left hand fingers till all are raised giving you ELEVEN.Step 12: Close left hand and raise a second finger on right hand. This counts TWELVE.If you now get the picture, you will eventually arrive at THIRTY that is left hand closed and all digits of right hand raised.If you now change hands and start again from thirty you will arrive at SIXTY.This is the origin of the duodecimal system as taught to me at school fifty years ago. That is, ten digit hands give you a duodecimal system
Justin Ions - a poor discussion
I'm sorry to have to say this, as a regular listener to 'In our time', but this was probably the most hopeless discussion I have heard during all of the years that I have been listening to the programme. 'Time' is philosophically problematic as a concept, and although Bragg made some efforts to problematise the concept (albiet far too politely) the experts were obviously tied into a conventional scientific attitude to understanding time, be it relative or absolute. There really was some need for a serious philosopher on the panel.
Steve
Another fascinating glimpse of the underlying reality of existence.From what we know there is no universal measurement of a unit of time. We do know that time as measured by atomic oscillations slows into a stronger gravitational field and speeds up into a weaker one, and while we can calculate this we do not know how it occurs.And since every mechanism we have devised to measure time distorts the fabric of spacetime with its 'mass energy', we will never be able to measure the absolute passing of time, what we will measure will be very slightly slower.Presumably though there is a calculation that can be made to determine what the relationship is between our second and the absolute, universal second.Of course, not knowing what constitutes a second means that the statement that the speed of light is constant is more a statement of belief than a universally demonstrable fact and has lead to the necessity that rulers shrink with slowing time to maintain the constancy of light. We also do not know how these rulers shrink, just that they must.I am hoping someone with Einstein's imagination comes along soon to give us a clearer insight as to how gravitational fields affect the passage of time, and how the knots of energy that we recognise as particles distort spacetime to create gravitational fields.
Andy Liggins, Peterborough
What a fantastic programme. I recorded it, cut it up into pieces and then listened to them in a random order but I think I preferred the chronological way you approached the topic... :)
Frank - Time.
I have been pondering over some of the facts put forward during the program. I checked on the podcast and here is what I found. The speed of light finite. The present age of the Universe is some 13.7 billion years. The Universe is expanding at an accelerating rate. In the past all matter in the Universe was closer together than it is now. When we look at a distant galaxy to measure its distance from us, we are looking at it in a position that it occupied at some time in the past due to the travel time of light. The example given in the program was the eight or so minutes the light from the sun takes to reach us. So if by some strange happenstance the Universe were to switch-off now we would know the sun had gone out eight minutes later. It would take another four years for our nearest star to go out, and another 75,000 years for the most distant stars in our Milky Way galaxy to blink out. 78,000 years later the light from the Large Magellanic Cloud would start to go. In this extreme example, the Universe would, for those of us still around to see it, switch off in 13.7 billion years. Extrapolation from the information put forward by the guest speakers we find the further back in time the images of the galaxies were generated, the closer the galaxies were to us and each other. This means the past distance beween galaxies is always shorter than the distance indicated by the look back time. It follows that at the time everything was closer together the light from even the most distant protogalaxies would have only taken a few years to reach the portion of space we occupy. My problem is this. Why are we still seeing light from gallaxies and quasars that should have come and gone at least 13.4 billion years ago?
peter holland time
another excellent programmekeep covering these big science topics
Time
A timely quotation --Wisdom of THE GAUCHO MARTIN FIERRO(the Argentine epic poem by Jose Hernandez, 1878 -- part of the the traditional payada, a singing contest when two gauchos improvise and answer each other's chosen themes.) (Part II canto 30)"El Negro":If you can reply to this question consider that you've won.I can acknowledge the better man ... So answer me right awaywhen it was that God made Time,and why he divided it up.Martin Fierro:I'm going to tell youas far as my knowledge goes.Time is only the delayingof things that are to come –it never had a beginningnor will it ever end,because Time is a wheel,and another wheelis Eternity.And if man divides it uphe only does it, I guess,to know how much he's lived so far or how much he's got left to live.(Kate Kavanagh, translator)
The Concept of Time
Thanks for a fascinating programme. As a pure layman I have often wondered, when reading articles on what happened during the "first milliseconds of the Big Bang" or the "first 10 billion years of the formation of the universe", that there were no seconds, years or any measurement of time until man started dividing the revolutions of the Earth. Surely what is needed if we are to begin to answer question like "what is time?" or "how big is the universe" is a totally new perspective". If a man running one hundred metres filmed on a DVD could actually see the DVD at the same time, he might see that his run took up say 20cm of DVD track if it was near the centre of the DVD or maybe 60cm if the recording was nearer the outer rim the DVD. Taking this analogy further, if it were technically possible, the closer the recording of this run was to the centre of the disk it would take up almost no space at all. Maybe if we could separate ourselves from the goldfish bowl of our concept of time and space we would see that a so-called microsecond of "Big Bang" was the same as a million years appears from our present perspective. So the speed of light is constant? How do we know that the speed of light is not being measured against an ever increasing or decreasing standard which we call time? We have no way of know that if we could view all this from outside our limited perspective we might be able to see that the universe has an infinitely faster beginning than its end or vice versa or that the beginning and the end exist at the same time like the DVD, or that we have to forget our preconception that there is any such thing as beginning or ending. I could go on!Has anyone else been thinking along these lines or should I go see a doctor
Space time gravity
I liked the picture of space time being like a taut sheet which distorts, pulling inwards, when an object is in it, the heavier the object, the greater the 'gravity pull' produced. However, when I thought about it I realised that the 'sheet' is a 2D object, whereas space (and presumably space time) is 3D. I now find it hard to imagine an object distorting space which completely surrounds it. Also, surely the object would be weightless in a vacuum (if not a vacuum a dark matter 'soup'). Can anyone enlighten me?
Peter Jones: Further to the nature of time...
Prior to my retirement I worked as a picture framer. In my workshop I had anelectric clock with a large seconds hand which moved smoothly over the face ofthe clock, and not in jerks as is sometimes the case. In idle moments I discoveredthat by concentrating on the clock I could make the hand speed up or slow downwithin quite wide limits. Another observer looking at the clock would havedetected no change because the clock was in my consciousness and not his. The clock appearing in his consciousness would not be the same clock !"Doesn't time fly when you're enjoying yourself" has been oft repeated. When oneis enjoying oneself the mind is being subjected to many events - even thoughts are events. Since the creation of time is the mind's way of experiencing events, it follows that during moments of enjoyment, time will speed up. When one is bored events are few and far between and time will slow down.Time is a subjective phenomenon. Without consciousness it would not exist.
Ian H
The Big Bang is misleading. No one heard it. It was a big expansion. It has been suggested that God created us to witness this expansion.
Steven Time
Eric: Entropy was mentioned but perhaps it was omitted from the evening repeat.Perhaps we are talking about two different concepts confused in our minds by sharing the same word. Our impression of time is a function of the brain and has nothing to do with reality. The past lives as (unreliable and individual) memory; the future does not exist and the present lies at a point that is neither the one nor t'other. But if one tries to nail down the point at which the present occurs it is impossible.The other concept of time is mathematical and helps to describe our current understanding of the universe. It was quite revealing that, after Ian Stewart had described Einstein's theory where spacetime just is and that we are in any one place at any one time, Jim said that he did not believe we live in the determinist world that this would imply because he did not want to believe it!
Michael Stewart The sexagesimal base for Time
HelloI was disappointed that Melvyn did not get a satisfactory answer to his question about the number 60 as a basis for time calculation. If I am not very much mistaken I think the answer lies with the Sumerian/Babylonian gods. The sexagesimal system was a divine concept and was a 'gift' of the gods. Perhaps someone else could throw more light on this subject?mwstewart@hotmail.co.uk
Sonya Perry Time
Whatever happens, in language and in 'Nature' (life as we humans know it), happens through time - 'through' in the two senses of the word. It is contradictory to say we can conceive of 'nothing' happening. Even nothing 'noths'; that is, any report, perception, thought experiment or imagining of 'nothing happening' still involves an occupation of time by this non-event. And when it stops, then something happens. Therefore, 'to happen' means 'to occupy time'. So this causes us to ask: How did the Big Bang happen before time? (it did not simultaneously create time, because that invokes time = means 'at the same time'.. and anyway, it had to, let's say, 'work up to it'... in time.This shows there are many linguistic, semantic, conceptual, logical and phenomenological puzzles always remaining, in the analysis of time as 'an entity' within our ontology. We have to 'critique' what is said, analytically about it, even by physicists, because translating the maths of physics into linguistic explanation creates paradoxes, conceptual confusions. Direction, and images of linear 'arrow' of time is in our minds, in we could say our cognitive wiring. We have no choice but to think, and say, 'it goes in one direction'. But the concepts of 'going' and in our case 'ageing' (natural decay) are linked, in our thoughts of time.... So yes, more than any other physics, we needed to touch on entropy at least in the prog... Nevertheless, thank you Melvyn and Producers for taking this on. Food for further thought and progs we hope.
Jane - response
I've read some really excellent responses on the subject of time, each the product of a different consciousness, and will look up some more things as a result. I am not clairvoyant as such but I have an automatic knowledge which often presents me with 'the future'. I do not want it, it is deeply unsettling as I would prefer time to unfold in its familiar sequence. This knowledge, usually about others, comes instantly and unequivocally - not as pictures but as an absolute knowing, the exception being when I accurately foresaw my two children. This foreseeing, though visual, was still through my mind, not my eyes, but in space non the less, a little way from me. The word 'unequivocal' is paramount in the process - there is an inevitability present. I do think, commendable and engrossing as our intellects are, we are destined to see and interpret the universe "as we are and not as it is" to a very large degree. Can't remember where I heard the words "God is a verb" but I rather liked them. A dear, deceased friend of mine used to frequently quote the phrase "Oh how I wasted time and now doth time waste me" - bit gloomy but as James Baring said - probably the best thing to do with time is to use it....inimitably. Very best wishes and thanks not only to the IOT team but to all those who seize the opportunity to respond so interestingly.
Ian Harrison - In Our Time
Terrific subject, very well presented. But doesn't Bill Bryson hold the copyright to all this knowledge?
In our time
I enjoyed your program: In Our Time. Your three guests reflected well Einstein’s view of time, which will always be confusing, according to a new book (Problem’s with Einstein’s relativity). Einstein’s concepts are based on no propagation medium for the transmission of light. His General Relativity is a stoke of genius, but his Special Relativity is a misinterpretation of Lorentz’s Transform, which is based on a propagation medium. It appears the correct interpretation that removes the confusion, based on Lorentz, is as follows: 1) Time is a sequence of events (rate of happening), which can be measured with a clock. 2) Time is an observed effect, one has to experience (see) it, before it can be realised. 3) Time therefore depends on the transmission of light waves through its propagation medium. 4) The speed of events (rate of passage of time) therefore depends on the motion of the source and observer through the medium. 5) To predict time, the electromagnetic wave equation has to be solved based on Lorentz’s Transform and the propagation medium. Einstein never solved this equation, his interpretation of observations are not reliable - hence the confusion. 6) There are two types of time change: a) transient (regular wave dynamics) similar to water or sound waves. These determine that only visual time travel is possible, and only to the past, not the future. b) permanent (Lorentz time and space contraction) this is where a traveller returns home younger than his stay at home twin. But this is not time travel it’s just slowing time down. This new theory appears to account for all know observations without ambiguity or paradox.
Hiram Baddeley Time
Why hexadecimal? Because 60, though smaller than 100 has ten divisors compared with only 7 for 100, and is more convenient for sharing. So an hour divides into 60 first-order minutes and these into 60 second-order-minutes (seconds). Before watches seconds were timed musically or by pulse. Galileo timed pendulums and accelerating bodies using his pulse at the wrist. The friar Mersenne timed the speed of sound by chanting 'Benedicam Dominum' to make and time an echo from a distant wall. His result, equivalent to 320 metres per second was very close.www.HistoryofHumanPhysics.com
marcus
I would like to take up something that Jil said ie 'that when we look at stars we are seeing them 'as they were'and that we are looking into the past..If we see a supernovae of a star that is 1800 light years away can we conclude that this happened '1800 years ago' ? If it really happened '1800 years ago' an observer from that star, shortly before events occured that even an asbestos deck chair couldn't help him deal with,should have been seeing events on the earth in 1400 BC, although I suspect (without, frankly, being sure) that if we are seeing the supernova now the last things the observer saw on earth happened in 200AD from which he could conclude, following jil's reasoning and knowing that the earth is 1800 light years away that he was blowing up in 2000 ad earth time which is effectively when we see the supernova.Can we say that 'now' or 'in the future' people a long way away but with rather good telescopes 'are' or 'will' be taking photos of earth's dinosaurs?
Michael Jewess: TIME (18 DEC):SIGNIFICANCE OF 24
Your programme gave only the approximate significance of the day of 24 hours. The earth does not, as apparently stated a few times, rotate about its axis every 24 hours but every 23 hours and 56 minutes (to the nearest minute). 24 hours is the average time for the sun apparently to rotate about the earth as a result both of the axial rotation of the earth and of its orbital rotation about the sun. (Precisely expressed,24 hours is the average time between successive noons, a noon being defined as the time when the sun is at its highest.) The word "average" in this context is reflected in the "Mean" of "Greenwich Mean Time". The full mathematical description of the apparent movement of the sun in 1672 was due to the first Astronomer Royal, John Flamsteed. The "equation of time" which he derived is sometimes seen plotted out on the face of sundials.
Chris J Cooper; The Physics of Time
Yes! I agree with Monica Grady: a philosopher in the discussion group would have been interesting- in an already interesting program!As for poetry on time, how about Thoreau:"Time is but the stream I go a-fishing in. I drink at it; but while I drink I see the sandy bottom and detect how shallow it is. Its thin current slides away, but eternity remains. I would drink deeper; fish in the sky, whose bottom is pebbly with stars." And speaking of time, why not make the show a full hour long!
Colin: Time
As Ford Prefect put it "time is an illusion, lunchtime doubly so". Surely what we call space is the distance between units of matter in motion and what we call time is the name humanity has given to the MEASUREMENT it has devised to try to make sense of relative motion. I don't see a space/time continuum I see a motion/space continuum. No motion no space, no motion no time. For me time is a point of motion in the fragmented energy unit we call the universe. In Our Time makes for excellent education though Lord Bragg, thank you.
Nick Devine 'The Physics of Time'
Interesting program. I wonder also if, considering the multi-dimensions at the high energy state at the beginning of the universe and with the collapse of some those dimensions , those collapsed dimensions are in fact oscillating producing frozen states of existence that with the loss of parity between the states (governed by the laws of physics) zig-zag along (similar to time going back and forwards) giving this illusion of time. I realize to talk of oscillation and time being an illusion is somewhat of a none-sense. How does this grab you for an idea.
Eric - Time
Why was there no mention of entropy on the recent programme? Were the participants asked not to use it? It is the one entity which makes the direction of time significant.
Time
It's the earth's orbit through the the solar system space-time that generates our time. The rate is determined by our unique distance from our sun, I reckon. Good show, pretty stimulating, as usual. Thanks, Anthony Redman.
John; Time
Space,Time and Language are programmed into our genetics: they formapriori intuitions or groundplans in our living consciousness.All of us are programmed to die in 3score years and ten.To abstract time from the rhythm ofthat span is to take us away from theliving pulse of our own humanity.A philosopher or a poet will keep thisrhythm section or base line of ourthought going when astrophysicists havegutted its substance and thrown it tothe seven winds of string-theory.Toquote Shakespeare:-Now entertain conjecture of a timeWhen creeping murmur and the pouring darkFills the wide vessel of the universe.
Paulpic "another" time
It seems like the definitions of the constants 'aether' and 'time' have changed to 'gravity' and 'light'. But, isn't that sort of like changing the definition of 'beer' to 'alcohol'? Valid, but misses the broad point.
John A. Jewell -- Time and Space
Most interesting discussion on Time this morning. For us, time is surely measured by the movements of the sun and moon. Away from this planet by what standard is time to be measured. And who says there is anything such as time anywhere else anyway. Yes, stars as other suns give off light as a result of a nuclear reaction. But that is a process not subject to time. And if it was, then by what standard is one to measure it by. And if looking at several stars all engaged in their nuclear reactions whose standard of time will you use.This brings us to the question of space. Scientists do use the term The ends of the universe - this infers that there is a limit to the universe. If there is then who imposed the limit, and what lies beyond that limit. More universe? I would suggest yes, that's exactly what's there. I would suggest there is no limit to the universe. What we are looking at is "infinity"! In such a scenario time cannot exist. We must therefore reach the conclusion that time, as we know it, can only exist on this planet and its immediate environs.I would be interested in comments.
Keith Upton TIME
The best programme yet.Congratulations Melvyn, on dealing with such a 'tricky'subject in such straightforward and understandable language. The analogies were brilliant. May I suggest that perhaps a further foray into TIME in a future programme would be beneficial ? Anyway, speaking as a retired scientist, I am impressed with your ability to extract the essence of the subject from your guests in a way that we can all understand. Long may the programme continue !Keith Upton
Peter Jones: The nature of time
Time, like the universe itself, only exists in one's consciousness.Consciousness is the only true reality. It is a mistake to believe that the brain creates consciousness - contrary to what most scientistsseem to think. It is in fact consciousness that creates the brain.Once this is realized, the nature of time becomes quite evident. It is themind's way of separating events, so giving rise to one's experiences.An analogy would be the ability of a DVD player to separate the eventsrecorded on a DVD disc in order to experience the film.I could go on ... !
Ralph Carter ,Time
A most interesting programme. I pose the question;Where in time do we exist? The present ? It is transient and has no magnitude.The past, things which have already happened.The future, which has not yet happened.So does this mean we only exist in the past ??
Ajai Kapur - Time
Great programme about Time.I am not a physicist or a philosopher or a mathematician but I found the discussion understandable at least some of the time. It was a fascinating discussion.To my mind, isn't time a function of movement and decay? If there was no movement or decay in the universe at planetary or atomic levels then Time would not exist, I venture to say! If we had a world where there was no movement, no beginning, and therefore no end, only stillness then would time exist?. Infact is Nirvana or ultimate spritual salvation, that stillness mentioned by Spritual Masters, in Hinduism and other religions, an absence of Time ?Many questions, few answers! Thank you Mr. Bragg for an excellent topic
Tom Milner-Gulland - Time
Time is a product of a conscious being's inherent wilfulness (being pulled towards a goal), and its being framed in the form of a life cycle. Consider consider birth, death and - their synthesis - life, as a Hegelian triad. The arrow of time is rendered essential to consciousness by virtue of the logic that it is impossible to die before being born. Thus, in all conscious judgements, there is something of birth (in nascent naivety) and something of death (in the capacity to judge, as God - one might supose - judges us at death); such is what contextualises them within the flow of time. The fact that we are all, in this universe, bound within a single time - a set of mechanical interactions - is testament to the fact that in receiving sensory data, the sensibility of every being in this universe is tuned to a set of frequencies that is common to all, enabling the identification of public objects. The cycle of proceding from birth to death is imposed upon us in two ways: 1) our inherent sensibility, and 2) the fundamental constants of nature - they are, to my mind, unified in a realm that transcends us. Time is not an intuition (as kant would insist) but a subconscious intellectual process of framing, in logical terms, our sensory intuitions.
Petrina Blair Babylon numbers
Really enloyed the physics of time, but I note they did not answer your question as to why the Babylonians < actually the sumerians> choose sixty ?! Would love to know their opinion. Is it 5X 12 phalanges on 4 fingers in one hand ??
Lynne Palmer; Science & Spirituality
I enjoyed the prog. this morning Dec. 18th. on Time.
Gerald Lambert: The Physics of Time
One of the best episodes of this programme, a real treat for the brain, and well handled by Melvyn Bragg.However, the most important question came up late, and didn't get much of a look in, and that is 'Does Time exist?'. Physicists, who use Time throughout their equations, should be put in thumbscrews and forced to give proof that Time is a Real Thing! They cannot of course; Time is merely a human concept used to measure the occurrence of events. That means that Newton, Einstein, Hawking et al are wrong; but once that is accepted, it simplifies Physics mightily and we can really start to move forward instead of circling the drain.More programmes like this please!
tony woodd..........time
Given that our perceptual ability in being human is of a small part of the spectrum of the energy of all that is,could it be that "time" is an "emergent property" of the limited awareness of consciousness moving through the senses and conditioning of the human, as it's life as thought (of the particulars of it's finite and insecure reality) implys time? It could be that time does not exist for the unrestricted consciousness or omniscience...
David Greenhill: NOT A FOURTH DIMENSION!
Nay, surely 'time' is a poetic description of our appreciation of the dispersal of energy between the Big Bang and the moment of Heat Death, universal absolute zero. Given entropy, dispersal of useful energy, those exchanges of energy slow down - towards total zero material energy. So in response to Franl Brown; there is a velocity of time which is slowing and so interpreting the equal decay between points a and b 100 years ago would not be the same as now. The numbers may well 'work' but are only an alternative description, like the word 'time'.What is significant about this is that it means the Geological Timescale is erroneous in its description of world/universal history. Consider applying referential observance over the Velocity of Time and the normal dates given are going to be more and more wrong the further back one goes.As all the molecules in the universe lose useful energy - entropy - the possibilities of further exchanges reduces in scope and number, until there is no energy left and everything freezes. At this point nothing can happen and all molecules in the universe are static - ordered, in a fixed state with no possibilty of changing. Surely Entropy is an increase in order not a decrease.When entropy is complete; Heat Death occurs; Absolute Order - 'time' ends (as it is only the expression of material energy transfer etc) – infinity?
Frank 'TIME'
As Craig Sawyers, an earlier commenter, has pointed out the three guests did wander off into the mystical in their otherwise excellent treatment of the subject. After all, when attempting to model such an abstruse subject, it is necessary to keep rigidly to known scientific facts while consolidating a synthesis from observation. To my mind our three professors added to the confused and misleading picture of time when they tried to anlyse mathematically the part relevant to their speciality. I prefer to see time as an entity in its own right. It is a force or influence that acts on and in conjunction with energy. The relationship between energy and time is symbiotically close. One cannot exist without the other. Time can be thought of as energy's way of quantising itself. Certainly it is the case that energy cannot exist without time. No process can take place or matter exist, without both energy and time. We know that energy is comprised in and emanates from the atom. It does not take a great leap of imagination to realise that the source of time will need to be the atom also if it is to parallel energy from its inception.Once the postulate is accepted that time has a source and does not merely exist in a flat continuum, requiring objects to warp and twist it, as in general relativity, then we have the explanation for a great number of the quandaries of science and philosophy, including the concerns of Fran Brown, Kerrie Brown, Craig Sawyers and the other commentators. At least they, and the guest speakers, can take heart from the knowledge that this tempo field theory provides more satisfying answers to their questions than has been available up to now.
Graham Jones: The Physics of Time
I have been thinking along the same lines as Franl Brown i.e that the mechanism that is causing the expansion of the universe could have started an infinite time ago. The assumption that the Big Bang occurred 13.7 billion (of our modern) years ago is the result of linear extrapolation backwards. Perhaps we should consider non-linear asymptotic regression to the beginning. Why should we assume that physical processes and laws were the same billions (or quadrillions) of years ago as they are today? Of course, even this approach doesn't say how it all started.
Jane - the process of unravelling 'time'
Einstein wrote these words "The scientific theorist is not to be envied. For Nature, more precisely, experiment, is an inexorable and not very friendly judge of his work. It never says "Yes" to a theory. In the most favourable cases it says "Maybe", and in the great majority of cases simply "No". If an experiment agrees with a theory it means for the latter "Maybe", and if it does not agree it means "No". Probably every theory will someday experience its "No" - most theories, soon after conception".
Stephen Shea - Time
I really enjoyed this morning's programme. I did just think it was a bit of a shame that you did not have any philosophers on the panel. If so, they might possibly have mentioned Kant's teaching that time is not inherent in the nature of external things, but is an internalised intuition of our minds, which we use to order sense impressions (a rough paraphrase - apologies to any experts out there). Kant points out that we can imagine a time in which nothing happens, but we can't imagine anything happening other that in time - this shows that time is an a priori concept, and that its existence cannot be established empirically.In view of this, I found it intriguing that, in this morning's discussion, the speakers referred a number of times to the idea of a time in which nothing happens - validating Kant perhaps! It would have been such fun to hear this picked up by a philosopoher - the interaction (on this and other points) could have been quite magical, I think.Kant also says that the distinguishing characteristics of time, as we conceive it, are that (a) it only ever moves in one direection and (b) two different times never co-exist. Again, fascinating to hear how Enstein and others have apparently dispensed with both of those points. However, doesn't this just nmean that Kant and Einstein were using the same word - "time" - to refer to two different things. Einstein was (surely) talking about phenomena in the external world. Kant was talking about our internalised ways of knowing. I do not see that the two ideas (although labelled by the same word) necessarily impinge on one another in any way. On the contrary, as already noted, some of the things that the physicsists were saying this morning, albeit only in passing, were direct validations of Kant.Come on, "In Our Time, we need another rogramme - about (what else) time!
Geoff Lunn: The Physics of Time
"Does Time Exist?" is as much a philosophical question as it is scientific. Plato was as hazy about how abstract nouns work as the programme. Try W. Quine's essay "On What There Is"
james lewis about time!
on LW, iot is appropriately followed by the Daily Service. both are examples of interpreting the unknown, particularly this week when the subject was the equally spiritual time! time is not the fourth dimension as it has different units from the other three - is mass the fifth? maths has no symbol for a unit, so can it be relied upon to investigate an inter-related space-time using its unproven number continuum? (Godel). like religion, faith is needed!
John - Time
Happy Holidays to all at In Our Time.Another great episode. It was stated clearly at the start of the program that time is a human made creation. (eg 60 seconds, 60 minutes are (base six) Babylonian units that are made up by humans. That time marks our subjective perceptual sense of change rather than being an intrinsic aspect within or outside the universe. Time needs Humans. We can measure oscillations of cesium atoms so very accurately. But accuracy does not negate the fact that time exists only as a subjective consensus. Just because our rotation around the sun is our chosen marker of aging, balding, getting fatter etc, does not validate time as an intrinsic aspect of the universe. We still made it up as it suits the way we as humans think about change and movement. It matches the way our brains process spacial environments.Time, as the experts hit on, seems to be more a marking of change, or of motion, or a "marking of difference between two states or positions" - between a former state or position and a later state or position. No wonder time and space are connected.Birthdays are less about time, and more about celebrating where we were in earth's orbit around the sun on the day we were born. And every time the earth is in that same position relative to the sun when we were born, we call it a birthday and notice if we're fatter, balder, or taller and stronger.Great Show IOT.
James Baring - On Time
This is the most difficult subject and quite some sense was talked. Current scientific thinking was well summarised and ways at looking what evidence we can agree on were intelligently suggested. The distinction between absolutes, fundamentals and emergent properties was well made on two occasions, both in the macro universal and the quantum context.I would like to pick up an important misunderstanding however about 'action a distance' and 'instant effect' when it come to understanding what we think of as Einstein's version of space-time and the Principle of Equivalence (which we know to be precise to the ultimate possible measurement).The inertial properties of mass are, as we can verify, instantaneous. The presence of e.g. our Sun eight light-minutes away affects the 4D inertial gradient (like in the 3D analogy of the billiard ball dropped in the sheet), while having only a miniscule effect on the intrinsic effective mass of our planet, or the head of an exemplary hammer in our hand. Should the Sun (impossibly and magically) cease to exist, it would take 8 minutes for a gravitational wave to reach us, causing a (for us) huge ripple in space-time which, after it has passed, would leave us with no local gradient to hold us in any orbit. The inertial mass of our planet and hammer would hardly be affected at all because these are maintained by the effective fabric of space-time which is dependent, in an inverse direct (not inverse square) law on the mass/energy of the rest of the universe.This different mathematical relationship means that the instantaneous inertial property of our hammer is an early emergent (perhaps I should say emerged) property that depends on all the mass of the universe but most on parts which we would subjectively consider to be 6-8 billion years old, to which we are instantaneously linked in 4+ dimensions but not conventionally in 3. We see the distant parts as they were, and we have the benefit of the historical past both in our laws of physics and effects - such as the starlight from a star which, if we were where it is 'now', was long gone. They bequeathed (to our 3D way of thinking) the inertial frame of reference in its current effective density. Gravitational gradients in this form locally when matter agglomerates.As to the future being determined or indeterminate. if you can put all the evidence together you will find that Shakespeare had a lot of insight. For us as humans, there is a destiny that shapes our ends, rough-hew them how we may. Our personal actions are within our own control within the limits set by nature and nurture and what we can make of them, in the dynamic scenario shaped all the other people, their actions and reaction to us and ours to theirs. There can be a statistical determinism that allows within it an effectively infinite freedom.When it comes to what we call the universe, it is in the same position as a human, though we are as one neuron in its activity. To be, or not to be, is not only the question for Hamlet. It is/was/will be the universal question to which the answer To Be is why we are here asking these questions. The evidence is that Nature will find a way, because we know that it has. That is what nature does. HOW it does it is by trial and error and therefore while the end is sure we are free to make any mistake we like. Humanity here on Earth can make it through, and we should. But unless we, here, are the only possible example of intelligent life in (and I can assure you that is not the case) Nature not fail to achieve its desire to be, to know and to experience.As humans we can (well some of us can and maybe many more will) develop an understanding of geometry and dimensions and how to think not just outside the box but outside the boxes, but first it might be a good idea to learn to think inside one. One thing I can say is that to understand time, it takes time, and most people don't have that amount to spare and also make a living. The thing to do with time is to use it. If you are Darcy Bussell, use it to dance to the music. Th
Anne Cooper - Time
Time - It has occurred to me that the 'present' exists only within consciousness. When we are conscious we can talk of 'now' and remember the past and refer to the future as unknown and yet to come.If there were no conscious beings in the universe - to observe events, to be able to record past events and to wonder about the future - all time would be as one whole. No past, no present and no future.The future would seem to be only unknown to us conscious mortals. This would appear to rule out free will - but, could it not be that consciousness is the catalyst for free will? Does consciousness create a 'now' which otherwise would not exist and interject yet another dimension into the 'wholeness' of time?It would be great to hear Melvyn and his experts cover this aspect if further talks on time are planned.Thank you for an excellent and stimulating series of discussions.
Andrew Crocker - The Physics of Time
Thank you for today's programme on time. I was especially struck by the notion of time as a feature of interaction between the various elements of the universe. It would have been good to hear a philosophical contribution to the discussion. I imagine though this might add to the task of maintaining continuity in the thread of the programme.
Gareth - The Physics of Time
It would be better if the "Have Your Say" page used commonly available forum software. So that posters could debate with each other inside dedicated topics, with a clear time ordering etc - just a suggestion!Anyway, back to "my" topic.... Monica Grady is inaccurate. She says that gravity act instantaneously across space. This is incorrect - gravitational effects (eg gravitational waves) move at the speed of light. She also repeats the received wisdom that we see the stars as they were in the past and not as they are now; but this is a Newtonian perspective. Einstein taught us that there is no absolute simultaneity and so we can't actually envisage stars "as they are now" in this way. The light that has travelled from them experiences no time passsing (due to total relativistic time dilation) and so shows the star as "it is now" - but from our perspective. There is no other perspective for us - for us here on Earth.Now; are these two contributions of mine contradictory?!
Barbara Booth - The Physics of Time
Fascinating programme today. May I ask, as a layman, is it possible that the film reel referred to exists as past present and future with all the physical structures and interactions and it is our 'soul' that passes through this physical existance before passing on to the next dimension/layer/film reel?
Franl Brown: The physics of time
I am neither a physicist nor a mathematician and I have great trouble in thinking that the universe, and time itself, began about 13 or so billion years ago. What was happening, say, 15 billion years ago? But suppose time itself were getting faster. If that were the case then as we look into the past time would be getting slower. If it were getting slower following a line that gradually approached zero, but reached zero only at infinity, we could have a universe that did, indeed, start with the Big Bang, which we may calculate as 13 point something billion years ago, but that in reality happened an infinite time ago. Is this a possibility?
Kerrie Brown - Time
The programme today on 'Time' was fascinating, but it seems to me that the alternative to the existence of linear time as we know it as an independent entity isn't just one pre-ordained future, but an infinite number of probable futures, all dependent on the path an individual chooses to take in life. The elephant in the room with physics, in my opinion, is that consciousness forms matter, not the other way around. We are all, individually and collectively, creating the 'reality' we know according to individual perceptions and beliefs about the nature of that reality.
Time 18th Dec 2009....
I have never been disappointed with In Our Time and it is, together with news coverage, worth every penny of my licence. Would it be possible to have a transcript or printed edited version of the programme for further assimilation?
Craig Sawyers - Time
I'm always massively impressed with Melvyn Bragg's willingness to tackle subjects that are very foreign to his real specialism of Dark Ages history (Read his novel Credo - which is suberb).I'm an addict to the programme when I have that hour free.However it was unfortunate in today's (18th December) programme that it all seemed a little mystical, alas, whereas, although sometimes rather subtle, time (even relativistic effects) can be understood by example. No need to repeat this - simple explanations of time dilation and spatial contraction can be found by googling.Other interesting points that were missed are:(a) The first test of general relativity was to explain a small and long-known inconsistency in the precession of mercury's spin axis. The GR solution can be written precisely as a Newtonian term plus a GR term (which is rather small - but precisely the right size to explain Mercury's orbital wobble).(b) Another consequence of and GR is that clocks run slow in gravity. The GPS system we all use in our SatNav's and GPS navigation aids use a constellation of orbital atomic clocks. Since these are in the earths gravitation field, and moving relative to the user, they run out of time by about 38 microseconds per day by comparison to someone on earth. Doesn't sound like much - but it is equivalent to a drift of 10km per day! So your satnav system has to compensate for General Relativity.Furthermore, the direction that time flows - always from the past to the future - has been a matter of hot scientific and philosophical debate for a century or more. There is a thermodynamic argument relating to entropy (the boiled egg example given in the programme, or un-mixing milk from coffee etc), but the real hard physics does not exist yet to explain time's arrow.Lots more examples out there apart from those.Craig Sawyers
Brian Cowell - The Physics of Time
Enjoyed the Programme.I'm reminded of Alexander Pope's lines on Sir Isaac Newton and Sir John Squire's lines on Albert Einstein.Alexander Pope (1688-1744): Nature, and Nature's laws lay hid in night: God said "Let Newton be!" and all was light. Sir John Squire (1884-1958): It did not last: the Devil howling "Ho! Let Einstein be!" restored the status quo. I do not like Squire's sentiments and propose the following.Merc'ry's path though was an aberration; God decreed: "Let Einstein solve th'equation!"
Jane - Time
I looked forward to this programme more than any other and just want to say "thank you". It was wonderful and it also nudged open the door on two phrases which I particularly like: "Where's it written?" and "Why not?". 'Nuf said - except that as far as I'm concerned, Melvyn outshines anybody in our media - I'm sure many other listeners agree. Enormous thanks for this superlative programme. It contributes hugely to my life and I'm always changed for having listened to it. Warmest wishes to all for both Christmas and the coming year.
T Kingham the nature of time
The speakers dwelt on the question of a 'pre-ordained' or 'open' future they also said that time could be viewed as non existant at the particle level they omitted the other option this,( if you belive in the many-worlds theory) is because all possible outcomes of the present do and will (and indeed did) exist. thus the scattering of a single photon going through two slits at once and of couse the world where each person individually lives to an impossible old age avoiding the most impossible odds on accidents while on other paths or branes Elvis lives Hitler won and the ice age came again-read up on the many world theory its facinating.
Dave Nicholson Time
Fascinating as usual. Loved the bit where a lady admitted to ignorance about “ string “ theory. Wonderful!But less seriously , on time, but more down to earth, I was helping in my daughter’s school in a class of five year olds (I think) a few years ago and the fantastic lady teacher, Welsh, was teaching “ time”. Not this academic stuff about the sun getting up late every morning etc but “ big hand on two, little hand on ten, what’s the time Timmy?” stuff.At the end I said “ yes but Mrs Jones aren’t the children more likely to meet time as digital clock numbers not hands nowadays?”Back came her lovely north Wales voice “ yes but with this national curriculum we do not have time to teach time properly.”
Alan Shepherd - Time in Verse
TimeTime - according to EinsteinIs a continuous line.String-theory - stretching outLike a ribbonPreordained, when we are bornPreordained, the momentThat we die.The past is as real asThe future,The present as real asThe blink of an eye.ButIf Quantum Theory Is right,Einstein is wrong.How can that be?By what applianceOf thought?It’s not rocket science.Except that it probably is.But if Einstein is wrongAbout time,Then, perhaps, I should giveTime a miss?“I Had The TimeOf My Life“.Or was that “Dirty Dancing”?Is, “I could show you a Good time”Just a Big SpenderRomancing?If my timing was right,You’d have hadA good night,But time flewLike a bird on the wing.At my time of lifeThere’s no time for such strife.It’s too late for all thatSort of thing.Of time, Sandy once asked“Who knows where it goes?”In the blink of an eye?In the blow of a nose?Well, don’t look at meI haven’t the timeIt’s quite plain to seeI just struggle with rhyme.Einstein should know.He knew relativityWhen did time start?When wasIts nativity?Where does it go?How long does it last?And why all the fuss?Is my watch really that fast?Time ran out for us.Time has flown pastI just missed my last bus.
Jonathan Chase - A rhyme about Time
The ancient Greeks had two words for time that they boast,Would help them understand the changes in the Cosmos,A moment in which something special happens was called KairosAnd measured, sequential time is what they called Chronos,Now it’s true the things we do today, leads us to tomorrow,Cause and effect is the result of time’s arrow,If I could only go back and undo all of my sorrows, Like in Groundhog Day, but which route shall I follow,To see the future of the now is known as pre cognition,Phillip Dick’s minority report explores the vision,“Can you see?”, “The future’s history” so act upon the wisdom,But journeying through time is yet another situation.Thinking of time travel, it was Wells who raised the caseThat there’s one dimension of time, as well as three in space,If one can ‘imagine a ship to take us from place to place,why not through the fourth dimension let’s just change the datesTravelling through time like Dr Who messing with clocks,Using a car, a TARDIS, magic wand or just a watch,A quantum Leap into the past can change the future what a shockStay away from grandfather to avoid the paradox,The Butterfly effect was first announced in Sounds of Thunder,In nineteen fifty two a science fiction sense of wonderAnd later that’s what chaos theory could be labelled under,But in an Allo history it’s more than just the numbers,It’s a counterfactual; another version of historyAssuming that the past can be understood scientifically,The universe is a machine that’s running down on energy,The heat death of the universe towards maximum entropy,The end of time is on a clock that’s christened as doomsday,With five minutes to midnight shown on the display,When Fritz Lang invented countdowns to avoid a delay,The time closing to zero was a new form of decay.
Physics of time to days programme
If time can be said to be static and that we observe time as passing. Is it possible that we have a built in on/off switch built in that blanks off segments of time in the way that a film works thus giving a concept of movement?RegardsTim Ingram
Noel Edwards - The use of divisions of 12
The basic use of 12, 60 and 144 as divisions is based upon counting on one's hands. The four fingers of one hand have 12 sections (3 sections and 2 joints to each finger). The thumb can then be used as a pointer so for example one can count to twelve on one hand. Bringing the other hand into use the thumb can be used as a pointer again and provide multiples of 12 up to 144 (or 60 if just using the fingers and thumb as single multipliers).
