What IS space?

[damocles]

Space and time are the same thing except...

 

They are different types of direction in space-time. Timelike directions and spacelike ones have opposite signs of the interval squared. Null directions are those for which the interval squared is zero, light and other massles particles go in null directions, while one with mass goes in a timelike direction. No Lorentz coordinate transformation changes one type of direction into another.

 

That brings up a question I have.

 

I always understood that the interval a photon had from emission to reception was an observed interval exterior to the photon's local frame of reference; that within the photon's frame of reference, that there was no time.

 

Did I mis-understand this completely?

 

Best wishes;

[coldcreation]

The question of what happened before the ‘beginning’ has very often been shrugged off as irrelevant, as there was no time or space to even think about. In the language of geometry, the void is a spacetime that contains no points: i.e., there is no spacetime, no language of geometry.

 

It would characterize absolutely “nothing.” The ‘nothingness’ prior to the creation of the universe is considered (by several specialists) as the most complete void imaginable—no space, no time, no matter, no radiation, no light, no darkness, no temperature, no dimensions, no size, no vacuum, no energy, no pressure, no force, no particles, no fluctuation, no density, no mass, no general relativity, no quantum mechanics, no thermodynamics, no laws of nature, no order, no disorder, no universe, no God, and no Astrophysical Journals—the empty set—as referred to by mathematicians.

 

Because all scientific theories are formulated on a spacetime manifold, all explosion theories break down before the colossal creation (destruction) event, ab irato. Hence, because of the impossibility to predict any events before time t = 0, they are simply cut out of the theories; swept under the carpet.

 

coldcreation

[HydrogenBond]

I agree with you that the beginning is important and may be necessary to nail down the one true theory among all the contenders. Without an origin how does one know if the theory lines up with the present. Most theory don't want to address the problem, not because it is irrelavent ,but becasue it has already been attempted based on their assumption, and it can not be done. What does that tell us about these theories? Thet can not line up with an origin they can not find.

[sergey500]

spacetime, we know it the same thing, what was your main point Boersuem?

 

People please, damn. I am confused by reading some of your stuff. You can you all just use dumbass language, you know the one....with like four letters per word. The one idiots, like me, can understand with out picturing an array of mental experiments.

[Qfwfq]

I always understood that the interval a photon had from emission to reception was an observed interval exterior to the photon's local frame of reference; that within the photon's frame of reference, that there was no time.

Sorry, I've been terribly busy on my job.

 

The interval squared being zero means that proper time is zero for the massless particle, such as a photon. For the bystander, time is greater than zero but ds^2 = t^2 - x^2 = 0 (in natural units). The quantity ds^2 is an invariant for any interval in space-time. In particular, its invariance when it's zero is what explains the observed invariance of the velocity of light.

[damocles]

Sorry, I've been terribly busy on my job.

 

The interval squared being zero means that proper time is zero for the massless particle, such as a photon. For the bystander, time is greater than zero but ds^2 = t^2 - x^2 = 0 (in natural units). The quantity ds^2 is an invariant for any interval in space-time. In particular, its invariance when it's zero is what explains the observed invariance of the velocity of light.

 

That clarified it. The photon exists in time, but the interval for it is zero, So I did completely misunderstand this, originally. Thank you for the explanation.

 

Best wishes,

[CraigD]

… Thank you for reading - and inspiring - this missive.

 

- That Rascal Poof (er, I mean Puff.).

Good to see you back at scienceforums, Puff/poof. You’re arguably the most colorful personality to grace these forums - no mean feat – and while you seem far from a paragon of formal Science, I find your posts insight-provoking. Keep on rocking in the free world.

[goku]

what is space?

a lack of something (almost nothing) :hyper:

[coldcreation]

Re: What IS space?

 

--------------------------------------------------------------------------------

 

"To paraphrase Einstein, Space is the thing that keeps everything from happening in the same place..."

 

Cheers,

Buffy

******************

Clearly, neither Einstein nor Buffy are without a sense of pensive frivolity? (Continued).

 

"Although we may grow weary of Dr. Einstein's theory, the world will always controversy Newtonian Mechanical space and time, as Albert's space-time goes by..." ('I thought I told you never to play that song - here it comes - again, Sam...'

 

'What IS space?'

 

It will always be a stimulating - perhaps never finalized theoretical - question.

There's a lot of data out there on that subject; more enroute.

That Truly Yours knows of - learned from some of the earlier modernist scientists, like Sirs James Jeans, Arthur Eddington, Bertrand Russel, Murchie, Whitehead, Ouspensky, Minkowski, to honor a few - there's a formidable consensus that (*metric, 'functional') space is:

 

the interval between, dividing or otherwise seperating two or more events.

 

(*Whereas, 'non-metric space' is often defined by two or more correct mathematical proofs, that mutually contradict each other. 'Non-metric' space - as often as not - categorically having a lot to do with fickle, antrhopomorphically fabricated or tampered with numeration, and little or nothing to do with formally defined, scientifically confirmed reality.)

 

THE WHERE WE WERE ('What IS space?', continued:)

Worth repeating:

The interval between, dividing or otherwise seperating two or more events.

 

An 'event' is an 'occurence', or 'happening' - an occasion, episode, incident, phenomenon, and/or development. All of these definitions of space beget time, and conversely - requiring 'some thing' (occupies space, disallows the simultaneous occupation of that space by any other entity/thing, and, when at rest, inertially opposes a resistance to forces acting upon it; when in motion, inertially proceeds in a straight line, opposing any forces or obstacles tending to change its course, slow down or stop it.

 

An alternative - antithetical/contentious - construance is barren of anything; consider the testimony of Hume on this ponderously gossamer, brutishly delicate note; with more than one correct answer, response or definition: 'Nothing begets nothing'.

 

Space is something, a reservoir of intervals and events, a duration, from one entity, point, location, to another - perhaps squared (more likely than not). The commendable thought problem also seems (somehow?) to elicit Locke's observation that 'a given event - entity - cannot occur simultaneously in two different spaces'. In the interests of brevity the potentially tractable arguments with that - and several other contingencies herein - will be spatially detoured at this time.

 

There are growing political schools of straight faced New World spin doctors who conjure people and things arriving at their destinations before departing their points of embarcation; but then there are also oodles of Lost Platoons disposing Steady State and Cosmological Constant; clinging to a woefully over-inflated. spun-out herd-think hypothesis- -fantasized-as-'theory' of a Big Bang Beginning accompanied by Entropic Heat Death Ending, hysterically alleged to be based on the 2nd Law of Thermodynamics (There's no accounting for waste?); schools and universities swimming, dog-paddling and swinging with strings, tachyeons, gravitons, foam, quarks, dark matter, heydrons, strangeness, lexicons, charms, Right-ons, Jungions, glueons, Freudions, Holland interpretations, time tunnels and a fleet of juggernaut oncoming eighteen wheelers preceived as lights at the end of a Riemannian funnel.

 

Thankful (to all those lucky, celestially vaulted Hydrogen stars?), there still are some palpably thought provoking, inspirational interrogatives, like: 'What IS space?' And those who venture to ask and answer these perhaps too often taken for granted; endlessly challenging, infinitely inspiring, tantamountly courageous inquiries.

Bravissimo Muchissimo.

 

(As for 'The Final <'Everything'> Theory'... Dimentia, arrogance, 'the last word', deluded grandiosity and 'the beginning & end of space-time and the world' is an ominously snowballing time of the TV GUIDE (the most widely read printed material in the United States - draw yer own conclusions) reading signs.

Consider WW I - 'The war to end all wars'... Gonna put Newton and Einstein in the rumble seat and on the back burner any day now. All kinds of whippersnappers, one-uppers, high rollers, fish story trollers and gotcha guys - :hihi: gonna win what's yet to be won, do what's yet to be done, relative to the pillars and cornerstones of Modern Science. Especially Newton & Einstein. Gonna over-run and displace their work - levitate and jack up the known - in situ - universe and put a new one under it - anytime now :lol:

<'Say "When"?>)

 

Thank you for reading - and inspiring - this missive.

 

- That Rascal Poof (er, I mean Puff. Kent Benjamin Robertson).

 

 

Not bad Rascal Puff. I would add though that space is the stage upon which all things dance and spin in harmony, often in near equilibrium. Space is something with properties and qualities that can be defined. Mostly, space is treated as if it were nothing, or something that adapts to a theory, or that can be stretched and compressed endlessly. The new array of conceptual options wielded by vacuum physics has only uncovered a truth that has been here forever, an interactive communicative logic, a natural extension in a dynamic process. In essence, space, the cosmological constant is the 'missing' component, the point of confluence that will remain significant in contemporary cosmology, in a unified field theory. To be clear: an ultimate theory (whenever, or if ever, one will fall on our laps) should guide viewers toward a richer, more meaningful dialogue with nature, while simultaneously offering content, a sense of delight in the world around us, and above all a clear definition of 'what is space.'

 

From the mid-twentieth century, the big bang was the archetypal model in the heat of a cosmological revolution. The promise of observational confirmation of predictions seemed within reach, hard work at the desk and ingenuity at the telescope went well beyond utility. Cosmology became a vehicle of self-expression: to free us from world-weariness, drudgery, obscurity, and transport us to elegance and coolness beyond our wildest dreams.

 

More than five decades later, these are the only things that haven't changed. Publications in astrophysics journals have risen by several orders of magnitude. Yet never has there been more uncertainty about the theory's future. The cosmological revolution seems to have ended. Though the standard theory has mutated several times, some form of explosion and expansion are essentially established, the most powerful telescopes and colossal super-colliders have done little to appease detractors. And unlike the mid-twentieth century, there are about 101 more theories on the market: at least a 99% surplus of capacity over demand. Ask any researcher if the general public needs more theories, and she's likely to answer, “No, what the general public needs are more meaningful theories.”

 

We have enough theories, but never enough certainty.

 

A central theme in recent theoretical speculation that appears on its way to becoming commercially successful in a dramatic way, but has not yet found unanimous support amongst sagacious connoisseurs, states that our universe began in a monumental collision with another universe; a kind of pre-world war. In this way, space is presumed to have existed before the cosmic match ignited the furor that followed. The new theory takes place in the fifth dimension (5D). Not only are the four known dimension 'floating' in the fifth dimension, but a rogue wave (soliton or 5D brane) can form like a tsunami, or tidal wave, on the surface of an ocean, that can smash into a pre-existing cold dark space, the result is a huge fireball.

 

I doubt Her Einstein would have appreciated this type of new dimension, new geometry, new physics, that nevertheless transpires, or results in, an expanding flat space.

 

“The very name geometry indicates that the concept of space is physiologically connected with the Earth as an ever present body of reference…The purely logical (axiomatic) representation of Euclidean geometry has, it is true, the advantage of greater simplicity and clarity…The fatal error that logical necessity, preceding all experience, was the basis of Euclidean geometry and the concept of space belonging to it, this fatal error arose from the fact that the empirical basis, on which the axiomatic construction of Euclidean geometry rests, had fallen into oblivion. [Furthermore]…we have not yet arrived at a new foundation of physics concerning which we may be certain that the manifold of all investigated phenomenon, and of successful partial theoretical systems, could be deduced logically from it.” (Einstein 1936, see 1954, p. 297, 298, 301)

 

The principle of dark energy, in one form or another (quintessence, lambda), often plays an important leading role in these new physics scenes. And in the process of familiarizing everyone with the concepts of Holy geometry, the visionary entrepreneurs whose nightmares and daydreams have contoured so much of modern discipline have developed sometimes large groups of raucous followers, special-ops, activist umbrella groups, insurgents, assistants, sycophants, People of the Book, students, geeks, apprentice healers (witch doctors), future black hole hunters, great white sharks, distant relatives, disciples, tribal praise-singers, black-clad prelates and assorted cathode tube educated hanger-ons who worship and embellish those unsung heroes who's writings are legible only to the spirits. The young tyros are susceptible to letting themselves go astray in enthrallment for black hole oratory.

 

The truth is much more fascinating.

 

Coldcreation

[coldcreation]

Up until now, I have not evaded the expressions currently used in theoretical deliberation among cosmologists, science historians, artists, servants, pilates, jezebels, ecclesiastics, benevoles, shamans, shammahs, prophets, apostles, pulpits, thieves, robbers, disciples, enchanters, witches, abominations, archangels, venerables, eminencies, holinesses, patriarchs, suffragams, beatitudes, majesties, saints, pilgrims and dungeon masters. Did I skip anyone?

 

The precise meanings of key words in these discussions are both extremely solid in their implication and obvious enough. However, I have chosen not to employ these terms expansively in these Hypography threads except either where they are particularly appropriate or where definitions are generally acknowledged (SPACE is not one of those).

 

Scientific writings laden with technical terms and over-complicated style have always been vigorously challenging to infiltration by the unqualified layperson. I am not lured in this direction, because I observe the development of a self-perpetuating assemblage of scientific technocrats as the very probable outcome of the conquest of such writings.

 

Certainly, it is difficult to decipher then prove or disprove ones contentions without a comprehensive academic education. Nonetheless, both language and writing have evolved since the first prehistoric grunt and stick drawing in the sand: to limit the vocabulary to the simple, would be to limit the discussion of the complex. In this way the coffee table bookworms should be able to negotiate the repertoire of words without descending into absolute obscurity beneath an accumulation of indigestible verbiage.

 

About space, about time, about geometry:

 

It took mathematicians two thousand years to seriously question the axiomatic fundamental nature of Euclid's fifth or parallel postulate (correspondingly: parallel lines are everywhere equidistant). Compelled by intuition, Saccheri (1667-1733), Gauss (1777-1885), Lobachevsky (1793-1856), Bolyai (1802-1860), amongst others, independently worked to find solutions that would accurately describe the 'real world.'

 

For fear that his reputation would suffer if he were to articulate that non-Euclidean geometry's were possible, Gauss withheld his early discoveries from early publication.

 

Lobachevsky recognized the universal characteristics of his new geometry, yet nevertheless thought it essential to establish experimentally which geometry truly occurs in nature.

 

So too would Her Einstein. We shall see how this will play a key role in our comprehension space, time and the evolution of the universe.

 

Einstein had seen gravitation as rooted in the experience of nature: four-dimensional and geometric. He stressed this heavily, and at the same time brought out the flatness and dislocations of Newton's transformations of nature-with the conceptual aspect of multiple perspectives and curved spacetime. The importance of relativity, he accepted, was to emphasize the idea that everything visible (matter) and invisible (the field) has a 4-dimensional geometric basis (an idea he associated with 'the evolution of the notion of space and time into that continuum with metric structure'). This posture is exemplified, likewise, by his attacks involving the contradictions of quantum theory - 'if one tries to consider the theoretical quantum description as a complete description of the individual physical system or event.'

 

So what is space? That question has already been answered. The real question shouold be: What are the properties of space?

 

The symmetry of pure space is altered in the presence of matter and energy. Though, this modulation or transformation still carries with it symmetry - albeit not with opposite sign, but with the same sign. The difference is that before all arrows were free to point is any direction, and in fact pointed in all directions. Once matter/energy is introduced into the vacuum, arrows (lines of force) are compelled to point in specific directions, i.e., the spacetime coordinate system is modified conforming to the mass-energy density. The change in the metric properties of space is gravitational curvature. Symmetry with regard to changes in electromagnetic properties of space, vacuum polarization or electromagnetic fields, is altered as well. But because these features are operational within the vacuum substratum, space, the cosmological constant, they obey the same symmetry principle as gravity. So space acts as a reflective surface for all phenomena.

 

Coldcreation

[Little Bang]

There is no part of space that is free of gravity. Every point in space is influenced to some extent by gravity.

[coldcreation]

There is no part of space that is free of gravity. Every point in space is influenced to some extent by gravity.

 

Welcome back LB.

 

Look up Lagrange point L1, the inner Lagrange point, the libration point.

 

cc

[Tormod]

Welcome back LB.

 

Look up Lagrange point L1, the inner Lagrange point, the libration point.

 

cc

 

L1 isn't free of gravity, though. It is simply a point where gravity between two objects are equal and thus cancel each other out with respect to any object in that location.

[coldcreation]

L1 isn't free of gravity, though. It is simply a point where gravity between two objects are equal and thus cancel each other out with respect to any object in that location.

 

...canceling out to zero. That is why a test particle placed at L1 will feel no gravitational force. Much still needs to be learned of Lagrangian points, their relation to quasi-stable equillibrium configurations, orbits, the cosmological constant, empty space.

 

Certainly, L1 is unstable: the slightest perturbation from a distant planet or moon will cause an object placed at L1 to move, either towards one mass or the other. I defy anyone to show that gravity is not zero at L1.

 

Conclusion: one of the properties of space, in relation to massive bodies, is that there exists in the combined field (say of a 2-body system, but that would be applicable to any number of bodies in a system) at least one point (that acts as a repulsive force from certain points of view, and attractive from others) where space is gravity-field-free (there is electromagnetic radiation, or field, there). I realize this goes against what Einstein had written: 'there exist no space without a field.'

 

I will explain further soon.

 

cc

[Tormod]

I defy anyone to show that gravity is not zero at L1.

 

Did you know that SOHO - the Solar Heliospheric Observatory - is in orbit *around* L1? L1 represents a "missing" body and SOHO orbits it just as if it were a planet.

 

Lagrange points are related to the three-body problem and are not "cavities" in gravity. If one gravitational mass could rule another out, you would theoretically have a gravity shield, which is still far beyond our theoretical insight.

 

L1, L2 and L3 are unstable and AFAIK there is not a point anywhere between them where there is zero gravity. Rather, the gravity from the bodies create a stable position for a third body.

 

Wiki has a lot on Lagrange points for the interested:

http://en.wikipedia.org/wiki/Lagrange_point

[coldcreation]

Did you know that SOHO - the Solar Heliospheric Observatory - is in orbit *around* L1? L1 represents a "missing" body and SOHO orbits it just as if it were a planet.

 

Lagrange points are related to the three-body problem and are not "cavities" in gravity. If one gravitational mass could rule another out, you would theoretically have a gravity shield, which is still far beyond our theoretical insight.

 

L1, L2 and L3 are unstable and AFAIK there is not a point anywhere between them where there is zero gravity. Rather, the gravity from the bodies create a stable position for a third body.

 

Wiki has a lot on Lagrange points for the interested:

http://en.wikipedia.org/wiki/Lagrange_point

 

Actually SOHO is in a halo orbit around the libration point L1. That is not the same as orbiting a planet. L1 is also called a saddle point, because if you could see the field around L1 in reduced dimensions it would be hyperbolic like a saddle. The trick is to now visualize in 3-D (forget about time for now).

 

Lagrange point are not restriced to the 3-body problem. They are active in all systems, when any number of bodies is present. Lagrange points exist in the combined fields of galaxies and cluster as well.

 

Another way of looking at L1 is as the top of the hill, while at the bottom of the hill, on one side, there is a mass m1, or say, the earth. And on the other, there is a mass, m2, the moon. The earth and the moon are each in their repective gravitational wells (at the bottom of the hill). Now, an astronaut going to the moon riding a bike would ride up the hill. When he reached L1 he could remain there at rest for a while, then he could roll down the other side to the moon. The point is that precisely at L1 he will feel no gravitational force. The field indeed cancels to zero. There is no curvature at L1. This is why L1 is considered pure space, pristine and field-free. Had the value of curvature at L1 been nonzero a test particle or our astronaut could not remain there motionless even for a fraction of second. There would be an acceleration. When two forces cancel the result is zero force.

 

Certainly one can choose whatever objects she wishes. Take two galaxy clusters, with hundreds of galaxies respectively, seperated by an expanse of space. There existes a place (a point) between the two clusters where an object will remain at rest for a short period of time. On either side of that point the object will accelerate towards one cluster or the other. On that point, called the inner Lagrangian point, L1, a particle will experience zero gravity, i.e., because the two fields have canceled to a total gravity field (spacetime curvature) value of zero.

 

Much more needs to be said of Lagrange and his ingenious geometric deductions.

 

Tormod, did you know that SOHO reached its halo orbit well ahead of schedule? There is a nonmainstream reason for this. It has to do with a deviation from the inverse square law of the gravitational field along the line connecting the center of m1, L1, and m2.

 

A simple experiment can be made to show that the field is not in accord with the inverse square law along the line connecting the center of m1 and m2 (the earth and moon in this case, but any two gravitational bounded objects will do). Place a rock, or any other object at L1, then place an identical object at the same distance anywhere else in the field (not on L1) and see which reaches the earth first (assuming the object placed at L1 does not drift toward the moon).

 

So as not to highjack this thread I will elaborate (if there are any interested) in a different thread, to be determined.

 

Yes Tormod, alot can be found in the literature about Lagrangian points, but the literature is not yet complete. Missing is the fundamental importance of these points in the stability mechanism: what keeps objects in stable orbits.

 

So what is space, and what are (at least one of) its properties? Space is an ultimate surface, the curvature value of which is zero absolute.

 

Rascal Puff, I'm still reading your texts. I will comment eventually, once I sift through it and extract the juicy bits.

 

Coldcreation

[Tormod]

Good post, cc. I acknowledge I have much to learn.