1

New Theories / Re: Was the light speed problem really solved by Einstein in 1905 ?

« on: 15/01/2021 06:33:53 »

There is no way to detect absolute gravitational potential, but there is a way to detect the gradient and direction.
- Some of the most accurate atomic clocks have been used in an experiment where they were synchronised to each other, and then one was raised by 1 foot, and the difference in clock rates was measurable.

That was measuring the difference in an accelerated reference frame, which works anywhere in space, even in a completely flat gravitational field. It was detecting the direction of acceleration, which can be more easily determined with a plumb bob than a million dollar clock.

As you say, this is not exactly a local measurement.

Is OK. The plumb bob isn't a local measurement either, but both can be done in a box, and that's what counts.

Point is, you can't measure which way Earth is using your method in a non-accelerated environment (anywhere where the plumb-bob doesn't work).  So two clocks a meter apart in a satellite will stay in sync regardless of their orientation.

2

Physics, Astronomy & Cosmology / Re: Crewed or uncrewed missions?

« on: 13/01/2021 13:20:49 »

Do you support crewed or uncrewed missions? Nowadays space technology is developing so rapidly as you can see. Personally, I support uncrewed missions. It's much easier and more important secure to send uncrewed missions ( we just don`t have to risk the crew) But still, there is a lot of important stuff in particular missions machines cannot do without humans
What do you think about that?

What do you mean by 'support'?  Am I suppose to attend a protest rally if they do the wrong kind?
Whether or not a mission has a human crew depends very much on the purpose of the mission, so a blanket statement that you seek seems not to apply since mission have different purposes.

I can think of very little 'stuff' that machines can't do without the aid of humans. The crew's purpose is rarely to deal with the machines.

3

Physics, Astronomy & Cosmology / Re: The influence of space weather on the space crafts` launches

« on: 11/01/2021 14:26:39 »

Does space weather on the space crafts` launches and do scientists check it before space crafts go to space?
I know there is such a fact like space turbulence and it can influence a space craft, but can space weather?

It is hard to tell, but I think you're asking if there is weather in space, enough to influence launch decisions. I'd have to say yes since I'd guess that something like a period with a strong solar storm would seem to be a poor choice for a launch window since it affects if not the craft, at least the ability to track/communicate with the craft.

4

New Theories / Re: Was the light speed problem really solved by Einstein in 1905 ?

« on: 07/01/2021 14:03:18 »

May I inquire as to your motivation for requiring an absolute frame of reference?

Such a frame (which I again stress is not inertial) is commonly used by very large scale cosmology.  Under an inertial frame, nothing moves faster than c.  There are two primary coordinate systems using the cosmological frame.  One measures proper distance, and is the frame used when saying something like a galaxy with redshift 11 is moving at over 2c relative to us. That means its proper distance along lines of constant cosmological time is increasing at that rate.  The other coordinate system uses comoving distance, where all galaxies are close to stationary.  In that frame, redshift is still a function of distance, but none of the galaxies are moving fast.  In both cases, the speed of light (the rate at which the location of a given pulse of light changes over time) is not constant.
The proper-distance coordinate system has light speed dependent on the direction it moves, and can be negative.  In the latter (comoving distance, not proper), the speed of light is the same everywhere at a given time, but changes over time.  These are all abstract coordinate differences, not different theories.
In the former, speeds add the normal (A + B) way. In the latter, speeds add the relativistic way.
Each of the two coordinate systems can be generated by the other by multiplication/division by the scalefactor, which is a function of the expansion rate of the universe over time.

I would think that Newton's 3rd for the Milky Way galaxy would be found mostly in the relationships with respect to the galaxies and galaxy clusters in the immediate neighborhood surrounding our Milky Way galaxy.

Do you have data for relative velocity of nearby galaxy wrt milky way? We could then calculate their velocities wrt cmb. So we'll know if there is a net momentum in the galactic neighborhood.

All the galaxies nearby are moving kind of as a group in the same direction.  Andromeda is behind us but catching up despite our motion away from it.  A real predator-prey chase it seems.  Our peculiar motion (motion relative to that CMB frame) is due to attraction to (in order of proximity) the Virgo supercluster, the Great Attractor, and the Shapley Attractor, and also partly due to the Dipole Repeller which is pushing us from behind.  Anyway, the reaction momentum to our momentum resides in these various attractors and the material being attracted to them from the other side.

This site has a 4D (3D + time animation) of the peculiar motion of our local supercluster.  Virgo is the big red dot, and nothing is close to it at first since anything that was has already been eaten and is not tracked. Click on the map at the top. Takes a minute to load. Use the scroll wheel to zoom in and the mouse to rotate.  The yellow dot is us, and green is Andromeda. A few other colors show some larger masses.  All the dots are real galaxies, but they don't show the little ones.
https://earthsky.org/space/detailed-map-galaxy-orbits-local-supercluster

5

Physics, Astronomy & Cosmology / Re: Why did the Space X Starship test fail?

« on: 05/01/2021 13:08:50 »

The reason given was that the fuel tank pressure was too low, apparently giving inadequate thrust during the final braking phase which was otherwise optimally timed.

Yes, the test was a data gathering exercise and they got all the telemetry data they needed, so the test was considered a success.

6

That CAN'T be true! / Re: Are these two inconsistencies in SOHOs and STEREOs photos?

« on: 03/01/2021 20:46:42 »

Since STEREO images are photos - not 2D slices of 3D map of region, post-processing can only be in the form of color filters, and can in no way affect objects (adding or erasing) and their relative position to each other.

They are not photos, since the cameras are nowhere near the point of view presented (which is something like Jupiter, depending on where in its orbit that is).

I notice that the image you post is about 300 pixels across, and with Earth in the center, perhaps 150-180 pixels between Earth and the sun.  Earth, Venus, Mercury, and even the comet seem to consume several pixels, meaning the image does not have these object focused down to their actual size.

The moon is a light-second away and the sun is about 500 seconds away, making the moon about a 3rd of a pixel from Earth.  That means it isn't in the picture because it's too close to distinguish the two at the resolution presented.

7

That CAN'T be true! / Re: Are these two inconsistencies in SOHOs and STEREOs photos?

« on: 03/01/2021 17:36:04 »

Why there is no Moon near the Earth on the STEREOs photos?

I don't know how the images are generated, but they do not appear to be photos.  A stereoscopic sensory system generates a 3D maps of a region, not a photo, which would only be 2D.
It is possible that the image is generated as a 2D slice of that 3D map along the orbital plane.  It may be that the moon is well outside that plane, and being so close, it not in the cross section at all.

My argument does not explain the funny curved part that seems to intersect the sun, and the blank 'shadow' region off to the right, nor the fact that Venus seems to track almost straight toward's Earth during the 1-week animation.  Also, Mars is portrayed as being inside the orbit of Earth, which implies more of a point-of view choice (from well to the side, but again in the orbital plane) from which the 2D image is created from the 3D map.  The image point of view might have been chosen in this case to put the comet in the cross section generated.

Just some thoughts. As I said, I don't know how the images are generated from the data gathered by the STEREO probes.

8

That CAN'T be true! / Re: The nature of light and the size of the Universe.

« on: 01/01/2021 20:30:42 »

Dear moderator Halc, would you please be so kind to move two my topics "New model of the Universe." and "The nature of light and the size of the Universe." to the section "New Theories".

Can do if the assertions made are accompanied by evidence. You've a reputation for not providing such, hence this forum seems to be the appropriate classification.

The topic is already under discussion on other sites under various categories of 'speculations'. Continue the discussion there if you will.

9

That CAN'T be true! / Re: The nature of light and the size of the Universe.

« on: 01/01/2021 17:22:18 »

This topic is being posted on multiple sites, in violation of the rules of this site.

The latest has earned the author a suspension for failing to use anything but ignorance to support the ignorance presented, being evasive resorting only to repetition. The post is just soapboxing.

Had the topic been posted in New Theories, I would have left it there, but since it was posted in the mainstream section, it has been moved to 'That Can't Be True" section.

10

General Science / Re: The journey to the red planet: does humanity need Mars colonisation?

« on: 29/12/2020 13:45:09 »

if we send crewed mission to the red planet, we will send the crew to die, how they survive there???

If they come back, it's not colonization. If they die there, it isn't successful colonization. If the task isn't colonization, the task can probably be accomplished on a fraction of the budget with unmanned missions.

11

Physics, Astronomy & Cosmology / Re: Is there a simple explanation of Bell's experiment?

« on: 22/12/2020 21:36:11 »

Isn't that a polite way of saying nobody understands it?

It's a polite way of saying Philip Ball doesn't understand it.

12

New Theories / Re: How much information can we get from a single photon?

« on: 21/12/2020 13:48:22 »

Let's say a source sends a 1 TeraHertz photon to a receiver. The receiver is moving towards the source at 0.5c. What is the frequency and wavelength detected by the receiver?

Assuming the 1THz is relative to said source, about 1.3 THz as measured by the approaching receiver. The light appears blue shifted.
Same light velocity in this case (as compared to a receiver that is stationary relative to the 1THz source), but different frequency, wavelength, energy and momentum.  You need an example with more than one dimension to get a velocity change.

13

New Theories / Re: Consciousness/identity

« on: 04/12/2020 20:14:52 »

Link to your minutes-old post on quora removed.
If you have an argument to make, do it here. The purpose of this site is not to draw traffic to one's personal blog.

Some people claim that after you are gone, it may be possible by chance to be reborn again if for example multiple universes exist or there is a series of Big Bangs and collapses.

This statement is too vague to be meaningful. What exactly is 'reborn'?  How is some other life the same identity as the one you have now?  It is indeed a question of identity.  Suppose you now are a 'reactivation' (as you put it) of 'Bob', 300 years ago, Earth. How is that meaningfully different than you and Bob not being the same person?

This idea reminds me of the 5 minute hypothesis  which of course it’s not true

Also known as Last-Tuesdayism.  It seem to have nothing to do with reincarnation.

says the Universe began 5minutes ago within a simulation and you have all the memories of the past in it.

It says the universe has all these memories. Memory is a physical thing. Information (physical) cannot be destroyed, so if the universe is young, all the current state that comprises its memory must be put into place.

If a new identity or consciousness is born with all the memories, you don’t actually realize you,  as a conscious mind, were just born maybe a few minutes or days ago.

Even if it was, it doesn't seem to be a reactivation of some prior identity, which is why I don't think the 5-minute thing is relevant to the question initially asked.

14

General Science / Re: Is Mathematics Falsified?

« on: 04/12/2020 17:57:39 »

There is no largest number.

https://www.smbc-comics.com/comic/the-largest-number
https://www.smbc-comics.com/comic/the-largest-number-2

I wish posters on this site were allowed to put "mottos" under their posts.  Like they can on other sites.

members->forum profile
which gets you to:
https://www.thenakedscientists.com/forum/index.php?action=profile;area=forumprofile

Put your motto under the signature section, just above the map.

15

Physics, Astronomy & Cosmology / Re: Does our material reality exist because we observe it?

« on: 24/11/2020 22:08:54 »

So matter can be material and immaterial....

By definition, matter is material.
Whether it exists in a particular state without being measured is another (unresolved) issue, and that is where the philosophy comes in.

If we observe the world we create one reality out of many possibilities.

It has nothing to do with us (humans, consciousness, etc), but yes, there are interpretations that posit reality only relative to measurements. I happen to favor such an interpretation, despite the sarcastic remarks by some of the responders.

How can we interpret this to our life? Does our material reality exist because we observe it?

If you like that, then sure. Otherwise pick something else from the list of valid options. There's plenty of invalid ones as well, but those are not consistent, which seems not to bother their adherents.

Is the world only there because we can see it?

To me, the world is only there because I see it. If I didn't measure it, it would not exist to me. Not a particularly revolutionary statement. It doesn't mean things go away for others when some critical person dies.

As for your poll, it makes no sense. How is it that I can choose from only one option, or a question?

16

Physics, Astronomy & Cosmology / Re: Does time have more than one dimension?

« on: 19/11/2020 14:19:01 »

I have often wondered about what exactly is it that is moving from the past to the future.

The whole point of spacetime (as opposed to space in time) is that there is nothing that moves from past to future. If there was, then the location of it would define the present, which would be a form of presentism, which is any view that defines a privileged moment in time.

In other words, what is the sense of "now" that we each take for granted, that advances from one moment to the next to define our passage through time?

As you say, it is just a sense, given to you by evolution since without it you’d not be fit to make the predictions needed to survive.

1. Wouldn't being able to draw a loop onto a timeplane allow time travel to the past in a hypothetical universe with more than 1 time dimensions? Isn't paradox free time travel possible?

Depends on what you consider to be time travel. 24 hours ago I experienced Wednesday. Today I experience Thursday. That’s time travel, no?
Under presentism, there is but the one current state of space, and no other state to which one can ‘travel’.  Under a block interpretation, there is no motion, only worldlines, and time travel would I suppose be a worldline that is I guess discontinuous.  I don’t see any inherent paradox in any of that.

What do you mean by there is no backwards in time as there is no forwards in time? What are the implications of time being a volume?

For instance, which way is forwards in space?  If you were locked in a box without windows, how would you determine the direction of forwards?  If space was one dimensional, there’d only be two choices.
Perhaps there is a forwards in time with multiple dimensions.  Any direction with greater entropy (if such a thing is meaningful in this weird place) is forwards and v-v.  There may be several directions which meet this criteria, and locations in time that locally have maximum or minimum entropy and thus lack a choice of both forwards and backwards.

2. How to calculate speed of light in 12 temporal and 8 spatial dimensions?

Yet again, by equating length in all 20 dimensions.  That’s more of a definition than a calculation.  I would have no idea how the operation of ‘calculation’ might proceed with the physics of multiple time dimensions, if it is possible at all in physics where there are not particular solutions to the partial differential equations involved. The inability to meaningfully calculate is a good deal of the reason why an observer is not likely to evolve under such physics.

3. Suppose there is something other than tachyons that travels faster than speed of light, what would its light cone be like and would it allow time travel?

You can make up any story you like. There’s no wrong answer to questions supposing such things.

4. If point in time has no meaning, then what was the big bang? Everything seems to be moving away from everything else, so big bang was probably not a point in space but a point in time(like center of balloon is not on its surface but at its center so big bang time and time dimension in general is the interior?).

You can look at it like that.  The balloon analogy was always meant to be a local analogy, so the universe isn’t really a super-finite surface of an expanding hypersphere.  If it’s radius was 14 BLY, then its circumference would only by 88, small enough to see the entire universe from anywhere since the size of the visible universe is about 92 BLY.  In principle we’d see the same ‘most distant object’ in all directions.
I’ll let Evan answer questions about this ‘black hole cosmology’ about which I know little, let alone buy into. He also gave some excellent replies to 5 and 6.

7. So a clock fell into a black hole in finite time, what happened to the clock then if time ended completely(why would time end by the way)?

Time ending means there is no more process. Nothing to measure.  It can happen for us for instance if the big rip ever happens. It seems unlikely, but if that is the future, then time ends at a singularity just like it began.  But not a point singularity, just a temporal one. It’s a singularity since there is all the equations go to zero or infinities, and there is no meaningful physics as we know it.

Was the clock imprinted onto black hole surface area and led to black hole's growth and would eventually leak out as Hawking radiation?

No imprint. A black hole singularity has no features other than those listed in the no-hair theorem.  Yes, as measured in external time, the mass of the black hole eventually ‘leaks out’ as you put it.
I sort of wonder how a big-rip scenario would handle the black holes existing at the time.

8. How would hypersphere be 5D if our 4D universe has time in its interior

Our universe does not appear to be a hypersphere.  It is best modeled as a flat 4D block of spacetime with local areas of deviation from Euclidean flatness. There’s no ‘interior/exterior’ to it.

Anyway, you said 4D of space, so I figured you were talking about a 4-sphere which has a 4D surface and encloses a 5-ball.

9. Is this analogy correct: We lived in the chromosomes & the chromosomes are parts of us.

We lived in the  chromosomes?  No idea what that means.

But they probably aren't aware of us, neither are all the cells that make us up.

Neither are we necessarily aware of the existence of the larger thing of which we are a part. Don’t assume you’re at the top of that progression.

So it could be some abstract higher dimensionality(maybe more spatial or temporal dimensions) could allow a thing to see all the events across all of space and all of time simultaneously.

Define simultaneously as you use it here then.  ‘Seeing’ is a process, and by definition doesn’t occur ‘simultaneously’.  ‘Seeing’ also seems to require light to go from the thing seen to the observer, and no known photon leaves the universe to get to this ‘thing’ at all, let along all this light converging to a single event.  So that leaves only abstraction, and yes, the entire universe can be considered in abstraction, which is what modeling does.

17

Physics, Astronomy & Cosmology / Re: Does time have more than one dimension?

« on: 18/11/2020 14:19:57 »

Please help me answer these questions:

1. Still can't understand a time plane. How would it eliminate causality? What is meant by circular paths on a time plane?

It means you can draw a loop on a plane, but not on a line.
More technically, for the types of partial differential equations involved in systems of multiple time dimensions, a set of initial data doesn’t determine a unique solution to the system. You can google ‘initial value problem’ for more info on this.

Do cause and effect even exist macroscopically?

Of course.  I step in front of a bus. That causes me to die. Sounds pretty macroscopic to me.

Isn't time just a macroscopic increase in entropy with very low probability of entropy dip happening? Would entropy prevent additional time dimensions?

Time isn’t entropy. The properties of entropy only make for a weak arrow of time, but our physics is time reversible at scales below thermodynamics, which is not always the case.


Evan gives some good answers for point 2.

Even in our regular 4D universe, after an incredibly long period of time, wouldn't the earth still end up falling into the barycenter/sun due to the sun's curving of 4D spacetime?

Earth is actually moving away due to 2 effects, and moving closer due to 2 other effects.  Currently the former effects far outweigh the latter, but yes, gravity wave radiation must win in the end.  That isn’t an example of the orbital instability of which I was talking. It is entirely stable all the way.

3. I didn't get the speed of light part. Please rephrase it and what it implies in the context of 2 time dimensions.

It has nothing to do with the number of dimensions. Spacetime is a bunch of dimensions, some of which are space and some of which are time.  So you can have a meter of time.  The constant c tells you how long a meter of time is (or a second of space), even if there are 12 time dimensions and 8 of space.

4. Please list the properties of tachyons and what they can do. I mean like can they actually travel back in time?

They go faster than light.  That means that one can select an inertial frame where the source of a tachyon event is ordered after the destination event of a tachyon.  That’s time travel in that frame, but not time travel in a different inertial frame that orders those two events differently.  Reference frames essentially are just an abstract ordering of events. There’s no actual preferred orientation of the physical time dimension, so it is at best an abstraction to say that tachyons travel back in time.  Since they don’t exist or at least don’t interact with normal matter, no message can be sent with them, and locality laws are preserved.  One must break locality laws to actually (not abstract) travel back in time.

What would their light cone be like and how would it allow traveling back in time?

They don’t seem to have a light cone at all since they don’t interact with anything. A thing that cannot be measured is the same as a thing that doesn’t exist.

I was assuming a hypothetical observer like a photon(by IIT, even it should have a bit of consciousness but that isn't what I want to discuss here at all so please forget it) which is 3+1 dimensional and how would it differ from spacepoint timecubed tachyons. Just think of a normal person and an advanced species living in more time dimensions. What things would be accessible to that species and what sorts of feats could it achieve? Could it travel back in time and maybe go across full spectrum of universal wavefunction?

I cannot answer how a species can form in a universe with one spatial dimension (the 1+3 one with the tachyons).  There is no ‘backwards in time’ any more than there is a forwards in it since time is a volume there, not a line with an arrow head.

The only way to escape from inside a black hole is to travel back into the past, how would tachyons do it?

I don’t think a tachyon can escape a black hole. That would be physical time travel, not just abstract time travel.

I don’t know the mathematics. I don’t know why tachyons result in such a scenario. Read up on it if it interests you.

Could access to more time dimensions allow all sorts of time travel in a 1 time dimensional universe?

If it is a 1t universe, there doesn’t seem to be more time dimensions to access. Maybe some of the 11+ dimensions of string theory are temporal.  Only 4 are macroscopic, and the others are there but very finite (closed) in scale, so they’re not noticed at the macroscopic level.  Access to that kind of time and space doesn’t really change anything macroscopically.

5. So is it safe to say singularity is a point in time just like the big bang being a point in time?

A singularity is a limit where mathematical laws and physical laws break down. Not all of them are points.  For instance, the event horizon of a black hole is a singularity in some coordinate systems, but not in others.  So only the latter coordinate systems can be used to model what it’s like to fall into one, but it cannot be used to model an observer hovering there because that introduces singularities again, just like trying to do the same thing here on Earth with a device capable of infinite acceleration.

I’m not sure if ‘point in time’ has meaning in a universe without absolute time. Space and time had not yet separated at the big bang, so it simply may not be entirely accurate to model it as a point in time. That’s the singularity talking again. You can’t use normal terms in a place where the rules break down.

Since 1 spatial dimension(the radial one) has become time dimension inside black hole, does that mean the radial dimension actually became infinite in length since time dimension is also infinite?

A clock falling into a black hole reaches the central singularity in a calculable finite time.  Time is not infinite there. It ends abruptly.

Would black hole singularity be infinitely 1D and maybe contain or connect to a 4D universe?

All I know is that the mass of the black hole is preserved, so from the perspecitve of the outside, it doesn’t leave our universe.  The mass/energy is radiated back into normal space over finite time, and it would seem that could not be true if anything went to another universe.

6. Can light never escape from inside a black hole and hence Bob can never send a message to his wife? But how can Bob receive the birth message if upon falling inside, he travels faster than light towards singularity?

He doesn’t fall faster than light.  ‘Down’ is a time dimension now. 
Here’s a Kruskal-Szekeres diagram of a black hole with all our players in it.

The dotted line is the wife in normal space ‘I’ at some fixed distance r from the event horizon.  Blue line is Bob. Region II is the black hole, and red line is the singularity.  Lowest magenta line is the news of ‘I’m pregnant’ which reaches him before he crosses. Not shown is the ‘it’s a girl’ message sent at about t1.8 that reaches him inside.  The t2 message is the last possible light that can reach him.
Last magenta line (from t3) is the news of the first steps, which never reaches Bob.
This comes from a thread debunking the idea that since time freezes at the event horizon, somebody falling in will witness the end of the universe. They don’t.

I didn't get the past light cone part, please rephrase it. Is it related to how I can only see the past due to speed limit?

You can only be causally effected by events in your past light cone. You mostly can only see events on (not in) your past light cone, which is why you cannot see the dinosaurs despite them being in your light cone.  I say mostly.  You can see the dinosaurs with a well placed mirror.

7. So a hypothetical 3 spatial dimension sphere having its own intrinsic time cannot exist/be contained inside a regular 4D universe?

It’s space and time would not be instrinsic. The thing is just an object countained by a universe. A universe is not a containned object, at least not by any meaningful definition of ‘universe’.  I tried to give an example of a simulation of such a thing, but the simulation is still just a contained object or process, not an actual universe. That’s why I think that while it is in principle possible for a universe to be simulated, it is not possible for the universe to be a simulation. The simulation reduces it to a contained thing, and thus not a universe.

8. Is time not intrinsic to a 4D block universe being at the surface of a 4+1D hypersphere that is expanding? So there is no 2nd time dimension to an expanding hypersphere?

The surface of a 4D hypersphere is 3D just like the surface of 3D Earth is 2D.  If radial dimension is intrinsic time, then it expands over time, and that makes it 4D again. I don’t see a 2nd time dimension described.

9. What would be the dimensionality of a being with all its events being simultaneous?

How would it qualify as a ‘being’ if it exists for but an instant?  How would the set of those events be simultaneous if they’re not at the same spatial location? A pair of separated events that are simultaneous in one frame are not simultaneous in another, so they’d have to be all the same event. One event is not a ‘being’.

18

Physics, Astronomy & Cosmology / Re: Does time have more than one dimension?

« on: 18/11/2020 05:38:38 »

I entered this topic out of my personal confusion with an Einstein block universe where one time dimension and three spatial dimensions configured a universe of absolute cause and effect and no possibility of inabilities to determine a fixed relationship between the past and the future

Einstein was not the first to posit a block universe, and was initially resistant to it.  It being a block had little to do with the sort of hard determinism that you seem to suggest here. Quantum mechanics interpretations seem to be the grounds on which determinism or the lack of it come into play.  The block universe, or a 3D one with flowing time are interpretations of time, and both support both deterministic and non-deterministic physics.

other cosmic investigations seem to conclude that multiple universes are generally too separate to have intimate inter-reactions on the mere mind sets of physics experiments.

If they interact, they're not really separate universes then, are they? Not the way I define the terms anyway.

This seems to leave the possibility of indeterminate outcomes of experiments the necessity of this universe to contain multiple timelines although each of us normally are only aware of our own time line of existence.

There are valid interpretations that have only one
very much determined outcome to any experiment. I personally don't favor them, but that's just a choice of mine. There is no known falsification of them. Yes, there are equally valid indeterminate interpretations as well.

19

Physics, Astronomy & Cosmology / Re: Does time have more than one dimension?

« on: 17/11/2020 19:56:54 »

it seems to me that a film strip quite simply substitutes one element of space for time whether or not it is projected.

Yes, exactly.

Can you please elaborate in simple terms:

1. How more than one dimension of time would result in unpredictability?  Suppose a block universe had more than one dimension of time, what would it mean?

Instead of a timeline, you’d have something like a time plane. You can have circular paths on it, which eliminates what we think of as causality. Without causality, things are not meaningfully predictable since they’re not necessarily a function of a nearby state which is considered a ‘prior’ one.

How would more than 3 dimensions of space be unstable?

Things like planetary orbits and formation of atoms only works in 3D.  With more dimensions, the entire universe tends towards either a continuous solid or a haze of meaningless radiation, neither of which is likely to evolve an observer capable of gleaning the rules.
So say we have a planet orbiting in a perfect circle around a 4D star.  The slightest deviation from that perfect circle sends the planet into the star or off into the distance.  That’s not a stable orbit.

Would speed of light limit still be an issue?

Speed of light seems to be a relation between distance in time vs distance in space.  So a pair of events separated only by one nanosecond has the same interval between them as a pair of events separated by about a foot of space. That ratio is the speed of light, whether or not there is actual light in the physics being considered.

What is implied by tachyons having 1 dimension of space and 3 dimensions of time?

I don’t know the mathematics well enough to understand why tachyons are the only solution to such an arrangement. Tachyons are simply physical particles that can move no slower than lightspeed, and have greater (absolute) energy near light speed, just like normal matter.

How is its experience different from 3 spatial and 1 temporal being's experience like a photon?

Not sure what you mean.  A photon isn’t an experiencing temporal being, but a photon can be experienced by such a being.
It is unclear if an experiencing entity can be constructed from only such elementary particles.

 

What things are tachyons capable of doing?

Well, if our universe has any, they don’t seem to interact at all with matter that we can measure, so that sounds an awful lot like not doing anything. They seem not to exist in our universe any more than does real negative mass objects, despite the mathematics allowing them as valid solutions to the equations.

3. Inside a black hole, since radial and temporal dimensions change their roles, does this in any way affect dimensionality of 4D spacetime inside black hole?

No, it’s still 3+1 in there, which is why you can fall in and not know when you’ve crossed the event horizon.  The singularity is now not in some spatial direction, but rather in the future, so it is unclear how that effects tidal forces on you as you go forth. Gravity is not usually described as pulling you into the future, but we can’t really apply our normal concepts to the bent spacetime inside a black hole.

Can a 10 m^3 black hole's inside be bigger than 10 m^3?

It seems so.  What was the time dimension becomes space, and that goes potentially a long way in both directions, so you perhaps have finite space in 2 dimensions but much more in the 3rd, sort of like a long hose, but in 3D. Not sure. I’m not an expert there.

Is time completely different inside a black hole? Is black hole's interior, actually on a different timeline completely?

Not really different. As I said, it’s still 3+1 in there.  The events inside have no simultaneity with events outside using a typical coordinate system like that Earth uses, but other coordinate systems order the events across the event horizon just fine, and show things like certain events on the outside can be measured from somebody inside, but others cannot.  So Bob falls in, leaving his pregnant wife behind forever.  She gives birth and announces it’s a girl, and he gets that message, but he misses the message send showing her first steps since that event is outside the past light cone of any part of his worldline.
Bob of course can send no reply that his wife can hope to get, even after infinite time.

If a hypothetical 3 spatial dimension 10 m^3 sphere(of non-expanding fixed volume existing within a universe) had its own intrinsic time, then from the point of view of the whole universe, is it safe to say the system(sphere + universe) is 3 dimensions of space and 2 dimensions of time, or would that sphere would need to exist outside the universe(and cannot be part of the universe if it had its own time)?

It would be one object existing inside the other.  The spacetime of the internal object would be separate (not interact with) the external spacetime.  Being a contained object, yes, it occupies a swath of external spacetime, but whatever definition you’re giving that space internally has no interaction with external spacetime.
So for instance I can program a cellular automata simulation, and I can make it go as slow or fast as I want (its intrinsic time), or pause it for a month, and those make zero difference to the outcome of the structure.  Not running it at all doesn’t change the structure.  5+7 is still 12 whether or not somebody actually figures it out somewhere.

Because an expanding hypersphere results in 4 dimensions of space and 2 dimensions of time to give it time to expand hence hypersphere is actually 6D?

Sorry, but if it is expanding over time, thats 1 temporal dimension. Where’s the other one?  I counted 5D in all.

What is meant by "Spacetime is one 4D thing, not time that passes and space that doesn't (different things)"? How can we be 4D beings if we cannot know simultaneously all the events that happen at all times at once inside a block universe?

You are aware of all the events on your worldline. You do experience them all.
They’re not simultaneous, since that would make them all at the same time, which is just as silly as your arms and legs all being at the exact same point in space.  You’d not be a 4D thing if all your events were simultaneous.

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Physics, Astronomy & Cosmology / Re: Does time have more than one dimension?

« on: 16/11/2020 12:57:21 »

In dealing with dimensions on a perceptual basis rather than that of mathematical theoretics, one dimension is visually a line, two dimensions become a surface, and three dimensions are a volume. Time, the accepted fourth dimension, is difficult to envision, but by substituting time for one of the three perceptual space dimensions a partial comprehension can be managed.

Yes.  It being difficult to depict 4 dimensions on a 2-D page, some (all but one?) of the space dimensions can often be ignored in order to add time into the illustration.
What physicists mean by time being a 4th dimension is that time has the same ontological status as space and cannot be separated.  The universe is not a thing existing within time, but rather time is part of the universe.  Thus, if there is a lower bound to time (big bang say), then it is meaningless to ponder the state of things a day before the bang similar to it being meaningless to ponder the color of a rock a meter beyond the rock.

Any book describing a series of events has made time one of the dimensions in the length of the book. A movie film strip has flattened space into two dimensions and the third dimension becomes time in the succession of frames to create the illusion of movement.

Good examples, but the physics view is typically a book without a reader, or a film without a projector.  Without the reader or projector,  all the pages/frames have equal ontological status and no frame is the ‘current’ one.  The physics resulting from there being a current frame in the projector leads to certain interesting contradictions.

The attempts  of physicists to popularize Einstein's concepts of how gravity distorts the shape of three dimensional space to cause objects speeding in a gravity field to be captured into orbits around stars and planets is managed by visually  reducing the three dimensional volume of space to a kind of two dimensional trampoline type surface where a heavy object lies at the bottom of a pit created by its gravitational force and a speeding object slides into that pit and is forced into orbit in the distorted space.

The trampoline illustration is useful, but not perfect, and can only be taken so far.
If a speeding object comes from outside and into such a well, it will speed its way out again, not falling into orbit.  To do the latter it needs to lose energy.  Falling into orbit is as expensive (for a rocket say) as leaving it.  Apollo spacecraft expended more fuel going into orbit about the moon than they did leaving it.

What remains a mystery is the direction of the depth of that pit which I suspect is the fourth dimension of time.

The direction is easy.  An event is a point in 4D spacetime, so just define any two successive events.  Drop a ping pong ball on a table.  The first hit on the table is event 1, and the second hit (same spatial location on the table) after the bounce is event 2.  A line drawn through spacetime connecting those two events is oriented in the direction of time.

In the theoretical problems contained in dimensional multiplication, there is a consistent resistance to the possibility that there is more than one time dimension.

The possibility of universes with different numbers of time dimensions exists.  The physics of things would be different, and it seems difficult to have any complexities that would allow the emergence of an observer.
Tegmark put out this chart graphing the nature of various configurations of time and spatial dimentions:

This shows that say 2 time dimensions is quite plausible, but nothing interesting results.  The tachyon universe is somewhat interesting, but has only 1 dimension of space and 3 of time.