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Science and Astronomy Questions

Posted: 29 Jan 2018 12:03
by Terran
How are you making an observational connection if does not come from performing an observation?  How can one be justified in saying "X looks like what would be expected from Y", if the expectation from Y did not arise from experiment or by math?
It went a little like this: "Hey that looks odd, but familiar, like this:" I rather created a connection that I would later have to do the math to check, as in I need to see if the math still checks out, this is by far no where near a full blown alternative model. What I am seeing so far is like at a "proto-conjecture" stage. I don't think the Schrodinger equation is wrong at all. On my own time I am just going to be trying to work out the math for matter over time, I wan't to see if I can express a system over an infinite amount of time by just inputting the system, direction of causality, orientation, local time rate, and so on... Thats how I got myself into the whole relativity mess, I wanted to find the local time rate. I started with time dilation and accidentally got escape velocity and rapidity and minkowski space, I would say the problem evolved. Then I tried to express a particle changing states in a multi-dimensional timeline (to express all possibilities) and accidentally got a section of the Schrodinger equation embedded in a pensrose diagram... So excuse me if I am a little over my head in my questions and responses, because I am XD, but this certainly has been a learning experience!

2nd thing (added later so I don't double post): What is time rate in relation to time? Is it the "wavelength" of systems in time or is it the "phase" of a system in time? Is there a difference? One being objects experience time at different speeds, and the other objects actually progress through time at different speeds (settings its "phase" farther back thus creating an effect like that of a light cone)?

Science and Astronomy Questions

Posted: 05 Feb 2018 03:12
by JackDole
I have a question: (possibly a stupid question)

Are wormholes moveable?

A wormhole is a hole in the structure of the space. Would such a hole be moveable at all? Could you, for example, load it into a spaceship?

I mean, if I make a hole in a house wall, it's immobile in the wall. It would be movable with the house, with the earth, with our solar system, but it would be immovable in the wall of the house. If I inflated the house like a balloon, however, two holes in the wall would move apart. (The holes have doors that close airtight.)

So if I had any two wormholes in the room, they would move away from each other as the room expands, but still be immovable.

Of course, such wormholes would be completely useless. If such a wormhole appeared here, I would move away with it over 200 kilometers per second. (I do not know the exact speed.)

Is it possible to prove that wormholes are mobile, so could be loaded into a spaceship?

Science and Astronomy Questions

Posted: 05 Feb 2018 08:41
by Gnargenox
While there is no observational evidence for wormholes, spacetime containing wormholes are known to be valid solutions in general relativity. They were theorized during the analysis of mass in terms of an electromagnetic field energy. This analysis forces one to consider situations where there is a net flux of lines of force through what topologists would call a handle of the multiply-connected space and what physicists might perhaps be excused for more vividly terming a ‘wormhole’ or Einstein-Rosen bridge. These are bridges between areas of space that can be modeled as vacuum solutions to the Einstein field equations by combining models of a black hole and a white hole. Before the stability problems of wormholes were apparent, it was proposed that quasars were white holes forming the ends of wormholes of this type.

Wormholes are hypothetical areas of warped spacetime with great energy that can create tunnels through spacetime. Wormholes don't just exist by themselves, they have to be created by a form of matter called exotic matter, according to physicist Kip Thorne, capable of withstanding the immense forces involved. Which almost certainly doesn't exist, but let's gloss over this. To construct a wormhole you need to gather up some exotic matter and arrange it in a particular configuration. While Schwarzschild wormholes are not traversable, their existence inspired Kip Thorne to imagine traversable wormholes created by holding the 'throat' of a Schwarzschild wormhole open with exotic matter (material that has negative mass/energy).

Theories of wormhole metrics describe the spacetime geometry of a wormhole and serve as theoretical models for time travel. An example of a (traversable) wormhole metric is the following:

ds²=-c²dt²+dl²+(K²+l²)(dΘ²+sin²ΘdФ²)

If a Minkowski spacetime contains a compact region Ω, and if the topology of Ω is of the form Ω ~ R x Σ, where Σ is a three-manifold of nontrivial topology, whose boundary has topology of the form dΣ ~ S2, and if, furthermore, the hypersurfaces Σ are all spacelike, then the region Ω contains a quasi-permanent intra-universe wormhole.

The basic notion of an intra-universe wormhole is that it is a compact region of spacetime whose boundary is topologically trivial but whose interior is simply connected. So if the exotic matter is moving the wormhole will move along with it. However you may find that a considerable force is required to move the matter at the two ends of the wormhole because as they move energy will have to be put into the spacetime warping between them.

So, yes, at least according to all the TV shows I watch....

Science and Astronomy Questions

Posted: 05 Feb 2018 10:01
by Watsisname
A wormhole will move or orbit in a gravitational field the same way as a planet or black hole would. So one could be moved by gravity.

Science and Astronomy Questions

Posted: 06 Feb 2018 02:24
by JackDole
A wormhole will move or orbit in a gravitational field the same way as a planet or black hole would. So one could be moved by gravity.
Is that so?
A wormhole needs exotic matter to be opened and kept open.
But is this matter part of the hole? Is not it just a tool?
I also need a tool to make hole in a wall. And when I make a hole in an elastic substance, I also need something to keep the hole open.
For example, the famous rubber sheet for gravity experiments. It could be made of a material in which holes close themselves, unless they are kept artificially open.
Oh yes, and a hole that I make in this cloth would not be movable.
(A black hole would not be a hole, it would still be topologically on the surface of the cloth.)  
A hole makes the cloth topologically a torus.

Science and Astronomy Questions

Posted: 06 Feb 2018 03:56
by Watsisname
Yes, they would move. :)  They key is to use the equivalence principle.  The mouth of the wormhole will follow a geodesic path through the space-time.  There's really not anything else it can do.  It must obey the space-time geometry in its vicinity just like everything else does.  "Not accelerating" in the space near Earth actually means to freefall towards Earth.
A wormhole needs exotic matter to be opened and kept open.
Not quite.  Exotic matter is often cited as a requirement for having a traversable wormhole, but it is not what what enables a wormhole to exist (if it could exist).  The most basic property of a wormhole's geometry (besides being a torus) is that infalling trajectories get spread apart, rather than converge to a central singularity as in a typical black hole.  A good analogy is that the wormhole must act like a lens that defocuses light.

We know of at least two things in nature that have this effect within general relativity: rotation, and electric charge.  Rotation of course flings things away from the center by the centrifugal effect.  Charge (less intuitively) also causes a repulsive effect, because of some quirks of how the electric field modifies the space-time.  This behavior shows up in the vacuum solutions for rotating (Kerr) and charged (Reissner–Nordstrom) black holes.  Both have the geometry of a wormhole leading to another universe, though these wormholes are not stable to the transfer of matter through them.  (So they're really just mathematical curiosities to the vacuum solutions).

To stabilize a wormhole, something more is required.  That's where the idea arises for threading the throat of it with exotic matter which has this de-focusing effect, preventing the wormhole geometry from pinching off into singularities.  How to do that is an exercise left to the reader. :)


One more fun think to think about.  If you believe Susskind's ER=EPR conjecture, then if you create two systems of entangles particles, and collapse each into a black hole, then those black holes will be joined by a wormhole inside.  (This doesn't mean you can go in one and pass out through the other, but rather two people who jump in either side at appropriate times will meet in the interior before the inevitable crushing.)  Is this unfalsifiable?  Not exactly, but it is not conceivably testable either.  Mainly it is a consequence of thinking about fundamental principles of physics where general relativity and entanglement come together.  And as usual when those topics come together, things get really weird.


Addendum:  To add my own question, I've sometimes wondered what would happen if the two mouths of the same wormhole merge.  Or to quickly make things even more complicated, what if mouths of different wormholes merge?  I have done some looking around but haven't found rigorous answers.

Science and Astronomy Questions

Posted: 06 Feb 2018 06:44
by JackDole
To add my own question, I've sometimes wondered what would happen if the two mouths of the same wormhole merge.  Or to quickly make things even more complicated, what if mouths of different wormholes merge?  I have done some looking around but haven't found rigorous answers.
I think there are only two possibilities.

First, it would destroy the wormhole.
In the first scenario simply with the collapse of the wormhole.
In the second case with a collapse also of the other ends of the wormholes. A wormhole with only one end is probably unimaginable. Or?
How this destruction works is of course another matter. Whether with a bang or with a whimper.
Maybe space-time would be torn apart at that point?!

Or, in the first case, perhaps a wormhole loop would form, separate and outside of our space-time. Who knows, maybe there are many such loops out there, outside of our spacetime!
In the second case, the two wormholes will probably unite into a single wormhole.

Science and Astronomy Questions

Posted: 07 Feb 2018 01:17
by midtskogen
To add my own question, I've sometimes wondered what would happen if the two mouths of the same wormhole merge.
This paper seems to touch on the issue.  If you move the mouths together it's argued that a time-machine is created and the holes would collapse or repel.

Science and Astronomy Questions

Posted: 07 Feb 2018 08:44
by midtskogen
Hopefully this is not too off-topic: I'm looking for opinions or advice, and the people here may have that.  I've received a request from a production company making a show for Discovery's Science Channel called "Strange Evidence".  They're interested in doing something on my trees on fire video that went viral a few years ago.  So I googled this show and became a bit sceptical.  Well, perhaps the show does offer scientific explanations for unusual and spectacular phenomena, but the main focus seems to be all kind of outlandish hypotheses.  It's likely not a show I would bear to watch myself.  Does anyone know this show?  I'm not sure how helpful I should be.  What's going on in my video is really no mystery at all.

Science and Astronomy Questions

Posted: 07 Feb 2018 20:22
by Watsisname
I did some googling too, and... yeah, the premise of the show sounds awful. So I agree with your reluctance to get back to them. Your footage is amazing (what an arc!) but I would hate to see it used as viewing bait for their purposes.

Science and Astronomy Questions

Posted: 08 Feb 2018 08:55
by midtskogen
I had a chat on the phone today with a guy in that company (UK based).  He was understanding enough, but the show consciously targets the less educated American audience.  That's their choice, and I need not care much.  But if it comes to me being interviewed about this I will have to be conscious about not saying something that can be cut wildly out of context.  I immediately knew what it was since I remembered having skied beneath that power line minutes before.

One of my daughters who was six at the time (4 years ago) is still a bit afraid of skiing beneath power lines.  Which isn't wrong, since one should be aware of the dangers of power lines in winter, whether there are trees leaning too close or the lines are hanging dangerously close to the snow.  So the video is quite educating in that respect and I'm glad it got the press coverage that it got in Norway.  It got more than a million views.  Had I knew, I would spent a few more minutes editing it, though...

Science and Astronomy Questions

Posted: 09 Feb 2018 14:55
by Gnargenox
Another armchair astrophysicist musings; Dark Matter - What a confusing name. How are we so sure that it is a "thing", a particle, an "it" and not some other intangible consequence of reality? Yes, we see indirect evidence of DM by how other things are affected by the presence of "it" specifically. Some places we look we see alot, some places not so much. Has the amount of it increase or decreased over the eons?

So, I was on the road alot today, hypnotized by the passing lights and road markings, and wondered... What if Dark Matter is not a particle, nor is it actually producing the gravitational lensing we attribute to it. Perhaps there is nothing there at all other than the warping of space-time. Maybe we understand gravity perfectly well, at any scale, but don't understand this thing called Space-Time.

I thought maybe space-time, since it CAN be twisted and bent, can sometimes STAY bend if enough baryonic matter has passed through that area. Just like a piece of notebook paper, crumpled in our hand just like how matter bends ST. When we let go, the paper is still crumpled but soon starts to smooth out, and lets say eventually it will smooth itself nearly completely. But there are usually still wrinkles and folds and bends in the paper that wont ever go away.

Could it be that space-time can be wrinkled permanently by normal matter? Could these wrinkles also be the reason for asymmetry and the lumpiness of the CMB? Was it Alien telepathy that created the electrical arcs to the tree in Midtskogen's video? Could I have indeed ingested too much sugar again? Just wanted to get shot down for thinking outside the box, of which I am totally clueless about what is inside it to begin with! :)

Sorry, but there aren't any links to post that exist about this BS LOL

Science and Astronomy Questions

Posted: 09 Feb 2018 17:47
by Watsisname
I think the name makes sense.  "Matter" because it has mass and is non-relativistic.  "Dark" because it is non-luminous.  Maybe a better name could be chosen, but dark matter seems to have stuck, both popularly and in the cosmologist's jargon.

How can we be sure it is a particle and not something else?  We're not! :)  It's a model.  We only know that this model has the best agreement with observations and the best predictive skill.  Just like how we have no idea what light "really is".  Only that wave-particle duality is a good description for how it behaves.
Has the amount of it increase or decreased over the eons?
 
This is a very good question!  If the amount of dark matter has changed, then what we can say is that it has not changed enough to affect cosmological observations.  Perhaps surprisingly, this is actually testable.  For example, if there is much more dark matter now than in the early universe, then the LCDM model would require a time-varying matter density parameter to fit the evolution of the size of the universe over time.  More dark matter would also be required to explain galactic rotation curves of nearby galaxies than to explain cosmic web formation.  

Another test would be to examine velocity dispersion of galactic clusters as a function of redshift, compared to expectation from LCDM.  This gets tricky though since additional dark matter (from filaments of cosmic web) falls into galactic clusters as they grow, which the models account for but it is not very well constrained.

In short, observations do not suggest any time dependence to the dark matter.  Modeling it as constant, in the sense that what we have now is what was there at the time of the CMB, works sufficiently well that no further physics for its creation or destruction over time appears necessary.

I thought maybe space-time, since it CAN be twisted and bent, can sometimes STAY bend if enough baryonic matter has passed through that area.  Could it be that space-time can be wrinkled permanently by normal matter?
If it can, then this would contradict the equations of general relativity very severely.  General relativity says that mass and space-time curvature are intimately linked.  You cannot have one without the other.  Removing the mass (or moving it somewhere else) does not keep the curvature behind.  (And if it did, this would raise deep problems in terms of "moving with respect to what", since there is no absolute space.)

And this idea is testable as well.  If mass leaves curvature behind in its wake, then it should affect orbits and light rays.  The Sun orbits the Milky Way, so if it makes a wake then we may see it as a pattern of deflection of light around the Sun which deviates from spherical symmetry.  The Milky Way also moves about the Local Group, so orbits of stars should be affected by its wake.  Or by the wake of the SgrA*.  Perhaps the most sensitive test would be timing variations in binary pulsars.  Or gravitational microlensing, which would produce asymmetric light curves.

Could I have indeed ingested too much sugar again? Just wanted to get shot down for thinking outside the box, of which I am totally clueless about what is inside it to begin with!
Throwing out ideas is good!  It can be helpful to go through the exercises of seeing if they are testable, and if so, how. :)

Science and Astronomy Questions

Posted: 10 Feb 2018 15:59
by midtskogen
What is "matter"?  Warped spacetime, or is matter only one if more ways spacetime can be warped?

Science and Astronomy Questions

Posted: 10 Feb 2018 17:16
by Gnargenox
Leptons (like electrons) and quarks (like protons) are elementary fermions, and are considered matter because that is what atoms are made of, which make molecules. Molecules have a resting mass and take up volume. Force carriers like the W and Z elementary bosons mediate the weak force and are not made of quarks or leptons, and so are not ordinary matter, even though they have mass. In other words, mass is not something that is exclusive to ordinary matter. Sometimes matter is considered as anything that contributes to the energy–momentum of a system, that is, anything that is not purely gravity. In the context of relativity, light and other massless particles and fields are then too all a part of "matter".