Once they are inside a BH the only thing you know about them is their mass and angular momentum. It is a possible way to hide baryonic matter.
However, I think it is unlikely that primordial BH would provide the right sort of CDM to allow galaxies to form if the latest simulations are correct. You might hope to see some evaporate or make remote stars twinkle in a characteristic way which rules out some mass ranges.
It is embarrasing that cold dark matter is proving so hard to detect. The experimentalists are trying very hard - I have been to the Boulby facility at the deepest mine in Europe 1200m of rock above it.
Interesting place with a clean room inside a mine where the air is laden with glistening salt crystals and everything tastes of salt. sadly the mine is scheduled to close which will mess things up for the researchers
- the new lab was under construction when I visited.
Am 01.09.2016 um 10:56 schrieb snipped-for-privacy@gmail.com:
No, only NASA dropped out. It is continued by ESA. Last december, they started Lisa pathfinder to check out the critical points like stabilizing the location of a mass to the required accuracy. That was successful.
There are also some very strong limits on parameters, whether variable or not. For instance, if G were too small in early history, galaxies couldn't have formed; and we have data showing they formed quite early indeed, a billion years or so. Physicists love alpha, a dimensionless constant; matter as we know it would not exist outside of a narrow range of alpha.
How many of those parameters can change, jointly, while producing observations, I don't know. It seems exponentially less likely that multiple parameters might be functions of time or space, but one could invoke the anthropic principle and make all probabilities equal...
Or it is possible that these constants are not independent - that there is a single underlying factor that has varied during the history of the universe, and other "constants" have changed as this single factor changed. Then it is not too far a stretch to see that everything from nucleons to galaxies has remained stable. After all, it is mostly combinations of parameters that set the limits, rather than individual parameters. You can double the speed of light, and quadruple the elementary charge - and still keep the fine-structure constant (and therefore matter) stable. (Yes, I know such a change would cause other problems - it's just a simple example.)
In my uninformed opinion, I don't see it as impossible that there could be many of the values currently labelled "fundamental constants" which are neither fundamental, nor constant.
I merely think that when a theory is getting too complicated, and incorporating too many new features with little evidence, it is important to go back and question the assumptions. Is it likely that the universe expanded at ridiculous speeds (/far/ faster than the speed of light) for a ridiculously small length of time - or is it more likely that there is a flaw in the theory, or an unwarranted assumption?
I don't know. But I keep hoping that someone will get a flash of genius and find a way to simplify the whole theory, and bring back a sense of logic and elegance to it, rather than adding more and more layers of bizarre workarounds.
Theological question: why did God make the universe so complex? If the physics of the universe is to be self-consistant, maybe even God was constrained by some fundamental mathematical and physical limits.
A nice simple Newtonian universe would be easier to understand. Maybe we will never understand this one.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Well, for one thing, a Newtonian universe is in principle deterministic, which would exclude free will. Without free will, we could never freely unite ourselves in love with God, which (for a Christian) is the whole point of why we're here.
For another, the existence of matter requires quantum mechanics in some form, because otherwise all those moving charges would radiate and collapse into a very dense state.
Quantum indeterminacy is also a very neat way to allow essentially unimpeded divine providence while maintaining stable and (in the short term) predictable physical laws. ( I wrote a blog post about that some years back that is now only on the Wayback Machine:
Explaining that away is more or less the whole point of the many worlds interpretation of quantum mechanics, but the attempt fails philosophically--if every branch of every quantum transition is taken in some universe, why do we find ourselves in this one? That leaves us back at square one, except with this ridiculous uncountable multitude of inaccessible universes we've thought up.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
A nice Newtonian one would not be interesting enough. Without the strong & weak nuclear forces in about the right amounts you would end up with still born universes that either never light up or burn out too fast. Martin Rees's book "Just 6 numbers" is fairly accessible if you are interested. The way the constants are so finely tuned begs some awkward questions - but a posteriori we would not be here to ask these questions if the constants of nature were even slightly different.
Religious interpretations aside - one devious variant of the universe that is tricky to disprove is one where every time some eminent person makes a grandiose claim about X being solved within the decade as demon/angel is dispatched to make sure that the next experiment gives results that are inconsistent with current theoretical models but consistent with everything that has gone before.
ie from Artistotle until Gailieo heavier objects did fall faster etc.
That and the Okla natural reactor tends to suggest the laws of physics are well behaved and we can refine to ever greater levels of detail.
Dirac was amongst the first to consider the possibilty that the constants of nature might vary with time.
Many worlds isn't all that different to the way that light travelling in a straight line is the result of the photon exploring all possible paths simultaneously. I would be loathe to rule it out as a solution.
Path integrals cancelling out is one way it might be realised.
Equally if someone can ever make a true and powerful quantum computer in our universe then the probability that we are actually inside a simulation becomes quite significantly non-zero.
Introduce me to your other selves, then. ;) The point is that the unique time stream/universe we traverse is just as unlikely and therefore just as providential as if there were only one. It just reframes the question without answering anything.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
I understand the popularity of the idea of trying to solve the problem of determinism using QM, but it doesn't work.
The motivation is to try to save free will (meaningful choices made by individuals). QM allows true randomness, which means that outcomes are not pre-determined - but that doesn't make particular outcomes meaningful - just random.
If you're a Cartesian dualist (or Platonist, since the dual-realm idea is associated first with him), you think that the visible world is a puppet world, where the puppets are directed by spirits in another realm. QM uncertainty then allows the puppet world to unfold mostly predictably, but for those spirit agents to still have effective agency (their actions are meaningful, from the POV of the visible world).
However that doesn't solve the problem of free will, because the spirit world must still operate according to some laws (or it is chaotic) and those laws must still be breakable or bendable (or it isn't meaningful). In other words, the problem of meaningful choice has just been pushed back one dimension. It's turtles all the way down!
That's before you even consider the reality behind the idea of "individual". To be an individual means to have a clear boundary between self and not-self. If this boundary is impermeable, then the individual does not live in society, nor in meaningful relation with other individuals. But if the boundary is permeable, then the choices are less meaningful - to some extent an individual choice is affected by society and it becomes less the choice of that one individual.
Our observation of the physical world shows that the "individuals" are intricately interconnected with everything else. The butterfly effect extends to the motion of a single electron at the far end of the universe, interacting via the weak force of gravity - and this can and has been proved numerically. There are no true "individuals", just processes. So where does "meaningful choice" inhere?
The Cartesian/Platonic model is just plain wrong and misguided, and so are (at least) the three monisms that adopt this POV.
That doesn't matter. If they're not random, but meaningful, then the meaning has to come from somewhere. Platonism delegates meaning to another realm, and then you have turtles.
Rev Dr. John Polkinghorne proposed th following thought experiment.
Consider a molecule of air at room temperature. Its collisions are elastic, and on average, about 50 per tenth of a nanosecond. So how much do you need to know in order to predict its momentum, a tenth of a nanosecond from now?
It turns out that if you ignore the gravitational attraction of a single electron at the far edge of the universe, the errors mount up so much that after 50 collisions, you have no idea of its momentum.
So from this we draw the conclusion that nothing is truly 100% predictable in isolation; there is effectively no isolation possible. If you can't make a prediction about a single molecule further forward than a tenth of a nanosecond... what can you predict?
Not at all. The point of making a universe where free will is possible is to make us free actors. It's a beautiful and terrible gift, which we unfortunately have abused. Sin has damaged our freedom, so that in our fallen state we are weakened and constrained by things like addictions and vices, but it hasn't destroyed it.
The aim of human life, for a Christian, is, as the Westminster Confession puts it, "To love God and enjoy Him forever."
What would an authentic source of freedom look like? Is it even intelligible in your system?
Neither, thanks. See above.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
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