It's software this time!

[ClockworkCoder]

I think it is time for Dave Shah to confirm he has got his pyra to get this thread back on the rails

There's usually no return once a news thread has derailed. We need a fresh thread, I feel.

 

[Bosbeetle]

Sadly, squarely back in the boring world of classical logistics, the Pyra is still sitting in a depot in Nürnberg so an arrival tomorrow as originally forecast seems unlikely (but not impossible as Fedex can suddenly move things quickly).

It's a bit like we are all anxiously awaiting a package

 

[ClockworkCoder]

Sadly, squarely back in the boring world of classical logistics, the Pyra is still sitting in a depot in Nürnberg so an arrival tomorrow as originally forecast seems unlikely (but not impossible as Fedex can suddenly move things quickly).

You may be right, although my order (Pyra mug) appeared faster than it inferred in the tracking.

 

[Djoga'Ro]

Fedex sounds like something you would use to get FBI agents out.

 

[daveshah]

Anything seems possible at the moment, between various couriers I've had both West Coast US to UK in under 40 hours; to Italy to UK taking over 6 weeks...

 

[λ the β-Redex Reducer]

There is no need to 'believe' in science you can check it for yourself.

I do not understand how checking things for yourself would remove the need to believe. Believing is part of knowledge, if you do not believe then you cannot gain knowledge. You would just gain ideas of which you have no opinion as to their truthfulness.

Post automatically merged: Jul 19, 2020

There's usually no return once a news thread has derailed. We need a fresh thread, I feel.

But for the needed new news thread we need new news!

 

[Phlyra]

Anything seems possible at the moment, between various couriers I've had both West Coast US to UK in under 40 hours; to Italy to UK taking over 6 weeks...

@daveshah Might be worth bearing this in mind for post-31st December 2020...: https://tamebay.com/2020/07/amazon-fba-brexit-bombshell-efn-and-pan-european-fba-ends-for-uk.html

 

[Phlyra]

Agreed. But to jump from that statement to, "There must be some magical invisible undetectable fairy dust substance for which we have to take the presence of based on faith that we will call Dark Matter," isn't science anymore. I am in the camp that such exotic explanations are likely unnecessary. Far more likely, there is normal matter/mass in the universe that we're simply not seeing because it is not currently involved in a massive ongoing nuclear fireball (star).

When calculating the mass of the universe, there are several known bits.
We know the mass of stars.
We know the locations of and can get a pretty solid estimate of the mass of black holes
We know the -hot- portion of the IGM (Intergalactic Medium) - the part that emits X-rays and other radiation and can estimate the net mass/energy of that.
We know from observation that there must be more mass/energy in the universe than the above can account for.

Jumping from, "We know that there is mass unaccounted for" to "Exotic Fairy Dust (Dark Matter / Dark Energy) that we cannot see or detect is 95% of the mass/energy of the universe" is a cop out.
Much more likely, we have a higher density of high velocity neutrons and hydrogen in the Intergalactic Medium than previous guesstimates can account for.

The volume of the universe is estimated at 3.58*10^80 m^3.
The mass of observable 'ordinary matter', which translates to 'hot observable matter' is around 1.5*10^54 kg.
The 'missing mass/energy' that gets called "Dark Matter" is estimated at around 20 times the 'ordinary matter' - which would be around 3*10^55 kg.
The mass of a neutron is 1.67492749805×10−27 kg.
If the entirety of "Dark Matter" were replaced with neutrons, that would be 8.95*10^80 neutrons.
Spread those 8.95*10^80 neutrons evenly through the 3.58*10^80 m^3 of volume results in an average density of 2.5 -static- individual neutrons per cubic meter of space. The faster those neutrons are moving, the fewer of them would be needed to make the calculation work (energy).

So, which hypothesis is more likely to be true?
A. That we haven't got detection equipment necessary to spot an average additional density of 2.5 "cold" non-radiating neutrons per cubic meter of intergalactic space.
or
B. That there is this exotic fairy dust that we cannot see, classify or detect called "Dark Matter" that is the equivalent of 95% of the mass/energy of the universe.

@Grench IIRC from what I read a few years ago in Manjit Kumar’s “Quantum”, John Gribbin’s “In Search of Schrödinger’s Cat” and Michio Kaku’s “Physics of The Impossible”, “Dark Matter” is the name given to antiparticles popping into existence in the vacuum of Space and then being annihilated by corresponding “real” particles

 

[levi]

I also think that some of what Grench is talking about is Dark Energy, rather than dark matter. But on the other hand, I've never heard the spontaneous appearance and disappearance of microscopic matter as dark matter, but I perhaps just haven't read the same things as you. But I always thought that came out of quantum mechanical theories, whereas dark matter was predicted from the movement of macroscopic matter in space.

It's a fast moving field though, and I'm not as well read as you. But I didn't feel like putting my head above the parapet and contradicting Grench because apart from what he was calling it, his theories otherwise were interesting to me.

 

[Djoga'Ro]

Dark matter is supposed to be particles that don't interact electromagnetically. The quantum guys have mathmatical canditates at the ready - forgot what they call them. The collider gangs try to produce those. Since that particles couldn't be detected, I guess they'd look for some particular portion of energy that's missing repeatedly. ?

 

[levi]

I think those are WIMPs [weakly interacting magnetic particles]. I'm not convinced that they are anything more than a theory though as of yet.

 

[Grench]

Dark matter is supposed to be particles that don't interact electromagnetically.

See also neutrons. Known. Not exotic. No magic, faith or 4th+ dimensional math required.

Occam's razor - Wikipedia

en.wikipedia.org

 

[ible]

@Grench: neutrons are made out of charged particles. they just add up to zero electric charge. two down quarks (-1/3 charge each) and one up quark (+2/3 charge).

so there is a non-zero probability that light interacts with neutrons. i don't have a good source for this, but here's a related article. thus neutrons aren't dark matter...

scientists (and physicists) are generally very aware of Occam's razor... even string theory people, who introduce a lot of things, are still trying to use those things to show that they produce other results that we do see but don't fully understand. (not that i imagined i'd ever defend string theorists... -- i'm hoping for a simpler theory myself!)

[edit] my current favorite pet theory, which tries to unify QM, relativity, and information theory, is Verlinde's emergent gravity idea (which i guess is discussed here). it also purports to explain dark matter, which would be a nice bonus. i don't fully understand it yet, but also i haven't applied myself...

 

[Bosbeetle]

I do not understand how checking things for yourself would remove the need to believe. Believing is part of knowledge, if you do not believe then you cannot gain knowledge. You would just gain ideas of which you have no opinion as to their truthfulness.

Post automatically merged: Jul 19, 2020

Indeed I think more in the line of workable models that can describe "stuff" than, the truth.

It might also be a language thing beleving (at least if I use the dutch translation) is a bit to void of falsification and also seems to imply a not changing view of things. No need to check truthfullness if you beleive in it. Also I think beleiving in science as a method might be okay but beleiving in science as a whole is to much, like I said before when you're dealing with the bleeding edge of science it's very healthy to take things with a grain of salt and don't discard any hole in the theory you can think of. And discuss or think of ways to unmask or remove that hole. But I might be to much working inside of science to percieve an outsiders look on it.

 

[Bosbeetle]

BTW I think that physicists should make up a new name for "particles" because the general public thinks of quite solid things, while a lot of these "particles" that come about in the standard model are more or less mathematical entities used to predict behaviour of the particles we can directly measure.

 

[matzesu]

How many % of the Mass on Universe are the allready finished Pyrae ?

 

[netlinker]

Without wanting to crush your expectations, 0,000000000000000000000000000000000000 .... (very many zeroes here) .......... 01%

 

[λ the β-Redex Reducer]

Indeed I think more in the line of workable models that can describe "stuff" than, the truth.

Then you still need to believe that they are workable.

It might also be a language thing beleving (at least if I use the dutch translation) is a bit to void of falsification and also seems to imply a not changing view of things. No need to check truthfullness if you beleive in it.

If that is how you use "belief", then what word do you use for beliefs in general including those that are falsifiable, mutable, or false?

BTW I think that physicists should make up a new name for "particles" because the general public thinks of quite solid things, while a lot of these "particles" that come about in the standard model are more or less mathematical entities used to predict behaviour of the particles we can directly measure.

Maybe "mathematical particles"? That's a bit long and will probably get shortened to just "particles", though.
Anyway, what's the point of the general public being informed about a field of expertise that they are generally not even interested in?

 

[Bosbeetle]

They already have virtual particles and psuedo particles.

And to your first question instead of beleive I would use the word "know" or maybe "acknoledge" or "accept". Just a bit less fuzzy and religious than beleive.

 

[Grench]

@Grench: neutrons are made out of charged particles. they just add up to zero electric charge. two down quarks (-1/3 charge each) and one up quark (+2/3 charge).

so there is a non-zero probability that light interacts with neutrons. i don't have a good source for this, but here's a related article. thus neutrons aren't dark matter...

Agreed that neutrons are not, "Dark Matter". However, they are 'normal matter' that is -very- hard to detect at low densities at great distances. If they were standing still, enough neutrons to make up the "missing mass/energy" of the universe, they would only need to have a density of 2.5 neutrons per cubic meter of the universe. 2.5 neutrons per cubic meter is the -maximum- density to fulfill the "missing mass/energy". They are likely not standing still, but would likely be whipping around at velocities ranging up to near the speed of light. The faster the average neutron velocity (energy), the fewer actual neutrons are required for this possible solution.

We have no ability to directly detect "Dark Matter".
We have no ability to directly detect 1.5 - 2.5 neutrons per cubic meter densities of neutrons in the intergalactic medium either.

Issue: "There is a whole lot of mass/energy in the universe that we cannot detect."

Assuming that there is a magic fairy dust and magical energies coursing about, "Dark Matter / Dark Energy" instead of assuming that maybe our measurement capabilities for normal matter might not be adequate (yet) to get a full tally of normal matter / normal energy seems a bit of a stretch.

I am not saying, "This is the way it is." I am proposing an alternate solution model, hypothesis, that fulfills the scenario presented. We do not, to my knowledge, have any current technological means to test either the, "Dark Mater / Dark Energy" hypothesis or my "Presence of Neutrons at Low Densities in Intergalactic Space" hypothesis.