Scientist find Universe's missing mass - well most of it!

[renormalised (Carl)]

There's that much conjecture about what dark matter/energy is that for the most part the best thing they can say is they don't know what they're looking at or really understand it. Yes, there are some reasonable hypotheses being suggested and I think the next decade of results from the LHC will bear out whether supersymmetry might be a deciding factor, or not, but that's for experimentation to decide. It's one thing to hypothesise the existence of supersymmetric particles through theory but it's something entirely else to actually produce the results empirically. I'd say given the track record of particle physics, they may find them (or they may have to ramp up the LHC's beam intensity further to find them), but you never know until you actually do the experiments at the proper energies. I wouldn't entirely rule out some form of baryonic matter either but I'm not going to hazard a guess as to what it might be for certain. I have a feeling that this question isn't going to go away for quite some time, yet. Not until we can actually sample or detect with certainty what's there.

As far as other theories go, interstellar magnetism/electrical fields, interactions with higher dimensions, modifications of Newtonian gravity, etc etc etc, they'll have to live or die on their merits through further observation and testing. For all we know, it might be a combination of factors which produce the results that we see. Sometimes, Occam's Razor doesn't cut properly because it's blunt

[astroron (Ron)]

Why do we still stick to the Baryonic measurements when we keep finding Galaxies that are Larger and further back in time.
Would some one please explain how we deduce how much matter is in the Universe when we keep finding more and more galaxies and other Stuff.
We find that the Voids are not Voids after all, but filled with Millions of galaxies that don't show in most of the electromagnetic spectrum.

[Nesti (Mark)]

All this hub-hub about dark matter and dark energy...we can't see light, only detect its presence, yet everyone seems to think they know what that is (yet we don't). Same goes for every other particle...what makes the dark side so interesting.

Perhaps Obi Wan was right, the dark side is more seductive

[Nesti (Mark)]

Originally Posted by astroron

Would some one please explain how we deduce how much matter is in the Universe when we keep finding more and more galaxies and other Stuff.
We find that the Voids are not Voids after all, but filled with Millions of galaxies that don't show in most of the electromagnetic spectrum.

Because WMAP - built under contract of the lowest bidder - said so, now behave Ron!

[Jarvamundo (Alex)]

As far as other theories go, interstellar magnetism/electrical fields, interactions with higher dimensions, modifications of Newtonian gravity, etc etc etc, they'll have to live or die on their merits through further observation and testing. For all we know, it might be a combination of factors which produce the results that we see. Sometimes, Occam's Razor doesn't cut properly because it's blunt

EM has been powering: Sun spots, CME's, auroras, solar currents between planets and moons + 2 Trillion Watts, between sun and planets, between planets and planets, radio astronomers are now mapping it in detail of galaxies, both our own and others. ie.. it's everywhere we've sent a probe, and there's loads of it.

It's all experimentally verified, tested in the lab. Empirical as it gets.

Lets also keep in mind what is powering this precious LHC experiment... yep a giant electro-magnetic dumping massive currents into it.... we are building the biggest EM machine ever to try and have a chance at finding a higgs, so we can patch up a gravity-dominant model?... anyone else see the irony in this? where is that razor?

The current mainstream gravity-dominated-cosmological models flat out ignore EM, a well understood empirical science, and in doing so are required to create these mathematical conjectured entities. A gravity dominated model cannot produce a spiral galaxy, EM's been doing it for 30+ years. Connect the dots?

I agree it'll end up being a "combination" of these theories that get through... it'll be a "hey look what we (re)discovered moment".... Mainstreams now extending the hand...

[renormalised (Carl)]

Originally Posted by Jarvamundo

EM has been powering: Sun spots, CME's, auroras, solar currents between planets and moons + 2 Trillion Watts, between sun and planets, between planets and planets, radio astronomers are now mapping it in detail of galaxies, both our own and others. ie.. it's everywhere we've sent a probe, and there's loads of it.

It's all experimentally verified, tested in the lab. Empirical as it gets.

Lets also keep in mind what is powering this precious LHC experiment... yep a giant electro-magnetic dumping massive currents into it.... we are building the biggest EM machine ever to try and have a chance at finding a higgs, so we can patch up a gravity-dominant model?... anyone else see the irony in this? where is that razor?

The current mainstream gravity-dominated-cosmological models flat out ignore EM, a well understood empirical science, and in doing so are required to create these mathematical conjectured entities. A gravity dominated model cannot produce a spiral galaxy, EM's been doing it for 30+ years. Connect the dots?

I agree it'll end up being a "combination" of these theories that get through... it'll be a "hey look what we (re)discovered moment".... Mainstreams now extending the hand...

I'm not disputing the evidence and/or influence of EM in the cosmos. As a matter of fact it's an important part of understanding the processes which go on within stars, planets, galaxies etc etc. But like anything else, it still requires ongoing study, testing and such. No field of science can be considered static, and neither should those that work in them consider it as being as such.

We also have to look at stuff such as MHD, condensed matter physics and the like to fully appreciate what's happening out there.

[Jarvamundo (Alex)]

I know you're not... consensus cosmo models currently ignore it.

Condensed matter theories also have difficulties and violations of empirical nuclear physics... the current gravity-neutron-star (spinning neutronium) is a shining example... direct violation of all matter we know.

These are of course one of the conjectured spinoffs of ignoring EM in the stellar models, and relying on gravity to 'hold together' a postulated sustained fusion reaction, of man has yet to empirically verify.

[sjastro]

Originally Posted by Jarvamundo

Condensed matter theories also have difficulties and violations of empirical nuclear physics... the current gravity-neutron-star (spinning neutronium) is a shining example... direct violation of all matter we know.

I fail to see the connection. Neutron stars are formed by the collapse of stellar cores composed of iron nuclei.
How is this related to the island of stabilty?

Regards

Steven

[Jarvamundo (Alex)]

Neutron stars are 'hypothesised' to consist of a core of free neutrons... hypothesised 'neutronium' or these 'condensed matter' postulations.

The island of stability essentially describes the empirical nuclear physics of the relationship of protons to neutrons that are stable in atoms... 1 to 1 for light elements... kick it up to 1.5 to 1 for the heavy ones... you can see from the diagram it's a near 1:1 sorta line...

As the island describes... if there are too few neutrons the atoms will emit protons to stabilize... vicer versa...

With the neutron star we are talking about a nucleus, not of iron, but of free neutrons, or postulated condensed neutronium only, that according to the island is completely unstable and will immediately decay.

My point being... The hypothesis of a 'neutronium', 'quark matter', 'strange matter', 'neutron core' neutron star is stretching out far beyond empirical nuclear physics.

Best,

[bojan]

Originally Posted by Jarvamundo

With the neutron star we are talking about a nucleus, not of iron, but of free neutrons...

Are they really free?
The density of neutron star seems to be very close to nucleus density..

[sjastro]

Originally Posted by Jarvamundo

Neutron stars are 'hypothesised' to consist of a core of free neutrons... hypothesised 'neutronium' or these 'condensed matter' postulations.

The island of stability essentially describes the empirical nuclear physics of the relationship of protons to neutrons that are stable in atoms... 1 to 1 for light elements... kick it up to 1.5 to 1 for the heavy ones... you can see from the diagram it's a near 1:1 sorta line...

As the island describes... if there are too few neutrons the atoms will emit protons to stabilize... vicer versa...

With the neutron star we are talking about a nucleus, not of iron, but of free neutrons, or postulated condensed neutronium only, that according to the island is completely unstable and will immediately decay.

Gravity is the reason why neutron stars are stable. A free neutron will decay (via the weak force) in about 15 minutes, as will a neutron only nucleus.

One of the principal reaction pathways for the formation of neutrons in a neutron star are electrons being squeezed into the iron nuclei due to the immense gravity and interacting with protons to form neutron only nuclei.
These nuclei in turn form neutron degenerate matter which is a major component of neutron stars.

In this state if a neutron decays into a proton and electron, gravity causes the proton and electron to form a neutron. In other words neutrons are in equlibrium with protons and electrons.

For every neutron that decays, a neutron is created hence neutron stars are stable.

Regards

Steven

[Jarvamundo (Alex)]

Alot of hypotheticals there again SJ...

I'm familiar with the 'gravity' being hypothesized mechanism for the existance of this process. Zwicky coined it up not more than a year after the discovery of the neutron.

My comparisons were between empirical nuclear physics and hypothesis, in response to Marks comments on empirical verification required for competing models.

You are right with a neutron and the 15 minute decay.... lets take a look at the other proposed neutron matter

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

Mononeutron: Isolated neutrons undergo beta decay with a mean lifetime of approximately 15 minutes (half-life of approximately 10 minutes), becoming protons (the nucleus of hydrogen), electrons and antineutrinos.
Dineutron: The dineutron, containing two neutrons, is not a bound particle, but has been proposed as an extremely short-lived state produced by nuclear reactions involving tritium.
Trineutron: A trineutron state consisting of three bound neutrons has not been detected, and is not expected to exist even for a short time.
Tetraneutron: A tetraneutron is a hypothetical particle consisting of four bound neutrons. Reports of its existence have not been replicated. If confirmed, it would require revision of current nuclear models.[4][5]
Pentaneutron: Calculations indicate that the hypothetical pentaneutron state, consisting of a cluster of five neutrons, would not be bound.
And so on, through the numbers, up to icosaneutron, with 20 neutrons.[6]

Only one of them really exists... (the first one)

Are they really free?
The density of neutron star seems to be very close to nucleus density..

Well has anyone actually dissected a neutron star? Has anyone ever been able to get 2 neutrons to stay together? Has anyone ever been able to produce a sustained fusion reaction?

We have yet to really get 2 neutrons to hangout together, let alone a spinning star full of em.

I'm just saying, we are invoking alot of stuff they we don't have empirical verification for, and we haven't even started to talk about how fast these massive objects are 'supposed' to spin....

mainstream sets the bar high for competing models to provide empirical evidence, just seems to me consensus can coin up as many terms as it wants without equal empericism. 'Strange matter' cmon...

[bojan]

Dissected star? no...
But, if we assume the rot momentum is preserved during collapse, a very simple calc will show that the spin of couple of hundred rotations per second for solar mass star actually could started as much more common couple of days for one rotation prior to collapse.
This way, you know how big the neutron star is and what is its mass - there are gravitationally bound systems with at least one neutron star (pulsar) as a component, so masses of components are known very precisely.

[Jarvamundo (Alex)]

Yes i'm familiar of the gravity model. Just saying neutronium does not empirically exist, it's hypothesized to exist based on the insane speeds this things are said to "spin". This was spin rate NOT expected or predicted, Neutron Star was invented as the only thing that could stand those rotational speeds.
If you get the island of stability chart... then doink a neutron star on it... it's off the graph paper.

Whilst on speed of rotation... even neutronium flings apart when we hit this speed (24,000 RPM): http://prl.aps.org/abstract/PRL/v83/i19/p3776_1

so now we invent 'strange matter' as even the super dense hypothetical neutronium would fling apart...

Yes gravity is hypothesized to save the day.

Comments are on empirical perspective component of this proposed science. I do not question the maths invoked to infer the existence, as you have described.

[sjastro]

Originally Posted by Jarvamundo

Alot of hypotheticals there again SJ...

I'm familiar with the 'gravity' being hypothesized mechanism for the existance of this process. Zwicky coined it up not more than a year after the discovery of the neutron.

My comparisons were between empirical nuclear physics and hypothesis, in response to Marks comments on empirical verification required for competing models.

Alex,

Hypothesis and theory are based on observation/experiment. Hypothesis is not invented to support theory. My explanation of gravity in this context is a case in point.

It is based on two pieces of observation.
(1) Neutron stars do exist.
(2) Neutron stars last longer than 15 minutes.

Now if gravity plays no role (or doesn't exist) for neutron stars (which can't exist long term without gravity anyway) then we have a very serious problem in explaining the whole concept of nucleur fusion in stellar cores. The KE of nuclei due to the stellar temperature of the core is not enough to sustain long term nucleur fusion. Fusion also occurs through the conversion of gravitational potential energy into KE.

You are right with a neutron and the 15 minute decay.... lets take a look at the other proposed neutron matter

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


Only one of them really exists... (the first one)

Free neutrons only exist in neutron stars because the matter is degenerate. If neutron matter is not degenerate there is nothing preventing the neutron star from collapsing into a black hole.

mainstream sets the bar high for competing models to provide empirical evidence, just seems to me consensus can coin up as many terms as it wants without equal empericism. 'Strange matter' cmon...

Once again it's not the case of inventing terms or hypothesis to support theory. Strange matter is a theoretical outcome of Quantum Chromodynamics.

Antimatter strange nuclei have been recently discovered at the RHIC.
http://physicsworld.com/cws/article/news/41917

Regards

Steven

[Jarvamundo (Alex)]

Once again it's not the case of inventing terms or hypothesis to support theory. Strange matter is a theoretical outcome of Quantum Chromodynamics.

Ok... it might be palatably said as... it seems todays cosmological models are quick to pickup the nearest convenient discovery and mould it to fit the difficulties in observations... Well prior to any empirical lab observational confirmations that the process can take place.

* sustained nuclear fusion (aint happened)
* magnetic reconnection (aint happened)
* 24,000 rpm super heavy beyond anything dreamt of in the lab_ matter star (?)

....
1933 Chadwick discovers the neutron
1934 Zwicky uses it to fit the problem of these fast spinning stars

The type of star existed before the 'Neutron' Star did
The type of star lasts longer than 15 minutes

Quark and strange follow suit... they now have their own hypothetical stars...

I'm just sayin... never seen a cup of neutrons under pressure (of any force) staying together...

I think we know where this is going.... just my empirical conscience having a rant...

Best