Neutron Stars: Total Compaction?

[Chris Peterson]

Space seems to be the one intangible aspect of our physical experience we have trouble understanding. Quantum theory (the little I understand) depicts it to contain short-lived particles.

You are perhaps conflating space with the vacuum. They are different things, though easily confused.

[Ron-Astro Pharmacist]

I'd have to admit that's true. My understanding of the short-lived particles is that they can be created in a vacuum. But doesn't space exist even in a vacuum? I think of space as the area between points or groups of matter. That light travels through vacuum faster than other matter only fuels my delusion of what we call dark matter could be.

[geckzilla]

The new Cosmos show is going to talk a lot about dark matter. Bill Moyers did an interview with Neil deGrasse Tyson the other week and I think Neil had a great way of putting it. That is, don't think of it as matter or anything because we have no idea what it is. He'd like to refer to it simply as dark gravity.
http://billmoyers.com/episode/full-show ... ew-cosmos/

[Ron-Astro Pharmacist]

Well, there goes that delusion. It obviously doesn't add the gravity to my idea. Unless there is also a version of dark matter that adds to gravity but not to overall mass. Although light is affected by gravity curiously...

[Chris Peterson]

The new Cosmos show is going to talk a lot about dark matter. Bill Moyers did an interview with Neil deGrasse Tyson the other week and I think Neil had a great way of putting it. That is, don't think of it as matter or anything because we have no idea what it is. He'd like to refer to it simply as dark gravity.
http://billmoyers.com/episode/full-show ... ew-cosmos/

That's a horrible term. Dark matter is excellent, because everything points towards it actually being energy in matter form, but not interacting with the electromagnetic force (which isn't a problem at all). That is, particles that will fit into the standard model.

If anything "dark gravity" would be a reasonable term for dark energy. But not dark matter.

[geckzilla]

Well, if he uses the term in Cosmos, we'll possibly have a lot of people calling it that, then. Maybe you should email him about it!

[Ann]

Space seems to be the one intangible aspect of our physical experience we have trouble understanding. Quantum theory (the little I understand) depicts it to contain short-lived particles.

You are perhaps conflating space with the vacuum. They are different things, though easily confused.

Chris, do you have a short and snappy way to explain the difference between the two?

Ann

[Chris Peterson]

Chris, do you have a short and snappy way to explain the difference between the two?

Not really. Space itself is more like a coordinate system, while the vacuum is the lowest level of structure that exists in that framework? Space is the container, and everything else- including the vacuum- is inside that container? Something like that.

Of course, "space" has different meanings. In this discussion, it was mostly used in the sense of regions not occupied by matter. But at a very small scale, that definition becomes problematic.

[rstevenson]

Chris, do you have a short and snappy way to explain the difference between the two?

Short answer: "Vacuum is space that is devoid of matter." (That's from the Wikipedia page on Vacuum, where you can find a much longer answer.)

Rob

[Ann]

Thanks, Rob!

So an alternative definition of the Earth might go something like this:

A flattened sphere of space, with a volume of 1,083,21 x 10¹²km³ and a density of 5.515 g/cm³, whose surface is mostly covered in liquid water, and whose English-speaking inhabitants call it the Earth.

Ann

[Jim Leff]

And is the space outside the atom the same as the space between the nucleus and its electrons; provided they are not ionized

My assumption is that, quantum issues aside, space is space.

But I'm not sure space can be ionized....

[Jim Leff]

"Vacuum is space that is devoid of matter." (That's from the Wikipedia page on Vacuum)

That may be an apt example of why Wikipedia isn't always the place to go for particularly thoughtful or precise expression.

I'm not among the harsh anti-Wikipedia detractors, but while it does certain things very well (awesome recaps of Firefly episodes!), some critical encyclopedia aspects really do require one single individual (and her/his editor) weighing every single word with great care.

[Chris Peterson]

"Vacuum is space that is devoid of matter." (That's from the Wikipedia page on Vacuum)

That may be an apt example of why Wikipedia isn't always the place to go for particularly thoughtful or precise expression.

I'm not among the harsh anti-Wikipedia detractors, but while it does certain things very well (awesome recaps of Firefly episodes!), some critical encyclopedia aspects really do require one single individual (and her/his editor) weighing every single word with great care.

Actually, as the introductory definition in a technical article intended to be widely accessible, "Vacuum is space that is devoid of matter" is quite good, and broadly accurate. It's probably about the best definition of "vacuum" that can be stated for somebody who isn't going to read beyond that point. However, for those interested in a deeper understanding, the remainder of the Wikipedia article offers a great deal of expansion and clarification, as well as some excellent references.

Like nearly all science articles in Wikipedia, I doubt there's a better source for quality information, and that's why I always recommend Wikipedia as the first stop for people exploring scientific ideas.

[Ron-Astro Pharmacist]

But I'm not sure space can be ionized....

I was not thinking that space is ionized; just that the area outside the nucleus of an atom (even devoid of electrons) may have a unique characteristic that has not been totally defined.

Also, I was hypothesizing that it could be further elucidated whether that area could contain a type of substance that is capable of absorbing a photon pushing electrons to higher energy states or releasing a photon with wave/particle properties we call light. What the substance (space) surrounding the atom’s nucleus is or could be has been a reoccurring idea I’d like help to clear from my mind. Dark matter; not likely but if any group could help me eliminate it as a possibility, it would be this site’s readers.

[Chris Peterson]

Also, I was hypothesizing that it could be further elucidated whether that area could contain a type of substance that is capable of absorbing a photon pushing electrons to higher energy states or releasing a photon with wave/particle properties we call light. What the substance (space) surrounding the atom’s nucleus is or could be has been a reoccurring idea I’d like help to clear from my mind. Dark matter; not likely but if any group could help me eliminate it as a possibility, it would be this site’s readers.

At this scale, it is probably better not to think in terms of "substance" or "matter" or "material", but rather in terms of fields and field carriers.

[BDanielMayfield]

Jim Leff, welcome to starship asterisk. I like your persistence in seeking an answer. Someone famous once said “keep on asking, and it will be given you; keep on seeking, and you will find; keep on knocking, and it will be opened to you.”

So has your question been answered to your satisfaction yet?

Ann mentioned an exchange of ideas we shared about neutron stars. The point I made was that there need to be many charge carriers toward the surface of neutron stars for them to have the intense magnetic fields that they display, so they can’t be entirely made of neutrons, which being neutral, can’t carry electric current. Some limited descriptions of neutron stars imply that neutrons are all that they are made of, which can’t be the case for them to have the observed magnetic characteristics.

I enjoyed reading what Chris mentioned about neutron stars:

Neutron stars vary in composition with depth below their surface. The outer layer is iron (which is why such stars have magnetic fields). Different elements are present below the surface, until the pressure becomes so high that you end up with a degenerate neutron fluid. A neutron doesn't have a size in the classical sense, so it's a bit meaningless to talk about the space between neutrons that isn't part of those same neutrons. But the spacing between neutrons depends on density, which increases deeper in the star.

So the surface region of neutron stars should therefore have layers of increasingly more massive nuclei where protons still exist inside individual atomic cores, moving up from iron with increasing depth. In this region the intense gravitational field must hold these nuclei against one another in some kind of a quasi crystalline lattice, or are the nuclei able to flow about like some kind of a nuclear fluid? Electrons must still be able to move though this material to electrically balance the positively charged protons, I would think, like water being able to flow between the gaps around particles of gravel. Finally though as the pressure increases with depth a point is reached where electrons fuse with protons and nothing but neutrons are left. Is this picture reasonable?

This topic is MASSIVE y’all. Which reminds me, since E=MC², the following would also be true:

Mass = Energy / C²

My point is simply that all matter is composed of energy. Fundamentally, the universe isn’t made of mass, it is made of energy. Mass can be thought of as a way of measuring the energy content inside any given space, even down to a point (singularity).

Bruce

[Ron-Astro Pharmacist]

At this scale, it is probably better not to think in terms of "substance" or "matter" or "material", but rather in terms of fields and field carriers.

Fields and field carriers do seem to be the language that defines space and allows the forces to be characterized. I’d gauge it tough to learn at this point and have to leave it to the physicists. But additionally on space, electron orbitals take on some interesting shapes.

http://www.youtube.com/watch?v=K-jNgq16jEY

What would define those shapes is probably very mathematically complex and is part of my inability to understand this to the degree I’d wish. I’ll keep trying not to degenerate along with those electrons and pose answerable questions.

[BDanielMayfield]

Ron, electron orbitals are fascinating as shown in your link, but in the states of matter we’ve been discussing all the “space” or more precisely the area in a bound electron’s domain has been crushed out of existence. (Which you may have already known.) Gravitational induced pressure inside neutron stars squeezes atoms down to nuclear densities, so in the surface regions where atoms still exist it would be just fully ionized atomic cores (nuclei) jostling against one another (with electrons bouncing around like crazy in the gaps?).

What do the electrons do or where do they go in such a state? The magnetic fields that are observable in pulsars (rotating neutron stars) would have to be generated by enormous electric currents, so could many of the electrons be pushed out to the surface? But still electrons must be able to exist down to the bottom of the atomic nuclear layer, because electrons must be able to fuse with protons when the pressure rises which happens whenever the star accretes mass.

These conditions could be amoung the most extreme possible on our side of the black hole information barrier.

Bruce

[Chris Peterson]

What do the electrons do or where do they go in such a state? The magnetic fields that are observable in pulsars (rotating neutron stars) would have to be generated by enormous electric currents, so could many of the electrons be pushed out to the surface? But still electrons must be able to exist down to the bottom of the atomic nuclear layer, because electrons must be able to fuse with protons when the pressure rises which happens whenever the star accretes mass.

Electrons aren't pushed to the surface. Pressures at the surface aren't high enough to overcome the electron degeneracy pressure, and normal elements remain- in particular, iron, in which electrons are highly mobile. That's why neutron stars have magnetic fields. There are no electrons deep in the neutron star, because as the pressure rose during collapse the electron degeneracy pressure was exceeded and the electrons and protons combined to form the neutrons which make up most of the neutron star. The degenerate neutron fluid is neutrons, and nothing but neutrons.

[Ron-Astro Pharmacist]

electrons and protons combined to form the neutrons

Does this reaction need a neutrino too? But back to “Where’s the space?” again. I wonder to where the space left over from the electron shells goes? Guess that must be why the universe is getting larger. Heisenberg certainly thought it had a purpose in keeping all those electrons from each other. Well, maybe not exactly. But I’m still uncertain if it could be something else? It seems I’m stuck on there being a “space holder”.

“Oh tell me the home to where the all spa-ace must roam and the electrons are cloudy sometimes…” Hey it’s Friday !! Time to have some fun. Do you think there was ever a nerd who wanted to serve drinks at the H Bar? Very small drinks. Besides me.

[Chris Peterson]

I wonder to where the space left over from the electron shells goes?

An electron shell is already space. All that those complex looking shapes represent is the probability of an electron existing somewhere inside the volume they define. They aren't things themselves. And since electrons are generally treated as point particles- they occupy no volume at all- an electron orbital consists of nothing but space.

[Ron-Astro Pharmacist]

The one question I was hoping someone could answer is:

Is it possible that dark matter interacts in our universe gravitationally as the electro-magnetic wave phenomena we call light?

The original reason this question came to my mind was that I could conceive light as “something” that was moving through space and causing an interaction. As depicted below in a two dimensional wave train that I could imagine as a three dimensional wave packet.

Hence my going on and on about dark matter and photons and space. The most likely answer is that I have a misconception somewhere in my conceptualization.

[geckzilla]

You know, I don't know that much about quantum physics but the feeble understanding I do have is reacting strongly and telling me that idea makes zero sense. Possibly less than zero sense. What are you trying to say, Ron?

[Chris Peterson]

Is it possible that dark matter interacts in our universe gravitationally as the electro-magnetic wave phenomena we call light?

The energy carrier of all electromagnetic radiation is the photon. It is a well understood particle. While many physicists would like to reconcile gravity with the other forces, no such unified theory has yet been described. There appears no reason to link light with dark matter in any way. Indeed, the primary defining characteristic of dark matter appears to be its lack of interaction with the electromagnetic force.

[saturno2]

Jim Left wrote:
"My original question was whether the density of a neutron star
is absolute"
I think:
In a white dwarf have level 1 of high density.
In a neutron star have level 2 of high density, but
it is not the maximum density.
In a black hole have level 3, it is the limit maximum
of density.
If we compacted the matter over this limit of maximum
density, the matter explodes with the power of many
bomb H.
( For me), it there is not infinite density in the Universe.
The density has a limit.