[HN Gopher] Strongest Magnetic Field in the Universe
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Strongest Magnetic Field in the Universe
Author : blnqr
Score : 60 points
Date : 2020-09-16 17:17 UTC (5 hours ago)
(HTM) web link (www.nanowerk.com)
(TXT) w3m dump (www.nanowerk.com)
| _Microft wrote:
| Magnetars are even more mindblowing than blackholes, in my
| opinion.
|
| Here is an excerpt from the Wikipedia article on Magnetars, to
| blow _your_ mind as well:
|
| _" X-ray photons readily split in two or merge. The vacuum
| itself is polarized, becoming strongly birefringent, like a
| calcite crystal. Atoms are deformed into long cylinders thinner
| than the quantum-relativistic de Broglie wavelength of an
| electron." In a field of about 10^5 Tesla atomic orbitals deform
| into rod shapes. At 10^10 Tesla, a hydrogen atom becomes a
| spindle 200 times narrower than its normal diameter._, from
| https://en.wikipedia.org/wiki/Magnetar
|
| Edit:
|
| _" Die Massendichte, die einem derartigen Magnetfeld uber seine
| Energiedichte in Kombination mit der Aquivalenz von Masse und
| Energie gemass E = m c^2 zugeordnet werden kann, liegt im Bereich
| einiger Dutzend Kilogramm pro Kubikmillimeter (kg/mm3)"_, from
| german Wikipedia,
| https://de.wikipedia.org/wiki/Magnetar#Entstehung
|
| says that the mass density (via energy-mass equivalence) of such
| strong magnetic fields might be dozens of kilograms per cubic
| millimeter (kg/mm^3).
|
| _Mind. Blown._
| SirLuxuryYacht wrote:
| How do those rod-shaped atoms, like hydrogen, interact with
| other hydrogens or other atoms? Can chemical reactions still
| even happen in the traditional sense?
| DecoPerson wrote:
| Layman here.
|
| Most classes of stars are already hot enough that molecules
| are torn apart. The atoms are in a gas or plasma state. Pairs
| of atoms will pass through transient states that could be
| classed as "molecules" but they're very short-lived.
| Electrons--a key part of chemical reactions--flow freely like
| in metal.
|
| Hydrogen atoms are just a single proton with some number of
| neutrons. I'm not sure if the proton itself is stretched (Is
| a gluon a particle like a proton is a particle??), or if the
| EM field around the proton is so influenced that electrons
| move around it like it's a rod/cylinder.
| yk wrote:
| Depends, chemistry looks very differently simply because in
| such environments it is better to think of an electron gas
| that moves in a magnetic field, and is slightly perturbed by
| the presence of nuclei, rather than thinking of electrons
| being bound in atoms and being slightly perturbed by a
| magnetic field.
|
| So you certainly have to recalculate all your reaction rates
| compared to laboratory conditions, and my guess would be,
| that in general the chemistry should look a lot more than
| reactions in plasmas, rather than normal (nicely stable)
| chemistry.
| robocat wrote:
| The temperature is expected to remain above plasma
| temperatures even if a neutron star could cool for a billion
| years, so presumably normal chemistry couldn't occur.
|
| https://astronomy.stackexchange.com/questions/14387/what-
| hap...
|
| The coldest neutron star detected "T < 42,000 Kelvin" :
| https://arxiv.org/abs/1901.07998
|
| Disclaimer: I am not an astrophysicist.
| anm89 wrote:
| This is almost certainly not the strongest in the uninverse based
| on the sample size of our observations right?
|
| This is the strongest we have observed. Still really fascinating.
| jcims wrote:
| This has been a pet peeve of mine forever. I've just given up
| on it and mentally inject 'known' as necessary to avoid the
| cortisol.
| samcgraw wrote:
| My thoughts exactly. The title should be updated to reflect
| this (I was expecting some sort of theoretical limit to a
| magnetic field).
| robocat wrote:
| "a significance level of > 20s"
|
| Insane! Clearly that doesn't include the uncertainty in our
| understanding of physics or neutron stars.
|
| Edit: I tried to work out the % that 20s is, but it is so mind
| bogglingly small that there should be a law against using such an
| insane number in any serious context.
| aaron695 wrote:
| I assumed it'd be on earth like the hottest temperature in the
| Universe.
|
| > which is tens of millions of times stronger than what can be
| generated in Earth laboratories.
|
| How hard is this to achieve? Billion $ or impossible?
|
| Not sure, but Wiki says labs get higher?
|
| https://en.wikipedia.org/wiki/Orders_of_magnitude_(magnetic_...
| SubiculumCode wrote:
| hell of a MRI they got over there. The jealously is real.
| AnimalMuppet wrote:
| OK, ELI5: Why should a neutron star have a strong magnetic field?
| the8472 wrote:
| The same reason earth or the sun have a magnetic field. But the
| collapse of the star's core compresses the dynamo into a much
| smaller volume and speeds up the rotation due to conservation
| of angular momentum, thus making it more powerful.
|
| https://en.wikipedia.org/wiki/Solar_dynamo
| AnimalMuppet wrote:
| But that requires an electrically conducting fluid. Neutrons
| aren't electrically conducting, are they?
| wiml wrote:
| I think the theory is that there is enough proton
| degenerate matter to form a superfluid and hold a magnetic
| field, even if the majority of the star's matter is
| neutrons.
| treeman79 wrote:
| At pressures neutron stars deal with, the laws of know
| physics are more like vague suggestions.
| AnimalMuppet wrote:
| Meaning that, for example, the neutrons could dissolve
| into just a sea of quarks, and then it's a charged fluid?
| OK, I could see that.
| dredmorbius wrote:
| At their surface, and possibly internally, the neutronium
| likely breaks down, if only briefly, giving protons and
| electrons.
|
| Voila, spinning charges.
|
| _Current models indicate that matter at the surface of a
| neutron star is composed of ordinary atomic nuclei crushed
| into a solid lattice with a sea of electrons flowing
| through the gaps between them._
|
| https://en.wikipedia.org/wiki/Neutron_star#Structure
| the8472 wrote:
| Neutron stars don't entirely consist of neutron soup. It's
| more of a mix which gets gradually more neutron rich
| towards the core.
|
| https://en.wikipedia.org/wiki/Neutron_star#Structure
| [deleted]
| rini17 wrote:
| Neutrons do have magnetic moment after all. [1] says it's
| about 1000 times weaker than electron, so...no idea how
| much it contributes to the neutron star's field as compared
| to degenerate electron matter crust (which is very
| conductive kind of fluid).
|
| [1] https://en.wikipedia.org/wiki/Neutron_magnetic_moment
| the8472 wrote:
| > ~1 billion Tesla
|
| Magnetars supposedly have up to 1011 tesla. But I guess the
| evidence for that is more indirect.
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