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Astrophysicists detect the strongest magnetic field in the universe
- AnimalMuppet 6y agoOK, ELI5: Why should a neutron star have a strong magnetic field?
- the8472 6y agoThe 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 https://en.wikipedia.org/wiki/Solar_dynamo
- AnimalMuppet 6y agoBut that requires an electrically conducting fluid. Neutrons aren't electrically conducting, are they?
- dredmorbius 6y agoAt 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 https://en.wikipedia.org/wiki/Neutron_star#Structure
- treeman79 6y agoAt pressures neutron stars deal with, the laws of know physics are more like vague suggestions.
- AnimalMuppet 6y agoMeaning 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.
- the8472 6y agoNeutron 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 https://en.wikipedia.org/wiki/Neutron_star#Structure
- wiml 6y agoI 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.
- deleted 6y ago[deleted]
- rini17 6y agoNeutrons 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 https://en.wikipedia.org/wiki/Neutron_magnetic_moment
- the8472 6y ago> ~1 billion Tesla Magnetars supposedly have up to 10¹¹ tesla. But I guess the evidence for that is more indirect.
- _Microft 6y agoMagnetars 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 https://en.wikipedia.org/wiki/Magnetar Edit: "Die Massendichte, die einem derartigen Magnetfeld über seine Energiedichte in Kombination mit der Äquivalenz von Masse und Energie gemäß 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 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 6y agoHow 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 6y agoLayman 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 6y agoDepends, 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.
- anm89 6y agoThis 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.
- samcgraw 6y agoMy thoughts exactly. The title should be updated to reflect this (I was expecting some sort of theoretical limit to a magnetic field).
- jcims 6y agoThis 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.
- kstrauser 6y agoIn cosmology, "in the known universe" is always implicit. If the universe turns out to be flat and infinite, then whatever unlikely thing you can think of happens an infinite number of times in any infinitely small time period you care to mention. Somewhere, in the field of infinity, a whale materialized above a Three Stooges convention and landed on a newly sentient petunia, an infinite number of times since you started reading this sentence. Perhaps not in the known universe, sure, but somewhere. So "known" is always the implicit qualifier, but it'd be a pain in the neck to diligently write "known universe" every single time when the people familiar enough with the material to note the distinction also understand that's what you meant anyway.
- anm89 6y agoFor one, I appreciate this perspective, I was not aware of that. On the other hand this feels unconvincing to me. The language of science and physics is already obtuse and overly wordy, that's what seperates it from the noise of everyone else talking, because it trades precision for brevity and so it feels reliable . So there are infinite places to draw that line in the sand. Why do we stop right there? Why don't we just say what we mean instead of piling up a bunch of words into a statement which is objectively false without all the context.
- robocat 6y ago“a significance level of > 20σ” Insane! Clearly that doesn’t include the uncertainty in our understanding of physics or neutron stars. Edit: I tried to work out the % that 20σ is, but it is so mind bogglingly small that there should be a law against using such an insane number in any serious context.
- btilly 6y agoEach tail is bounded above by e^(x^2/2) / (x sqrt(2 pi)). Take logs and you get (x^2 / 2) - log(x) - log(2 pi)/2. Calculate that out and you get to about 1.44 * 10^85. You can double that for 2 tails. But it is still an impressively small number.
- SubiculumCode 6y agohell of a MRI they got over there. The jealously is real.
- aaron695 6y agoI 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_field) https://en.wikipedia.org/wiki/Orders_of_magnitude_(magnetic_...
- curryst 6y agoProbably impossible without damaging the earth. The article talks about the magnetic force crushing particles electron fields to be flat or spindle; I would imagine generating a field like that anywhere on Earth would have a chance of flattening the magnetic core of our planet into a disk. On the funny side, the flat earthers would finally be right.
- stevespang 6y agoLet's not forget that this neutron star is measured at 5.8 kiloparsec distance from earth which is 18,917.1 light years. Even if observable electromagnetic radiation was traveling at the speed of light, which most is not, we are looking at ancient history, because once this EM reaches earth we are studying phenomena that occurred >189 centuries ago. We don't have a way to know if this star is even still there. Everything studied in astronomy at significant light years distance is ancient phenomena, we are just seeing it/sensing it/evaluating it now.
- occamschainsaw 6y agoThe concept of “still there” in time is not very meaningful for cosmology. All of our observations are in ~space-time~ not just space or time.
- baron816 6y agoSort of related—Tom Scott did a survey to determine “The Best Thing”: https://youtu.be/ALy6e7GbDRQ https://youtu.be/ALy6e7GbDRQ The second runner up is the Earth’s magnetic field. He makes fun of his audience for ranking it that high, but planetary magnetic fields are no joke.
- 7OVO7 6y agointeresting