Comments URL: https://news.ycombinator.com/item?id=44524054

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(Hey fizx!)

Comments URL: https://news.ycombinator.com/item?id=43017562

Points: 6

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Comments URL: https://news.ycombinator.com/item?id=41632999

Points: 2

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These highly magnetized neutron stars—objects only ~20 km in diameter—have magnetic fields that may reach up to 1015 Gauss, a quadrillion (thousand trillion) times our Sun’s pitiful 1 Gauss. The energy density of just these magnetic fields (via E=mc2) is 10,000x the mass density of lead. Magnetars are a likely source of Fast Radio Bursts and can also emit giant gamma-ray flares—one flare, GRB 200415A, was seen to emit the same amount of energy as our Sun does over 100,000 years, but in only 0.016 s. We don’t really know how these flares form, but if they involve large mass motions, they could also produce gravitational waves, something LIGO and other gravitational wave observatories are watching for. Near a magnetar, “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 (pdf),” resulting in a breakdown of anything resembling what we think of as chemistry. It’s believed that their magnetic fields decay relatively quickly over about 10,000 years, so magnetars are a transient state. We know of about 30 magnetars so far. Oh, and they may also have volcanoes (sort of).