Magnetars are characterized by their extremely powerful magnetic fields of 108 to 1011 tesla.[5] These magnetic fields are hundreds of millions of times stronger than any man-made magnet,[6] and quadrillions of times more powerful than the field surrounding Earth.[7] Earth has a geomagnetic field of 30–60 microteslas, and a neodymium-based, rare-earth magnet has a field of about 1.25 tesla, with a magnetic energy density of 4.0×105 J/m3. A magnetar's 1010 tesla field, by contrast, has an energy density of 4.0×1025 J/m3, with an E/c2 mass density >104 times that of lead. The magnetic field of a magnetar would be lethal even at a distance of 1000 km due to the strong magnetic field distorting the electron clouds of the subject's constituent atoms, rendering the chemistry of life impossible.[8] At a distance of halfway from earth to the moon, a magnetar could strip information from the magnetic stripes of all credit cards on Earth.[9] As of 2010, they are the most powerful magnetic objects detected throughout the universe.[4][10]
As described in the February 2003 Scientific American cover story, remarkable things happen within a magnetic field of magnetar strength. "X-ray photons readily split in two or merge together. 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."[2] In a field of about 105 teslas atomic orbitals deform into rod shapes. At 1010 teslas, a hydrogen atom becomes a spindle 200 times narrower than its normal diameter.