Magnetars: Stars So Magnetic They Would Erase You From 1,000 km Away
Answers: “what is a magnetar?”
Take a dead star — a neutron star, already the densest object short of a black hole — and give it a magnetic field a thousand trillion times stronger than Earth’s.
You’ve made a magnetar: the most magnetic object known to exist.
The numbers around magnetars read like threats:
- At a distance of 1,000 kilometers, a magnetar’s field would tear apart your body’s atoms — not burn you, not crush you, but distort the electron clouds of your atoms until chemistry itself stops working
- Its field could wipe every credit card and hard drive on Earth from half the Moon’s distance
- The crust of a magnetar is under such magnetic stress that when it cracks — a “starquake” — the flash can be detected across the galaxy
That last one isn’t hypothetical. On December 27, 2004, a magnetar called SGR 1806-20 — 50,000 light-years away, on the far side of the Milky Way — suffered a giant flare. In one-tenth of a second it released more energy than our Sun emits in 100,000 years.
The blast physically ionized Earth’s upper atmosphere and briefly blinded satellites. From fifty thousand light-years. If a magnetar flared like that within 10 light-years — thankfully, none are that close — it could strip our ozone layer.
Where do these monsters come from? Some massive stars, when they collapse, spin so violently that their interiors act like a colossal dynamo, winding the magnetic field up to breaking point. The magnetar phase is short — after about 10,000 years the field decays and the star quiets down.
Astronomers know of only around 30 of them in our galaxy. Given how briefly they blaze, millions of burnt-out ex-magnetars must be drifting silently among the stars — retired monsters, keeping to themselves.