Magnetars

You don’t want to get close to a magnetar. From a distance of hundreds of miles, the universe’s most powerful magnets would tug at the electrons in your body’s atoms, pulling the atoms out of shape — and causing you to fall apart.

The first magnetar was discovered 40 years ago today. A wave of gamma rays swept across the solar system — the most powerful outburst seen to that time. It was detected by spacecraft in Earth orbit and beyond, allowing astronomers to pinpoint the source: clouds of debris from an exploded star.

It took a while for astronomers to understand what they were seeing, though: the star’s highly magnetized corpse, now called a magnetar.

A magnetar forms at the end of a massive star’s life. The star can no longer produce energy in its core, so the core collapses. The core is about twice the mass of the Sun, but it’s compressed into a ball only about a dozen miles across. The resulting “corpse” is known as a neutron star.

As the core shrinks, its magnetic field intensifies. The “squeezed” field can be more than a million million times the strength of Earth’s magnetic field.

The field is strong enough to trigger “quakes” in the star’s ultra-dense surface. These tremors produce intense outbursts of gamma-rays — like the one detected in 1979.

A magnetar’s magnetic field decays quickly. So in about 10,000 years, the magnetar loses most of its field — and settles into life as a “normal” neutron star. More tomorrow.

Script by Damond Benningfield