Odd Source

The heart of the galaxy is filled with many wonders: a supermassive black hole, thousands of pulsars, looping magnetic fields, and odd sources of radio waves.

Perhaps the oddest of the radio sources was reported last year. It’s no more than about 30,000 light-years away, toward the center of the galaxy. That suggests that it’s in the Milky Way’s busy heart.

Astronomers watched the object — which doesn’t have a proper name — for two years.

At first, it would switch on and stay on for weeks, although its brightness varied dramatically. Later, though, it appeared and disappeared in as little as a day. And its light was polarized — all the radio waves lined up like a marching band. The astronomers looked for the object at many other wavelengths, with telescopes on the ground and in space. But they saw nothing.

The astronomers say it’s not a single star, a binary star, or a pulsar — a dead star that flickers with a steady beat. They’ve also ruled out anything beyond the Milky Way.

It’s similar to a class of objects known as galactic center radio transients, which also are poorly understood. But there are many differences, too. So it could be something new — a new addition to the list of wonders at the heart of the galaxy.

Although you can’t see it, the object is quite low in the south-southeast at nightfall. It’s to the right of the Sagittarius “teapot” and just above the “stinger” at the tail of the scorpion.
 

Script by Damond Benningfield

Today's program was made possible by Mercer Caverns, in Calaveras County in California's historic Gold Country.