Stellar Explosion Reveals How Black Holes Form from Massive Stars

In October 2012, a massive stellar explosion erupted in space. At the time, the European Southern Observatory used its Very Large Telescope (VLT) in order to take accurate polarimetric measurements of the phenomenon. Now, scientists have taken a closer look at this data, and have reconstructed exactly how a black hole is formed.

The stellar explosion, called the GRB121024A, occurred about 11,000 million years ago. Yet it took that long for the light to reach Earth. This particular explosion is known as a Long Gamma-Ray Burst (LGRB), which is an event that produces masses of energy; in just one second a single GRB can emit as many as hundreds of stars like the sun during its 10,000-million-year-lifetime.

For the past decade, scientists have suspected that LGRBs occur when so-called massive stars burst. These massive stars have masses of up to hundreds of times bigger than our own sun, and spin rapidly on a rotation axis. Because of these properties, the stars don't explode normally; instead, the implosion of these stars produce a huge spinning top. This top then turns in the way that water rotates down the plughole of a basin until a black hole is formed. The energy given off by this explosion is then emitted in two jets.

Because these stars have magnetic fields, the fields themselves are intensified further if they rotate rapidly. This means that during the internal collapse of the star, the magnetic fields intensify and a "magnetic geyser" is produced and then ejected from the environment of the black hole being formed. Light emitted during the explosion of the star would be circularly polarized as if it were a screw.

Now, scientists have found evidence of this scenario. They've detected circularly polarized light that is the direct consequence of a black hold recently created on the outer reaches of the universe. Finding GRB121024A shows a bit more about how black holes are formed, and confirms that theories are, indeed, correct.

The findings are published in the journal Nature.