spaceSpace and Physics

Clues About Black Hole Formation Found in Massive Stellar Explosion

guest author image

Lisa Winter

Guest Author

880 Clues About Black Hole Formation Found in Massive Stellar Explosion
NASA/Goddard Space Flight Center/S. Wiessinger

A massive international collaboration involving 27 institutions in 13 countries has found clues about how black holes are formed, due to the massive explosion of the star GRB121024A, in the constellation Eridanus. These clues have made it possible for construct computer simulations about how black holes came to be. The results of the study were published in Nature.

Though the demise of GRB121024A was discovered in October 2012, the star actually exploded about 11 billion years earlier. It was first detected by scientists operating NASA’s Swift Telescope, and observatories around the world were alerted soon after. (I’d like to think that there’s some kind of Batphone protocol set up to call everyone so quickly—glass cloche and all.) The ESO’s Very Large Telescope (VLT) was the only observatory to collect meaningful measurements from the event.


The star GRB121024A was massive; hundreds times larger than our Sun. It also spun on its axis incredibly rapidly, which intensifies the magnetic field. In comparison, our Sun rotates fairly slowly as it takes about a month to complete one rotation. Because of its size and rotation rate, GRB121024A did not explode like less massive stars, which expand outward like a firework. 

Instead, scientists believe that its mass and magnetic field caused the star to implode, swirling around like a sink full of water going down the drain. The rotation axis of the star, however, still has a job to do. Before the star collapses, the magnetic field rotates at both ends of the star around the axis. When the end finally comes and the star collapses into a black hole, the magnetic field is ejected outward into the Universe along the line of the axis. These explosions are called Long Gamma Ray Bursts (LGRB) and produce more energy in one second than hundreds of Sun-like stars could collectively produce in 10 billion years.

The data obtained from GRB121024A’s collapse by the VLT revealed a very important clue about the LGRB: circular polarization of the light. Essentially, instead of pushing through the Universe in a straight line, the light moves like a corkscrew. Though this idea that light behaves this way had been theorized previously, this event was the first time data has been collected that shows light emitted from a black hole moving as a screw, therefore supporting the model. This explosion was also the most distant and strongest instance of light being detected that exhibited circular polarization.


spaceSpace and Physics
  • tag
  • black hole,

  • star collapse,

  • circular polarization