Jet Of Material From Neutron Star Collision Appears To Eclipse Light Speed

When two neutron stars collided in August of 2017, the resulting black hole emitted a jet of cosmic material at extremely high speed.

Artist's rendering of neutron star collision and resulting jet
D. Berry, O. Gottlieb, K. Mooley, G. Hallinan / NRAO/AUI/NSF

When two neutron stars collided in August of 2017, the resulting black hole emitted a jet of cosmic material at extremely high speed.

As reported by the Inquisitr in June 2018, the collision of two neutron stars in the cosmic event known as GW170817, perceived by humans in August of last year, appears to have created a black hole. It also appears to have created a jet of superfast material, detected and measured by a collection of National Science Foundation radio telescopes, and the results of those measurements seemed to show the jet moving at nearly four times the speed of light, an impossibility in our current understanding of the laws of physics.

In observations less than half a year apart, the jet seemed to cover a distance greater than two light years. Since a light year is defined as the distance light can travel through a vacuum in a year, that would indicate that the jet was hurtling toward Earth at nearly four times the speed of light, according to Space.com.

The truth, though, is a little different. Because the jet was pointed almost exactly at Earth, and because it was moving very fast, that created an illusion known as “superluminal motion,” which makes the movement appear to be much faster than it actually was, as Adam Deller (Swinburne University, formerly with the National Radio Astronomy Observatory) explains.

“Based on our analysis, this jet most likely is very narrow, at most 5 degrees wide, and was pointed only 20 degrees away from the Earth’s direction. But to match our observations, the material in the jet also has to be blasting outwards at over 97 percent of the speed of light.”

A visual summary of Deller’s explanation is below.

Neutron star collision rendering
  Sophia Dagnello / NRAO/AUI/NSF

Scientists learned of the existence of the collision when a magnetic wave detector alerted them to an imminent event. As stated on ScienceAlert, radio telescopes around the globe coordinated to observe the once-in-a-lifetime event, giving scientists an unprecedented collection of data and radio images. They learned that a cocoon of cosmic debris created by the collision initially masked and inhibited the jet, expanding outward until it could no longer hold the jet. As shown in the image at the top of this post, the jet on the opposite pole of the debris field was squelched, and didn’t make it out of the debris field, but the one pointing toward Earth did. And since its existence was masked by the debris field’s radio interference before it broke through the boundary, it appeared to move faster than the speed of light.