A collision of two neutron stars spewed out matter that appears to spread much faster than the speed of light, something that would be impossible.
Astronomers around the world detected an epic collision between two neutron stars in August 2017 that released energy like a supernova, it was the first combined detection of gravitational waves and gamma radiation, but what they did not know is that this would be just the beginning, as the effects that came after would be very interesting and provide information for future research. Scientists have revealed that this incident expelled a jet of material that appeared to be shot into space at seven times the speed of light, a fact that according to Einstein’s physics, is simply impossible.
The aftermath of a neutron star collision
Neutron stars are “compacted” surviving cores of massive stars that have exploded heavier than the sun. Now that we know this, a chunk of their surface material would weigh at least 4 billion tons on Earth. When two such stars collide head-on they ripple the fabric of time and space, a phenomenon known as gravitational waves, and can be measured by detectors here on Earth.
[Photo: Elizabeth Wheatley (STScI)/HUBBLE]
Just two days after the explosion, Hubble was pointed at the site of the explosion, which occurred in a black hole with powerful gravity that began to pull material toward it. The material formed a rapidly spinning disk and generated jets that moved away from its poles.
Then, the jet of radiation that was ejected at nearly the speed of light hit the material surrounding the two colliding neutron stars. The astronomers used Hubble to measure the motion of the blob of material that the jet hit.
As we know, according to current physics, exceeding the speed of light is impossible. But such events, which are an optical illusion, are known as superluminal velocities. It is not that it really broke the speed of light, but it is an illusion due to the angle of view, as the object gets closer the distance needed for the light to travel to us is shortened.
[Isolated neutron star in a supernova: NAF-Osservatorio Astronomico di Palermo/Salvatore Orlando]
Astronomers used the incredible precision of NASA’s Hubble space telescope and other radio telescopes to make the measurements and were able to develop a system called Very Long Baseline Interferometry (VLBI), which indicated that the jet driven by the titanic collision between the two stars emerged at speeds greater than 99.97% of the speed of light.
“I am amazed that Hubble can give us such an accurate measurement, rivaling the precision achieved by the powerful VLBI radio telescopes scattered around the world,” said the lead author of the paper published in the journal Nature, Kunal P. Mooley of Caltech Pasadena.
“We have demonstrated that precision astronomy with space-based optical and infrared telescopes is an excellent means to measure the proper motions of jets in neutron star mergers,” they wrote in the paper. That is why this event was an important breakthrough in the emerging field of time-domain astrophysics and multiple messengers such as light and gravitational waves to study the universe as time changes.
Story originally published in Spanish in Ecoosfera