Home Science They detect gravitational waves from neutron star fusion

They detect gravitational waves from neutron star fusion

For the first time in history this phenomenon is detected from the fusion of two neutron stars, which happened millions of years ago.


At last there has been official confirmation. Many years ago, in a very distant galaxy (but clearly identified, as we will explain later)  two neutron stars merged  to form either another neutron star “daughter” (called “kilonova”) or even a  black hole . The remnant energy of this fusion did not reach the earth until August 17, just a few days before the Sun eclipse, which was visible, for example, from the US.

Speaking of the Sun and of neutron stars … Let us quickly remember that a neutron star is what remains after the supernova explosion of a star a little bigger than our “star king.” In this case, the electrons and protons ended up fusing and forming neutrons and neutrinos. The latter escape at almost the speed of light, but the former will remain “bundled” forever, forming the heaviest and hardest objects in the cosmos.

But let’s return to the main topic of this article. In spite of overcoming many technological obstacles to reach the detection of gravitational waves and to have produced this already in several occasions, still were skeptical people against these achievements. After all, there has never been corroboration by other observatories and / or experiments. But after the find, there is no longer any right to have more doubts.

As we said and already predicted the rumors, scientists have discovered the fusion of two neutron stars that happened millions of years ago to millions of light years.

But what is really interesting about this detection is that the same event has been observed both in the “spectrum of gravitational waves” and in the electromagnetic spectrum.

We also remember that the latter is where we are accustomed to work and that involves all kinds of “light”: visible, radio, infrared, ultraviolet, gamma, etc.

Chronology of discovery

It all started on August 17 at 8:41 am (Eastern Time) when LIGO detected a clear gravitational wave pattern we have already discussed on other occasions. This signal lasted about 100 seconds (the longest to date and coincides with the expected shape produced by the fusion of two neutron stars). About two seconds later, the Fermi telescope and the Integral satellite detected a gamma-ray emission (electromagnetic spectrum).

For many years it has been thought that gamma ray bursts came from the fusion of neutron stars, but there had never been clear evidence until this moment. Everything seems to indicate that the detection of gravitational waves by Ligo and the location of gamma rays carried out by two different telescopes came from the same cosmological event.

Unlike with black holes, in the collision of   neutron stars light is emitted and it continues to generate even seconds after the cataclysm has ended. Thanks to the coordination of data from Fermi, Integral and Ligo, it has been possible to specify the area of space where neutron star fusion could have occurred with astonishing precision.

But also, with Virgo data (which was already operational), this region narrowed even more: barely the size that would have 140 full moons on the horizon.

A few hours later, astronomers from the VLT telescope in Chile directed their sensors to that area of space,  clearly identifying a change in the brightness of a point in the galaxy NGC 4993: the aftermath of our fusion of neutron stars.

In short:  a new era in astronomy begins.  A new era in which we are a little less “blind” to the events of the universe. A new era in which we combine our perfected vision ability in the electromagnetic spectrum with a new sixth sense:  the talent to measure the zigzags of space itself and of time itself.


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