A Cosmic Collision
Posted by on Tuesday, October 17, 2017 Under: Astronomy
There was an interesting joint announcement today from the LIGO, Virgo, and Fermi telescope teams, and one that will have great value to the astrophysics community. For the first time, all three simultaneously detected a neutron star collision and were able to collect data regarding both its gravitational wave signature and its gamma-ray signature. This new data will provide for interesting new studies on the physics of neutron stars and on the origin of several heavier elements in the Universe.
In our galaxy and in the Universe at large, stars are constantly being formed in various sizes, masses, and temperatures. Each have their own interesting properties and life cycles. As these stars get older, they can shed their outer layers and leave only a dense core of heavy elements in a superheated plasma. If the core is very heavy it can collapse down to a black hole. But if it is a little lighter, then the nuclear repulsion between nuclei can prevent this collapse and instead leave a superdense mass of neutrons. This object is called a neutron star.
In this particular system, located roughly 130 million lightyears away in the Hydra constellation, there were two neutron stars that were orbiting each other. Due to their mass, they were each slowly losing energy to gravitational waves, which in turn caused their orbits to slowly decay and the two massive stars slowly approached each other. Eventually they had lost so much energy that the two neutron stars collided in a violent reaction, and scattered their contents throughout their region of the Universe.
As a result of this collision, both gravitational waves and high energy gamma-rays were sent out into space. Those emissions traveled for 130 million years, before being detected on Earth on August 17, 2017. LIGO and VIRGO used their large interferometers to detect the gravitational waves, while the Fermi telescope detected the gamma rays.
However the collision did not only produce gravitational and electromagnetic emissions. Astronomers pointed their telescopes toward the location of the collision and were able to detect large quantities of heavier elements such as gold, mercury, platinum and uranium. This immediately solves one of the lingering mysteries of astrophysics, as the source of these elements in the galaxy were not known before. Lighter elements are forged in the nuclear fusion reactions inside stars, but these processes are not energetic enough or efficient enough to produce heavier elements in significant quantities. It was previously suspected that neutron stars could be the source, but this one collision has now proven that to be true. It would appear from the early data that neutron star collisions could be the source of more than half of the heavy elements in the Universe!
This is an amazing discovery, and for many astronomers and astrophysicists this will be their career highlight. The data from this collision will likely be analyzed for decades to come, in the same way as the 1987 supernova that is still being studied thirty years later. And it makes this year's selection of the LIGO team has the Nobel Prize recipients even more appropriate!
Congratulations to all of the scientists involved in both the detection of the signal and the subsequent studies and analysis. This is an amazing discovery, and one that will have a significant impact on the future of physics!
In our galaxy and in the Universe at large, stars are constantly being formed in various sizes, masses, and temperatures. Each have their own interesting properties and life cycles. As these stars get older, they can shed their outer layers and leave only a dense core of heavy elements in a superheated plasma. If the core is very heavy it can collapse down to a black hole. But if it is a little lighter, then the nuclear repulsion between nuclei can prevent this collapse and instead leave a superdense mass of neutrons. This object is called a neutron star.
In this particular system, located roughly 130 million lightyears away in the Hydra constellation, there were two neutron stars that were orbiting each other. Due to their mass, they were each slowly losing energy to gravitational waves, which in turn caused their orbits to slowly decay and the two massive stars slowly approached each other. Eventually they had lost so much energy that the two neutron stars collided in a violent reaction, and scattered their contents throughout their region of the Universe.
As a result of this collision, both gravitational waves and high energy gamma-rays were sent out into space. Those emissions traveled for 130 million years, before being detected on Earth on August 17, 2017. LIGO and VIRGO used their large interferometers to detect the gravitational waves, while the Fermi telescope detected the gamma rays.
However the collision did not only produce gravitational and electromagnetic emissions. Astronomers pointed their telescopes toward the location of the collision and were able to detect large quantities of heavier elements such as gold, mercury, platinum and uranium. This immediately solves one of the lingering mysteries of astrophysics, as the source of these elements in the galaxy were not known before. Lighter elements are forged in the nuclear fusion reactions inside stars, but these processes are not energetic enough or efficient enough to produce heavier elements in significant quantities. It was previously suspected that neutron stars could be the source, but this one collision has now proven that to be true. It would appear from the early data that neutron star collisions could be the source of more than half of the heavy elements in the Universe!
This is an amazing discovery, and for many astronomers and astrophysicists this will be their career highlight. The data from this collision will likely be analyzed for decades to come, in the same way as the 1987 supernova that is still being studied thirty years later. And it makes this year's selection of the LIGO team has the Nobel Prize recipients even more appropriate!
Congratulations to all of the scientists involved in both the detection of the signal and the subsequent studies and analysis. This is an amazing discovery, and one that will have a significant impact on the future of physics!
In : Astronomy
I am a theoretical physicist & mathematician, with training in electronics, programming, robotics, and a number of other related fields.
