For several weeks raged rumors that scientists have recorded gravitational waves — tiny ripples in space and time — a new type that is not associated with the collision of black holes. And here we got the final confirmation that saw similar waves produced by the violent collision of two massive superdense stars 100 million light years from Earth.
The discovery was made on 17 August by the global network of modern gravitational-wave interferometers consisting of two LIGO detectors in the United States and its European cousin, Virgo in Italy. The discovery is extremely important, not least because it helps to solve the biggest mysteries in astrophysics — including the reason for the bright flashes, known as “gamma ray bursts”, and perhaps even the origin of heavy elements such as gold.
Hereinafter in the first person: Martin Hendry, Professor of gravitational astronomy and cosmology at the University of Glasgow.
As a member of the LIGO scientific collaboration, I was ecstatic as soon as saw the original data. The next period was definitely the most intense and restless, but also exciting two months of my career.
The announcement followed a few weeks after the three scientists were awarded the Nobel prize in physics for their important work, which led to the discovery of gravitational waves, first announced in February 2016. Since the detection of gravitational waves from colliding black holes closer to us — it was another four such events. But as far as we know, the collision of black holes opens a window only on the dark side of the Universe. We would not be able to capture the light from such events, with any tools.
But GW170817 — event name 17 August changed everything. Because the source of the waves this time were two “neutron star” is an incredibly dense remnants of stars the size of a city, each weighing more than the sun. These stars are worn around one another on a giant speed, and then merge in a terrible clash that we saw the stunning very fabric of space and time.
Solved puzzles
The space concert was only the beginning. Astronomers have long suspected that the merger of two neutron stars may be the Overture for short gamma-ray burst, a powerful flash of gamma-rays, which emit more energy in a split second than the sun in ten billion years. We observed gamma rays for decades, but didn’t know what causes them.
However, in just 1.7 seconds after gravitational waves from GW170817 arrived on Earth, NASA’s Fermi satellite detected a short burst of gamma-rays in the same region of the sky. LIGO and Virgo found the Smoking gun and the link between the collisions of neutron stars and short bursts of gamma-rays has been installed completely and clearly.
The combination of gravitational wave and gamma-ray observations allowed us to determine the position of cosmic explosion with a precision of up to 30 square degrees of the sky — or 100 times larger area than the full moon. This, in turn, allowed a battery of astronomical telescopes sensitive to light of the electromagnetic spectrum to search this small area of sky in search of the afterglow of the explosion. And they found him in the back of a fairly modest NGC4993 galaxy, in the constellation Hydra.
In the following days and weeks, the astronomers watched the agony until the embers from the explosion flashed and faded, beautifully merging into the picture, describing the so-called “celonova”. It is born when the material is rich subatomic particles — neutrons, from the original merge is ejected at high speed under the action of gamma-ray burst. All of this is emitted into the surrounding space leads to the production of heavy radioactive elements.
Unstable elements then decay to a stable state with emission of radiation. This leads to the illumination of Bulanovoj, which we confirmed, making a detailed map. Our observations also confirmed the theory that the stable end products of these chain reactions include the abundance of precious metals such as gold and platinum. Although we suspected that neutron stars play a key role in the creation of these elements in space, this hypothesis now seems much more convincing. In fact, celonova, which was formed from the shards GW170817, could produce gold by mass of the whole Earth of 1000 trillion tons.
Watching Bulanovoj “intimate” for the first time and seeing how well it fits in the unfolding astronomical storyboard, which began with the merger of neutron stars, astronomers realized a huge leap to understanding these violent cosmic events.
The idea that we are all made of Stardust, are incredibly popular in the cultural consciousness — everything from documentary films to song lyrics. But mind-blowing concept that the gold in our wedding rings and Rolex are made of neutron star dust, the more interesting. Even more exciting is the huge potential that opens in a new radical approaches to the study of the cosmos.
Working together — using the tools that work not only across the spectrum of light, but sensitive to gravitational waves, and even the neutrino astronomers are ready to open a new window into the Universe. For example, they’ve used their observations to make a first measurement of the speed of expansion of the Universe using gravitational waves, and light.
New results will follow soon. With this explosion of exciting new multiplayer era of astronomy is just beginning.
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