In first, scientists detect gravitational waves and light from star collision

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These studies showed signatures of newly synthesized elements, confirming that such mergers are indeed the birthplaces of half of the elements heavier than iron - including most of the gold and platinum in the universe.

This is the fourth gravitational wave event documented by LIGO in the last two years, although the newest cosmic event is unique.

The discovery was made using the USA -based Laser Interferometer Gravitational-Wave Observatory (LIGO); the Europe-based Virgo detector, with its detection centre at Pisa; and some 70 ground- and space-based observatories.

Paranal Observatory's Visible and Infrared Survey Telescope and VLT Survey Telescope, La Silla Observatory's Rapid Eye Mount telescope, Las Cumbres Observatory's LCO 0.4-meter telescope, and Cerro Tololo Inter-American Observatory's Dark Energy Camera were all used to observe further developments.

LIGO first announced the detection and direct observation of Einstein's theorized gravitational waves back in February 2016, nearly 100 years after he published his General Theory of Relativity. But here we are again and, far from getting old, the news is more exciting than ever: we've picked up a new kind of signal, from merging neutron stars rather than black holes.

The new Virgo detector in Italy didn't directly see the gravitational waves because they were in its blind spot.

Gravitational wave astronomy offers a powerful new way to study such high-energy events. "It's the fulfillment of dozens, hundreds, thousands of people's efforts, but it's also the fulfillment of an idea suddenly becoming real", says Peter Saulson of Syracuse University, who has spent more than three decades working on the detection of gravitational waves. This detection was like experiencing a storm in a room with windows, changing everything scientists thought they knew.

British Ligo scientist Professor BS Sathyaprakash, from the University of Cardiff, described the new discovery as "truly a eureka moment". A lead of 1.7 seconds after a journey of several million years isn't all that much, but it still hints that there's intriguing physics at work here.

Europe's Virgo becomes the third detector in the hunt for gravitational waves.

"We immediately rang our team in Australia and told them to get onto the CSIRO telescope as soon as possible, then started planning our observations", she said.

In a collaboration with UC Santa Cruz, Carnegie Observatories were the first in the world to discover this event.

"On the cosmological scale, this happened in our neighborhood", says Andreas Freise of the University of Birmingham and a LIGO collaborator.It's good luck, then, also on a cosmological scale that humans happen to have invested in building the right instruments to watch such an event at just about the right time.

That's because following a kilonova explosion radioactive heavy chemical elements, including gold and platinum, that are formed by nuclear reactions, are thrown out into space. A gravitational wave stretches space in one direction and compress it in a perpendicular direction.

"This singular event finally solves all these problems, bringing together all these mysteries at once", Piro said.

Detectors from the USA and Europe also found the collision had produced a short gamma ray burst - extremely energetic explosions often regarded as the brightest electromagnetic event in the universe. The result is a white dwarf, a slowly cooling stellar remnant with up to 1.44 times the sun's mass packed into a body the size of a small planet. So think of the sun, compressed into a major city. Experts knew that the collision outcome "depends very much on how large the stars are and how "soft" or "springy' - in other words, how much they resist being deformed by super-strong gravitational forces", Dent said".

Israeli physicist Tsvi Piran proposed in 1989 that some of these bursts could be created by coalescing neutron stars. Might it produce all of the elements in the periodic table?

That occurs only up to the level of iron.

One theoretical source for heavier elements is supernova explosions that happen when massive stars run out of fuel and die. That was what astronomers witnessed during this particular collision.

"He was able to predict that his theory said these things should exist, but said they will be way too small for us to ever measure them", Smith said.

Dr Douglas Bock, Director of CSIRO's Astronomy & Space Science team, said this extraordinary detection by an Australian team, using Australian facilities, made a significant contribution to the global discovery.

The LIGO observatory features two stations, one in Washington and the other in Louisiana, that each feature a pair of 2.5-mile-long vacuum tubes arranged in an L shape in which precisely tuned laser beams flash back and forth between multiple mirrors.

One question already answered is the origin of short-duration gamma ray bursts. To them, it is a once-in-a-lifetime discovery. This is actually the 50th year of the discovery of neutron stars. Analysis suggested that they were the result of a collision between two neutron stars but clinching evidence has always eluded astronomers. We only had theories regarding what gamma-ray bursts, as they are called, are made up of, but now it is confirmed that indeed colliding neutron stars produce gamma-ray bursts.

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