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  • Scientists witness huge cosmic crash, find origins of gold

    https://www.yahoo.com/news/scientist...140024492.html

    Scientists witness huge cosmic crash, find origins of gold

    Associated Press SETH BORENSTEIN,Associated Press 3 hours ago


    WASHINGTON (AP) It was a faint signal, but it told of one of the most violent acts in the universe, and it would soon reveal secrets of the cosmos, including how gold was created.

    Astronomers around the world reacted to the signal quickly, focusing telescopes located on every continent and even in orbit to a distant spot in the sky.

    What they witnessed in mid-August and revealed Monday was the long-ago collision of two neutron stars a phenomenon California Institute of Technology's David H. Reitze called "the most spectacular fireworks in the universe."

    "When these things collide, all hell breaks loose," he said.

    Measurements of the light and other energy emanating from the crash have helped scientists explain how planet-killing gamma ray bursts are born, how fast the universe is expanding, and where heavy elements like platinum and gold come from.

    "This is getting everything you wish for," said Syracuse University physics professor Duncan Brown, one of more than 4,000 scientists involved in the blitz of science that the crash kicked off. "This is our fantasy observation."

    It started in a galaxy called NGC 4993, seen from Earth in the Hydra constellation. Two neutron stars, collapsed cores of stars so dense that a teaspoon of their matter would weigh 1 billion tons, danced ever faster and closer together until they collided, said Carnegie Institution astronomer Maria Drout.

    The crash, called a kilonova, generated a fierce burst of gamma rays and a gravitational wave, a faint ripple in the fabric of space and time, first theorized by Albert Einstein.

    The signal arrived on Earth on Aug. 17 after traveling 130 million light-years. A light-year is 5.88 trillion miles.

    NASA's Fermi telescope, which detects gamma rays, sent out the first alarm. Then, 1.7 seconds later, gravity wave detectors in Louisiana and Washington state that are a part of the LIGO Laboratory , whose founders won a Nobel Prize earlier this month, detected the crash. It issued a worldwide alert to focus telescopes on what became the most well-observed astronomical event in history.

    Before August, the only other gravity waves detected by LIGO were generated by colliding black holes. But black holes let no light escape, so astronomers could see nothing.

    This time there was plenty to see, measure and analyze: matter, light, and other radiation. The Hubble Space Telescope even got a snapshot of the afterglow.

    "The completeness of this picture from the beginning to the end is unprecedented," said Columbia University physics professor Szabolcs Marka. "There are many, many extraordinary discoveries within the discovery."

    The colliding stars spewed bright blue, super-hot debris that was dense and unstable. Some of it coalesced into heavy elements, like gold, platinum and uranium. Scientists had suspected neutron star collisions had enough power to create heavier elements, but weren't certain until they witnessed it.

    "We see the gold being formed," said Syracuse's Brown.

    Calculations from a telescope measuring ultraviolet light showed that the combined mass of the heavy elements from this explosion is 1,300 times the mass of Earth. And all that stuff including lighter elements was thrown out in all different directions and is now speeding across the universe.

    Perhaps one day the material will clump together into planets the way ours was formed, Reitze said maybe ones with rich veins of precious metals.

    "We already knew that iron came from a stellar explosion, the calcium in your bones came from stars and now we know the gold in your wedding ring came from merging neutron stars," said University of California Santa Cruz's Ryan Foley.

    The crash also helped explain the origins of one of the most dangerous forces of the cosmos short gamma ray bursts, focused beams of radiation that could erase life on any planet that happened to get in the way. These bursts shoot out in two different directions perpendicular to where the two neutron stars first crash, Reitze said.

    Luckily for us, the beams of gamma rays were not focused on Earth and were generated too far away to be a threat, he said.

    Scientists knew that the universe has been expanding since the Big Bang. By using LIGO to measure gravitational waves while watching this event unfold, researchers came up with a new estimate for how fast that is happening, the so-called Hubble Constant. Before this, scientists came up with two slightly different answers using different techniques. The rough figure that came out of this event is between the original two, Reitze said.

    The first optical images showed a bright blue dot that was very hot, which was likely the start of the heavy element creation process amid the neutron star debris, Drout said. After a day or two that blue faded, becoming much fainter and redder. And after three weeks it was completely gone, she said.

    Scientists involved with the search for gravitational waves said this was the event they had prepared for over more than 20 years.

    The findings are "of spectacular importance," said Penn State physicist Abhay Ashtekar, who wasn't part of the research. "This is really brand new."

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    Follow Seth Borenstein on Twitter at @borenbears . His work can be found here .

  • #2
    https://www.yahoo.com/news/scientist...162758065.html

    https://www.yahoo.com/news/scientist...162758065.htmlhttps://www.yahoo.com/news/scientist...162758065.html A violent collision of two super-dense neutron stars in a distant galaxy has helped astronomers uncover cosmic secrets, including where gold comes from. Scientists revealed that detectors picked up the crash's faint signals in mid-August. (Oct. 16)

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    • #3
      What cosmic crash confirmed: Einstein was as good as gold

      Associated Press SETH BORENSTEIN,Associated Press 3 hours ago


      WASHINGTON (AP) When two extremely dense neutron stars crashed together in a distant galaxy, astronomers struck scientific gold, confirming previously unproven theories, including some from Albert Einstein.

      Scientists announced Monday that after picking up two faint signals in mid-August, they were able to find the location of the long-ago crash and see the end of it play out. Measurements of the light and other energy that the crash produced helped them answer some cosmic questions.

      GRAVITATIONAL WAVES

      Scientists, starting with Einstein, figured that when two neutron stars collide they would produce a gravitational wave, a ripple in the universe-wide fabric of space-time. Four other times that these waves were detected they were the result of merging black holes. This is the first time scientists observed one caused by a neutron star crash.

      WHERE GOLD COMES FROM

      The Big Bang created light elements like hydrogen and helium. Supernovas created medium elements, up to iron. But what about the heavier ones like gold, platinum and uranium? Astronomers thought they came from two neutron stars colliding, and when they saw this crash they confirmed it. One astronomer described it as a "giant train wreck that creates gold." They estimate that this one event generated an amount of gold and platinum that outweighs the entire Earth by a factor of 10.

      GAMMA RAYS

      Gamma ray bursts are some of the most energetic and deadly pulses of radiation in the universe. Astronomers weren't quite sure where short gamma ray bursts came from, but figured that a crash of neutron stars was a good bet. Watching this event confirmed the theory.

      EXPANDING UNIVERSE

      Astronomers know the universe is expanding, and they use a figure called the Hubble Constant to describe how fast. Two different ways scientists have of measuring this speed of expansion yields two numbers that are somewhat close to each other, but not quite the same. By measuring how far the gravitational wave had to travel, astronomers came up with another estimate that was between the earlier two, but it also comes with a large margin of error.

      HOW FAST DO RAYS AND WAVES GO?

      The crash showed that gravitational waves and gamma rays travel at nearly the speed of light which is what Einstein's General Relativity theory says. NASA astrophysicist Julie McEnery said: "Yet again, Einstein passes another test."

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