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In detecting star collision for first time, astronomers see a new era

An artist's depiction of neutron star merger. Credit: NSF / LIGO / Sonoma State University / A. Simonnet

Scientists announced today they've detected the collision of two neutron stars 130 million years ago. It's the first time one of the massive mergers has been witnessed, and that light detected with telescopes has been combined with gravitational waves detection to observe a cosmic event.

What it means: "This result provides definitive evidence for the first time that heavy elements like platinum and gold, are produced in these collisions," David Reitze, executive director of the LIGO Laboratory, whose founders will collect the Nobel Prize in physics this year. The so-called "multi-messenger astronomy" allows researchers to view events in both light and sound, and will be used to better understand the structure of stars, the rate of expansion of the universe and other fundamental questions in physics.

What they saw: 130 million years ago, two dense neutron stars — with masses 1.6 and 1.1 times those of our sun crammed into about 10-mile-wide spaces — merged. The highly energetic event sent ripples across space and time that physicists working with the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo detectors observed on Aug. 17, 2017. The collision, which occurred relatively close to Earth, released high-energy, gamma-ray light that was also then seen by 70 optical, X-ray, radio, ultraviolet, infrared, and gamma-ray telescopes around the world and in space over the following days.

What's next: Dozens of papers are being published today by the more than 3500 researchers involved in the work. The LIGO and Virgo detectors have finished their current run and will be offline for a year while researchers try to optimize them. "[They are] currently working at a fraction of their sensitivity. We expect to increase the overall network sensitivity by about a factor of 2," said LIGO spokesperson David Shoemaker. That would open up 8 times more space for surveying and, they hope, observing other events like supernovae.

Go deeper: Quanta's Katia Moskvitch has the play-by-play of the detection.