Science Is Awesome: Neutron Star Predictions Correct


Credit: University of California Santa Cruz and Carnegie Observatories, Ryan Foley

Credit: University of California Santa Cruz and Carnegie Observatories, Ryan Foley

All of the mainstream media outlets are trumpeting the news that gravitational and electromagnetic waves have been detected from the collision of two neutron stars. Two failed black holes, solar masses of neutronium, the densest stuff in the universe, slammed into each other at relativistic speeds. It’s something you’d want to watch from a safe distance. Say, a couple of parsecs of so.

They are all missing the point.

The point is pretty much complete verification of a hypothesis based upon a theory. Which is, you know, science. And the whole point of science.

Neutron stars aren’t news; astrophysics has known about them for decades. There are ample data of observations consistent with neutron stars.

Neutron stars rotating around each other isn’t a new thing, either. They’ve also been known for decades. In fact, they are so well observed that science can predict when neutron stars in orbit around each other will collide. A corollary of Einstein’s General Theory of Relativity holds that the generation of gravity waves will slowly leach energy out of rotating neutron stars, causing them to eventually collide. And astrophysicists have observed the slow – very slow – orbital changes Einstein’s theory would predict.

But here’s what’s so cool about this latest data.

Science made predictions about what would happen when two neutron stars collide: generation of a specific kind of gamma radiation; generation of a specific kind of sustained gravity wave; and generation of a specific kind of x-rays, except that in certain situations the x-rays would be undetectable; and generation of detectable amounts of certain heavy elements, including gold.

Those predictions went four for four, a stunning corroboration of theory.

Gravity waves? Check. On Thursday, August 17th, at 12:41:04 UT, Advanced Laser Interferometry Gravitational-Wave Observatory (LIGO) bagged its fifth confirmed gravitational-wave signal, now designated GW170817. The gravity wave detection apparatus detected gravitational waves for nearly 100 seconds, consistent with the relatively small neutron stars; black hole mergers produce detectable waves for only a fraction of a second.

Gamma radiation burst? Check. Just two seconds after the gravitational-wave event, at 12:41:06 UT, NASA’s Fermi Gamma-ray Space Telescope detected a short gamma-ray burst — a brief, powerful “flash” of the most energetic electromagnetic radiation in nature. The European Space Agency’s Integral gamma-ray observatory confirmed the outburst.

X-ray radiation? Hmm. Not detected. But the predictions say there should be “blind spots.” If this event was in such a “blind spot,” then it had to have occurred in a specific region of the sky. And, amazingly, when scientists looked, there it was, the visible light confirmation of the collision. That’s now, by a considerable margin, the most intensively studied spot in the sky in the last year.

The red circle on this chart shows the location of the galaxy NGC 4993 near the border of the sprawling constellation of Hydra, the Sea Serpent. ESO / IAU / Sky & Telescope

The red circle on this chart shows the location of the neutron star collision in the galaxy NGC 4993 near the border of the sprawling constellation of Hydra, the Sea Serpent.
ESO / IAU / Sky & Telescope

The photo at the top is from a stellar object that is 130 million light years away. But there it was, observable and exactly where the gamma ray and gravitational wave data predicted.

Generation of Heavy Metals? Check. The big scopes were able to pull in enough light for spectroscopy, and there are significant quantities of gold present. Also the so-called rare earth elements and other heavy metals like platinum and lead. But gold gets all the headlines.

Astrophysicists will be mining this data for years. But the most important bit is likely to be the complete confirmation of important elements of scientific predictions. The theory is proven, at least to the limits of current knowledge. Science works.

The venerable Sky & Telescope has a nice article on all of this and more. Must mostly WC just wants to take a moment to rub a little mud in the hair of all the climate science deniers, anti-vaxers, evolution skeptics and the rest of the “alternative facts” crowd.  At then end of the day, science works and their silly denials are revealed to be noise.

 

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