With all the big world events saturating media coverage, many may have missed recent back-page news reports that a colossal space collision released an estimated 200 Earth masses of gold and 500 Earth masses of platinum in a cosmic fireworks display.
Okay, just to be entirely forthright, I should probably add that this event actually occurred about 130 million light years away, while scientists only found out about it last August.
In any case, now that I’ve got your attention, I might as well tell you the rest of the story.
Apart from the perhaps disappointing fact that all the loot got pretty broadly scattered along with lots of nasty radioactive waste, that collision of two neutron stars yielded a veritable treasure trove of illuminating scientific information about the universe which followed another underreported discovery two years earlier. And yes, Einstein was once again proven right.
So let’s begin with that earlier February 2016 announcement of what the Royal Swedish Academy accurately described as “a discovery that shook the world.” That was when the detection of a collision between two massive black holes a billion light years away validated Einstein’s 1916 “General Theory of Relativity.” Just as he predicted, the resulting gravity waves jiggled space-time with invisible cataclysms that reached all the way to us.
Einstein foresaw a dynamic universe in which what we call “gravity” results when matter and energy warp the geometry of space-time in much the same way that a heavy sleeper sags a mattress…a condition so elastic that it can expand, tear and collapse into black holes which are so dense that even light can’t escape them.
He envisioned that those gravity waves from motions of black holes and other dense remnants of dead stars would stretch and compress space in orthogonal directions as they pass by an observer, just as sound waves compress air. And he correctly theorized that those waves would travel at the speed of light.
These radical ideas were all confirmed on September 14, 2015, when remarkably sensitive instruments in two different states first detected a gravity wave emanating from the collision of two gigantic black holes. That “chirp” signal which lasted only a fifth of a second was greeted by thousands of scientists as a loud opening bell for a whole new era of astronomical revelations.
The amazing discovery deservedly earned the award of a $1.1 million Nobel Prize in Physics last October to Rainer Weiss at MIT, along with Kip Thorne and Barry Barish of the California Institute of Technology. Together with legions of other dedicated scientists and technicians at the Laser Interferometer Gravitational-wave Observatory (LIGO) and its sister organization (the LIGO Scientific Collaboration), they innovated and demonstrated a marvel of dedicated achievement which was more than 40 years in the making.
The LIGO program constructed two L-shaped antennas, one in Hanford, Washington, and the other in Livingston, Louisiana, with a laser light bouncing along 2.5-mile-long arms in the world’s biggest vacuum tunnels to monitor the shape of space.
Weiss and Thorne hatched the idea in an all-night 1975 hotel brainstorming session.
Following the work of others, they calculated that a typical gravity wave would change the laser-measured distance between two detection mirrors by an almost imperceptible distance of one part in a billion trillion…less than the diameter of a proton.
Weiss reported that it took the team two months after that cheerful chirp before they were convinced that it was the real deal. Since then, most recently in conjunction with a new European detector (Virgo), at least four more black hole collisions have been documented.
Then on August 17, LIGO instruments detected ripples in the space-time grid produced by a different type of event. In addition to gravity waves, the collision of two neutron stars also released visible light which was observed by Earth-based telescopes. Initially appearing as a bright explosion of blue, the color soon faded to a deep red.
The discovery confirmed, as expected, that collisions of neutron stars produce enormous gamma-ray bursts, along with about half of all heavy elements (including that gold and platinum) which are dispersed in gases that eventually settle down and condense to form new stars and planets. The blast initially released a mushrooming cloud of radioactive waste about the size of a small city moving at a few tenths of the speed of light.
After a day, the cloud had reached the size of our solar system.
Neutron star collisions are rare events, estimated to occur less than 100 times per million years in a single galaxy. Yet as LIGO and Virgo detectors continue to search tens of millions of galaxies for more such marvelous events, who knows?
Maybe some of them will even be big enough to make prime time news.