An artist’s illustration of two merging neutron stars. The rippling space-time grid represents gravitational waves that travel out from the collision, while the narrow beams show the bursts of gamma rays that are shot out just seconds after the gravitational waves. Swirling clouds of material ejected from the merging stars are also depicted. The clouds glow with visible and other wavelengths of light. (Image credit: NSF/LIGO/Sonoma State University/A. Simonnet)
It was amusing that during a news conference yesterday about a cataclysmic collision between two neutron stars being detected via gravitational waves as well light perhaps the most recurring question was about the generation of gold and platinum as a result.
For the record, as pointed out by Edo Berger, professor of astronomy at Harvard University, this particular collision produced gold and platinum ten times the mass of Earth. Incidentally, Earth’s mass is 5.9736 x 1024 or 5,973,600,000,000,000,000,000,000 kilograms. Now multiply that figure by ten and you get the amount of gold and platinum that was flung in space by this particular event. Do I hear some epic slobbering on Earth?
Levity aside, the announcement is of extraordinary significance for science generally and the way astronomy is practiced. To be able to see a cosmic event like the collision and merger between two neutron stars both as gravitational waves as well the more traditional as light is a historic first. Quite apart from yet again confirming Albert Einstein’s prediction of gravitational waves a century ago, this particular advance illustrates how the scientific community is now able to view and confirm cosmic events in so many different ways.
It is a tribute to the collective and collaborative spirit of modern science that detection was made by the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO), the Europe-based Virgo detector, and some 70 ground and space-based observatories. It is for the first time that such a diversity of empirical proof has been offered for a theory that was born in the preternaturally brilliant mind of a single individual.
According to an official press release the gravitational signal, named GW170817, was first detected on August 17 at 8:41 a.m. Eastern Daylight Time. It was then quickly conveyed around the world to view it from many vantage points.
Let me quote from the release. “The LIGO (Laser Interferometer Gravitational-Wave Observatory) data indicated that two astrophysical objects located at the relatively close distance of about 130 million light-years from Earth had been spiraling in toward each other. It appeared that the objects were not as massive as binary black holes — objects that LIGO and Virgo have previously detected. Instead, the inspiraling objects were estimated to be in a range from around 1.1 to 1.6 times the mass of the sun, in the mass range of neutron stars. A neutron star is about 20 kilometers, or 12 miles, in diameter and is so dense that a teaspoon of neutron star material has a mass of about a billion tons.”
In our oppressive banalities we routinely forget, if many of us are even aware at all, of the absolute incomprehensible scale of the universe. This merger event is in our neighborhood in a manner of speaking as distances go. It might be useful to remember the scale of things. That has been my favorite theme since childhood.