Gravity waves aren't for surfing, but they are scientifically amazing
As we went to print last month, news was swirling about an “Unprecedented” announcement that would be coming from the folks at the LIGO observatory. “LIGO,” if you don’t remember, is the “Laser Interferometry Gravitational-Wave Observatory.” There are now three of these observatories in operation; two in the United States (in Washington and Louisiana) and one (called “VIRGO”) in Italy.
As the name suggests, what these Observatories are looking for are Gravitational Waves. These waves are produced when massive objects smash into each other and create literal waves in the space-time fabric of the universe.
It’s sort of like the waves you get when you throw a stone into a pond. But, instead of moving along with the waves as they pass, these waves pass through everything in their path, stretching and pulling the fabric of reality as they sweep past.
So, how do you detect something like that? Well, basically, each of these Observatories is a huge “L”-shaped building with lasers being fired down each of the arms of the “L.” At the end of each building (about 4 kilometers away) is a mirror that bounces the laser back to the source. Since we know the speed of light, and we know the distance the lasers should travel round-trip, we know how long it should take for the laser to bounce back.
However, if a gravity wave passes through the Observatory, one of the limbs will be stretched (or compressed) ever so slightly (typically, less than the width of a proton), changing the time it takes for the trip. Special software is constantly looking for these tiny differences and translates them into “chirps” that signify the passing of a gravity wave. Simple.
Since it started operation a couple of years ago, LIGO has detected a couple of gravity waves, both produced by the collisions of massive black holes. This time however, with the newer VIRGO Observatory operational, they were able to do something much more interesting: Detect and pinpoint the location of two colliding Neutron stars. (Neutron stars are very small, but very dense objects. How dense? A teaspoon of Neutron star material would weigh about a billion tons.)
But, even that’s not the most interesting bit. You see, because gravity waves travel at the speed of light, and because the addition of the third VIRGO observatory allowed scientists to pinpoint the location of the event (via triangulation), special software was able to match the gravity wave location to a Gamma-ray burst event that had been detected in the same spot by NASA’s Fermi space telescope.
That then led to telescopes of all types, from all over the world, being turned towards that patch of sky to observe the event using every type of wavelength that we can observe.
The end result is that this was the first gravity wave event that’s also been seen in actual wavelengths of light. And, since various telescopes are still looking at it, it’s also going to be one of the most observed and studied celestial events in human history.
But, what’s so fascinating about colliding Neutron starts anyway? Well, it’s long been theorized that these sort of collisions are what produce the heaviest elements. Things like lead and gold all get their start in these insanely powerful collisions as the resulting fireball (called a “kilonova”) flings them out into interstellar space.
Until this event, that’s been just a theory. Now however, observations are already coming in that seem to confirm it.
The future for this new kind of astronomy is bright. In the next few years, even more Gravitational Wave Observatories will come on line around the world (India and Japan are next up), which should make it even easier to see even “smaller” events and to pinpoint their locations even more precisely.
Combine this with all the other new ground- and space-based observatories that are coming online soon, and it’s looking like we are about to enter an exciting new era in astronomy. One that could well change everything we know about the universe and our place in it!
Steven W. Disbrow is a programmer who specializes in e-commerce and mobile systems development, an entrepreneur, comic-book nerd, writer, improviser, actor, sometime television personality and parent of two human children.