a sound? No! But it DOES generate a truckload of gravitational waves! (We think.)

Hi! I’m Ian O’Neill, space producer for Discovery News, and I wanted to take you on

a brief voyage into what links some of the craziest cosmic events we know about. I’m

talking about supernovas, black hole mergers, neutron star collisions, orbiting white dwarfs

and even the biggest bang of them all… the Big Bang!

So what exactly connects them all? That’d be gravitational waves; and if you’ve been

paying attention these last few months, you’ll know that these wiggles in spacetime have

been insanely hard to find.

Astronomers using the BICEP2 telescope located in the South Pole THOUGHT they’d identified

primordial gravitational waves embedded in the Cosmic Microwave Background radiation

last year. Unfortunately, it seems that these signals may have just been noise.

But that doesn’t mean it’s curtains for the search for gravitational waves and gravitational

wave detectors, not by a long shot.

Rather than seeking out ancient gravitational waves created by the Big Bang, the Laser Interferometer

Gravitational-Wave Observatory -- or LIGO -- is ACTIVELY looking for gravitational waves

passing through Earth right this second!

These waves were predicted by Einstein and are a product of his famous theory of general

relativity. In a nutshell, Einstein’s equations predicted that should a massive object like

a black hole or neutron star suddenly accelerate, decelerate or collide, energy will be lost.

But in these cosmic scenarios, energy is lost through powerful ripples in spacetime -- much

like the ripples that race across the surface of a pond after a pebble hits the water.

Although there is strong indirect evidence of their existence, we have yet to spot them

directly.

This is where LIGO comes in.

LIGO consists of two stations on opposite sides of the United States, and it uses a

highly sensitive method called interferometry to detect the TINY effect a propagating gravitational

wave will have on spacetime.

As gravitational waves wash THROUGH the Earth -- yes, I said THROUGH, as in through US!

-- there is the tiniest of tiny shrinkage or expansion in local spacetime.

But for LIGO, which has recently undergone an upgrade, such a minuscule spacetime warping

SHOULD be detectable and, since 2002, the project has been on the lookout. This thing

is so sensitive that it is probing distances on the smallest scales thought to exist in

spacetime -- it should be able to detect a distance change of 10,000th the width of a

proton.

Although LIGO has yet to see a definitive signal, it is using a process of elimination,

ruling out where these waves AREN’T and physicists are confident they are closing

in on the first detection in the coming years.

By firing a split laser down LIGO’s two perpendicular 4 kilometer-long L-shaped tunnels

and bouncing those beams many times, an interferometer can compare the two beams and detect any slight

shifts in frequency. This tiny shift could represent the passage of a gravitational wave.

Should that wave be detected by both LIGO locations, the source of the wave could be

derived and we could see the beginning of a new era of gravitational wave astronomy.

Although the LIGO instrumentation uses a complex system of shock absorbers, magnetic fields

and sophisticated filters to drown out any outside interference, the detector is so sensitive

that it can still pick up false signals from strong winds or passing vehicles, only making

this search for a gravitational wave in the proverbial haystack of noise even harder.

Fortunately this epic quest on the frontier of scientific discovery isn’t short of some

great physics minds. Students from Caltech recently created a colorful visualization

to connect known interference events with their corresponding signal detected by LIGO,

thus eliminating terrestrial noise from the continuing search for extraterrestrial sources

of gravitational waves.

But will this be enough to finally tease this tiny wobble out of the tangled, noisy mess

of spacetime? Let us know what you think in the comments below, and if you’re interested

in other cosmic peculiarities, check out my video about a weird cold spot in the universe and what it might mean