Gravitational Waves

Scientists have detected Gravitational Waves. The Franklin Institute’s Chief Astronomer, Derrick Pitts, explains why this discovery matters to you.

Gravity Wave

An artist's impression of gravitational waves generated by binary neutron stars.
Credits: R. Hurt/Caltech-JPL

In 1916, Albert Einstein published his monumental work on the general theory of relativity. Among many other things, the theory predicted the existence of waves of gravitational energy, generated by the most energetic phenomena in the universe including rapidly spinning neutron stars and colliding black holes. He theorized that the gravitational waves would propagate throughout the universe, carrying vital information about the phenomena that created them. Since then, researchers have been devising instruments trying to detect the incredibly faint ‘ripples in the cosmic pond’ produced by large, energetic events.

In 2001, the first ever gravitational wave detector went into use but scientists determined that it wasn’t sensitive enough to feel the undulating disturbance in spacetime. Last September, a new, much more sensitive detector called the Laser Interferometer Gravitational-wave Observatory, picked up what has now been conclusively identified as an actual gravitational wave created by the collision of two black holes 1.3 billion years ago.

Struggling to understand what gravitational waves are? Think of them as being just like the ripples on the surface of a pond created when you drop a rock into the water.  Just like the water, the ripples show the energy from the rock passing through the water. Gravitational waves show the energy of an enormous galactic collision as it moves through spacetime. Neither the water nor spacetime actually move. In fact, spacetime is said to ‘distort’ as the energy passes through. This new discovery is momentous, much like Galileo’s use of the telescope for astronomy opened new vistas of discovery. Astronomers should now be able to add a new layer of understanding about how the universe works as they collect new data using gravitational wave detectors.

The Journey of a Gravity Wave

What’s it really like? A visually-impaired person now able to see for the first time; a hearing impaired person able to hear for the first time; a person in a foreign country able to understand the language for the first time; an explorer discovering a new and unexplored continent. This is big!