 Our first step is to examine just what a ripple in spacetime means. Here, on Earth, far from an event that could create a gravitational wave, we have a relatively flat space with a Euclidean metric, G, that isn't changing with time. A ripple represents small deviations from this flat spacetime metric. We use H to represent these deviations. Solutions to Einstein's equations show that a gravitational wave's metric oscillates sinusoidally, just like light. And it travels at the same speed as light. As the wave moves down the z-axis, planes at different times experience different values for the metric used to measure distance on the plane. This makes the wave a transverse wave, just like light. We see two possible polarizations for a gravitational wave. We call one H plus for the action along the x and y-axis. We call the other H cross for action along the diagonal. To see what an oscillating H plus metric does, we'll measure the changes in the distance between two points on the plane when a gravitational wave passes. Here we have an x-y plane with the wave passing into the page. We mark two points on the x-axis, one meter apart, in Euclidean flat space, where H is zero. When H is greater than zero, the distance between the two points on the x-axis becomes longer than one meter. By an amount equal to H times the original distance. At the same time, a one meter distance on the y-axis will shrink to less than one meter by the same amount. When H returns to zero, the distance between these points returns to one meter. When H is less than zero, the distance between the two points on the x-axis will become shorter than one meter. And the distance between the two points on the y-axis will become longer than one meter. Here's an exaggerated look at what an oscillating H plus polarized gravitational wave does to a square plate it passes through. Again, the wave is passing into the page. For an H cross polarized wave, the effect would be similar, but shifted 45 degrees. When describing a gravitational wave, we can now be more precise than it's a ripple in spacetime. A gravitational wave is an oscillating polarized metric that operates in the plane perpendicular to the direction of the wave as it moves through space at the speed of light. And we have seen what this means for the objects that encounter such a wave. They are stretched and squeezed in various directions.