What’s With Gravitational Waves?

Simulation of gravity wave productionThe first observation of “gravitational waves,” a prediction of Einstein’s General Theory of Relativity, was announced in February, 2016.

Although the significance may be unclear to many, the discovery of these immensely tiny ripples in the fabric of space were the last major part of the theory to be confirmed by actual observation. They amount to slight distortions in space. Some have likened them to a sound wave traveling through air or water. However, sound waves are moving compressional waves (alternating areas of compression and rarefaction) in a medium like water or air. Gravitational waves are really more like transverse sinusoidal waves similar to ripples on the surface of a pond, although considerably more complicated. And rather than propagating only along the surface of a plane as water ripples propagate across a pond, gravitational waves travel outward in three dimensional space.

While any interaction between gravitating bodies produce gravitational waves, only waves produced by the interaction of massive bodies (such as black holes or massive stars)  out in space are currently within our observational grasp; the ripples are through what we normally consider a vacuum rather than through water or air; and they are phenomenally weak .

Although the discovery is a major breakthrough for physics and astronomy, and may lead to completely new ways of looking at the Universe, the exotic nature of gravitational waves has spawned some misconceptions.

Shortly after the announcement, a student asked me whether or not these waves could be used to explain such things as the occasional loss of communications with satellites, the purported dangers for ships and planes in the so-called “Bermuda Triangle,” and even the turbulence experienced by passengers on commercial airlines.

The following was my response:

Gravitational waves have nothing to do with any of the things you mention. Really. Nothing at all. Gravitational waves are so incredibly weak and faint that they have nothing whatsoever to do with everyday life, and certainly nothing to do with any disappearances in any area such as the so-called “Bermuda Triangle” and such.

Go to some big lake when the water on the surface is completely flat. Now drop a single small grain of sand into the water at one edge. How easy do you think it would be for someone on the opposite side of the lake to detect the ripple? Now just consider that the gravitational waves recently detected are millions of times fainter and weaker than that. They have no measurable or observable effect on human activities. Einstein himself was convinced that we would never be able to observe them at all.

And again, gravitational waves have nothing whatsoever to do with any loss of communication with satellites (although solar radiation can) and certainly nothing to do with lost aircraft or ships. Many reports of such things are either exaggerated or due to weather conditions and such. We may not have discovered the causes in some cases, but gravitational waves have no effect and it is highly unlikely that they are due to any as yet undiscovered aspect of physics. We may not know all the answers yet, but that doesn’t mean that the answers are anything exotic or due to some unknown force.

Turbulence in airplanes is due to pockets air at different densities, usually caused by uneven heating in the atmosphere, coupled with winds and perhaps other meteorological factors. The causes are complicated, but knowable with our current understanding of ordinary physics.

It is not that we know everything at this point. But we know enough to rule certain things out. There are connections between events and forces that are so subtle and complex that we cannot decipher them easily or at all. In fact there is a mathematic concept known as the “Butterfly Effect” that considers very minor effects that yield large results over time. Even if we were to consider gravitational waves in this context, I don’t think that they would have any effect because they are so small they would be masked and damped out by quantum effects (which is beyond the scope of this class).

For more, see The Landmark Discovery of Gravitational Waves by Brian Greene.


About Starman

Cosmic Awareness Facilitator. Astronomy, space, physics, science, planets, cosmology, reason, logic, clouds, sky phenomena, the environment, dogs and other animals, and other interesting stuff.
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