# How far should the source be, for the gravitation waves to be visible on Earth?

If I understand it well enough, gravitational waves cause ripples in the space-time fabric. To our eyes, that would look like those rippling-effects on amateur videos.

Where does a source have to be, in order for the effects of gravitational waves to be visible, here, on Earth.

• You cannot "see" a gravitational wave. Light is an electromagnetic wave, which is completely different. The videos are, to say the least, misleading. – HDE 226868 Feb 15 '16 at 16:22

The amplitude of the waves detected by LIGO was small, one part in $$10^{21}$$, Now while the intensity of the waves follows an inverse square law, because intensity is proportional to amplitude squared, the amplitude is inversely proportional to distance from source.
We are familiar with strains that are one part in 1000, that is a variation of one millimetre for every metre. To get that we would have to be a lot closer to the source, $$10^{18}$$ times closer. Since the black holes were about 1 billion light years distant, to get a strain of 1 part in 1000, the black hole merger would have to be about 10000km away