Right after the Big Bang, space rippled with gravitational waves, like those from a thrown stone. These tremors in the very fabric of the cosmos, predicted by Alan Guth, stretched across the entire universe. The ripples slightly compressed primordial matter in some places and thinned it out in others. Thus, invisible clumps — dark matter halos — formed, becoming the scaffolding for future galaxies.
New calculations show: for nearby galaxies, the effect is almost unnoticeable — a correction of about one percent. But for distant ones, seen at a distance of 13 billion light-years, the effect reaches a hundred percent! A surprising paradox: the wavelength of these ripples today is comparable to the size of the entire visible universe, so they can't be detected directly — only through the distorted pattern of galaxies.
If the gravitational waves from the Big Bang were slightly stronger, galaxies might have arranged themselves not in filaments and walls, but in giant rings and spheres.
In Carl Sagan's novel 'Contact', the heroine hears a message from another civilization through gravitational waves. Here, the waves themselves are a message from the infancy of the universe.