Researchers have also known about and documented periodic shifts over cycles of 21,000 years, 41,000 years and 100,000 years, all of them also driven by astronomical change. (climatenewsnetwork.net)
One of these — stretching from Cape Hatteras to Miami — was driven by the overlapping effects of El Niño, that periodic blister of heat most obvious in the eastern Pacific, and the North Atlantic Oscillation, another entirely natural periodic shift in atmosphere and current that can pile up the ocean waters. (climatenewsnetwork.net)
The new discoveries were made with the help of the radial velocity method, which looks for the periodic shifts of certain spectral lines in a star's light that are caused by the gravitational tug of invisible planets which orbit the star. (americaspace.com)