An article published in the journal “Astronomical Journal” describes a research that offers at least a partial explanation for the cosmic phenomenon called the Great Attractor. An international team used the 64-meter Parkes radio telescope in Australia to make observations through the galactic Zone of Avoidance, an area of space obscured by the Milky Way itself with its stars and dust clouds. In this way the researchers found hundreds of previously unknown galaxies, ea progress in the gravitational anomaly’s explanation.
The Great Attractor is located in the center of the galactic supercluster called Laniakea, which includes the Milky Way. In the ’70s the progress of astronomical instruments allowed to discover a gravitational anomaly compared to a homogeneous expansion of the universe. In the ’80s astronomers were able to estimate its distance between 150 and 250 million light years from Earth. The current estimate is 250 million light years.
The study of this gravitational phenomenon has always been hampered by the fact that the direction of view is close to the Milky Way’s galactic plane, with the consequence that there are stars, dust and gas obscuring it. Various hypotheses have been proposed over the decades but any verification failed. For decades, the existence of the Great Attractor was confirmed only by the gravitational pull detected on the galaxies of the supercluster Laniakea but now things could change radically.
The team used a radio telescope of 64 meters in diameter, nicknamed the Dish or the Big Dish of the Parkes Observatory in New South Wales, Australia, run by the Commonwealth Scientific and Industrial Research Organisation (CSIRO). It’s an old telescope that has been upgraded over time and is now sensitive enough to see beyond the obstacles in the Milky Way and to map the area that was almost impossible to study.
The result is that the team led by Lister Staveley-Smith of ICRAR (International Centre for Radio Astronomy Research) could observe 883 galaxies of which a third was unknown. For example, they found three concentrations of galaxies (called for now NW1, NW2 and NW3) and two new galactic clusters (called for now CW1 and CW2).
Lister Staveley-Smith expressed caution concerning the research results stating that we don’t know what causes the Milky Way’s gravitational acceleration. The discovery of galaxy clusters is an explanation at least partial and a significant step forward in the research on the mystery of the Great Attractor.
Only the observations made at radio frequencies with a very sensitive instrument provided useful information to better understand this phenomenon. It’s a promising result also thinking that in a few years the huge SKA (Square Kilometre Array) radio telescope will be operational. The Great Attractor is certainly one of the objectives for new research.
