Radio astronomy can be used to discover hidden galaxies, as is the case with Parkes radio telescopefrom Australia, which has detected 883 galaxies beyond the Milky Way, of which almost a third were unknown to astronomers. The Parkes Observatory (also informally known as "the plate") is an observatory radio telescope, located 20 kilometers north of the city of Parkes, New South Wales. It was one of several radio antennas to receive live televised images of the Apollo 11 and his landing on the moon on July 20, 1969.
As you can see in the video that heads this post, this discovery has taken place in the environment of the enigmatic Grand Attractor, so it could clarify the mystery surrounding this wall of galaxies that attracts others like ours. For the first time they have been able to study hundreds of nearby galaxies (located only 250 million light years from Earth) that remained hidden by the material of ours.
According to the astronomer Renée Kraan-Korteweg, from the University of Cape Town, in South Africa, another of the countries participating in the study, together with the US and the Netherlands:
An average galaxy contains about 100 billion stars, so finding hundreds of new ones hidden behind the Milky Way indicates a large amount of mass that we knew nothing about until now.