Humanity has been observing the heavens since long before Galileo pointed his telescope at them. However, it was not until the past century that we closed our eyes and listened to its faint whisper.
The major conflicts of the early decades of the last century urged the development of long-distance communication systems to connect allied nations. Karl Jansky was an engineer that searched for sources of noise that disrupted radio calls during the 1930s. He discovered a mysterious whistle from an invisible source soaring through the skies. He connected this murmur to the radio source Sagittarius A, home to the black hole Sagittarius A* at the center of the Milky Way. This is considered the birth of radio astronomy, and the first step towards the study of the light we cannot see.
Indeed, radio waves are just light that our eyes cannot see. Grote Reber, engineer and radio enthusiast, recognized their potential for astronomy and, in 1940, built the first radio telescope in history in his own backyard. The limited power of the early prototypes allowed the study of nearby objects, such as the Sun. Elizabeth Alexander and Ruby Violet Payne-Scott, the first female radio astronomers in history, studied solar activity and its impact on Earth’s magnetic field. Their legacy is crucial for satellite-based telecommunications.
More advanced radio-astronomy observatories (VLA, ALMA, GBT, Parkes, FAST, MeerKAT, and many more) have allowed us to transform Jansky’s mysterious whistle into a photograph of a black hole, to discover the remnant energy of the Big Bang known today as the cosmic microwave background, and even find planets orbiting other stars that might be hospitable to life.
The next generation of great observatories, such as SKAO and ngVLA, will open a new era of global and interdisciplinary collaborations, offering professional opportunities in numerous fields of engineering, computing, and physics. Citizen collaboration will be essential for analyzing their extensive observations. This new era of radio astronomy will offer anyone the chance to continue the legacy of the men and women who first listened to the sound of the Universe, and uncover the mysteries of the Cosmos.
MSc in Astrophysics and Particle Physics.
PhD candidate working in the field of Galaxy Evolution and Large Scale Structure.