The Fascinating World of Radio Astronomy
By Avani Sharan
Team Cosmofluencer
We see the stars twinkling when we look up at the night sky. Now what if we could get more information along with just the visible light from them?
This is precisely what radio astronomy does—it tunes into the cosmos by detecting radio waves emitted by celestial objects and views the “invisible universe”. This fascinating field has revolutionized our understanding of the universe, uncovering mysteries that would otherwise remain hidden.
Radio Astronomy: Unlocking the Secrets of the Universe
Radio astronomy is a branch of astronomy that studies celestial objects using radio waves emitted by them.
These waves are part of the electromagnetic spectrum (E M Waves), just like the light waves we percieve. Optical telescopes rely hugely on this visible light range of EM spectrum which is roughly 380 – 780 nanomaters(nm). On contrary, radiowaves are on the farther end of EM waves and have wavelengths ranging from 1 millimeter to 100 kilometers (0.039 inches to 62 miles). Radio telescopes detect these radio signals which are emitted by a variety of cosmic sources like stars, galaxies, Cosmic Microwave Background (CMB).
There are a series of radio telescopes stationed in multiple nations and a variety of ongoing projects by different countries’ space organizations and research institutions. Today, at the forefront of this radio astronomy exploration is the Square Kilometre Array (SKA), the world’s largest radio telescope project, set to revolutionize our understanding of space.
Radio astronomy has opened new windows into the universe by allowing us to:
- Detect objects obscured by dust and gas, such as newborn stars.
- Study phenomena like pulsars (rapidly spinning neutron stars) and quasars (extremely bright centers of distant galaxies).
- Investigate cosmic events like supernovae (massive explosion when a star dies) and black holes (massive and compact astronomical object).
- Explore fundamental questions about the origins of the universe through discoveries like cosmic microwave background radiation (CMBR), which provide evidence for the Big Bang.
In short, radio astronomy reminds us that there’s more to the universe than what meets the eye. It helps us understand how the universe works at its most fundamental levels.
History of Radio Astronomy
The field began in 1933 when Karl Jansky, an engineer, discovered radio waves coming from the Milky Way using makeshift antenna. Later, pioneers like Grote Reber built the first dedicated radio telescopes to map the sky.
From India, Prof. Govind Swarup was a pioneer in radio astronomy. He is credited with conceptualising and leading the team that set up the Ooty Radio Telescope (ORT) in Ooty and Giant Meterwave Radio Telescope (GMRT) in Pune. He is the “Father of Indian Radio Astronomy” and has made major contribution at CSIRO, Harvard and Stanford as well. Dr. Swarup was the founding director of the National Centre for Radio Astrophysics (NCRA) at the Tata Institute of Fundamental Research (TIFR). The GMRT has been instrumental in discovering evidence of ultra-low frequency gravitational waves, marking the first time an Indian radio telescope detected such waves. It has also observed the largest known universe’s explosion, the Ophiuchus Supercluster explosion.
How Do Radio Telescopes Work?
Radio telescopes are unique instruments designed to receive radio waves from the universe. In everyday life, TV and satellite dishes pick up signals that supply entertainment to people’s homes and other places.
Similarly, radio telescopes pick up signals from objects in the sky that aren’t made by humans. Some of these telescopes are big dishes, others look like fences or small vertical metal frameworks scattered across the landscape. They consist of these main components:
1. Antennas: These are large dish-like structures to collect radio waves from space.
2. Receivers and Amplifiers: These boost the weak signals collected by the antenna into reable and recognisable signals.
3. Recorders: These store the data for analysis and further usage.
4. Computers: Systems that process signals into images or data and prepare it for the analysis.
Unlike optical telescopes, radio telescopes can operate day and night and are totally unaffected by cloudy weather. For example, CSIRO’s telescopes in Australia operate 24×7. These telescopes are often located in remote areas to minimize interference from human-made radio signals which essentially lead to destroying the signals from cosmic events. Due to large wavelengths of the radio waves, the radio telescopes are large in size and are also installed in networks over an extensive area.
Conclusion
Radio astronomy has transformed our understanding of the universe by revealing what lies beyond visible light. Projects like the Square Kilometre Array represent humanity’s collective ambition to explore deeper into space than ever before.
By tuning into radio whispers from billions of light-years away, it will unveil secrets of cosmic dawn, galaxy evolution, and perhaps even extraterrestrial life. For students and curious minds, this is an exciting era where global teamwork and cutting-edge tech merge to decode the cosmos and answer some of our most profound questions: Where did we come from? What else is out there? And how does it all work?