Unlocking the universe: The power of radio waves
Our universe is filled with various wavelengths of light emitted by various objects around us. But apart from the light that is visible to our naked eyes, there are certain waves in the light spectrum which are invisible. Take radio waves for example. They are extremely useful, helping us broadcast signals on television, radio, air traffic control rooms and even cell phones. Also, radio waves are now helping us to visualise the universe around us!
What are radio waves?
Radio waves are a part of the electromagnetic spectrum. The electromagnetic spectrum is a range of electromagnetic radiations with different frequencies and energies. Radio waves have a lower frequency than microwaves (yes, the same microwaves that we use for cooking). They travel through the air in a straight line, reflecting off from clouds or sometimes satellites in the space. But where do they come from? Well, these waves are usually emitted by objects and activities in the universe. This includes the Sun, Jupiter and even some events occurring on Saturn! Even the universe is continuously sending us signals. Isn’t it fascinating? The radio wave signals from these sources are received by satellites in space and redirected to the earth’s atmosphere. Scientists use these signals extensively for communication. But how is it helping us visualize the universe? Let’s find out!
How do radio waves help us see the universe?
There are naturally occurring sources of radio waves throughout our universe and some even beyond our solar system! Yes, active galaxies beyond the Milky Way are the most powerful sources of radio waves. Supermassive black holes at the cores of these active galaxies emit radio waves. These waves, as well as radio waves emitted by objects in our galaxy, are detected by radio telescopes on Earth. These signals are then intercepted to obtain information about origins of galactical bodies. There is also a discipline of studies surrounding objects that emit radio waves. It’s known as radio astronomy which helps astronomers discover previously unknown galaxies. Actually, the radio waves emitted by astronomical bodies can sometimes be larger than a metre in length. To detect such large waves, we require even larger instruments. Did you know that some waves can reach the size of a mountain? But we can’t have a telescope the size of a mountain, right? In such cases, the radio interferometry technique is used.
Radio interferometry
Radio interferometry was developed in the mid-1940s. This technology was created to achieve the same result as using large telescopes but without actually using them! In this technique, multiple detectors are set up in parallel and pointed at the same source. This array of detectors functions as a single giant detector for capturing large radio waves.
Scientists have observed better results when these detectors are set at a distance from one another. This gave rise to a new technique known as ‘very long baseline interferometry’. This method allows telescopes to be located worldwide, including in the earth’s orbit! Radio interferometry allows us to visualise images of blackholes, undiscovered galaxies and objects floating in our universe, as long as they emit radio waves! As science develops more, we may even identify newer galaxies and solar systems with the help of radio waves.