Did you know that almost all stars have a companion planet, just like the Earth is to the Sun? But does life exist on extrasolar planets? 

To answer this, it is important to get to know the exoplanets and their ‘skies’ (atmospheres) a little more in detail. While astronomers have found a way to study what their skies are made of, little is known as to how they actually form and whether these skies can support life. “No atmosphere, no life”, quotes planet Mars. 

Astronomers think that studying the effects of weather and radiation in space will shed more light on exoplanetary skies and ‘livability’. But how can we study the effects of space weather on a planet orbiting another star outside our Solar System?

Astronomers often start by studying the ‘lookalike’ objects and phenomena in our own planetary backyard to compare to those elsewhere in space. 

One of the main contributors to space weather in our Solar System is coronal mass ejections (CMEs). CMEs are powerful explosions from the outer atmosphere of our Sun that release a hot ‘soup’ of energetic materials called plasma and magnetic fields like ‘birthday streamers’, into the Solar System. CMEs are often followed by a burst of fireworks of a peculiar faint radio ‘light’. 

Sometimes, if the energetic plasma reaches a planet with a strong magnetic field, like Jupiter in our Solar System, this ‘meet and greet’ can produce auroral emissions in radio light. That’s right! Jupiter has auroras, too! 

By studying these peculiar radio lights from the CMEs and auroras, astronomers think they can get a closer look at the hot plasma and the magnetic environment in our Solar System. Astronomers are actively looking for similar, brighter radio bursts from stars and planets outside our Solar System to understand how their atmospheres evolve and whether these planets could support life. Cool right! But wait, how can we really ‘see’ these peculiar radio lights?

Thanks to the super-sensitive radio telescopes on Earth, such as the LOw-Frequency ARray (LOFAR), Giant Metrewave Radio Telescope (GMRT), Karl G. Jansky Very Large Array (JVLA), Five-hundred-meter Aperture Spherical Telescope (FAST), and Australian Square Kilometre Array Pathfinder (ASKAP), astronomers are now closer than ever to uncovering new and diverse radio lights from stars and planets beyond our Solar System.
 

Image: An artist's impression of aurora on a planet around a red dwarf Credits: Olena Shmahalo/Quanta Magazine