The cosmos never ceases to amaze, and our understanding of it is constantly evolving. 

One of the intriguing questions that has fascinated astronomers and space enthusiasts alike is: How big can a planet get? With the discovery of exoplanets beyond our solar system, this question has taken on new dimensions.

Before 1992, Jupiter, with its width about 11 times that of Earth, was considered the largest known planet. However, the discovery of exoplanets has introduced us to worlds that dwarf even Jupiter. Some of these exoplanets, often referred to as “super-Jupiters,” have a radius nearly twice that of Jupiter. Solène Ulmer-Moll, an exoplanet researcher at the University of Geneva, points out that these colossal planets often orbit very close to their host stars, making them truly extreme objects in the universe.

Interestingly, size and mᴀss don’t always correlate in the world of planets. For instance, the gas giant HAT-P-67 b, with a radius about twice that of Jupiter, is among the largest known planets in terms of width. Yet, its low density means it possesses only about a third of Jupiter’s mᴀss. Another mᴀssive exoplanet, HD 39091 b, located 60 light-years from Earth, boasts a mᴀss around 12.3 times that of Jupiter.

But there’s a limit to planetary growth. Once a celestial body reaches a certain size and mᴀss, it transitions into a “brown dwarf” – often termed as “failed stars.” These objects are heavier than super-Jupiters but lack the mᴀss to initiate ordinary hydrogen fusion in their cores. The boundary between planets and brown dwarfs is believed to be around 14 times the mᴀss of Jupiter.

The universe is vast, and our quest to understand it is ongoing. As we continue to explore and discover, we come closer to answering the enigmatic questions that the cosmos presents. Who knows what other colossal worlds await discovery in the distant corners of our galaxy?