Stories from the Cosmos: Distant Worlds in Unexpected Settings

Just a few decades ago, the idea that other stars could host planets was more speculation than certainty. Today, thanks to a technological and scientific revolution, we know that exoplanets —those worlds orbiting stars outside our solar system—not only exist, but could be as common as stars themselves. What began as a tentative search has become one of the most dynamic areas of modern astronomy.

And now, with the James Webb Space Telescope (JWST) , our sharpest eye in space, we're beginning to look even where we once thought life was simply impossible.

For centuries, astronomers imagined the possibility of other worlds, but it wasn't until 1992 that the discovery of the first exoplanets was confirmed , and the curious thing is that they were not orbiting a star like our Sun, but a neutron star , that is, the collapsed core that remains after a massive star explodes violently as a supernova .

It was in 1995 that astronomers Michel Mayor and Didier Queloz detected the first exoplanet around a solar star, 51 Pegasi b , a scorching-hot, gigantic world that revolutionized our understanding of planetary systems. Their work earned them the Nobel Prize in Physics in 2019.

Since then, discoveries have multiplied. Missions like Kepler , launched in 2009, showed us that small, rocky planets are more common than previously thought. The diversity is astonishing, revealing worlds with showers of glass, gas giants that orbit their stars in just a few days, and others that float freely through space without a single star.

One of the great dreams of science is to find a world where life could exist . To do this, we search for planets within the habitable zone, that is, the area around a star where liquid water could exist given the temperature. But habitability depends not only on the distance from the star; atmospheric composition, the presence of water, magnetic fields, and even stellar activity are also critical factors.

In this context, JWST has ushered in a new era. With its infrared vision, it can study planetary atmospheres, detect molecules such as water, methane, and carbon dioxide, and observe protoplanetary disks—the nurseries where planets are born —in unprecedented detail.

Recently, new observations have revealed that even in the most hostile corners of our Galaxy, where ultraviolet radiation is thousands of times more intense than in our own solar system, planets can begin to form. An example of this is the XUE 1 system , a young star surrounded by a disk of gas and dust, right in the middle of a star-forming region bathed in intense radiation.

The surprising thing is that, despite the ultraviolet bombardment, the disk survived. What's more, the computational model developed by the team revealed that the inner region of the disk, where rocky planets like Earth could be born, is protected from radiation damage. Furthermore, they detected signs of water, a fundamental ingredient for life as we know it. This suggests that the formation of habitable worlds may be more common and resilient than previously thought, even in environments previously thought incompatible with life.

The most fascinating thing about these findings is that they force us to rethink the limits of habitability . If disks can survive in high-radiation zones, and if water can persist there, then the catalog of possible habitable worlds expands considerably. It's no longer just a matter of searching for temperate zones around quiet stars, but of understanding the incredible adaptability of matter on its path to life.

With future missions like PLATO and ARIEL , the study of exoplanets will continue to transform our understanding of the cosmos. New techniques, better models, and more data will perhaps bring us closer to answering the question that has always plagued us: Are we alone in the universe?

Astronomical Observatory of the National University