For a long time, planetary scientists have told a simple story: the Moon formed in a single, enormous collision between the early Earth and a Mars-sized body. It’s a compelling idea, and for decades it has shaped how we think about lunar origins. But growing evidence suggests that this picture may be too neat. Join us in today’s astrobito to learn how a sequence of collisions could have built the Moon we see today!

The atmosphere; that protective blanket of gases and aerosols that shields us from cosmic radiation, burning meteors, and makes life on Earth possible. We often take it for granted, but most rocky exoplanets (planets with a solid surface like Earth) likely lost their atmospheres long ago, early in their formation histories… or did they? New research suggests that the atmospheres of rocky exoplanets might be far more dynamic than we imagined, periodically depleting and then rebuilding over time. Join us in today’s astrobito to learn more about this intricate process!

Sub-Neptunes are among the most common planets in our galaxy, yet their true nature remains mysterious. Observations of TOI-270 d with the James Webb Space Telescope have revealed a surprising twist — its atmosphere may be shaped not by icy origins but by chemical reactions between molten rock and gas. In today’s Astrobito, we explore how magma–atmosphere interactions could explain TOI-270 d’s water and carbon-rich skies, and what this means for our understanding of planet formation and the diversity of worlds beyond our Solar System!

Astronomers may have found the first signs of a moon outside our Solar System and it isn’t just any moon. Observations from the James Webb Space Telescope (JWST) suggest that a volcanic satellite might be orbiting the exoplanet WASP-39b, spewing SO2, sodium, and potassium  into space much like Jupiter’s Io or Saturn’s Enceladus. Join us in today’s astrobito to learn why, if confirmed, this wouldn’t just be the first exomoon ever detected, but the first geologically active one!

Meet Ross 176b! This small exoplanet, newly discovered just 33 light-years away, is making waves, and not just because of its size. With a density of around 3.8 g/cm³, it’s believed to be a water world. Its history and composition could offer key insights into planetary diversity, how planets form, and the many evolutionary paths they can take. Join us in today’s Astrobito  to learn more about this fascinating new world!

To be or not to be… a planet? For centuries, astronomers have grappled with how to define what counts as a planet, and despite our best efforts, the question is still surprisingly unsettled. The current official definition leaves us with some inconsistencies: even well-established planets like Venus, Earth, and Jupiter don’t fit neatly within its rules, and things get even murkier when we turn to exoplanets. In today’s astrobito, we look at a new framework that aims to bring clarity: one grounded in measurable physical properties.

2017 OF201: A newly discovered object on the edge of the Solar System, with an orbit that doesn’t quite fit current models. This distant icy world is helping astronomers test one of the most debated ideas in planetary science: the possible existence of a hidden giant planet far beyond Neptune. What can this single object reveal about the structure of our Solar System—and the case for Planet X? Join us in today’s Astrobito to find out more!

Long-period comets have long been considered fleeting visitors to the inner Solar System, but new discoveries are changing that view. Thanks to modern sky surveys and the powerful capabilities of the James Webb Space Telescope, astronomers are uncovering unexpected cometary activity at great distances from the Sun. The case of comet C/2024 E1 (Wierzchos), which displayed CO2 outgassing at 7.2 au but lacked CO, challenges our understanding of these icy bodies. Could this reveal clues about the origins and evolution of comets? In today’s Astrobito, we explore how JWST is transforming our view of long-period comets and what this means for the study of the early Solar System.

The possibility of the existence of hydrogen worlds represents one of the most exciting ideas in astrobiology. Although their existence has not yet been confirmed, the idea of ​​planets with vast oceans and hydrogen-rich atmospheres opens new doors in the search for life beyond Earth. In today's Astrobito, we dive into how these hypothetical planets could transform our understanding of the cosmos and bring us closer to an answer to one of humanity's biggest questions: are we alone in the universe?

The discovery of the first confirmed exoplanet in the 1990s marked the beginning of an astronomical revolution. Fast forward to January 2025, and we’ve confirmed nearly 6,000 exoplanets! While much of the focus has been on the diversity of these planets themselves, less attention has been given to the systems they belong to. So, is our solar system truly one-of-a-kind? Or are there extrasolar systems that share similarities with ours? Join us in today’s astrobito to find out!

And just like that 2024 has come to an end. This year, astronomy enthusiasts were treated to an abundance of breathtaking events, from solar eclipses, and beautiful auroras, to passing comets, and dazzling meteor showers. Now, as we wrap up another exciting year of looking up at the night sky, let’s reflect on the remarkable moments that made 2024 unforgettable for amateur astronomers (and non-astronomers) around the globe. Join us in today’s astrobito as we celebrate the most awe-inspiring astronomy events of the year!

Today’s astrobito is a little bit different. Instead of talking about recent breakthroughs in astronomy, this time round I want to recommend a science fiction book that is not only full of space exploration but also deeply rooted in the realities of scientific research. In Ascension by Martin MacInnes follows Leigh, a marine biologist who transitions from studying ancient ocean organisms to working at a space agency, facing a life-altering decision that could take her across the universe. While the book dives deep into astronomy, it’s the human journey that stands out, showing the impact of scientific discovery on both the researcher and the world. If you enjoy stories that blend rigorous scientific ideas with complex human emotions, this book will keep you hooked from the first page.

3000K in daylight and 1500K overnight. These are the temperature conditions on WASP-33b, a tidally-locked ultra-hot Jupiter exoplanet, where one half of the planet is perpetually bathed in starlight, and the other half remains timelessly in the dark. Such extreme conditions trigger exceptional chemistry on the planet and, as always, spectroscopy can help us study that chemistry and how it shapes the planet’s atmosphere. Join us in today’s astrobito to learn more about the atmospheric structure of WASP-33b and how ground-based observations have helped improve our understanding of this blistering planet.

With over 5,500 exoplanets discovered to date, it is clear that exoplanets stretch far and wide across the universe. But how are these planets arranged in their own star systems? And what can that tell us about our own solar system? In today’s astrobito, we focus on a curious pattern found in many of these extra solar systems: the lack of Neptune-sized planets orbiting close to their stars. Why does this gap exist and what are its boundaries? Let's explore.

When we think about methods to monitor climate change on Earth, we often focus on temperature, the varying concentration of atmospheric gases over time, and the frequency of extreme weather events. However, today's astrobito showcases a rather different approach: how astronomer have used telescopes to track the abundance of iron (Fe) on the surface of Mars over thousands of years to better understand its climate history and the events that shape the Mars we see today.

Quantum chemistry unveils new pathways for chemical reactions in space's coldest environments. On Titan, Saturn's largest moon, frigid temperatures typically prevent molecular interactions from happening. However, quantum tunneling— a process where atoms and molecules can pass through energy reaction barriers—could facilitate these reactions even in extreme cold. In today's astrobito we discuss how advanced simulations show that proton transfer reactions, crucial for complex organic chemistry, could occur on Titan via quantum tunneling. This discovery suggests that other icy moons, exoplanets, and cold interstellar regions may also harbour unexpected chemical activity.

Green is often seen as the colour of life due to Earth's lush vegetation, visible even from space. This green hue, produced by chlorophyll in plants through photosynthesis, works as a potential sign for life when searching for extraterrestrial life. However, life on Earth predates this greenery. Early microorganisms displayed a variety of colours based on their metabolic processes. Notably, purple bacteria, which use bacteriochlorophyll for photosynthesis, absorb different light wavelengths and can thrive in light-limited environments. In today's astrobito we discuss how recent studies on purple bacteria suggest that extraterrestrial life might not be exclusively green.

While it is common to think that the development of new technologies makes older ones obsolete, this is not always the case. The launch of JWST has achieved groundbreaking milestones, but it has not made observations with the Hubble and Spitzer space telescopes irrelevant. In today's astrobito we talk about how JWST, Hubble and Spitzer are working together to strengthen our understanding of exoplanet atmospheres.

It is common to believe stars live in solitary. However, they frequently exist in dynamic relationships within binaries and clusters. These systems offer insights into star formation and evolution, with initiatives like the Gaia mission contributing significantly towards understanding these processes. In today's astrobito we talk about how comprehensive sky surveys are reshaping the way we do astronomy.