Two gas giants light as shaving foam, orbiting as one.
In a distant star system, NASA's TESS spacecraft has found two gas giant planets so extraordinarily light they have been nicknamed 'cotton candy' worlds — the least dense of their kind ever discovered. Their existence together in the same system is not merely a curiosity but a quiet challenge to decades of planetary science, suggesting that the universe forms worlds by rules we have not yet fully written. What we thought we knew about how giants are born and how they hold themselves together must now be reconsidered in the light of something that should not, by our models, exist — let alone exist twice.
- Two enormous planets have been found with densities so low they defy expectation — less substantial than shaving foam, yet as wide as Jupiter.
- Their presence together in one system rules out coincidence, forcing scientists to confront the possibility that current models of planetary formation are fundamentally incomplete.
- Researchers are now asking whether these worlds were always this light, or whether they once carried more mass and lost it — stripped by radiation, or simply never fully built.
- The TESS mission continues scanning the sky, and the discovery of this pair suggests more such 'super-puff' planets may be waiting in the data.
- The scientific community is navigating toward new theoretical frameworks that can account for gas giants that hold vast atmospheres without the gravity to justify them.
Somewhere in the cosmos, two planets orbit their star as if barely there. NASA's TESS spacecraft detected them, and what it found confounded expectations: gas giants enormous in size yet so insubstantial in density that researchers reached for the language of confection to describe them — 'cotton candy' planets, lighter than spun sugar, less solid than shaving foam. They belong to a category called 'super-puff' exoplanets, a class that has grown in recent years but remains poorly understood.
TESS identifies exoplanets by measuring the tiny dimming of starlight as a world passes in front of its host star. From those dips, astronomers calculate size and, combined with other measurements, mass. When the numbers returned for this pair, the densities were so low they bordered on the absurd — Jupiter-sized worlds with almost nothing behind them.
What elevates this beyond novelty is that both planets share the same system. Two cotton candy worlds orbiting the same star suggests not a fluke but a pattern — that certain conditions of formation reliably produce these impossibly light giants. This is where existing theory struggles. Did they form this way, gathering less solid material than typical gas giants? Or did they once carry more mass, only to have their atmospheres eroded by stellar radiation over time?
The answers remain out of reach for now, but the questions themselves are reshaping how planetary scientists think about atmospheric retention, core formation, and the full range of worlds the universe is capable of making. The cotton candy planets are a reminder that our models are maps, not territories — and that the territory is stranger, and more wondrous, than we had drawn it.
Somewhere in the cosmos, two planets orbit their star so lightly they seem almost unreal. NASA's TESS spacecraft—the Transiting Exoplanet Survey Satellite—has detected them, and they are unlike anything astronomers expected to find together. These worlds are enormous by Earth standards, yet so insubstantial that if you could somehow hold one in your hand, it would feel less dense than a cloud of shaving foam, less solid than spun sugar. Researchers have taken to calling them "cotton candy" planets, a nickname that captures something true about their nature: they are gas giants stripped of the weight we thought gas giants must carry.
The discovery matters because it forces a reckoning with how we understand planetary birth and evolution. For decades, astronomers have built models of how planets form and grow, how they accumulate gas and settle into their final shapes. These two worlds—found orbiting together in the same system—do not fit neatly into those models. They are what researchers call "super-puff" exoplanets, a category that has grown in recent years but remains poorly understood. What makes a gas giant so extraordinarily light? How does it retain such a vast atmosphere without collapsing under its own gravity? Why would two of them exist in the same place?
The TESS mission, which has been scanning the sky since its launch, identifies exoplanets by watching for the tiny dips in starlight that occur when a world passes in front of its host star. From these observations, astronomers can calculate a planet's size and, combined with other data, estimate its mass. When the numbers came back for this pair, the researchers found themselves looking at something remarkable: two gas giants with radii comparable to Jupiter, yet with masses so low that their overall density fell into the realm of the absurd. One researcher described them as "comparable to a nice blob of shaving foam"—a phrase that captures both the scientific precision and the sheer strangeness of what had been found.
What makes this discovery particularly significant is that both planets exist in the same system. This is not a fluke or an outlier. The presence of two such worlds orbiting the same star suggests that whatever mechanism produces these impossibly light giants is not rare or accidental, but rather a natural outcome of certain planetary formation scenarios. This challenges existing theories about how gas giants develop and lose or retain their atmospheres over time. If the standard models cannot easily explain one cotton candy planet, they certainly struggle to explain two.
The implications ripple outward. Understanding how these planets came to be so light could reshape our knowledge of planetary evolution across the universe. Did they form this way, accumulating less solid material than their more massive cousins? Or did they once carry more mass and somehow shed it, losing their rocky cores or having their atmospheres stripped away by stellar radiation? The answers matter not only for understanding distant worlds but for understanding the broader processes that shape planetary systems everywhere, including our own.
For now, the cotton candy planets remain a puzzle—a beautiful, counterintuitive reminder that the universe is far stranger than our models predict. TESS continues its work, scanning the sky for more transits, more dips in starlight that might reveal other worlds. Each discovery adds another piece to a picture that is still coming into focus, a map of planetary diversity that grows more complex and more wondrous with each new find.
Citas Notables
Comparable to a nice blob of shaving foam— Researcher describing the planets' density
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that these two planets are in the same system rather than scattered across different stars?
Because it suggests this isn't a cosmic accident. If you find one impossibly light planet, you might chalk it up to chance. But two in the same system? That points to something systematic about how they formed together, which means we're looking at a real mechanism, not an anomaly.
What would cause a gas giant to be so light in the first place?
That's the question nobody can quite answer yet. Either they never accumulated much solid material to begin with, or they lost it somehow—maybe their atmospheres got stripped away by radiation from their star, or they shed their rocky cores. The models don't have a clean answer.
How does TESS actually find these planets if they're so far away?
It watches for shadows. When a planet passes in front of its star from our perspective, the starlight dims slightly. By measuring how much it dims and how long the dip lasts, you can figure out the planet's size. Combine that with other observations, and you can estimate mass.
So these planets are huge but weigh almost nothing?
Exactly. Imagine a Jupiter-sized world that weighs less than shaving foam. The density is so low it almost doesn't make sense. That's what makes them so strange and so important to understand.
What happens next? Do we just keep looking for more?
Yes, but now with a new question in mind. Every new cotton candy planet we find helps us narrow down what's actually happening. Are they common? Do they cluster in certain types of systems? The more data we gather, the closer we get to understanding the mechanism.