lighter than shaving foam fresh from the can
Somewhere in the southern sky, 1,110 light-years from Earth, two Jupiter-sized worlds drift in quiet defiance of our intuitions about mass and matter — so insubstantial they are less dense than shaving foam. Astronomers using NASA's TESS satellite have confirmed these rare 'super-puff' planets orbiting a star in the constellation Volans, adding two extraordinary specimens to a category of fewer than 40 known worlds among thousands. Their existence invites us to reconsider what a planet truly is, and how the universe finds ways to build the enormous from almost nothing.
- Two Jupiter-sized planets have been confirmed as the lowest-density worlds ever found — lighter than cotton candy, lighter than shaving foam, lighter than almost anything we can hold in our hands.
- Super-puffs are vanishingly rare, representing fewer than 40 of the nearly 6,300 confirmed exoplanets, making each new discovery a significant disruption to our models of how planets form and survive.
- The sheer scale of the finding strains comprehension — Jupiter, our solar system's giant, is up to 35 times denser than these featherweight worlds orbiting 1,110 light-years away.
- Astronomers are now turning to NASA's James Webb Space Telescope to confirm whether hydrogen and helium alone account for the planets' ghostly lightness, or whether something stranger is at work.
- Each answer the Webb telescope returns will add another piece to the larger puzzle of planetary formation — and quietly reframe our understanding of how our own solar system came to be.
Two planets the size of Jupiter have been discovered orbiting a distant star, and they are so insubstantial they would drift past you like clouds. Astronomers working with NASA's TESS satellite have identified what may be the largest super-puff planets ever found — worlds so low in density that cotton candy seems heavy by comparison.
The pair orbits a star in the constellation Volans, 1,110 light-years away in the southern sky. Using ground-based telescopes to measure orbital characteristics, researchers calculated the planets' density with enough precision to confirm something remarkable: these worlds are lighter than shaving foam fresh from the can. Oxford astronomer George Dransfield, who led the study, noted that the two planets are the heaviest objects ever found with such an impossibly low density. For context, Jupiter is up to 35 times denser than these featherweights.
Super-puffs are rare — fewer than 40 exist among nearly 6,300 confirmed exoplanets. The two new discoveries, reported in Monthly Notices of the Royal Astronomical Society, are thought to be composed primarily of hydrogen and helium, though their exact chemical makeup awaits confirmation from NASA's James Webb Space Telescope. Dransfield suspects the planets appear white or blue, their skies clear or cloudy — certainly not the pink of actual cotton candy.
How such enormous yet nearly massless planets come to exist remains one of astronomy's open questions. Current theory suggests super-puffs form in gas-rich regions around young stars and gradually shed their substance over time. These two worlds represent an extreme version of that process — retaining their bulk while losing nearly all their mass. Dransfield emphasized that each rare planetary system studied adds another piece to our understanding of how worlds form, and ultimately, how our own place in the cosmos came to be.
Two planets the size of Jupiter have been discovered orbiting a distant star, and they are so insubstantial that they would float past you like clouds. Astronomers working with data from NASA's TESS satellite have identified what may be the largest super-puff planets ever found — worlds so low in density that they make cotton candy look dense by comparison.
The pair orbits a star called Volans, located 1,110 light-years away in the southern sky. That distance is almost incomprehensible: a light-year stretches nearly 6 trillion miles. Yet from Earth, using ground-based telescopes to measure the planets' orbital characteristics, researchers were able to calculate their density with enough precision to confirm something remarkable. These worlds are lighter than shaving foam fresh from the can. George Dransfield, an astronomer at the University of Oxford who led the study, described the finding in an email, noting that the two planets represent the heaviest objects ever found with such an impossibly low density. For context, Jupiter — the heavyweight of our own solar system — is as much as 35 times denser than these featherweights.
Super-puffs are rare. Among the nearly 6,300 confirmed exoplanets discovered so far, fewer than 40 belong to this category. The two new discoveries, reported Wednesday in Monthly Notices of the Royal Astronomical Society, expand our understanding of how planets can form and persist. Dransfield suspects these worlds are probably white or blue in appearance, their skies either clear or cloudy, though certainly not the pink of actual cotton candy. The planets are thought to be composed primarily of hydrogen and helium — the lightest elements in the universe — though confirming their exact chemical makeup will require follow-up observations from NASA's James Webb Space Telescope.
The question of how such enormous yet weightless planets come to exist remains one of astronomy's puzzles. Current theory suggests that super-puffs form in the disk of gas and dust surrounding young stars, in regions where gas vastly outnumbers solid material. Over time, these planets shed much of their substance, becoming progressively more ethereal. The two newly discovered worlds represent an extreme version of this process — Jupiter-sized objects that have somehow retained their bulk while losing nearly all their mass.
Dransfield emphasized the broader significance of the discovery. Each rare planetary system studied adds another piece to the puzzle of how worlds form and evolve. By examining these exotic outliers, astronomers learn not only about the diversity of planets that exist but also about the fundamental processes that shaped our own solar system and our place within the cosmos. The Webb Space Telescope observations will be crucial in determining whether these planets are indeed mostly hydrogen and helium, or whether some other explanation accounts for their remarkable lightness.
Citas Notables
These two planets have densities comparable to a nice blob of shaving foam, fresh from the can.— George Dransfield, University of Oxford
By studying exotic systems containing rare planet types, we add further pieces to the puzzle of planet formation and learn more about our place in the cosmos.— George Dransfield, University of Oxford
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How do you even weigh a planet that's 1,110 light-years away?
You don't put it on a scale. You watch how it moves around its star — the gravitational tug tells you the mass. Then you measure its size using the way it dims the starlight as it passes in front. Divide mass by volume, and you have density.
And these two are lighter than cotton candy?
Lighter, yes. Imagine a Jupiter-sized object made mostly of hydrogen and helium with almost no solid core. That's what we're looking at. It's like the planet never finished condensing into something real.
Why would a planet form that way and then just... stay that way?
That's the mystery. They probably formed in a gas-rich disk around a young star and shed material over millions of years. But something stopped them from collapsing further or losing all their atmosphere. We don't fully understand the mechanism yet.
So these are mistakes? Failed planets?
Not mistakes — just a different outcome. They tell us that planet formation is messier and more varied than we once thought. There are more ways to make a world than we imagined.
What will the Webb telescope actually tell you that you don't know now?
The chemical fingerprint. Right now we're inferring composition from density. Webb can actually read the light passing through their atmospheres and tell us what gases are there. That's the confirmation we need.