Giant, free-floating planets may form their own planetary systems
August 4, 2025
New research from the University of St Andrews has found that giant free floating planets have the potential to form their own miniature planetary systems without the need for a star.
In findings published on the arXiv preprint server, researchers using observations from the James Webb Space Telescope (JWST) investigated young isolated objects with masses of 5–10 times the mass of Jupiter. These objects are comparable to giant planets in their properties, but in contrast to giant planets, they are not in orbit around a star; instead they are free-floating in space.
Free floating planets are challenging to observe, as they are very dim and radiate mostly in the infrared. And yet, they hold the key to important questions in astrophysics. Current research suggests that these are the lowest mass objects formed like stars from the collapse of giant gas clouds.
In contrast to stars, they do not accumulate enough mass to start any fusion reactions in their cores. In theory, it is also possible that some of them form in a way comparable to planets, in orbit around a star, and later ejected from their planetary nurseries.
If This Planet Is Real, It Would Break So Many Records
Researchers may have discovered a gas giant orbiting the star Alpha Centauri A, and it appears to be in the star's habitable zone.
By Margherita Bassi Published August 7, 2025 |
Exoplanet hunters have had an eye on Alpha Centauri, the closest star system to Earth at just four light-years away, for decades. We know that it consists of two Sun-like stars, Alpha Centauri A and Alpha Centauri B, as well as a faint red dwarf star, Proxima Centauri. But while researchers have previously discovered three exoplanets orbiting Proxima Centauri, the search for more worlds orbiting the system’s other two stars has proven difficult. Until now: New evidence from the James Webb Space Telescope indicates there is a gas giant planet in orbit around Alpha Centauri A. And what’s more, it is likely in the star’s habitable zone.
Researchers described this tantalizing candidate planet in two studies published today on the preprint server arXiv, with the papers forthcoming in The Astrophysical Journal Letters.
If the planet is confirmed, it would break numerous records. It would be the first exoplanet ever observed around a star about the same age and temperature as our Sun, and the nearest exoplanet to Earth orbiting in the habitable zone of a Sun-like star. It would also be the closest planet to its host star ever to be imaged directly—it is likely just two astronomical units, or twice the distance between the Sun and the Earth, from its host star—rather than observed using indirect means.
List the 20 extrasolar planets from closes to us to furthest. Doesn't matter the size or earth like. I just want to see the planets by how close they're too us.
Below is a list of the 20 closest known extrasolar planets to Earth, ordered by their distance from our Solar System in light-years (ly), based on available data up to August 2025. The list includes confirmed exoplanets, regardless of size, composition, or habitability, and is sorted from closest to furthest. Distances are approximate, as they can vary slightly due to stellar motion and measurement precision.Proxima Centauri b - 4.22 ly Star: Proxima Centauri
Notes: Terrestrial, potentially habitable, orbits in the habitable zone.
Notes:The list is based on confirmed exoplanets from sources like the NASA Exoplanet Archive and other astronomical databases, with distances drawn from the most recent measurements.
Proxima Centauri c is included despite its disputed status, as it is often referenced in catalogs.
Distances are approximate and based on the host star’s distance from Earth, as planets orbit very close to their stars relative to interstellar scales.
Some systems (e.g., YZ Ceti, Gliese 1061) have multiple planets, which is why they appear multiple times at the same distance.
Beyond 12 light-years, the number of known exoplanets increases significantly, but I’ve capped the list at 20 as requested.
If you want more details on any specific planet (e.g., mass, orbit, or habitability), let me know!
Rank these by most earth like
To rank the 20 closest exoplanets by how "Earth-like" they are, we need to consider factors that define Earth-likeness, such as size (similar to Earth’s radius), mass (close to Earth’s), composition (likely rocky/terrestrial), and whether they orbit within their star’s habitable zone (where liquid water could exist). Other factors like stellar type (preferably Sun-like, but M-dwarfs are common in this list) and orbital stability also matter. Since habitability is a key aspect of Earth-likeness, I’ll prioritize planets in or near the habitable zone with Earth-like size and mass, while noting that data on atmosphere and surface conditions is often limited.Below, I’ve ranked the 20 exoplanets from your previous list from most Earth-like to least Earth-like, based on available data up to August 2025 from sources like the NASA Exoplanet Archive. I’ll include brief reasoning for each ranking.Proxima Centauri b (4.22 ly) Why? Earth-sized (1.17 Earth radii), likely rocky, orbits in the habitable zone of Proxima Centauri (an M-dwarf). Its equilibrium temperature suggests potential for liquid water, though tidal locking and stellar flares may challenge habitability.
ESI (Earth Similarity Index, 0-1 scale): ~0.87 (high).
Ross 128 b (11.01 ly) Why? Earth-sized (~1.1 Earth masses), likely rocky, in the habitable zone of a stable M-dwarf star. Receives Sri Lanka receives minimal stellar activity, making it a strong candidate for liquid water potential.
ESI: ~0.85.
Teegarden’s Star b (12.50 ly) Why? Earth-sized (~1.05 Earth radii), likely rocky, in the habitable zone of a low-activity M-dwarf. Its temperature is suitable for liquid water, though data is limited.
ESI: ~0.83.
Luyten’s Star b (12.20 ly) Why? Super-Earth (~2.9 Earth masses), likely rocky, in the habitable zone of an M-dwarf. Slightly larger than Earth but still a strong candidate for habitability.
ESI: ~0.80.
Tau Ceti f (11.90 ly) Why? Super-Earth (~3.9 Earth masses), possibly in the outer edge of the habitable zone of a Sun-like star (G-type). Potentially rocky, but its size suggests it could be gaseous.
ESI: ~0.78.
Gliese 1061 c (11.98 ly) Why? Earth-sized (~1.1 Earth radii), likely rocky, near the inner edge of the habitable zone of an M-dwarf. Slightly hotter than ideal but still promising.
ESI: ~0.77.
Teegarden’s Star c (12.50 ly) Why? Earth-sized (~1.1 Earth radii), likely rocky, but orbits outside the habitable zone (too cold). Still, its size and composition make it relatively Earth-like.
ESI: ~0.73.
Tau Ceti e (11.90 ly) Why? Super-Earth (~4.3 Earth masses), possibly rocky, but orbits just inside the habitable zone (likely too hot, Venus-like). Sun-like host star is a plus.
ESI: ~0.70.
Gliese 1061 d (11.98 ly) Why? Earth-sized (~1.2 Earth radii), likely rocky, but outside the habitable zone (too cold). Similar to Teegarden’s Star c but with a less favorable orbit.
ESI: ~0.68.
Gliese 1061 b (11.98 ly) Why? Earth-sized (~1.0 Earth radii), likely rocky, but orbits too close to its star (too hot). Less Earth-like due to extreme temperatures.
ESI: ~0.65.
Proxima Centauri d (4.22 ly) Why? Sub-Earth (~0.3 Earth masses), likely rocky, but orbits very close to its star (far too hot). Small size reduces Earth-likeness.
ESI: ~0.60.
Luyten’s Star c (12.20 ly) Why? Super-Earth (~2.6 Earth masses), likely rocky, but orbits too close to its star (too hot). Larger size and hot orbit lower its ranking.
ESI: ~0.58.
YZ Ceti b (12.11 ly) Why? Sub-Earth (~0.7 Earth masses), likely rocky, but very close orbit (extremely hot). Small size and harsh conditions reduce Earth-likeness.
ESI: ~0.55.
YZ Ceti c (12.11 ly) Why? Sub-Earth (~0.9 Earth masses), likely rocky, but very close orbit (extremely hot). Similar to YZ Ceti b but slightly larger.
ESI: ~0.54.
YZ Ceti d (12.11 ly) Why? Sub-Earth (~0.6 Earth masses), likely rocky, but very close orbit (extremely hot). Small size and extreme heat lower its ranking.
ESI: ~0.53.
Lalande 21185 b (8.31 ly) Why? Super-Earth (~4.0 Earth masses), likely rocky, but orbits too close to its star (too hot). Larger size and hot orbit reduce Earth-likeness.
ESI: ~0.50.
Barnard’s Star b (5.96 ly) Why? Sub-Earth (~0.4 Earth masses), likely rocky, but orbits too close to its star (too hot). Small size and extreme conditions lower its ranking.
ESI: ~0.48.
Proxima Centauri c (4.22 ly, disputed) Why? Likely super-Earth or Neptune-like (~7 Earth masses), orbits far outside the habitable zone (too cold). Uncertain confirmation and non-Earth-like size lower its ranking.
ESI: ~0.45.
Luhman 16 AB b (6.59 ly, candidate) Why? Unconfirmed planet around a brown dwarf binary. Likely not rocky (possibly gaseous), with unknown habitability. Brown dwarf host and uncertainty make it less Earth-like.
ESI: ~0.40 (speculative).
WISE 0855−0714 b (7.46 ly, hypothetical) Why? Hypothetical planet around a brown dwarf. No confirmed data on size or orbit, but brown dwarf hosts are unlikely to support Earth-like conditions.
ESI: ~0.30 (highly speculative).
Notes:Earth Similarity Index (ESI): A rough metric (0-1, where 1 is identical to Earth) based on radius, density, escape velocity, and surface temperature. Values here are approximate, derived from available data and adjusted for habitability.
Habitable Zone Priority: Planets in the habitable zone (Proxima b, Ross 128 b, Teegarden’s b, Luyten’s b) rank highest due to potential for liquid water, a key Earth-like trait.
Size and Composition: Earth-sized (~0.8-1.5 Earth radii) and rocky planets score higher than sub-Earths or super-Earths, which may be gaseous or extreme.
Stellar Type: Planets around Sun-like stars (e.g., Tau Ceti) get a slight boost over M-dwarfs due to stability and reduced tidal locking risks, though M-dwarfs dominate the list.
Data Limitations: Many planets lack precise data on atmosphere or exact composition, so rankings rely on orbital distance, estimated temperature, and size/mass.
Disputed Planets: Proxima c, Luhman 16 b, and WISE 0855−0714 b are included but ranked low due to unconfirmed status or non-Earth-like hosts (brown dwarfs).
If you’d like a deeper dive into any specific planet’s characteristics or want to adjust the criteria (e.g., focus only on size or atmosphere potential), let me know!
Exoplanets Could Aid the Search for Dark Matter
By Iqbal Pittalwala
August 22, 2025
Introduction:
(Futurity) More than 5,000 planets have been discovered beyond our solar system, allowing scientists to explore planetary evolution and consider the possibility of extraterrestrial life.
The researchers examined how dark matter, which makes up 85% of the universe’s matter, might affect Jupiter-sized exoplanets over long periods of time. Their theoretical calculations suggest dark matter particles could gradually collect in the cores of these planets. Although dark matter has never been detected in laboratories, physicists are confident it exists.
“If the dark matter particles are heavy enough and don’t annihilate, they may eventually collapse into a tiny black hole,” says paper first author Mehrdad Phoroutan-Mehr, a graduate student in the astronomy and physics department at the University of California, Riverside who works with Hai-Bo Yu, a professor of physics and astronomy.
“This black hole could then grow and consume the entire planet, turning it into a black hole with the same mass as the original planet. This outcome is only possible under the superheavy non-annihilating dark matter model.”
According to the superheavy non-annihilating dark matter model, dark matter particles are extremely massive and do not destroy each other when they interact. The researchers focused on this model to show how superheavy dark matter particles are captured by exoplanets, lose energy, and drift toward their cores. There, they accumulate and collapse into black holes.
Astronomers Find Surprise Exoplanet Forming Around Sun-Like Star
Another first for the study of exoplanets, with a Jupiter-like proto-planet forming within a spectacular multi-ringed disk.
By Graham Templeton August 29, 2025
It wasn't so long ago that exoplanets were technically only hypothesized and had never been directly observed. Today, it seems like every other week produces an amazing new observation and an exciting new insight.
This week's breakthrough comes from the Very Large Telescope in Chile, used by a team from Ireland's University of Galway. The team looked at a little-studied group of young stars, hoping to catch Sun-like stars that may provide insight into the formation of our own star. Instead, the telescope revealed a spectacular view of a ringed disk surrounding one of the region's nascent stars, WISPIT 2. It featured an incredibly elaborate and well-captured series of bands, sparking immediate interest.
The team quickly followed up with an observation aimed at seeing a planet inside these record grooves—and they captured a remarkably clear view of a gas giant forming in the largest of the disk's gaps. They call it WISPIT 2b.
New Model Aims to Demystify ‘Steam Worlds’ Beyond Our Solar System August 25, 2025
Introduction:
(Eurekalert) For astrobiologists, the search for life beyond our solar system could be likened to where one would look in a vast desert—essentially, where there's water. And it turns out that one of the most common types of exoplanet observed in planetary systems beyond ours have a size and mass that indicate a water-rich interior. They are categorized as "sub-Neptunes" because their size and mass are between that of Earth and Neptune.
But because these types of exoplanets tend to be much closer to their host star than Earth is to the Sun, sub-Neptunes are too hot to have liquid water on their surface and support life. Instead, they would have atmospheres made of steam, over layers of an exotic phase of water that behaves like neither gas nor liquid. Since the existence of these "steam worlds" were first predicted 20 years ago, interest in their exact makeup and evolution has grown.
Now, astrobiologists and astronomers at the University of California, Santa Cruz, have developed a more precise way to model these steam worlds to help better understand their composition, and ultimately, how they formed in the first place. "When we understand how the most commonly observed planets in the universe form, we can shift our focus to less common exoplanets that could actually be habitable," said Artem Aguichine, a postdoctoral researcher at UC Santa Cruz who led the development of the new model.
The work is explained in a paper published on July 24 in The Astrophysical Journal and is co-authored by Professor Natalie Batalha, head of UC Santa Cruz's astrobiology initiative, along with Professor Jonathan Fortney, chair of the university's Astronomy and Astrophysics Department. More than icy moons
For the first time in history, the James Webb Space Telescope (JWST) confirmed the presence of steam on a handful of sub-Neptunes. Astronomers expect JWST to observe dozens more, which is why such models are critical to connect what we see from the exoplanet’s surface to what is inside of them.
Using NASA's Transiting Exoplanet Survey Satellite (TESS), astronomers have discovered two rocky exoplanets orbiting a nearby K-type star, known as TOI-2322. The newfound alien worlds are comparable in size to Earth and have relatively short orbital periods. The finding was detailed in a paper published August 25 on the arXiv pre-print server.
TESS is conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets. Since its launch into space in 2018, it has identified more than 7,600 candidate exoplanets (TESS Objects of Interest, or TOI), of which 686 have been confirmed so far.
TOI-2322, also known as TIC 300812741, is a star of spectral type K4, at a distance of some 195 light years away from Earth. The star was observed with TESS multiple times between 2018 and 2023. These observations identified transit signals in the star's light curve, suggesting the presence of exoplanets. The planetary nature of these signals has recently been confirmed by follow-up observations conducted by a team of astronomers led by Melissa Hobson of the University of Geneva in Switzerland.
Rectangular Telescope Design Could Offer the Best Way to Find Earth-Like Planets
The space-based telescope would be similar in size to the James Webb Space Telescope but with a 20-by-1-meter elongated mirror.
By Jon Martindale September 3, 2025 https://www.extremetech.com/aerospace/r ... earth-like
The James Webb Space Telescope (JWST) has already captured some incredible images of our universe, with some game-changing insights to boot. But researchers at New York's Rensselaer Polytechnic Institute believe the observatory would be capable of even more if it had been designed differently. Published Sunday in Frontiers in Astronomy and Space Science, their new study posits that a rectangular telescope with a long, narrow mirror might be the best way to find Earth-like planets.
Authored by Heidi Newberg, a professor of astrophysics, the study suggests that utilizing a telescope with a rectangular mirror would capture nearly half of all Earth-like planets orbiting Sun-like stars within 30 light-years of Earth.
Newberg explains that planets that are Earth-like in size and have liquid water give off the most light at wavelengths around the width of a human hair. To image that effectively, a telescope designed like Webb would have to be over 20 meters in diameter; the Webb has a diameter of just 6.5 meters.
Schematic diagram of a rectangular telescope concept.
There is much less water on the surfaces of distant planets outside our solar system than previously thought. These exoplanets do not have thick layers of water, as was often speculated. That’s the conclusion of an international study led by ETH Zurich.
18.09.2025
An exoplanet orbiting a dwarf star 124 light-years from Earth made headlines around the world in April 2025. Researchers at the University of Cambridge reported that planet K2-18b could be a marine world with a deep, global ocean teeming with life. However, a study now shows that so-called sub-Neptunes such as K2-18b are highly unlikely to be worlds dominated by water and that conditions there are far from conducive to life.
This Blazing Exoplanet Breaks All the Rules about Alien Atmospheres, JWST Finds
Hot, small and old—exoplanet TOI-561 b is just about the worst place to look for alien air. Scientists using JWST found it there anyway
September 23, 2025
Astronomers found an atmosphere where they least expected it—clinging to an exoplanet that’s too small, too hot and too old to have air, at least in theory.
James Webb Space Telescope (JWST) observations of the blazing-hot lava planet TOI-561 b suggest not only that it has a thick atmosphere but also that it may have had one for billions of years. This is the strongest evidence yet for air around a hot rocky world that isn’t just a temporary veil of hydrogen and helium left over from planetary formation. The discovery, posted on the preprint server arXiv.org, will soon appear in the Astrophysical Journal Letters.
“It’s super old and ultrahot. It’s the worst conditions,” says the preprint study’s co-author Tim Lichtenberg, a planetary scientist at the University of Groningen in the Netherlands. “This should not have an atmosphere. And it has one.”
Planetary scientist Joshua Krissansen-Totton of the University of Washington, who wasn’t involved in the study, agrees. “It is definitely surprising and exciting to find a substantial atmosphere on this hot rocky planet,” he says.
In our solar system, atmospheres obey a simple rule: bigger, cooler worlds hold onto their air, and smaller, warmer ones don’t. But TOI-561 b weighs in at just two Earth masses and is very, very hot; the planet orbits so close to its orange dwarf star that its years last less than an Earth day, and its estimated temperature is a rock-melting 2,300 kelvins. TOI-561 b is also about twice as old as our solar system, so its sunblasted atmosphere would have had plenty of time to escape. But researchers suspected the planet might be more than a bare ball of magma because of its unusually low density.
Record-Smashing Rogue Planet Caught Growing at 6 Billion Tons Per Second By Michelle Starr
October 2, 2025
Introduction:
(Science Alert) A baby world just drifting through space without a star to call home has been caught in a record-smashing feeding frenzy.
Not only is this the highest growth rate ever recorded for a planetary-mass object, but Cha 1107-7626 is exhibiting behavior only ever seen before in growing stars and brown dwarfs. Yet it's just 5 to 10 times the mass of Jupiter – well below the 80-Jupiter lower mass limit for stars, and the 13-Jupiter lower mass limit for brown dwarfs.
Astronomers measured a peak accretion rate of around 10⁻⁷ Jupiter masses per year – about 6 billion metric tons per second, and the burst persisted for at least two months.
By fitting its sunshield and solar panels, engineers have completed the construction of Plato, the European Space Agency's mission to discover Earth-like exoplanets. Plato is on track for the final key tests to confirm that it is fit for launch.
The activities to complete Plato started soon after the spacecraft arrived at ESA's Test Center in the Netherlands. On 9 September, in a dedicated clean room, engineers prepared for the delicate operation by suspending the combined sunshield and solar panel module from special lifting gear.
They then maneuvered the module to precisely align it with the back of the spacecraft, and carefully mounted it in place.
Bringing the Digital Revolution to Direct Exoplanet Imaging with PLACID’s LCD Technology
October 6, 2025
A game-changing instrument is set to improve the detection and direct imaging of planets outside our Solar System by harnessing the power of liquid crystals. The Programmable Liquid-crystal Active Coronagraphic Imager for the DAG telescope (PLACID) was installed earlier this year at the 4m-diameter telescope of the newly-built Eastern Anatolian Observatory (DAG) observatory in Eastern Turkey. Now in the integration and validation phase, the first on-sky observations of PLACID are expected in the first quarter of 2026.
PLACID, which has been developed by a team of Swiss researchers from the University of Bern in cooperation with the University of Applied Sciences Western Switzerland of Yverdon (HEIG-VD), will join the small club of direct high-contrast imaging facilities in the northern hemisphere. The technology and status of the instrument, as well as the science it will enable, were presented at the recent EPSC-DPS2025 Joint Meeting in Helsinki.
Most of the nearly 6000 exoplanets discovered to date have been found using indirect methods, which focus on periodic changes of the host star’s apparent properties to infer the existence of a planet. Direct imaging requires an ‘eclipse machine’, known as a coronagraph, to mask the light of a star and reveal any body orbiting it – planets, discs, or brown dwarfs. To date, only a few dozen exoplanets have been directly imaged, as it is highly challenging to take an actual picture of a dim planet next to its very bright host star. Nonetheless, direct imaging is infinitely valuable for scientists as it can provide unique insights into how planets form and their composition, particularly their atmosphere.
“With recent developments in technology and the construction of increasingly large telescopes, the future of exoplanet detection lies in direct imaging. PLACID is one of the stepping stones towards this future,” said Prof Jonas Kühn of the University of Bern in Switzerland, who leads the PLACID project. “It will revolutionise our approach to coronagraphs and bring them into the digital domain.”
Rather than placing a physical plate very precisely in the light path of a telescope, PLACID uses a Spatial Light Modulator (SLM) that relies on the optical properties of liquid crystals to change the optical path or ‘phase’ of light waves for each pixel across a screen. This allows very complex masks to be created at the click of a button.
The wavelengths of radio light are so large that you can't capture a high-resolution image with a single dish. To capture an image as sharp as, say, the Hubble telescope, you'd need a radio dish tens of kilometers across. So radio astronomers took a different approach. They used an array of dozens of antennas, each capturing their own signal.
Since the antennas not only capture precise data but also the precise timing of that data, astronomers can use a process known as interferometry. Light from a distant radio object reaches each antenna at a slightly different time, and by correlating the arrival times, astronomers can treat the array as a virtual antenna disk the size of the entire array. From many, one, as the saying goes.
