Rubin's Algorithms Found a Possible Sixth Dwarf Planet
On 27 October 2026 the Minor Planet Center issued a circular announcing a new arrival in the outer Solar System: the object 2026 ED138, currently about 47 au from the Sun and brighter than almost anything else catalogued that far out. The unusual part is the method. Nobody was at a telescope. The detection came out of software comparing survey images, and the circular announcing it carried 74 observations strung across a decade with residuals of a tenth of an arcsecond. The object had been on camera since 2016, sitting in a crowded stretch of the Milky Way's plane, and nobody had noticed.
Beyond Neptune lies a population that would not be there if the Solar System had been built and then left alone. The Kuiper belt holds tens of thousands of icy bodies, most on near-circular orbits close to the plane of the ecliptic. Those are called cold classical objects, and they sit roughly where the protoplanetary disk left them. A minority tilt and stretch their orbits instead. Those are called hot, and they are the ones Neptune scattered when the giant planets migrated outward, which makes their inclinations a fossil record of that migration. The Minor Planet Center's orbit for ED138 gives a semi-major axis of 42.95 au, an eccentricity of 0.142, an inclination of 24.47 degrees and a Tisserand parameter of 5.3. That inclination puts it squarely in the hot population, and it is currently near aphelion at 49 au. Neptune has been near this object.
To count as a dwarf planet rather than a large asteroid, a body has to be round, which means its own gravity has to beat down the rigidity of its material. The International Astronomical Union recognizes five: Pluto, Ceres, Eris, Haumea and Makemake. Rubin's Solar System team puts ED138's diameter between 600 and 1,500 kilometres, which would place it among the largest candidates ever found beyond Neptune (NOIRLab, October 2026). That diameter is inferred from brightness rather than measured, and the difference decides whether this is a planet.
How it turned up matters more than the announcement. On the evening of 13 October, Matthew Holman, a Rubin Operations team member at the Center for Astrophysics | Harvard & Smithsonian, ran 2026 survey data through a search code written with CfA colleague Kevin Napier. The code takes billions of individual moving-object detections, compares them, and picks out the sets that belong to the same object. ED138 came out of that run. Holman's first reaction, as he described it, was "excited disbelief" (NOIRLab, October 2026). Objects that large are rare, so he went straight to work checking whether he or the code had erred.
Mario Jurić, Rubin's Solar System lead scientist at the University of Washington, went looking for more. Sifting through the observatory's catalogues and images, he turned up 20 further detections reaching back to 4 March 2026. All told the Simonyi Survey Telescope saw ED138 30 times on 20 nights between 4 March and 11 July. The next step was precovery, pulling the object out of old archives where nobody had thought to look: frames from the Dark Energy Camera on the Victor Blanco 4-m telescope at Cerro Tololo, run through the Asteroid Institute's ADAM precovery service, extended the trail back to 2016. The Minor Planet Center's current orbit solution reaches further still, to March 2010, using 89 observations across an arc of 5,959 days and eight oppositions, with an RMS residual of 0.07 arcseconds. Jurić and Holman presented the result at the 58th Annual Division for Planetary Sciences meeting in Spokane, and MPEC 2026-U85 went out the same day.
The decade of silence has little to do with faintness. ED138 sits close to the galactic plane, where the sky is thick with stars, and to most telescopes it was simply lost among the background sources (NOIRLab, October 2026). What changed is how Rubin looks. The LSST Camera is a 3.2-gigapixel focal plane built from 189 science CCDs in 21 rafts of nine sensors each, and it reads out in two seconds, about two orders of magnitude faster than a conventional astronomical camera (Brookhaven National Laboratory). Data comes off it at roughly 11 trillion bits per hour, so a ten-hour night of raw camera output runs to about 14 terabytes. The Simonyi Survey Telescope behind it has an 8.4-metre primary and a 3.42-metre convex secondary, feeding a 3.5-degree field that covers about 10 square degrees in one exposure (NOIRLab). The survey takes an image every 40 seconds and will do so for ten years. Software differences each exposure against a static model of the stars and hunts for what is left over and has moved. Repeating the same field thousands of times turns the sky into a film, and moving objects are what change between the frames.
The second half of the problem is turning brightness into size. The standard relation for a small body is D = 1329 / sqrt(p) * 10^(-H/5) km, where D is the diameter, p the geometric albedo and H the absolute magnitude. The Minor Planet Center lists ED138's H as 2.93 and its phase slope G as 0.15, and the object sits near magnitude 20 at opposition. Substituting gives D = 344 / sqrt(p) km, so a 600-kilometre diameter requires an albedo near 0.33 while a 1,500-kilometre diameter requires one near 0.05. Both are plausible for icy bodies, and that ambiguity is the difficulty: a single measurement of reflected light cannot separate a large dark object from a smaller bright one. Infrared settles it. At 47 au the equilibrium temperature works out to T = 278 / sqrt(p * D) * sqrt(40/r) K, which for a 900-kilometre body of albedo 0.15 comes to about 22 K. At that temperature nitrogen ice has largely sublimated away while methane and carbon monoxide hold on, so the ratio of thermal emission to reflected light fixes the albedo and the spectrum fixes the composition. No infrared follow-up has been scheduled yet, and the Centre lists the object as receding from Earth at 13.8 km per second, so whoever takes that measurement will be chasing it.
One detail in the orbit deserves a pause. ED138's perihelion fell on 4 February 1926. It has not been this close to the Sun in a hundred years and will not be again until 2207. Everything known about it comes from light that left it far beyond Neptune, spread thin enough that a single telescope sees a moving dot. Rubin's answer is not a bigger telescope but ten years of smaller ones, and the survey has barely started. In April 2026, before the formal ten-year run began, Rubin's Solar System team submitted more than 11,000 new asteroids to the Minor Planet Center, about 380 of them trans-Neptunian objects, and called the batch "the tip of the iceberg" (NOIRLab, October 2026). ED138 was already in the data collected before the survey started. The sky has been recording itself for billions of years. The new part is that someone finally built a camera fast enough to read the frames back.
Featured blog posts
A Transformer model called EarlyDetect, trained on SDO/HMI helioseismic and magnetic observations by an NJIT-led team including Princeton and NASA Ames, forecasts the emergence of solar active regions on the Sun an average of 9.24 hours before they become visible, outperforming LSTM baselines and revealing that temporal smoothing filters hid the faintest precursor signals (Tirona et al., JGR Machine Learning and Computation, 14 August 2026) 
Sixty-three relays over your head: how the U.S. Space Development Agency quietly built a sky internet. Posted on May 24, 2026
New observations from the James Webb Space Telescope are providing the clearest and most detailed view yet of the environment where these carbon structures form and evolve. 
Engineers and scientists are assembling a spacecraft designed for a specific and increasingly important purpose: finding potentially hazardous objects before they find Earth. Posted on May 4, 2026
An international team of researchers announced that NASA's Curiosity rover had identified more than 20 distinct organic molecules preserved in ancient Martian rocks. 
To truly shorten the distances between planets, something more powerful is required—something that does not merely burn fuel, but transforms matter itself into energy. 
There are moments in engineering when progress is obvious. And then there are moments when progress looks like subtraction. 
For as long as humans have pushed aircraft beyond the speed of sound, there has been a cost to that achievement—an invisible but unmistakable shockwave that ripples across the sky and crashes into the ground as a sonic boom. 
There are moments in the history of technology when an idea appears so simple in form and so vast in implication that it changes how we think about the future. 
The American Institute of Aeronautics and Astronautics has released a groundbreaking report identifying ten technologies that will fundamentally reshape aerospace. 
Every propulsion revolution has been delayed not by imagination, but by power. 
The LASER taught us that energy does not need to explode outward to be useful. It can be channeled. It can be persuaded to exit matter in an orderly way. 
The story of the LASER does not begin with light, but with order. 
Today we are joined byYasunori Yamazaki, Chief Business Officer at Axelspace. Axelspace are pioneers of microsatellite technology advancing the frontiers of space business, reimagining traditional ways of using space, and creating a society where everyone on our planet can make space part of their life. 
Today we are joined by Logan Ryan Golema, Founder & Principal, and Vishal Singh, Chief Scientist at Lunargistics. Latest blog posts
Pulled out of survey images by software rather than by eye, the object 2026 ED138 sits 47 au from the Sun on an orbit tilted nearly 25 degrees out of the ecliptic, and its orbit says it has not been this close to the Sun since 1926. Whether it counts as a planet depends on an infrared measurement nobody has made yet. 
NASA's 2001 Mars Odyssey marks 25 years at Mars on October 24, 2026, still mapping the surface with THEMIS and still relaying rover data, but its share of the Mars Relay Network has shrunk to the smallest of any active orbiter while NASA runs out of hydrazine and Congress has to decide whether to keep funding it 
India's NavIC navigation system had shrunk to three working satellites after clock failures and a spacecraft that never reached its orbit; the 2.2-tonne NVS-03 launched on 30 October restores the four-satellite floor and adds an L1 signal that ordinary phone chipsets already understand. 
NASA's Ultraviolet Explorer cleared its make-or-break review on October 27, committing the agency to a launch by January 2031 at a lifecycle cost of $590 million. With a 75-centimetre mirror and newly developed ultraviolet CMOS detectors, the observatory will reach fifty to a hundred times deeper than the survey it inherits, and turn neutron-star mergers and supernovae into spectra within hours of an alert. 
Encoding one logical qubit into 73 trapped-ion qubits, Quantinuum found the failure rate falls by about twelve for every two-step increase in code distance, leaving a logical qubit roughly a hundred times more reliable than the physical qubits underneath it. The slope, published on 19 October 2026, is far steeper than the factor of two that superconducting surface codes had reached, which is what turns error correction from a physics result into an engineering plan. 
"NASA's Neil Gehrels Swift Observatory falls back into Earth's atmosphere on 4 November 2026, nearly 22 years after launch, after a $30 million commercial boost attempt with Katalyst's LINK servicing spacecraft failed when the tug tumbled out of control and NASA gave up on the capture"' 
Banerjee and colleagues use archival SPHEREx spectrophotometry of the 2025 nova V572 Velorum, the third classical nova with an identified SU UMa dwarf-nova progenitor, to show the nova's circumstellar dust shell cooling from about 1030 K to about 480 K between roughly 178 and 393 days after the eruption, with the dust mass growing from about 10^-9 to 10^-8 solar masses, and the same archive had already caught the nova five days before its optical discovery 
The sunshade for NASA's NEO Surveyor has to do two opposite jobs at once: keep a 50-centimeter infrared telescope colder than 40 kelvin while generating the spacecraft's power from 864 solar cells mounted on its own panels. The structure passed thermal-vacuum testing in March 2026 and reached Boulder ahead of schedule in May. 
NASA's October 23, 2026 Artemis reset puts SLS, SpaceX's Starship and Blue Origin's New Glenn into a 2027 Earth-orbit docking test, and each of the three launch vehicles is getting a new upper stage, a new engine or a new variant to make the 2028 landing work 
NASA put four volunteers in a 1,700-square-foot 3D-printed habitat at Johnson Space Center for 378 days, with 22-minute one-way radio delays and equipment that fails on schedule, to measure what isolation and a year of waiting do to a crew. 
The Defense Intelligence Agency's 2026 Challenges to Security in Space report publishes the first full-resolution public image of China's reusable Shenlong spaceplane, captured in orbit in May 2024 by a Maxar (now Vantor) WorldView-3 commercial satellite, showing delta wings, a payload bay, a dark heat shield and a rear service module with solar arrays, alongside a flight record of four missions since 2020 and the agency's finding that China may field space-based directed-energy weapons by the late 2020s 
MIT engineers grew muscle cells less than 15 micrometres thick onto a half-millimetre gel film and got a pair of fins to pull a robot through water at four body lengths per minute. Freed from the stiff backing that used to kill thin muscle within minutes, the same film kept actuating for more than a month. 
What proof-of-work consensus faces once a cryptocurrency network stretches across the solar system: light delay breaks the chain long before relativistic time dilation does, and the workable answers are local settlement layers, cross-world bridges, and a single coordinate clock for every node 
The spacecraft's two main-belt flybys have already paid for themselves: one asteroid turned out to have a satellite that is itself a contact binary, the other a peanut-shaped body tumbling on more than one axis. The first close encounter with a real target is set for 11 August 2027. 
The Space Force pulled six military missions off ULA's Vulcan after one of its solid rocket motor nozzles melted through in February. The November 13 return flight carries 40 Amazon Leo satellites and, for the first time, six strap-on boosters. 
Subscribe to blog posts using RSS
