Hubble Solar System Views Track Planetary Weather and Collisions

Hubble is best known for galaxies, but NASA calls it something more modest closer to home: an interplanetary weather monitor. Since its launch in 1990, the telescope has watched storms grow and shrink on the giant planets, found moons no one knew existed and caught asteroids and comets in the act of breaking apart. NASA’s gallery of Hubble solar system images, and two new studies on how often things actually hit the planets, show how much of that work is still going on [1].

Hubble Solar System Observations of Outer Gas Giants

The gallery, curated for NASA Science by Faith Vowler, starts with Jupiter, where Hubble has spent decades watching the solar system’s largest atmosphere change. The planet’s trademark Great Red Spot was once vast enough that three Earths could fit inside its swirling boundaries, but long-term Hubble observations show the monster storm steadily shrinking [1].

Hubble rarely works alone. Images of the Great Red Spot gathered on June 27, 2019, combined data from the Hubble Space Telescope with observations collected by the Gemini Observatory. In February 2007, Hubble collaborated with NASA’s New Horizons mission to capture the auroras over Jupiter’s north pole as the spacecraft passed on its way to Pluto [1].

Saturn displays equally dramatic atmospheric changes under continuous space monitoring. Hubble captured a photo of Saturn on October 22, 2023, when the ringed planet was situated approximately 850 million miles from Earth, revealing delicate ring spoke variations and subtle atmospheric banding. During 2020, while the northern hemisphere experienced summer, Hubble detected multiple localized storms, complementing earlier 2018 ultraviolet composite observations of shimmering polar auroras. Beyond familiar rings, data gathered by the observatory revealed the unexpected Saturn Lyman-alpha bulge, a persistent hydrogen emission anomaly that puzzles planetary scientists [1].

Atmospheric Mysteries Across Uranus, Neptune, and Outer Moons

Planetary oddball Uranus rolls on its side around the Sun along an 84-year orbit, presenting unique atmospheric circulation patterns that contrast sharply with the upright rotation of Jupiter and Saturn. NASA’s Voyager 2 spacecraft flew past Uranus and Neptune only once during its historic twentieth-century tour, leaving the Hubble Space Telescope as our primary instrument for tracking atmospheric evolution across these distant worlds over multi-decade baselines. Hubble discovered that whirling winds and churning clouds on Uranus formed a monstrous dark feature spanning two-thirds of the planet’s hemisphere, while revealing ten of its seventeen inner satellites and four major ring structures. Between 2003 and 2005, Hubble observers identified two previously unknown small moons orbiting Uranus, as well as newly resolved outer dusty rings. On dynamic blue-green Neptune, Hubble snapshots uncovered an enormous dark storm accompanied by transient high-altitude methane clouds [1].

Moons and dwarf planets make up much of the rest of the gallery. In 1996, Hubble observed Jupiter’s moon Ganymede from half a billion miles away, documenting its icy terrain before tracking the satellite as it disappeared behind the jovian disk. Observations of volcanic Io revealed a distinct mound rising above the sulfurous surface, while four global projections of Saturn’s haze-shrouded moon Titan, separated in longitude by 90 degrees, mapped stable surface features. Looking outward to the Kuiper Belt, astronomers deployed Hubble to discover small moons Nix and Hydra orbiting dwarf planet Pluto, providing high-resolution target planning before the New Horizons flyby in 2015. In 2016, astronomers announced that Hubble had discovered another distant satellite orbiting the dwarf planet Makemake, proof that Hubble is still finding new members of the outer solar system decades after launch [1].

Asteroid Disruptions, Cometary Splitting, and Collision Physics

Some of the most striking images show small bodies falling apart. Hubble observed the main-belt asteroid P/2010 A2 in 2010, capturing an unusual comet-like debris trail that originated from a head-on collision between two smaller bodies rather than volatile ice sublimation. Another target exhibited a never-before-seen cluster of six radiating comet-like dust tails, while a separate fragile asteroid shattered into as many as 10 distinct tumbling fragments. In April 2020, Hubble photographed the solid icy nucleus of Comet C/2019 Y4 (ATLAS) breaking into multiple pieces, following earlier observations of Comet ISON disintegrating before perihelion passage [1].

Hubble’s pictures also guide missions. Its images of Vesta and Ceres helped engineers refine orbital rendezvous maneuvers for NASA’s Dawn spacecraft arrival in 2011 [1].

One collision was planned. On December 19, 2022, nearly four months after NASA deliberately crashed a projectile into asteroid Dimorphos, Hubble captured high-resolution views showing expanding debris cones and persistent gravitational drift. Closer in, Hubble has photographed Mars from 34,648,840 miles (55,760,220 km) away, resolving surface detail and dust storms [1]. Pictures like these raise a question the gallery cannot answer on its own: how often do asteroids and comets actually hit the planets, and do the models get that number right?

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Discrepancies in Planetary Impact Rates Across the Solar System

Inferring intrinsic planetary collision frequencies from observational data presents severe mathematical hurdles. Flash detections, bolide detonations, and fresh impact craters depend heavily on target-specific environments and uncertain selection effects. In an astrophysics preprint submitted to arXiv on September 18, 2026, researchers Qifeng Cheng and Daniel Scolnic investigated the persistent order-of-magnitude mismatch separating observational impact records from theoretical collision models across multiple worlds. Because these findings remain an unreviewed preprint, the conclusions serve as working scientific hypotheses rather than finalized consensus. Cheng and Scolnic converted twelve distinct observed impact datasets for Earth, the Moon, Mars, and Jupiter to a uniform pre-atmospheric impact rate (the frequency of bodies entering the upper atmosphere before disintegration) for diameters exceeding 10 meters [2].

The answer is that the models come up short everywhere. The observation-to-model median ratio ranged from 2.2 to 21.0 on Earth, 3.4 to 132.1 on the Moon, 14.2 to 118.6 on Mars, and 2.6 to 47.7 on Jupiter. The reasons differ from world to world. For Earth, incorporating simulated contributions from Jupiter-family comets significantly narrows the divergence, indicating that an unmodeled dynamical reservoir feeds terrestrial impactors. Conversely, disparate lunar crater records identified by lunar orbiters disagree with one another by up to two orders of magnitude, a conflict driven primarily by steep size-extrapolation uncertainties [2].

On Mars, where atmospheric deceleration remains minimal for intermediate bodies, the discrepancy stems chiefly from mathematical models that convert observed crater diameters back into original projectile sizes. Closing these gaps, the authors argue, will take better models of comet dynamics and wider observational coverage, the same kind of long record that Hubble has built for the solar system’s visible changes [2].

Jupiter’s Collision Environment and Predicted Bound Orbits

Jupiter, the biggest target in the solar system, has its own problem. In their preprint analysis, Cheng and Scolnic noted that Jupiter’s collision discrepancy depends predominantly on uncertain observational completeness thresholds and the estimated proportion of bound impactors captured into temporary jovian orbits. That feeds into a long-running debate over Jupiter’s gravitational shielding against cosmic debris: the planet deflects some objects away from the inner solar system and pulls others in [2].

A second preprint looks at real objects. In the paper, also submitted to arXiv on September 18, 2026, Cheng and Scolnic identified 2015 FK488, a Centaur (a class of icy bodies situated between Jupiter and Neptune) measuring approximately 1.8 kilometers across, whose nominal orbit projects an impact with Jupiter in roughly 200 years, although that orbit is still poorly known. Applying modeled impact rates, Cheng and Scolnic predicted that future wide-field surveys will discover 7 of 59 synthetic impactors heading toward Jupiter, with diameters between 200 and 2000 meters and discovery-to-collision lead times spanning 1.94 to 257.4 years. Two of these synthetic objects will be detected inside Jupiter’s Hill sphere (the gravitational sphere of influence where a planet dominates satellite retention). These observations would capture a small body transitioning from a temporary bound orbit into impact [3].

Advance Warning Forecasts for Earth and Future Surveys

Earth gets a candidate too. Cheng and Scolnic identified 2022 KG1, a near-Earth object measuring under 10 meters that was recently removed from official impact-risk lists. Its nominal trajectory currently leads to an Earth impact in approximately 260 years, though its orbit is poorly constrained. New astronomical facilities promise to transform early detection. The Vera C. Rubin Observatory and its Legacy Survey of Space and Time (LSST) will systematically scan the night sky, offering deep optical coverage that bridges existing observational gaps. When evaluated under observation-inferred impact rates, LSST forecasts indicate the observatory will discover at most 20 future Earth impactors and roughly 300 future Jupiter impactors measuring over 10 meters [3].

The two halves of this story fit together. Hubble’s decades of solar system imaging show atmospheres, rings and comets changing on human timescales [1]. As new facilities like the Vera C. Rubin Observatory prepare to track incoming impactors years to centuries before collision, synthesizing telescope imagery with numerical models will clarify whether cometary reservoirs or observational selection effects drive solar system impact discrepancies [3].

1. ^WEBSITE Vowler, F. (2026, September 21). Hubble’s Solar System. NASA Science. [Article Link]
2. ^PREPRINT Cheng, Q., & Scolnic, D. (2026). Asteroids Impacting the Solar System Planets and the Moon. II: Comparison with Observational Impact Records. arXiv:2609.22044. [Article Link]
3. ^PREPRINT Cheng, Q., & Scolnic, D. (2026). Asteroids Impacting the Solar System Planets and the Moon. III. Real Impacts from Known Objects and LSST Discovery Predictions. arXiv:2609.22045. [Article Link]