Hemmestorps Observatorium

27/10/2026

🧊 Pluto may have been born with a liquid ocean beneath its surface, rather than starting as a completely frozen world.

For years, scientists assumed Pluto formed cold, with ice and rock gradually warming as radioactive elements decayed inside it. That heat could eventually have melted some of the ice and created an underground ocean.

But New Horizons revealed a different clue.

Pluto’s surface is covered with enormous faults and fractures showing that its icy shell expanded over time. Researchers found plenty of evidence for expansion, but little sign of the early compression expected if Pluto had first warmed and melted from a frozen state.

That fits better with a “hot start.”

In this scenario, Pluto formed rapidly enough that energy released as material crashed together during its growth was trapped as heat. Water could therefore have been liquid beneath the surface almost from the beginning, around 4.5 billion years ago.

As that ocean slowly froze, water expanded, stretching Pluto’s outer ice shell and producing the tectonic features seen by New Horizons.

The models suggest Pluto could achieve such a hot start if the final stage of its formation happened in less than about 30,000 years. Slower growth could still work if large impacts carried heat deep into the interior.

The implication reaches beyond Pluto.

If large Kuiper Belt objects formed rapidly in the same way, worlds such as Eris and Makemake may also have begun with subsurface oceans despite forming far from the Sun.

There is an important caveat. Scientists have not directly detected a water ocean beneath Pluto today. New Horizons data provide geological evidence consistent with one, but NASA still treats a present-day ocean as a possibility, not a confirmed fact.

The study suggests that even the coldest worlds in the outer Solar System may have started surprisingly warm.

📃 RESEARCH PAPER
📌 Bierson et al., “Evidence for a hot start and early ocean formation on Pluto,” Nature Geoscience

27/10/2026

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27/10/2026

🔵 Neptune’s atmosphere is changing far faster than its seasons can easily explain, and scientists still do not know exactly why.

Astronomers analyzed nearly 100 thermal-infrared observations of Neptune collected between 2003 and 2020 using some of the world’s largest telescopes.

They expected a relatively gradual change.

Neptune takes about 165 Earth years to orbit the Sun, meaning each season lasts roughly 40 years. Its southern hemisphere passed summer solstice in 2005, so temperatures were expected to respond slowly.

Instead, researchers found something very different.

Neptune’s globally averaged stratospheric temperature fell by about 8°C between 2003 and 2018, even though its southern hemisphere was entering summer.

Then the planet changed again.

Between 2018 and 2020, Neptune’s south pole rapidly warmed by about 11°C.

Such a large change in only two Earth years was particularly surprising on a planet where seasonal changes are expected to unfold over decades.

The observations came from ESO’s Very Large Telescope, Subaru, Gemini, Keck and NASA’s Spitzer Space Telescope.

Infrared measurements allowed astronomers to track heat coming from different layers of Neptune’s atmosphere and showed that the changes were primarily occurring in its stratosphere.

Scientists still do not have a definitive explanation.

Possible causes include changes in atmospheric chemistry, shifting weather patterns and clouds, or effects connected to the Sun’s roughly 11-year activity cycle.

Neptune’s methane and other hydrocarbons absorb and emit radiation, so relatively small chemical changes could potentially alter how efficiently parts of its atmosphere heat and cool.

But none of these explanations has yet solved the mystery.

The observations cover less than half of a single Neptunian season, so astronomers need decades of further monitoring to understand whether these swings are unusual events or a normal part of the ice giant’s climate.

Neptune may look calm from billions of kilometers away, but its atmosphere is proving far more variable than scientists expected.

📃 RESEARCH PAPER
📌 Roman et al., “Subseasonal Variation in Neptune’s Mid-infrared Emission,” The Planetary Science Journal (2022)

27/10/2026

A 1,100-mile-long ice cloud forms near the martian volcano Arsia Mons every morning. New simulations suggest it’s built by a process long confined to theory.

27/10/2026

27/10/2026

🔭 One of the most powerful observatories ever built has opened its eyes, and in just 10 hours it discovered more than 2,000 previously unknown objects in our Solar System.

The Vera C. Rubin Observatory in Chile released its first public images in June 2025, offering an early demonstration of how quickly it can survey enormous areas of the sky.

At its heart is the 3,200-megapixel LSST Camera, the largest digital camera ever built for astronomy.

Each exposure covers an area of sky roughly equal to 45 full Moons, allowing Rubin to combine enormous detail with an unusually wide field of view.

During about 10 hours of test observations, the observatory detected 2,104 previously unknown small bodies in the Solar System.

They included 2,015 main-belt asteroids, nine trans-Neptunian objects and seven near-Earth asteroids. None of the near-Earth objects discovered in this batch posed an impact threat.

That was only a preview.

Another sequence, assembled from more than 1,100 exposures, revealed about 10 million galaxies. That sounds enormous, but Rubin estimates it represents only around 0.05% of the roughly 20 billion galaxies it could record during its decade-long survey.

Rubin also demonstrated its ability to detect objects that change with time. In one field, it measured 46 variable stars whose brightness shifted over minutes.

This time-domain capability is central to Rubin’s mission.

Rather than simply taking deep pictures, it repeatedly photographs the sky, allowing astronomers to spot moving asteroids, exploding stars, changing galaxies and other transient events almost as they happen.

Its 10-year Legacy Survey of Space and Time officially began in June 2026. Rubin will repeatedly scan the southern sky, building what is essentially an enormous time-lapse movie of the Universe.

The first images were therefore not just beautiful photographs.

They were a demonstration of scale: Rubin can find thousands of new objects in hours while simultaneously monitoring millions of stars and galaxies for change.

📃 SOURCE REPORT
📌 NSF-DOE Vera C. Rubin Observatory, “Ever-changing Universe Revealed in First Imagery From NSF-DOE Vera C. Rubin Observatory” (2025)