That is 0 articles you have read today.
The Aporia is free and carries no advertising, so readers are the only
thing paying for it. If you are getting this much out of it, a small
donation is what keeps it independent.
Daily limit reached
You have read 0 articles today.
That is more than the 15 a day The Aporia gives away,
and well past what it can carry on nothing. Your allowance resets at
midnight.
There is no advertising here and nothing about you is sold, so readers
are the only thing paying for it. If the site is worth this much of
your day, it is worth a few dollars.
Everything else stays open: the
maps, the
directory and
search do
not count against this, and neither does re-opening something you have
already read today.
Scientists studying Mars have discovered that a peculiar cloud, known as the Arsia Mons Elongated Cloud (AMEC), forms through an unusual process called homogeneous ice nucleation. This cloud, which can stretch up to 1800 km long and appears annually during spring and summer in Mars’s southern hemisphere, was analyzed using data from the European Space Agency’s Mars Express spacecraft and a sophisticated meteorological model. The study published in Nature Geoscience indicates that the AMEC forms when moist air near the Arsia Mons volcano rapidly cools, causing water vapor to freeze directly into ice particles without any dust or other condensation nuclei, revealing exotic atmospheric physics not typically observed on Earth.
Written locally by qwen2.5:14b on 2026-10-08,
using this article's own text rather than the other coverage of the
same event (that is the story summary below).
Story summary
Scientists from LMD/CNRS/Sorbonne Université in Paris have discovered "exotic physics" behind Mars's "oddest cloud," the Arsia Mons Elongated Cloud (AMEC), which appears every spring and summer over the planet’s southern hemisphere. Using data from the European Space Agency’s Mars Express spacecraft, researchers found that AMEC forms through homogeneous ice nucleation, a process where water vapor turns directly into icy particles without dust or other material as a nucleus. The cloud, up to 1800 km long—nearly twice the length of the UK—appears downwind of the 20-km-tall Arsia Mons volcano and repeats its daily cycle for several months each year. This research, published in *Nature Geoscience*, suggests that understanding such rare atmospheric phenomena on Mars could provide insights into Martian weather patterns and potentially similar processes on Earth.
Written for “Mars Odd Clouds Physics” on 2026-10-08,
grounded in this article and the 0 other(s) covering the same event.
Space scientists have said that Mars’s “oddest cloud” may be even odder than they thought.
uncertain
they → say → ?
Researchers using the European Space Agency’s Mars Express spacecraft, alongside a state-of-the-art meteorological model, have found that there may be some very “exotic physics” behind the planet’s “most curious cloud”.
uncertain
Researchers → use → cloud
A study published in Nature Geoscience suggests that the Arsia Mons Elongated Cloud (AMEC) forms through homogeneous ice nucleation – a process in which water vapour turns directly into icy cloud particles without first condensing on dust or other material.
uncertain
vapour → publish → dust
Mars’s “most visually striking cloud” – which is up to 1800 km long, nearly twice the length of the UK – appears every spring and summer in Mars’s southern hemisphere, during the Martian dusty season.
asserted
which → appear → season
The white wisp of water ice emerges downwind of the 20-km-tall Arsia Mons volcano.
asserted
wisp → emerge → volcano
It forms, grows and fades each day, stretching out before quickly evaporating.
asserted
It → form → ?
This cycle repeats every morning for several months.
asserted
cycle → repeat → months
The study suggests the cloud forms when winds over Arsia Mons rapidly lift moist air, cooling it so much that water vapour freezes directly into ice particles without dust or other condensation nuclei.
uncertain
vapour → suggest → dust
Jorge Hernández-Bernal of LMD/CNRS/Sorbonne Université in Paris, France, lead author of the new study, said: “To create the AMEC in our modelling, we found that we needed to include some exotic physics, physics that, while included in textbooks, is treated as theoretical and usually thought not to happen in nature.
asserted
that → say → nature
It certainly hasn’t been seen in action before.
asserted
It → see → action
Once we included this physics in our simulations, the AMEC emerged just as we hoped.
asserted
we → include → simulations
”
As winds flow past Arsia Mons, the volcano’s bulk triggers a powerful wave that lifts moist parcels of air several kilometres up in just a few minutes.
asserted
that → flow → minutes
This cools the atmosphere rapidly, causing temperatures to drop by 30 degrees in just ten minutes and relative humidity levels to spike.
asserted
levels → cool → minutes
Water vapour then spontaneously freezes directly into cloud particles, forming the AMEC.
asserted
vapour → freeze → AMEC
While some aspects of the modelled cloud don’t exactly match the observations, “the result is remarkable,” says Jorge.
asserted
Jorge → model → observations
“We don’t have nearly as much information about Mars’s atmosphere as we do about Earth’s, so reproducing the AMEC to this degree is a big success for the model.
asserted
reproducing → have → model
Beyond furthering our understanding of atmospheric processes on Mars and elsewhere, the result highlights that we should not discount unlikely processes when exploring the planets of the Universe (including exoplanets).
asserted
we → further → exoplanets
ESA Mars Express Project Scientist Colin Wilson said: “While clouds on Earth and Mars seem to be governed by the same ‘rules’, understanding this exotic martian cloud required exotic physics – and this may be true elsewhere in the cosmos.”
uncertain
this → say → cosmos
The Aporia
