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Mysterious gullies on Mars appear to have been carved by burrowing CO₂ ice blocks

Did life really exist on Mars after all? Unfortunately, there is no conclusive evidence for this yet. Nevertheless, it would seem that some form of life was the driving force behind the mysterious Martian dune gullies. Earth scientist Dr. Lonneke Roelofs from Utrecht University has investigated how these gullies were formed. In a test setup, she observed that blocks of CO2 ice “dug” these gullies in a unique way.

“It felt like I was watching the sandworms in the film Dune,” Roelofs says. Her findings are published in Geophysical Research Letters.

Other researchers had previously suspected that these blocks could play a role in the formation of the gullies. Roelofs has now proven this by having CO2 ice blocks actually dig those gullies in an experiment—a phenomenon that we do not know here on Earth and that had never been observed by anyone before.

Astronomers uncover collisional signature of filamentary structures in galactic G34 molecular cloud

Using CO (J=1–0) molecular line data obtained from the 13.7-meter millimeter-wave telescope at the Purple Mountain Observatory’s Delingha Observatory, Sun Mingke, a Ph.D. student from the Xinjiang Astronomical Observatory of the Chinese Academy of Sciences and his collaborators conducted a systematic study of the galactic molecular cloud G34. They revealed the collisional signatures and dynamical mechanisms of filamentary structures in this region. The results are published in Astronomy & Astrophysics.

Star formation is one of the key processes that drive the evolution of galaxies and the . Recent observations and suggest that interactions and collisions between large-scale filamentary structures may play an important role in triggering high-mass .

In this study, the researchers identified two giant filaments, designated F1 and F2, in the G34 region. By analyzing their and velocity field, the researchers found clear evidence of ongoing collisions between the filaments.

Shall we Dance in Free-Space? a Choice of Freedom!

Humanity stands at a crossroads. Our beautiful Earth, cradle of all we know, is straining under the weight of nearly 8.5 billion people. Environmental degradation, social inequity, and resource scarcity deepen by the day. We are reaching the limits of a single-planet civilization. We can face this challenge in two ways. Some will cling to the old patterns—fighting over dwindling resources and defending narrow borders. Others will rise above, expanding into space not to escape Earth, but to renew and sustain it. These pioneers—the Space Settlers —will carry the next chapter of civilization beyond our home planet.

The Humanist Path: Living in Free Space. When people imagine living beyond Earth, they often picture Lunar or Martian colonies. Yet, from a humanist perspective, a better path exists: rotating free space habitats, as envisioned by Gerard K. O’Neill. These are vast, spinning structures orbiting Earth or the Moon, or standing at Lagrange Libration Points, designed to simulate Earth’s gravity and sustain full, flourishing communities. Unlike planetary colonies bound to weak gravity, dust, or darkness, O’Neill habitats offer: 1g simulated gravity to preserve human health; continuous sunlight and abundant solar energy; freedom of movement, as habitats can orbit safely or relocate if needed. More than technical achievements, these habitats embody the Enlightenment spirit—the belief that reason, ethics, and creativity can design environments of dignity, beauty, and freedom.

Freedom and Human Dignity in Space. Freedom is at the heart of humanity’s destiny. Consider a lunar settler who finds his bones too fragile to withstand Earth’s gravity—trapped by biology, after a few years living on the Moon. In contrast, inhabitants of a rotating habitat retain the freedom to return on Earth, at will. Simulated gravity safeguards their health, ensuring that space settlement remains reversible and voluntary. Freedom of movement leads naturally to freedom of culture. In a habitat like “New Gaia”, thousands of people from all nations live together: Russians celebrating Maslenitsa, Indians lighting Diwali lamps, and space-born storytellers sharing ancient myths. New traditions also emerge—festivals, music, and art inspired by life between worlds. These habitats can become beacons of a new Renaissance —a rebirth of cultural and creative freedom beyond the constraints of geography and politics.

Observations inspect the nature of a newly discovered very faint X-ray transient

Using various space telescopes, an international team of astronomers have observed a newly detected very faint X-ray transient designated 4XMM J174610.7–290020. Results of the observational campaign, published October 2 on the arXiv pre-print server, yield new insights into the nature of this transient.

Very faint X-ray transients (VFXTs) are X-ray experiencing occasional outbursts with peak X-ray luminosities lower than an undecillion erg/s, therefore fainter than typical X-ray binaries. To date, only a few tens of VFXTs have been detected in the Milky Way, and about a dozen in the center of our galaxy.

Due to their typical low fluxes, the number of VFXTs that have been investigated in detail is still very small. Therefore, finding new VFXTs and studying them is essential to get a comprehensive view of the population of these transients.

Six billion tonnes a second: Rogue planet found growing at record rate

Astronomers have identified an enormous ‘growth spurt’ in a so-called rogue planet. Unlike the planets in our Solar System, these objects do not orbit stars, free-floating on their own instead. The new observations, made with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), reveal that this free-floating planet is eating up gas and dust from its surroundings at a rate of six billion tonnes a second. This is the strongest growth rate ever recorded for a rogue planet, or a planet of any kind, providing valuable insights into how they form and grow.

People may think of planets as quiet and stable worlds, but with this discovery we see that planetary-mass objects freely floating in space can be exciting places,” says Víctor Almendros-Abad, an astronomer at the Astronomical Observatory of Palermo, National Institute for Astrophysics (INAF), Italy and lead author of the new study.

The newly studied object, which has a mass five to 10 times the mass of Jupiter, is located about 620 light-years away in the constellation Chamaeleon. Officially named Cha 1107–7626, this rogue planet is still forming and is fed by a surrounding disc of gas and dust. This material constantly falls onto the free-floating planet, a process known as accretion. However, the team led by Almendros-Abad has now found that the rate at which the young planet is accreting is not steady.

Terence Tao on the cosmic distance ladder

Excellent visualizations and explanations here!

(30 mins. approx.)


The Cosmic Distance Ladder: How we learned distances in the heavens.
Patreon supporters see early views of new videos: https://www.patreon.com/3blue1brown.

Artwork by Kurt Bruns.
Thanks to Paul Dancstep for several animations, such as the powers of 10 zoom out and the simulations of shadows on the moon.

Terry has kindly cataloged many of the added nuances, including a few corrections, in this post:

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