Un amas géant, caché par la poussière, vient d’être découvert aux confins du cosmos et dérange les modèles actuels

Des astronomes ont poussé le radiotélescope le plus sensible du monde jusqu’à un record. Ils ont ainsi percé le voile d’une région du ciel pourtant déjà bien balayée par le télescope spatial Hubble. Ce qu’ils ont découvert alors que notre Univers n’avait qu’un milliard d’années défie toutes les prédictions.

Carbonaceous Cosmic Dust Analogs Distinguish between Ion Bombardment and Temperature

Carbonaceous Cosmic Dust Analogs Distinguish between Ion Bombardment and Temperature, Losurdo, Linda R., McKenzie, David R.

Is cosmic dust porous?

There is a long-standing discussion in the astrophysical/astrochemical community as to the structure and morphology of dust grains in various astrophysical environments (e.g., interstellar clouds, protostellar envelopes, protoplanetary and debris disks, and the atmospheres of exoplanets). Typical grain models assume a compact dust core which becomes covered in a thick ice mantle in cold dense environments. In contrast, less compact cores are likely to exhibit porosity, leading to a pronounced increase in surface area with concomitant much thinner ice films and higher accessibility to the bare grain surface. Several laboratory experimental and theoretical studies have shown that this type of dust structure can have a marked effect on several physico-chemical processes, including adsorption, desorption, mobility, and reactivity of chemical species. Porous grains are thus thought to likely play a particularly important and wide-ranging astrochemical role. Herein, we clarify what is meant by porosity in relation to grains and grain agglomerates, assess the likely astrochemical effects of porosity and ask whether a fractal/porous structural/morphological description of dust grains is appropriate from an astronomical perspective. We provide evidence for high porosity from laboratory experiments and computational simulations of grains and their growth in various astrophysical environments. Finally, we assess the observational constraints and perspectives on cosmic dust porosity. Overall, our paper discusses the effects of including porosity in dust models and the need to use such models for future astrophysical, astrochemical and astrobiological studies involving surface or solid-state processes.

Traces of the oxygen isotope composition of ancient air in fossilized cosmic dust - Communications Earth & Environment

Fossil I-type cosmic spherules may be used as an archive to study Earth’s ancient atmospheric triple oxygen isotope composition and CO2 levels or gross primary production, as shown by geochemical data from fossil I-type cosmic spherules extracted from Phanerozoic sediments.

If the Moon Were Only 1 Pixel - A tediously accurate map of the solar system

Hubble Discovers Cosmic Dust Coating Uranus' Moons, Not Radiation Scars

  The most recent Hubble Space Telescope observations indicate a twist in the narrative of Uranus' moons. Rather than the anticipated r...

A Synthetic Mimic for Cosmic Dust - ChemistryViews

Phenanthrene/pyrene hybrid microparticles can stand in for cosmic dust rich in polycyclic aromatic hydrocarbons (PAHs)