So that creationists can rehearse their excuses for dismissing science and retaining their childish delusion that Genesis is an accurate description of the universe, written or inspired by an omniscient creator god, in spite of the evidence to the contrary, here are some recent images and videos from the European Space Agency (ESA).
They were created from the most accurate three-dimensional map of star-formation regions in our Milky Way galaxy, based on data from the European Space Agency’s Gaia space telescope. The star-formation region that is mapped out (contoured by a circle) reaches out to 4000 light-years from our Sun. The Sun is located at the center of this region. The star-formation map is plotted on an artist impression of our Milky Way, based on Gaia data.. Credit: ESA/Gaia/DPAC, S. Payne-Wardenaar, L. McCallum et al (2025)
And some images to play with:
Credit: ESA/Gaia/DPAC, S. Payne-Wardenaar, L. McCallum et al (2025)
Licence: CC BY-SA 3.0 IGO and ESA Standard Licence
Credit: ESA/Gaia/DPAC, S. Payne-Wardenaar, L. McCallum et al (2025)
Licence: CC BY-SA 3.0 IGO and ESA Standard Licence
For the technically-minded, there are two papers explaining how these images were produced:
A three-dimensional, multiwavelength view and time-dependent analysis of the Milky Way’s local ionized gas.Images like these make plain how far the cosmos revealed by science is from Genesis’ picture of a flat world beneath a solid dome with waters above. Where that text speaks of lights fixed to the firmament—sun and moon included—astronomy shows vast galaxies and superclusters, innumerable stars and planetary systems, and a Sun that sits at the centre of our own. The biblical authors, without instruments or scientific method, described the world as it appeared to them; understandable, but not a reliable guide to reality.
Lewis McCallum, Kenneth Wood, Robert Benjamin, Dhanesh Krishnarao, Anna F McLeod
ABSTRACT1 INTRODUCTION
This work is the continuation of a series attempting to characterize the local warm ionized medium through both static and time-dependent simulations. We build upon our three-dimensional, observationally derived simulation of the local photoionized interstellar medium – based on static photoionization simulations constrained by 3D dust maps – to include metals required to predict collisionally excited optical and infrared emission lines, providing the first all-sky prediction of a series of lines including [S II] 6716 Å, [N II] 6584 Å, and [O III] 5007 Å. While these predictions only include O-star photoionization under ionization equilibrium, we also carry out a suite of radiation-hydrodynamics simulations including time-dependent metal ionization and the effects of supernova feedback to highlight missing features in our predicted skies. We use the simulations to estimate the very local (1 kpc2) Galactic star formation rate, finding a rate of 370 M⊙ Myr-1 kpc-2 provides the best match between the observationally derived and ab initio simulations. This is approximately a factor of 4 lower than previous estimates for the star formation rate required to support an observed layer of high-altitude diffuse ionized gas, possibly suggesting a ‘bursty’ star formation history in the region surrounding the Sun. We also investigate the effects of O-star environments on their ability to ionize large volumes of diffuse ionized gas, and find it is likely ionized by a small number of luminous O stars located in regions where the leakage of their Lyman continuum photons can produce the vast volumes of ionized gas observed in the mid-plane and at high galactic altitudes.
There are two principal methods to determine the record of recent (within the last 80 Myr) star formation in our solar neighbourhood. First, one can study the nearby interstellar medium (ISM) for nearby interstellar shells, filaments, clouds, and outflows. These structures provide evidence of the energy input back into the Solar environs from recent generations of massive stars, e.g. Cox & Reynolds (1987), Heiles (1998), Frisch, Redfield & Slavin (2011), and Zucker et al. (2023). And secondly, one can identify and characterize young clusters and OB associations near the Sun, examine their ages, dynamics, and chemical abundances, and search for commonalities in their histories, e.g. Blaauw (1964), Brown et al. (1999), and Wright et al. (2023.1).
For the first approach, advances in the three-dimensional mapping of dust (Marshall et al. 2006; Sale et al. 2014; Schlafly et al. 2014.1; Green et al. 2015, 2019; Chen et al. 2019.1a; Lallement et al. 2019.2; Leike, Glatzle & Enßlin 2020; Lallement et al. 2022; Vergely, Lallement & Cox 2022.1; Dharmawardena et al. 2024; Edenhofer et al. 2024.1; Mei et al. 2024.2; Rezaei Kh. et al. 2024.3; Zucker et al. 2025) constructed by obtaining extinction measurements (Anders et al. 2019.3; Zhang, Green & Rix 2023.2) and parallaxes for millions of stars (Gaia Collaboration 2016) have dramatically improved our understanding of the topology of the ISM out to distances of three kiloparsecs from the Sun (Zucker et al. 2023). These maps provide new details on numerous interstellar structures, including the ‘Radcliffe Wave’, a section of the Orion Arm (Morgan, Whitford & Code 1953) just outside the Sun’s orbit characterized by a kiloparsecs-long dust structure with both wavy morphology (Alves et al. 2020.1) and oscillatory kinematics (Thulasidharan et al. 2022.2; Konietzka et al. 2024.4), and ‘the Split’, a kiloparsecs-long dust band just inside the solar orbit (Green et al. 2019; Lallement et al. 2019.2) embedded with shells and star formation.
There have also been major advances in characterizing the spatial distribution and trajectories of nearby massive stars and their associated young clusters as well as the history of star formation in the solar environs (Chomiuk & Povich 2011.1; Kennicutt & Evans 2012; Vutisalchavakul, Evans & Heyer 2016.1; Binder & Povich 2018; Chen et al. 2019.4b; Zari, Brown & de Zeeuw 2019.5; Ruiz-Lara et al. 2020.2; Pantaleoni González et al. 2021; Poggio et al. 2021.1; Xu et al. 2021.2; Elia et al. 2022.3, 2025.1; Natale et al. 2022.4; Swiggum et al. 2022.5; Wells et al. 2022.6; Soler et al. 2023.3; Zari, Frankel & Rix 2023.4; Quintana, Wright & Martínez García 2025.2; Shen et al. 2025.3). Of particular note is Swiggum et al. (2024.5), who used the positions, velocities, and ages from a recently published catalogue of stellar clusters from Hunt & Reffert (2023.5), supplemented by radial velocities from other programmes and a catalogue of Young Local Associations (Gagné et al. 2018.1), to show that at least 57 per cent of 272 young (<70 Myr) clusters within one kiloparsec of the Sun originated in three distinct star-forming complexes. Each complex had an estimated gas mass of 1–2 million solar masses which started to form stars over 45 Myr ago, resulting in over 200 supernovae and three ‘families’ of clusters: the αPer family (82 clusters and young associations), the M6 family (34 clusters), and the Collinder 135 family (39 clusters). A smaller, fourth family of eight clusters, the γ Velorum family, was also identified.
These two approaches have started to merge with individual stellar clusters and associations being plausibly identified as the energy source for nearby interstellar structures.1 The origin of the Local Bubble has been attributed to the Upper Centaurus-Lupus and Lower Centaurus-Crux clusters of the αPer family (Zucker et al. 2022.7; Swiggum et al. 2024.5), the origin of the Gum Nebula to the Vela OB2 association of the γ Velorum family (Swiggum et al. 2024.5; Gao et al. 2025.4), and the origin of the HI supershell GSH 238+00+09 (Heiles 1998) to the clusters of the Collinder 135 family with some assistance from clusters of the M6 family. The linkage between some nearby bubbles/shells with local clusters is a bit less clear, e.g. the Orion-Eridanus superbubble (Foley et al. 2023.6) and the Perseus-Taurus shell (Bialy et al. 2021.3), but some connection is probable.
In order to associate shells and bubbles with the stellar energy input, one can compare the age and number of supernovae needed to create a bubble (using measurements of size and expansion velocity, and ambient density combined with expansion models) with the ages and number of supernovae expected from clusters that have passed through the same regions. These recent results indicate that multiple supernovae associated with clusters have contributed to bubbles near the Sun, producing a complex environment of time-evolving shells, bubbles, filaments, and secondary/tertiary star-forming regions (Cox & Smith 1974; Zucker et al. 2023).
However, gaps remain in our ability to fully explain the current structure and ionization state of the local ISM. It is unclear whether the known populations of nearby stellar clusters can account for all observed features, or whether additional sources or mechanisms are required. Moreover, the role of shocks, collisional ionization, and non-equilibrium processes in shaping emission-line signatures is not yet well constrained. These uncertainties complicate efforts to connect observed emission structures to specific past star-forming events. Bridging these gaps is critical for making full use of recent advances in 3D ISM mapping and for building a coherent picture of recent stellar feedback in our Galactic neighbourhood.
We have recently carried out three-dimensional Monte Carlo simulations of the radiative transfer of Lyman continuum (LyC) photons through the local ISM, as characterized by the high-resolution dust map of Edenhofer et al. (2024.1), and demonstrated that a sky projection of the three-dimensional distribution of model Hα emissivity is in good agreement with the observations (McCallum et al. 2025.5). These simulations allow us to reliably determine the temperature and ionization state of the gas throughout the local ISM. In this paper, we present two additional advances that allow us to make a tighter connection between the observed optical emission lines and the evolutionary state of the numerous bubbles and shells seen in the local neighbourhood. First, we update our earlier work to include predictions for the emission from a set of common optical and infrared emission lines, e.g. transitions of [N II], [S II], [O III], [Ne IIii], and [Ne III]. Secondly, we present a new suite of time-dependent radiation-hydrodynamics simulations using the framework described in McCallum et al. (2024.6a,2024.7b) to explore the role of shocks, collisional ionization, and non-equilibrium evolution in shaping the optical emission line sky. We summarize the inputs for our simulations in Section 2, present some of our principal results in Sections 3 and 4, discuss the implications of this work and comparison with prior results in Section 5, and provide a summary of results in Section 6.
Lewis McCallum, Kenneth Wood, Robert Benjamin, Dhanesh Krishnarao, Anna F McLeod
A three-dimensional, multiwavelength view and time-dependent analysis of the Milky Way’s local ionized gas Monthly Notices of the Royal Astronomical Society, (2025) 541(3), 2324–2340, DOI: 10.1093/mnras/staf1022.
Copyright: © 2025 The authors.
Published by The Royal Astronomical Society. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
The Hα sky in three dimensions
Lewis McCallum, Kenneth Wood, Robert A Benjamin, Dhanesh Krishnarao, Catherine Zucker, Gordian Edenhofer, L Matthew Haffner.ABSTRACT1 INTRODUCTION
We combine parallax distances to nearby O stars with parsec-scale resolution three-dimensional dust maps of the local region of the Milky Way (within 1.25 kpc of the Sun) to simulate the transfer of Lyman continuum photons through the interstellar medium (ISM). Assuming a fixed gas-to-dust ratio, we determine the density of ionized gas, electron temperature, and Hα emissivity throughout the local Milky Way. There is good morphological agreement between the predicted and observed Hα all-sky map of the Wisconsin Hα Mapper. We find that our simulation underproduces the observed Hα emission while overestimating the sizes of H II regions, and we discuss ways in which agreement between simulations and observations may be improved. Of the total ionizing luminosity of 5.84 x 1050 photons s-1, 15 per cent is absorbed by dust, 64 per cent ionizes ‘classical’ H II regions, 11 per cent ionizes the diffuse warm ionized medium, and 10 per cent escapes the simulation volume. We find that 18 per cent of the high-altitude (|b| > 30°) Hα arises from dust scattered rather than direct emission. These initial results provide an impressive validation of the three-dimensional dust maps and O-star parallaxes, opening a new frontier for studying the ionized ISM’s structure and energetics in three dimensions.
Understanding the creation and transport of Lyman continuum (LyC) photons from massive stars is a key element in determining the nature of galaxies as star formation engines. This ionizing radiation is mostly reprocessed into hydrogen and helium recombination and thermal dust emission, while some fraction of it can escape galaxies to produce the intergalactic radiation field. Measurement of the effects of this radiation allows us to quantify the star formation rate of galaxies and then compare to the structural and evolutionary factors that may regulate star formation (see, for example, Kennicutt & Evans 2012).
Observations of the local Milky Way provide an opportunity to study this process in detail because we can resolve individual ionizing sources and the structure of the surrounding gas and dust. In the 1950s, a primary focus of these investigations lay in determining the spiral structure of the Milky Way by using wide-area H sky surveys (Sharpless & Osterbrock 1952; Gum 1955; Sharpless 1959; Rodgers, Campbell & Whiteoak 1960) to identify nearby H II regions and measuring the distances to the exciting stars (Morgan, Whitford & Code 1953).
The original idealization of these H II regions as ‘Stromgren spheres’ (Strömgren 1939) in a uniform medium has been modified over the subsequent decades as our understanding of the complexity of the interstellar medium (ISM) increased. Massive stars are observed to form as part of clusters in dense molecular gas, but the combination of stellar winds, ionizing radiation, and supernovae leads to a complex density structure for the ISM, potentially filling the volume with networks of hot (T~106 K) bubbles and superbubbles, interstellar chimneys, and ‘galactic fountain’ flows (Cox & Smith 1974; Shapiro & Field 1976; McKee & Ostriker 1977; Bregman 1980; Norman & Ikeuchi 1989).
This framework had to be modified when pulsars in globular clusters were used to demonstrate a significant mass of warm ionized gas extending a few kiloparsecs above the Galactic plane (Reynolds 1989.1).1 This layer of warm ionized medium (WIM), sometimes called the ‘Reynolds layer’, or the diffuse ionized gas (DIG), exists in the volume beyond the classical H II regions, and analogous layers were detected in other edge-on spiral galaxies (Dettmar 1990; Rand, Kulkarni & Hester 1990.1). In a series of papers, Reynolds outlined several mysteries associated with this gas: what powers it, what ionizes it, what supports it at heights greater than a thermal scale height for 104 K gas, what fraction of ionizing photons emitted escape the galaxy, and so on (see Haffner et al. 2009). These mysteries, combined with the realization that WIM emission was a significant source of foreground emission for cosmological studies (Reynolds 1992), led to the construction of the Wisconsin Hα Mapper (WHAM), which obtained the first velocity-resolved all-sky map of optical line emission from the DIG of the Milky Way (Haffner et al. 2003).
Although numerous investigations have addressed the issues above, the unknown values of the filling factors and density structure of different phases have limited our ability to make conclusive statements about the energization and physics of the ISM. Previous modelling efforts of LyC transport (Miller & Cox 1993; Dove & Shull 1994; Bland-Hawthorn & Maloney 1999.1; Wood & Reynolds 1999.2; Dove, Shull & Ferrara 2000) explored the effects of different density structures, while Zurita et al. (2002) used H i maps of NGC 157 as an input to explore the role of H II region LyC leakage in ionizing the WIM. However, recent development of maps of the three-dimensional (3D) distribution of dust in the local ISM (Schlafly et al. 2014.1; Green et al. 2015, 2019; Lallement et al. 2019.2, 2022; Leike, Glatzle & Enßlin 2020; Vergely, Lallement & Cox 2022.1; Edenhofer et al. 2024.1) informed by parallax (Gaia Collaboration 2016, 2023.7) and extinction (Zhang, Green & Rix 2023.2) measurements for millions of stars make it possible to study the transport of Lyman continuum (and other) photons, turning the local ISM into a laboratory for the physical processes regulating the structure and dynamics of the Galactic ISM.
A realistic model of Lyman continuum transport would provide a 3D grid of free-electron density and hence local contributions towards dispersion measure along any sightline, crucial in interpreting dispersions from extragalactic fast radio bursts. The free-electron structure is also required for interpretation of surveys of Faraday rotation measure in constraining the 3D structure of the local magnetic field. Our simulations also estimate interstellar contributions of photoionized species with commonly used absorption lines (Mg, Ca, Na, etc.). They will help constrain Lyman continuum escape fractions with relevance to the study of cosmic reionization, give realistic fractions of ionizing photons lost due to dust absorption, and also help to identify the extent to which ionizing flux is able to escape individual H II regions. An estimate of direct versus scattered emission on every line of sight is also possible, as well as the ability to study the morphology and nature of individual regions of interest. It is also possible to determine contributions from individual ionizing sources, and constrain zones of influence of individual stars. Generating synthetic images also opens opportunities to fit for ISM and stellar parameters such as dust-to-gas ratio, ionizing luminosity, and distances to every O star in the local volume.
Lewis McCallum, Kenneth Wood, Robert A Benjamin, Dhanesh Krishnarao, Catherine Zucker, Gordian Edenhofer, L Matthew Haffner,
The Hα sky in three dimensions Monthly Notices of the Royal Astronomical Society: Letters (2025) 540(1), L21–L27, DOI: 10.1093/mnrasl/slaf023
Published by The Royal Astronomical Society. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
It doesn't take a genius to see the contrast between pre-scientific storytelling and evidence-based cosmology, and yet there are still people who believe the pre-scientific story-tellers produce the best available description of the cosmos, far surpassing for accuracy and reliability anything that science can produce.
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