GreenSpacealien — Quiet Cosmos

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Slow down and explore the universe with GreenSpacealien - Quiet Cosmos. Calm, chaptered astronomy documentaries journey through stars, black holes, planets and the space systems shaping everyday life. Follow the evidence, learn or unwind with Calm Space to Fall Asleep To. Watch our documentaries, discover original science Shorts and find every social profile: https://www.youtube.com/@GreenSpacealien15 Choose Spotify or your favourite podcast app: https://creators.spotify.com/pod/profile/greenspacealien15/

  1. 2d ago

    Cosmic Dawn — Evidence from the First Galaxies

    A quiet longform journey through the evidence for cosmic dawn: the galaxies we can measure, the hydrogen between them, and the questions that remain in their spectra. The film follows infrared color selection, spectroscopic redshifts, neutral hydrogen, quasar sightlines and the photon budget behind reionization. Each method brings its own selection limits and model assumptions. Early galaxies remain unresolved sources. Their measured light can constrain gas and stellar models, but does not directly identify the first stars. A radio upper limit is not a detected cosmic signal; a local sightline is not a map of the whole Universe. Artist concepts and explanatory diagrams remain separate from observed spectra and published data. Chapters:00:00:00 A Galaxy in the Early Light00:03:43 The Background That Remembers00:12:59 Listening to Neutral Hydrogen00:25:03 The Stars We Have Not Seen00:41:33 A Color Can Point the Way00:55:04 Turning a Candidate Into a Spectrum01:16:06 The Galaxies a Survey Can Count01:29:09 A Quasar Looks Through the Fog01:43:38 The Photon Budget01:57:12 The Questions Still in the Spectrum02:16:44 What Changed When the First Galaxies Lit Up? Sources and further reading:Naidu et al. (2026), MoM-z14 spectroscopy:https://astro.theoj.org/article/156033-a-cosmic-miracle-a-remarkably-luminous-galaxy-at-_z_-sub-spec-sub-14-44-confirmed-with-jwstCarniani et al. (2024), JADES spectra: https://www.nature.com/articles/s41586-024-07860-9Planck Collaboration (2020): https://doi.org/10.1051/0004-6361/201833910HERA Phase II (2026): https://doi.org/10.3847/1538-4357/ae2d54Witstok et al. (2025): https://www.nature.com/articles/s41586-025-08779-5Zhu et al. (2026), UV absorption in three galaxies: https://doi.org/10.1038/s41550-026-02988-2 Find us on:YouTube: https://www.youtube.com/@GreenSpacealien15Facebook: https://www.facebook.com/profile.php?id=61594406836899Instagram: https://www.instagram.com/greenbigspacealien15/X: https://x.com/GreenSpacealieTikTok: https://www.tiktok.com/@greenbigspace15Reddit: https://www.reddit.com/r/GreenSpacealien15/Dailymotion: https://www.dailymotion.com/user/green.hbw590Pinterest: https://www.pinterest.com/greenbigspacealien15/Rumble: https://rumble.com/user/greenspacealien15Threads: https://www.threads.com/@greenbigspacealien15Bluesky: https://bsky.app/profile/greenspacealien15.bsky.social

    Cosmic Dawn — Evidence from the First Galaxies

  2. 5d ago

    How We Know Other Worlds Are There

    How do astronomers find planets around other stars when most are too faint to image directly? This series follows the clues: a star’s motion, a repeating dip in its light, checks against false positives, and other methods such as direct imaging, microlensing and atmospheric spectroscopy. Each method answers a different question, and each depends on what the telescope can measure and the model used to interpret it. A candidate is not automatically a confirmed planet. A measured mass or radius is not a complete map of an interior, and atmospheric signals depend on wavelength, observing conditions and model assumptions. A potentially temperate orbit does not establish that a world is habitable or inhabited. The cover is an original conceptual illustration, not observational data. Chapters:00:00:00 The star that changed, and the world we inferred00:04:57 The glare problem00:13:27 The moving star00:25:49 A shadow with a period00:38:38 Could it be something else?00:52:18 Know the star01:02:42 Mass is not a map01:15:17 The planets we notice01:25:57 Suppressing the star01:36:08 Other kinds of clue01:47:07 Reading an atmosphere02:01:56 A possible home?02:11:04 The case file Selected sources:- Kipping & Sandford (2016), “Observational biases for transiting planets” — https://arxiv.org/abs/1603.05662- Espinoza et al. (2024), “Inhomogeneous terminators on the exoplanet WASP-39 b” — https://www.nature.com/articles/s41586-024-07768-4- NASA, How do you find—and confirm—a planet? — https://science.nasa.gov/universe/exoplanets/how-do-you-find-and-confirm-a-planet-10-things-about-the-search-for-exoplanets/- Wright & Gaudi, Exoplanet Detection Methods — https://arxiv.org/abs/1210.2471- Morton & Johnson, On the Low False Positive Probabilities of Kepler Planet Candidates — https://arxiv.org/abs/1101.5630- Fressin et al., The False Positive Rate of Kepler and the Occurrence of Planets — https://arxiv.org/abs/1301.0842- Carter et al. 2012, Kepler-36: a pair of planets with neighboring orbits and dissimilar densities — https://arxiv.org/abs/1206.4718- Rogers & Seager 2010, A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions — https://arxiv.org/abs/0912.3288- Lopez & Fortney 2014, Understanding the Mass-Radius Relation for Sub-Neptunes — https://arxiv.org/abs/1311.0329- Kopparapu et al. 2013, Habitable Zones Around Main-Sequence Stars — https://arxiv.org/abs/1301.6674- Rustamkulov et al. 2023, Early Release Science of the exoplanet WASP-39b with JWST NIRSpec — https://arxiv.org/abs/2211.10488- Faedi et al. 2011, WASP-39b: a highly inflated Saturn-mass planet orbiting a late G-type star — https://arxiv.org/abs/1102.1375- NASA Exoplanet Archive — https://exoplanet.ipac.caltech.edu/ Find us on:YouTube: https://www.youtube.com/@GreenSpacealien15Facebook: https://www.facebook.com/profile.php?id=61594406836899Instagram: https://www.instagram.com/greenbigspacealien15/X: https://x.com/GreenSpacealieTikTok: https://www.tiktok.com/@greenbigspace15Reddit: https://www.reddit.com/r/GreenSpacealien15/Dailymotion: https://www.dailymotion.com/user/green.hbw590Pinterest: https://www.pinterest.com/greenbigspacealien15/Rumble: https://rumble.com/user/greenspacealien15Threads: https://www.threads.com/@greenbigspacealien15Bluesky: https://bsky.app/profile/greenspacealien15.bsky.social

    How We Know Other Worlds Are There

  3. Oct 22

    Reading Bennu: The Journey of an Asteroid Sample

    NASA’s OSIRIS-REx mission returned 121.6 grams of material from asteroid Bennu. This episode follows what scientists can learn from a returned sample: how it was collected and curated, what its minerals and isotopes record, and how comparisons with Ryugu, Itokawa, and meteorites help test ideas about the early Solar System. Each result applies to particular samples and measurements; no whole-asteroid census is claimed. Proposed parent-body settings are reconstructions from evidence, not a direct map of an ancient orbit. Organic chemistry informs prebiotic possibilities; the data do not establish life. Chapters:00:00:00 One Grain, Several Clocks00:02:59 What a Fall to Earth Changes00:15:21 What the Remote View Could See00:30:18 A Local Collection, Not a Whole-Asteroid Census00:44:33 The Chain That Protects a Measurement00:57:17 Ingredients With Different Addresses01:18:18 Water Rewrites the Record01:32:20 Ryugu and the Meteorites Beside Bennu01:42:23 What Itokawa Adds to a Returned Sample01:53:41 Chemistry Before Biology02:04:36 Where Could the Parent Bodies Have Formed? Sources and further reading:NASA Science, “NASA Announces OSIRIS-REx Bulk Sample Mass” (15 Feb 2024). https://science.nasa.gov/blogs/osiris-rex/2024/02/15/nasa-announces-osiris-rex-bulk-sample-mass/Lunning et al., “OSIRIS-REx Curation: The First Year with Bennu Samples on Earth,” NASA Technical Reports Server 20240010710. https://ntrs.nasa.gov/citations/20240010710JAXA, Ryugu sample curation. https://curation.isas.jaxa.jp/en/sample-curation/ryugu/Nakamura et al. (2023), Science. https://doi.org/10.1126/science.abn8671Yabuta et al. (2023), Nature Communications. https://doi.org/10.1038/s41467-023-36904-3Koga et al. (2026), Nature Astronomy. https://doi.org/10.1038/s41550-026-02791-zJAXA, Itokawa sample curation. https://curation.isas.jaxa.jp/en/sample-curation/itokawa/Nakamura et al. (2011), Science. https://doi.org/10.1126/science.1207758Yurimoto et al. (2011), Science. https://doi.org/10.1126/science.1207776Glavin et al. (2025), Proceedings of the National Academy of Sciences, e2512461122. https://doi.org/10.1073/pnas.2512461122Barnes et al. (2025), “The variety and origin of materials accreted by Bennu’s parent asteroid,” Nature Astronomy 9, 1785–1802. https://doi.org/10.1038/s41550-025-02631-6Schönbächler et al. (2026), Science Advances 12(39), eaei9107. https://doi.org/10.1126/sciadv.aei9107Kawasaki et al. (2026), “Refractory inclusions in Bennu samples indicative of outer Solar System accretion,” Nature Communications 17, 8797. https://doi.org/10.1038/s41467-026-73868-6 Visual data credit: Schönbächler et al. (2026), DOI 10.1126/sciadv.aei9107, CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Table 1 values redrawn from the article’s reported data; no article figures or supplement graphics used. Find us on:YouTube: https://www.youtube.com/@GreenSpacealien15Facebook: https://www.facebook.com/profile.php?id=61594406836899Instagram: https://www.instagram.com/greenbigspacealien15/X: https://x.com/GreenSpacealieTikTok: https://www.tiktok.com/@greenbigspace15Reddit: https://www.reddit.com/r/GreenSpacealien15/Dailymotion: https://www.dailymotion.com/user/green.hbw590Pinterest: https://www.pinterest.com/greenbigspacealien15/Rumble: https://rumble.com/user/greenspacealien15Threads: https://www.threads.com/@greenbigspacealien15Bluesky: https://bsky.app/profile/greenspacealien15.bsky.social

    Reading Bennu: The Journey of an Asteroid Sample

  4. Oct 20

    Dark Matter: Following the Evidence

    A galaxy’s outer regions can keep moving faster than a calculation based on its visible stars and gas predicts. That difference begins a careful journey through the evidence for unseen gravitating matter—and through the places where the explanation remains open. We follow how spectral shifts become rotation curves, how many faint shape distortions become a statistical lensing profile, and why the Bullet Cluster’s displaced hot gas matters when compared with a lensing reconstruction. The oldest-light matter fit, primordial deuterium and fast-radio-burst dispersion add different constraints, each with its own model assumptions. Compact-object surveys and laboratory searches test particular possibilities; they do not name the cosmic component. A galaxy-scale alternative such as MOND also deserves a fair comparison, especially beyond rotation curves. The story’s conclusion is measured: several observational routes fit a framework with gravitating mass beyond luminous ordinary matter, while the particle identity remains unknown. A colored lensing map is an inference from distorted light, not a photograph of dark matter. Cosmological densities depend on the stated model and combined data. Chapters:00:00:00 The galaxy that keeps moving00:06:10 Reading a galaxy in its light00:17:34 What the light can weigh00:29:56 A relation across galaxies00:43:13 Gravity bends background light00:54:07 When clusters collide01:05:40 The inventory in the oldest light01:18:54 What “dark” and “cold” mean01:43:59 Searching for a name01:55:53 One event, and what it does not say02:02:30 What else could gravity be doing?02:11:10 The case we can close Sources: Rubin et al. (1980): https://articles.adsabs.harvard.edu/pdf/1980ApJ...238..471RSPARC (2016): https://arxiv.org/abs/1606.09251RAR data: https://astroweb.cwru.edu/SPARC/DDO 154 data: https://zenodo.org/records/16284118RAR (2016): https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.201101CFHTLS (2007): https://arxiv.org/abs/0707.1698Clowe et al. (2006): https://arxiv.org/abs/astro-ph/0611496Planck VI (2018): https://arxiv.org/abs/1807.06209DESI DR2 (2025): https://arxiv.org/abs/2503.14738Cooke et al., deuterium (2018): https://arxiv.org/abs/1710.11129Kislitsyn et al., deuterium (2024): https://arxiv.org/abs/2401.12797LUNA deuterium burning (2020): https://www.nature.com/articles/s41586-020-2878-4Connor et al., FRB baryon census (2025): https://arxiv.org/abs/2409.16952Liu et al., joint FRB/SN/BAO/Planck (2026): https://doi.org/10.1103/mdvc-wq7tOGLE LMC compact-lens search (2024): https://arxiv.org/abs/2403.02398OGLE SMC compact-lens search (2025): https://doi.org/10.3847/1538-4365/adf842Milgrom, original MOND proposal (1983): https://adsabs.harvard.edu/pdf/1983ApJ...270..365MZhang et al., Bullet Cluster MOND/IGIMF (2026): https://journals.aps.org/prd/abstract/10.1103/6zrp-q7c4LZ low-mass WIMP search (2025, later version): https://arxiv.org/abs/2512.08065XENONnT WIMP search (2025): https://arxiv.org/abs/2502.18005ADMX axion search (2025): https://arxiv.org/abs/2504.07279LZ nuclear-recoil analysis (2026 preprint): https://arxiv.org/abs/2609.02823 Find us on:YouTube: https://www.youtube.com/@GreenSpacealien15Facebook: https://www.facebook.com/profile.php?id=61594406836899Instagram: https://www.instagram.com/greenbigspacealien15/X: https://x.com/GreenSpacealieTikTok: https://www.tiktok.com/@greenbigspace15Reddit: https://www.reddit.com/r/GreenSpacealien15/Dailymotion: https://www.dailymotion.com/user/green.hbw590Pinterest: https://www.pinterest.com/greenbigspacealien15/Rumble: https://rumble.com/user/greenspacealien15Threads: https://www.threads.com/@greenbigspacealien15Bluesky: https://bsky.app/profile/greenspacealien15.bsky.social

    Dark Matter: Following the Evidence

  5. Oct 4

    How Far Can We Actually See? | Calm Space to Fall Asleep To

    What can we see when light has crossed an expanding universe, and what does “distance” mean in that setting? This quiet journey separates light-travel time, lookback time, present distance, and cosmological horizons. In the selected flat Planck-baseline ΛCDM model, the particle-horizon radius today is about 46 billion light-years. This is a model estimate of causal reach, not a directly seen object at that distance or a physical edge. Other distance definitions give different answers. Selected sources and credits - Planck Collaboration, 2018 cosmological parameters (https://doi.org/10.1051/0004-6361/201833910) and 68% parameter tables (https://wiki.cosmos.esa.int/planck-legacy-archive/images/d/d4/Result_table_2018_68pc.pdf). - Davis & Lineweaver (2004), cosmological horizons (https://doi.org/10.1071/AS03040); Hogg (1999), distance measures in cosmology (https://arxiv.org/abs/astro-ph/9905116). - NASA, what a light-year is (https://science.nasa.gov/exoplanets/what-is-a-light-year/); ESA, Planck and the cosmic microwave background (https://www.esa.int/Science_Exploration/Space_Science/Planck/Planck_and_the_cosmic_microwave_background). - Selected Webb image credits: NASA, ESA, CSA, STScI, Webb’s First Deep Field (SMACS 0723) (https://science.nasa.gov/asset/webb/webbs-first-deep-field-nircam-image/); NASA, ESA, CSA, STScI, Rohan Naidu (MIT), image processing Joseph DePasquale (STScI), COSMOS Field MoM-z14 Galaxy (https://science.nasa.gov/asset/webb/cosmos-field-mom-z14-galaxy-nircam-image/). - DESI Collaboration, 2026 Lyman-alpha results (https://www.desi.lbl.gov/2026/07/30/new-desi-dr2-lyman-alpha-results-shed-light-on-dark-energy/). This is a specific data/model comparison, not a final verdict on dark energy. 0:00 The View Arrives Late 5:42 How Far Away Is “Now”? 14:45 The First Ruler 26:44 Candles Across the Galaxy 39:31 When the Grid Itself Changes 51:41 Reading a Faint Patch of Sky 1:03:06 Galaxies From the Early Universe 1:13:40 Before the Sky Turned Transparent 1:22:14 The Distance to the Last Light 1:32:10 The Particle Horizon 1:44:15 The Hubble Sphere Is Not the Edge 1:50:02 What We Cannot Map From Here 1:59:00 A Horizon That Changes With Time 2:14:24 One Sky, Several Distances

  6. Oct 3

    The Moon Changed Earth—and Earth Changed the Moon | Calm Space to Fall Asleep To

    Earth’s spin, lunar orbit, and oceans have changed together over deep time. This calm documentary traces evidence from competing Moon-formation accounts through tides and incomplete geological records to today’s laser-ranging measurements. The current average recession rate is about 3.8 centimetres per year; it has not been constant through Earth’s history. Ancient sediment preserves local, incomplete records. The Moon affects Earth’s tides and axial dynamics, but the evidence does not show that it was required for life. Selected sources and credits - NASA, Moon facts (https://science.nasa.gov/moon/facts/) and lunar laser-ranging data (https://data.nasa.gov/dataset/cddis-llr-data); Young et al. (2016) (https://doi.org/10.1126/science.aad0525). - Visual source credit: James St. John, Tidalites (Elatina Formation, Neoproterozoic; Pichi Richi Pass stream cut, South Flinders Ranges, South Australia) 2 (https://commons.wikimedia.org/wiki/File:Tidalites_(Elatina_Formation,_Neoproterozoic;_Pichi_Richi_Pass_stream_cut,_South_Flinders_Ranges,_South_Australia)_2_(30441202460).jpg), CC BY 2.0. The photo is cropped and laid out beside a separately authored schematic. - Williams (2000) (https://doi.org/10.1029/1999RG900016) on geological constraints; Huang et al. (2024) (https://doi.org/10.1073/pnas.2317051121) on changing rotational deceleration. - Li & Batygin (2014) (https://doi.org/10.1088/0004-637X/790/1/69), Lissauer et al. (2012) (https://doi.org/10.1016/j.icarus.2011.10.013), and Song et al. (2024) (https://doi.org/10.1073/pnas.2412784121). The laboratory study does not show that the Moon was necessary for life. 0:00 A Small Retreat, a Long Memory 4:51 Two Worlds, One Ledger 13:07 Before There Was a Moon 22:25 The Impact Account—and Its Unfinished Parts 32:20 From Hot Debris to a Lunar Crust 41:38 The First Great Exchange 50:57 How the Moon Learned One Face 59:53 The Ocean Is Part of the Engine 1:09:28 A Day Preserved in Stone 1:19:24 Why the Moon's Past Is Not a Straight Line 1:29:06 Continents Rebuild the Tide 1:33:18 Does the Moon Steady Earth's Seasons? 1:43:12 Tides and the Conditions for Life 1:52:58 The Moon Reads Earth Back 2:02:24 The Clock Keeps Changing

  7. Oct 2

    Why Venus’s Sky Outruns Its Planet | Weather Beyond Earth | Calm Space to Fall Asleep To

    Venus offers a striking opening: its cloud tops circle the planet in roughly four to five days while the solid world turns much more slowly. From that contrast, this calm documentary asks how energy, chemistry, rotation, and measurement shape weather on other worlds. The journey compares Venus, Titan, Mars, Jupiter, Saturn, and distant exoplanets. It distinguishes measured motion and instrument readings from inferred maps and model explanations. A reconstructed exoplanet temperature pattern is not a photograph. Selected sources and credits - Venus rotation and cloud tracking: NASA Venus Facts (https://science.nasa.gov/venus/venus-facts/), Peralta et al. (2020) (https://doi.org/10.1038/s41467-020-19385-6), Horinouchi et al. (2021) (https://www.nature.com/articles/s41586-021-03636-7). - Titan’s Cassini record: Turtle et al. (2018) (https://doi.org/10.1029/2018GL078170). Mars’ dust-storm measurements: Guzewich et al. (2018) (https://doi.org/10.1029/2018GL080839). Jupiter’s deep jets: Kaspi et al. (2018) (https://doi.org/10.1038/nature25793). - Exoplanet methods: NASA Webb overview (https://science.nasa.gov/mission/webb/science-overview/science-explainers/how-will-webb-study-exoplanets/). - Visual credit for the cropped ESA/Webb WASP-43 b MIRI phase-curve chart: NASA, ESA, CSA, R. Crawford (STScI), T. Bell (BAERI), J. Barstow (The Open University), M. Roman (University of Leicester). The original graphic was cropped and resized for the curve panel. Source (https://esawebb.org/images/WASP43b-2/) · CC BY 4.0 reuse terms (https://esawebb.org/copyright/). 0:00 The Sky That Outruns Its World 5:44 Weather Without a Familiar Ground 13:14 The Energy That Starts the Motion 24:30 Air That Filters Its Own Sunlight 32:57 Rotation Draws Broad Currents 41:11 Venus: The Fast Sky 52:07 Titan: A Methane Cycle 1:04:01 Mars: Dust Changes the Air 1:14:40 Jupiter: The Weather Below the Clouds 1:22:02 Saturn: The Jets That Draw Polygons 1:31:51 The Seasons Written in Slow Motion 1:42:37 The Day Side and the Night Side 1:51:40 Reading Weather in Starlight 1:59:59 What a Forecast Can and Cannot Say 2:08:31 Returning to Earth as a Comparison

  8. Oct 1

    How Do We Map a Galaxy We Can’t Leave? | Calm Space to Fall Asleep To

    The Milky Way is all around us, but we observe it from within its disk. This quiet journey combines Gaia’s sky map with distances, stellar motions, spectra, and evidence of past encounters to reconstruct our Galaxy’s structure and history. Every method adds evidence, and every map carries uncertainty. The final chapters compare published forecasts for the Milky Way–Andromeda system. They do not promise a collision. Selected sources and credits - ESA, Gaia EDR3 all-sky map (https://www.esa.int/ESA_Multimedia/Images/2020/12/Interactive_map_of_the_sky_from_Gaia_s_Early_Data_Release_3), Gaia DR3 Milky Way sources (https://www.esa.int/ESA_Multimedia/Images/2022/06/Gaia_Milky_Way_stars), and how Gaia studies the Galaxy (https://www.esa.int/Science_Exploration/Space_Science/Gaia/How_does_Gaia_study_the_Milky_Way). - Distances and maps: Bailer-Jones et al. (2021) (https://doi.org/10.3847/1538-3881/abd806), Reid et al. (2019) (https://doi.org/10.3847/1538-4357/ab4a11), Gaia asymmetric disk (https://doi.org/10.1051/0004-6361/202243797), chemical cartography (https://doi.org/10.1051/0004-6361/202243511). - Halo evidence: Helmi et al. (2018) (https://www.nature.com/articles/s41586-018-0625-x). Separate Milky Way–Andromeda models: Sawala et al. (2025) (https://doi.org/10.1038/s41550-025-02563-1) and Wu et al. (2026) (https://doi.org/10.3847/2041-8213/ae5799). Neither is a guaranteed outcome. - M74 is used only as an external-galaxy analogy: NASA, ESA and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration; acknowledgement: R. Chandar and J. Miller (image record (https://science.nasa.gov/image-detail/m74-xlarge_web/)). Its full associated credit is embedded beside the image in the video. 0:00 The View from Inside 5:04 Where Is “Here”? 17:58 Turning Light into Distance 33:28 Drawing the Spiral from Within 49:24 The Map Moves 1:02:30 Chemical Address, Long Memory 1:16:30 Fossils in the Halo 1:33:52 A Living, Disturbed Disk 1:50:56 The Future Is a Distribution 2:05:22 What We Can Know from Inside

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Slow down and explore the universe with GreenSpacealien - Quiet Cosmos. Calm, chaptered astronomy documentaries journey through stars, black holes, planets and the space systems shaping everyday life. Follow the evidence, learn or unwind with Calm Space to Fall Asleep To. Watch our documentaries, discover original science Shorts and find every social profile: https://www.youtube.com/@GreenSpacealien15 Choose Spotify or your favourite podcast app: https://creators.spotify.com/pod/profile/greenspacealien15/

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