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Thread: Mysteries in Astronomy (my short list)

  1. #61
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    Quote Originally Posted by antoniseb View Post
    I think better still would be at the L4 & L5 points for Venus.
    Venus Equilateral? Whatever works, do it.
    Do good work. —Virgil Ivan "Gus" Grissom

  2. #62
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    Here is another: What happened to Wilhelm Albrecht Oeltzen? He is known for the processing of a part of Friedrich Wilhelm August Argelander's Zones from 1849-1852 in Bonn Germany. Often these are labeled "A. Oe." or "AOe" in catalogs. This was a two step process, I am uncertain if the abbreviations differentiate the two projects. In 1875, he disappeared. I have been unable to find any reference to what he was doing at that time.

    Since the 1870s are an interesting time period, it would be no surprise that the man simply passed away of natural causes, far from home.

    Edit: Hey! It took me a while to research this, why don't I post the key highlights of that work?

    Born on Oct 2nd, 1824.
    Studied at University of Göttingen in 1846.
    First Assistant at Vienna Observatory 1849-1859, before moving to The Paris Observatory.
    The Oeltzen's catalogue of Argelander's Southern Zones. 1857-58.
    The Oeltzen's catalogue of Argelander's Northern Zones. 1851-52.
    Schwerd's Beobachtungen von Circumpolarsternen in mittleren Positionen published in 1856, with Friedrich Magnus Schwerd.
    "Disappeared" in 1875.
    Solfe

  3. #63
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    Back to the ANITA anomaly:

    https://arxiv.org/abs/1907.06308

    The pros and cons of beyond standard model interpretations of ANITA events
    L. A. Anchordoqui, I. Antoniadis, V. Barger, F. Cornet, C. García Canal, M. Gutiérrez, J. I. Illana, J. G. Learned, D. Marfatia, M. Masip, S. Pakvasa, S. Palomares-Ruiz, J. F. Soriano, T. J. Weiler (Submitted on 15 Jul 2019)

    The Antarctic Impulsive Transient Antenna (ANITA) experiment has observed two air shower events with energy ∼500 PeV emerging from the Earth with exit angles ∼30∘ above the horizon. As was immediately noted by the ANITA Collaboration, these events (in principle) could originate in the atmospheric decay of an upgoing τ-lepton produced through a charged current interaction of a ντ inside the Earth. However, the relatively steep arrival angles of these perplexing events create tension with the standard model (SM) neutrino-nucleon interaction cross section. Deepening the conundrum, the IceCube neutrino telescope and the Pierre Auger Observatory with substantially larger exposures to cosmic ντ's in this energy range have not observed any events. This lack of observation implies that the messenger particle (MP) giving rise to ANITA events must produce an air shower event rate at least a factor of 40 larger than that produced by a flux of τ-neutrinos to avoid conflicts with the upper limits reported by the IceCube and the Pierre Auger collaborations. In addition, the sensitivity of ANITA to MP-induced events must be comparable to or larger than those of IceCube and Auger to avoid conflict with the non-observation of any signal at these facilities. Beyond SM interpretations of ANITA events can be classified according to whether the MPs: (i) live inside the Earth, (ii) originate in neutrino-nucleon collisions inside the Earth, (iii) come from cosmological distances. In this communication we investigate the positive and negative facets of these three classes of models.
    Do good work. —Virgil Ivan "Gus" Grissom

  4. #64
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    Quote Originally Posted by Van Rijn View Post
    One thing I recall reading is that part of the trouble is that it is hard to see asteroids that are between us and the sun, and much easier to see asteroids coming our way looking out away from the sun. As more and more asteroids are mapped, the issue decreases (since the asteroids we care about cross Earth orbit) but I believe it's also been suggested to put one or more space telescopes in closer solar orbit to look outward. (Perhaps in an Earth-Sun L1 halo orbit, for instance.)
    We missed another one yesterday, a city killer named 2019 OK.
    Do good work. —Virgil Ivan "Gus" Grissom

  5. #65
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    Quote Originally Posted by Roger E. Moore View Post
    Back to the ANITA anomaly:
    Again. This might explain it, but I don't understand any of it.

    https://ui.adsabs.harvard.edu/abs/20....017E/abstract

    Explaining the ANITA events by a Le−Lτ gauge model
    Esmaili, Arman; Farzan, Yasaman

    The ANITA experiment has registered two anomalous events that can be interpreted as ντ or bar nuτ with a very high energy of Script O(0.6) EeV emerging from deep inside the Earth. At such high energies, the Earth is opaque to neutrinos so the emergence of these neutrinos at such large zenith angles is a mystery. In our paper, we present a model that explains the two anomalous events through a Le −Lτ gauge interaction involving two new Weyl fermions charged under the new gauge symmetry. We find that, as a bonus of the model, the lighter Weyl fermion can be a dark matter component. We discuss how the ANITA observation can be reconciled with the IceCube and Auger upper bounds. We also demonstrate how this model can be tested in future by collider experiments.

  6. #66
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    Repeating Fast Radio Bursts: close to the answer?

    https://www.nature.com/articles/d41586-019-02455-1

    NATURE NEWS 13 August 2019

    Astronomers closer to cracking mystery of fast radio bursts
    Canadian telescope finds another eight repeating blasts — energetic events from deep in the cosmos.

  7. #67
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    A new mystery: what's up with the magnetic fields of Uranus and Neptune?

    https://arxiv.org/abs/1908.05821

    Metallic liquid H3O in a thin-shell zone inside Uranus and Neptune
    Peihao Huang, Hanyu Liu, Jian Lv, Quan Li, Chunhong Long, Yanchao Wang, Changfeng Chen, Yanming Ma
    (Submitted on 16 Aug 2019)

    The Solar System harbors deep unresolved mysteries despite centuries-long study. A highly intriguing case concerns anomalous non-dipolar and non-axisymmetric magnetic fields of Uranus and Neptune that have long eluded explanation by the prevailing theory. A thin-shell dynamo conjecture captures observed phenomena but leaves unexplained fundamental material basis and underlying mechanism. Here, we report the discovery of trihydrogen oxide (H3O) in metallic liquid state stabilized at extreme pressure and temperature conditions inside these icy planets. Calculated stability pressure field compared to known pressure-radius relation for Uranus and Neptune places metallic liquid H3O in a thin-shell zone near planetary cores. These findings from accurate quantum mechanical calculations rationalize the empirically conjectured thin-shell dynamo model and establish key physical benchmarks that are essential to elucidating the enigmatic magnetic-field anomaly of Uranus and Neptune, resolving a major mystery in planetary science.

  8. #68
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    Quote Originally Posted by Roger E. Moore View Post
    8. May 12, 2017: What produces the weird radio signals recently detected from the nearby red dwarf Ross 128?
    Oh, well.

    https://www.seti.org/signals-nearby-star-system

    UPDATE July 24, 2017

    Encouraged by the strange signals recorded at the Arecibo radio telescope, the Allen Telescope Array was used to try and confirm same, as noted. The ATA observed Ross128 for about 16 hours over three days, and while there was human-generated interference, there was no evidence for a signal originating from the star system. The Green Bank Telescope, part of the Breakthrough Listen project, and the Arecibo antenna itself also went into “confirmation mode” to check out these signals.

    It now seems clear that the Arecibo detections were due to transmissions from Earth satellites in geosynchronous orbit. Ross 128 has a declination (a coordinate which can be likened to latitude) of close to 0 degrees, which places it in the thick of a phalanx of these satellites. It was telemetry from these satellites, and not extraterrestrials, that accounts for the signals.
    Do good work. —Virgil Ivan "Gus" Grissom

  9. #69
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    A video about the Ashen Light on the dark side of Venus, might be of interest. No one knows what causes it.

    https://www.space.com/39251-on-this-day-in-space.html
    Do good work. —Virgil Ivan "Gus" Grissom

  10. #70
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    News article on the recent ANITA anomalies.

    https://www.livescience.com/antarcti...y-deepens.html
    Do good work. —Virgil Ivan "Gus" Grissom

  11. #71
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    Quote Originally Posted by Roger E. Moore View Post
    6. July 2007: Did a comet or meteor airburst over North America produce the Younger Dryas cold period, 12,900 years ago, killing off the woolly mammoths and damaging the human Clovis culture of that time?
    Same fragmented comet is now suspected of destroying a human settlement in the Middle East, many thousands of years ago.

    https://phys.org/news/2020-03-eviden...ion-world.html
    Do good work. —Virgil Ivan "Gus" Grissom

  12. #72
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    Quote Originally Posted by Roger E. Moore View Post
    I had a few other mysteries, but some of those were solved a few years ago (like the WOW! signal).
    What was the explanation for the WOW! Signal?

  13. #73
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    The sign of the Cross was seen in the sky over Europe during the Dark Ages. What caused that?

    https://arxiv.org/abs/2003.04192

    Provenance of the Cross Sign of 806 in the Anglo-Saxon Chronicle: A possible Lunar Halo over Continental Europe?
    Yuta Uchikawa, Les Cowley, Hisashi Hayakawa, David M. Willis, F. Richard Stephenson
    (Submitted on 9 Mar 2020)

    While graphical records of astronomical/meteorological events before telescopic observations are of particular interest, they have frequently undergone multiple copying and may have been modified from the original. Here, we analyze a graphical record of the cross-sign of 806 CE in the Anglo-Saxon Chronicle, which has been considered one of the earliest datable halo drawings in British records, whereas another cross-sign in 776 CE has been associated with the aurora. However, philological studies have revealed the later 806 event is derived from Continental annals. Here, records and drawings for the 806 event have been philologically traced back to mid-9th Century Continental manuscripts and the probable observational site identified as the area of Sens in northern France. The possible lunar halos at that time have been comprehensively examined by numerical ray tracing. Combined with calculations of twilight sky brightness, they identify a visibility window supporting monastic observation. Cruciform halos are shown to be fainter and rarer than brighter and more commonplace lunar halos. Physically credible cloud ice crystal variations can reproduce all the manuscript renditions. The manuscript records prove less than desirable detail but what is presented is fully consistent with a lunar halo interpretation. Finally, the possible societal impacts of such celestial events have been mentioned in the context of contemporary coins in Anglo-Saxon England and the Carolingian Empire. These analyses show that we need to trace their provenance back as far as possible, to best reconstruct the original event, even if graphical records are available for given astronomical/meteorological events.
    Do good work. —Virgil Ivan "Gus" Grissom

  14. #74
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    Quote Originally Posted by CaptainToonces View Post
    What was the explanation for the WOW! Signal?
    Unresolved, though I once thought it had been figured out. See this link.

    https://forum.cosmoquest.org/showthr...68#post2467068
    Do good work. —Virgil Ivan "Gus" Grissom

  15. #75
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    More on Mystery #2, the radiation event of the mid-770s AD.

    https://ui.adsabs.harvard.edu/abs/20....913N/abstract

    "A red cross appeared in the sky" and other celestial signs: Presumable European aurorae in the mid AD 770s were halo displays
    Neuhäuser, D. L.; Neuhäuser, R.

    The interpretation of the strong 14C variation around AD 775 as one (or several) solar super-flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the mid AD 770s in Europe: A red cross/crucifix in AD 773/4/6 from the Anglo-Saxon Chronicle, inflamed shields in AD 776 (both listed in the aurora catalogue of Link 1962), and riders on white horses in AD 773 (newly proposed as aurora in Usoskin et al. 2013), the two latter from the Royal Frankish Annals. We discuss the reports about these three sightings in detail here. We can show that all three can be interpreted convincingly as halo displays: The red cross or crucifix is formed by the horizontal arc and a vertical pillar of light (either with the Sun during sunset or with the moon after sunset); the inflamed shields and the riders on white horses were both two mock suns, especially the latter narrated in form of a Christian adaptation of the antique dioscuri motive. While the latter event took place early in AD 774 (dated AD 773 in Usoskin et al. 2013), the two other sightings have to be dated AD 776, i.e. anyway too late for being in connection with a 14C rise that started before AD 775. We also sketch the ideological background of those sightings and there were many similar reports throughout that time. In addition, we present a small drawing of a lunar halo display with horizontal arc and vertical pillar forming a cross for shortly later, namely AD 806 June 4, the night of full moon, also from the Anglo-Saxon Chronicle; we also show historic observations of halo phenomena (mock suns and crosses) from G. Kirch and Hevelius - and a modern photograph.

    ===

    https://ui.adsabs.harvard.edu/abs/20...7955N/abstract

    Presumable European aurorae in the mid AD 770s were halo displays
    Neuhaeuser, Dagmar; Neuhaeuser, Ralph

    The interpretation of the strong 14-C variation around AD 775 as one (or several) solar super-flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the mid AD 770s in Europe: A "red cross/crucifix" in AD 773/4/6 from the Anglo-Saxon Chronicle, "inflamed shields" in AD 776 (both listed in the aurora catalogue of Link 1962), and "riders on white horses" in AD 773 (newly proposed as aurora in Usoskin et al. 2013), the two latter from the Royal Frankish Annals. We discuss the reports about these three sightings in detail here. We can show that all three were halo displays: The "red cross" or "crucifix" is formed by the horizontal arc and a vertical pillar of light (either with the Sun during sunset or with the moon after sunset); the "inflamed shields" and the "riders on white horses" were both two mock suns, especially the latter narrated in form of a Christian adaptation of the antique dioscuri motive. While the latter event took place early in AD 774 (dated AD 773 in Usoskin et al. 2013), the two other sightings have to be dated AD 776, i.e. anyway too late for being in connection with a 14-C rise that started before AD 775. We also sketch the ideological background of those sightings and there were many similar reports throughout that time. In addition, we present a small drawing of a lunar halo display with horizontal arc and vertical pillar forming a cross for shortly later, namely AD 806 June 4, the night of full moon, also from the Anglo-Saxon Chronicle; we also show historic drawings of solar and lunar halo crosses from G. Kirch and Helevius and a modern photograph.

    ===

    http://articles.adsabs.harvard.edu/p...BAA..115..261B

    Astronomical references in the Anglo-Saxon Chronicles
    Beard, Darren
    Journal of the British Astronomical Association
    Pub Date: October 2005
    Do good work. —Virgil Ivan "Gus" Grissom

  16. #76
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    Quote Originally Posted by Roger E. Moore View Post
    The sign of the Cross was seen in the sky over Europe during the Dark Ages. What caused that?

    https://arxiv.org/abs/2003.04192

    Provenance of the Cross Sign of 806 in the Anglo-Saxon Chronicle: A possible Lunar Halo over Continental Europe?
    Yuta Uchikawa, Les Cowley, Hisashi Hayakawa, David M. Willis, F. Richard Stephenson
    (Submitted on 9 Mar 2020).
    Les Cowley's site can be found here, one of my favourite internet haunts.
    https://www.atoptics.co.uk/

  17. #77
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    Some of these medieval signs-in-the-sky show up in old UFO books.
    Do good work. —Virgil Ivan "Gus" Grissom

  18. #78
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    A new (not new) mystery: what causes sky-quakes? Meteors, or exotic matter as below?

    https://arxiv.org/abs/2003.07363

    Axion Quark Nuggets. SkyQuakes and Other Mysterious Explosions
    Dmitry Budker, Victor V. Flambaum, Ariel Zhitnitsky
    (Submitted on 16 Mar 2020)

    We advocate an idea that some mysterious explosions, the so-called sky-quakes, which have been known for centuries could be a manifestation of the dark matter Axion Quark Nuggets (AQN) when they propagate in the Earth's atmosphere. We specifically study the event which occurred on July 31-st 2008 and was properly recorded by the dedicated Elginfield Infrasound Array (ELFO) near London, Ontario, Canada. The infrasound detection was accompanied by non-observation of any meteors by an all-sky camera network. Our interpretation is based on the AQN dark matter model which was originally invented with a completely different purpose---to explain the similarity of the dark and visible cosmological matter densities Ω dark ∼ Ω visible. Our estimates for the infrasonic frequency ν≃5 Hz and overpressure δp∼0.3 Pa are consistent with the ELFO record. We propose a detection strategy for a systematic study to search for such explosions originating from AQNs by using Distributed Acoustic Sensing and briefly mention other possible detection methods. Specific signals from AQN tracks may also be detected by an existing network of seismic stations.
    Do good work. —Virgil Ivan "Gus" Grissom

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    This might explain some sky- quakes, but seemingly not those that occur repeatedly over specific areas. The best known of these is the famous 'Guns of Barisal' in East Bengal (now- Bangladesh). One assumes that dark matter particles would be randomly distributed.

  20. #80
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    Quote Originally Posted by Roger E. Moore View Post
    2. 774-775 A.D.: What caused the superabundance of carbon-14 detected in ice cores and tree rings worldwide? Did the Sun erupt?
    https://arxiv.org/abs/2003.11295
    Reply to "Rapid 14C excursion at 3372-3371 BCE not observed at two different locations"
    F. Y. Wang, H. Yu, Y. C. Zou, Z. G. Dai, K. S. Cheng
    (Submitted on 25 Mar 2020)
    The nuclide 14C can be produced in the atmosphere by high energy particles and γ-rays from high-energy phenomena. Through the carbon cycle, some of 14CO2 produced in the atmosphere can be retained in annual tree rings. Four events of rapid increase of the 14C content occurred in AD 775, AD 994, BC 660 and BC 3371 were found. Recently, the data of Jull et al. (2020) was inconsistent with our records around BC 3371. We measured our sample again and found the 14C records are consistent with the value in Wang et al. (2017). Therefore, our 14C records are robust. The inconsistency may be caused by the difference of calendar ages for the wood samples, or the physical origin of the event. First, crossdating on ring width can be performed only between trees whose growth has the same environmental conditions. Because the master tree-ring for dendrochronology is lack for Chinese trees. The master tree-ring from California has to be used. Therefore, the calendar ages derived from dendrochronology may be not precise. Second, the 14C even may be not global. One evidence is the variation of 14C content around AD 1006. The 14C contents of Californian trees increase 12 per thousand~ in two years, while Japanese trees show no 14C increase.
    Last edited by Roger E. Moore; 2020-Mar-26 at 05:14 PM.
    Do good work. —Virgil Ivan "Gus" Grissom

  21. #81
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    Evaluative comment: 16-year-old me would never have believed some of these things would turn out to be solvable. Or even real mysteries, and not fake UFO stuff.
    Do good work. —Virgil Ivan "Gus" Grissom

  22. #82
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    Quote Originally Posted by Roger E. Moore View Post
    22. 1821: What is the peculiar body orbiting Almaaz (epsilon Aurigae) that eclipses the yellow supergiant every 27 years? Also, how large is Almaaz and how far away is it, and why it is so difficult to discover these things even using the best technology we have?
    Two recent papers on Epsilon Aurigae and its mysterious companion.

    https://konkoly.hu/pub/ibvs/6201/6258.pdf

    DISTANCE, LUMINOSITY AND EVOLUTIONARY STATUS OF epsilon AURIGAE (F0IAEP) FROM GAIA DR2 PARALLAX
    M. PARTHASARATHY; S. MUNEER

    From Gaia DR2 parallax of epsilon Aurigae the distance, Mv, Mbol, and log(L∗/L⊙sun) are found to be 445 parsecs, −6.5 mag, −6.5 mag, and 4.5 respectively. These results clearly indicate that ǫ Aurigae (F0Iae) is post-AGB star. The progenitor of ǫ Aurigae is most likely an intermediate mass star of 4 to 5 solar masses or the progenitor may be a star which is lower limit of a super-AGB star.

    ==

    https://ui.adsabs.harvard.edu/abs/20...2161G/abstract

    Structure in the disc of epsilon Aurigae - analysis of ARCES and TripleSpec spectra from the 2010 eclipse
    Gibson, Justus L., et al.

    Worldwide interest in the recent eclipse of epsilon Aurigae resulted in the generation of several extensive data sets, including high-resolution spectroscopic data sets. This lead to the discovery, among other things, of the existence of a mass transfer stream, seen notably during third contact. We explored spectroscopic facets of the mass transfer stream during third contact, using high-resolution spectra obtained with the ARCES and TripleSpec instruments at Apache Point Observatory. One hundred and sixteen epochs of data were obtained between 2009 and 2012, and equivalent widths and line velocities of high- and low-eccentricity accretion disc lines were measured. These data sets also enabled greater detail to be measured of the mid-eclipse enhancement of the He I 10 830 Å line, and the discovery of the P Cygni shape of the Pa β line at the third contact. We found evidence of higher speed material, associated with the mass transfer stream, persisting between third and fourth eclipse contacts. We visualized the disc and stream interaction using SHAPE software, and used CLOUDY software to estimate that the source of the enhanced He I 10 830 Å absorption arises from a region with nH = 1011 cm-3 and temperature of 20 000K, consistent with a mid-B-type central star. Van Rensbergen binary star evolutionary models are somewhat consistent with the current binary parameters for their case of a 9 plus 8 solar mass initial binary, evolving into a 2.3 and 14.11 solar mass end product after 35 Myr. With these results, it is possible to make predictions which suggest that continued monitoring prior to the next eclipse (2036) will help resolve standing questions about the mass and age of this binary.
    Do good work. —Virgil Ivan "Gus" Grissom

  23. #83
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    Quote Originally Posted by Roger E. Moore View Post
    7. February 9, 1913: What was the true nature of the "Freight Train" meteor procession seen over the Western Hemisphere this night? How were these objects able to maintain such a tight aerial formation?
    https://arxiv.org/pdf/1912.01895.pdf
    Where Did They Come From, Where Did They Go. Grazing Fireballs
    P.M. Shober, T. Jansen-Sturgeon, E.K. Sansom, H.A.R. Devillepoix, M.C. Towner, P.A. Bland, M. Cupák, R.M. Howie, B.A.D. Hartig
    (Submitted on 4 Dec 2019 (v1), last revised 31 Mar 2020 (this version, v3))
    For centuries extremely-long grazing fireball displays have fascinated observers and inspired people to ponder about their origins. The Desert Fireball Network (DFN) is the largest single fireball network in the world, covering about one third of Australian skies. This expansive size has enabled us to capture a majority of the atmospheric trajectory of a spectacular grazing event that lasted over 90 seconds, penetrated as deep as ~58.5 km, and traveled over 1,300 km through the atmosphere before exiting back into interplanetary space. Based on our triangulation and dynamic analyses of the event, we have estimated the initial mass to be at least 60 kg, which would correspond to a30 cm object given a chondritic density (3500 kg m-3). However, this initial mass estimate is likely a lower bound, considering the minimal deceleration observed in the luminous phase. The most intriguing quality of this close encounter is that the meteoroid originated from an Apollo-type orbit and was inserted into a Jupiter-family comet (JFC) orbit due to the net energy gained during the close encounter with the Earth. Based on numerical simulations, the meteoroid will likely spend ~200 kyrs on a JFC orbit and have numerous encounters with Jupiter, the first of which will occur in January-March 2025. Eventually the meteoroid will likely be ejected from the Solar System or be flung into a trans-Neptunian orbit.
    Do good work. —Virgil Ivan "Gus" Grissom

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    How do you get a one-armed barred spiral galaxy? No idea, man.

    https://www.space.com/34-image-day.html
    https://phys.org/news/2020-03-image-...rm-galaxy.html

    Actually, I think the Large Magellanic Cloud was thought at one time to be a one-armed barred spiral.
    Do good work. —Virgil Ivan "Gus" Grissom

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    UPDATE TIME: Recent, Previously Discussed Additions to the Big List of Astronomical Anomalies, provided by alert and thoughtful readers of this thread (thank you all).

    27. 18 June 1178: Gervase of Canterbury's observation of an event on the Moon (near the crater Giordano Bruno)
    28. Potassium flares seen in the spectra of red-dwarf stars
    29. What causes the "ashen light" of Venus?
    30. Magnetic monopoles--do they exist?
    31. Has anyone discovered long-lived superheavy elements in galactic cosmic rays and supernovae?
    32. The Anomalous ANITA Events of 2019
    33. What happened to German 19th-century astronomer Wilhelm Albrecht Oeltzen?
    34. Magnetic field anomalies of Uranus and Neptune
    35. The "Sign of the Cross" seen over Europe in the Dark Ages: what was it?
    36. Sky-quakes and other mysterious atmospheric explosions (caused by impacting exotic matter?)
    37. The one-armed barred spiral galaxy, NGC 4618, and what created it


    And now a few "new" ones.


    38. What was the "moving star" seen by astronomer Hofrath Huth in 1801-1802?

    https://www.nature.com/articles/014291a0
    https://www.futilitycloset.com/2010/...s-moving-star/
    https://mysteriousuniverse.org/2019/...y-astronomers/
    https://books.google.com/books?id=Nx...20star&f=false
    https://books.google.com/books?id=zX...20star&f=false


    39. How can you have a galaxy that is made almost entirely of dark matter, with few stars in it? (Dragonfly 44)

    http://www.sci-news.com/astronomy/dr...ter-04135.html
    https://arxiv.org/abs/1606.06291
    https://arxiv.org/abs/1705.08513
    https://arxiv.org/abs/1904.04838
    https://arxiv.org/abs/1905.10373
    https://arxiv.org/abs/2003.11029


    40. How can a ring-shaped galaxy with a core in the center be formed, having no arms? (Hoag's Object)

    https://www.nasa.gov/multimedia/imag...ture_1747.html
    https://en.wikipedia.org/wiki/Hoag%27s_Object
    https://apod.nasa.gov/apod/ap191127.html
    https://www.livescience.com/hoags-ob...g-mystery.html
    https://astronomy.com/magazine/weird...7-hoags-object
    http://articles.adsabs.harvard.edu/p...pJ...191...61O


    41. What caused the fantastically huge, long-ago explosion in the Ophiuchus galaxy cluster?

    https://forum.cosmoquest.org/showthr...galaxy-cluster
    Last edited by Roger E. Moore; 2020-Apr-05 at 08:32 AM. Reason: additions
    Do good work. —Virgil Ivan "Gus" Grissom

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    42. A massive blue variable star in another galaxy vanished. What happened to it?

    https://arxiv.org/abs/2003.02242
    The disappearance of a massive star in the low metallicity galaxy PHL 293B
    Andrew Allan, Jose Groh, Andrea Mehner, Nathan Smith, Ioana Boian, Eoin Farrell (Submitted on 4 Mar 2020)
    Our current understanding of the final stages of massive star evolution is largely incomplete, particularly in low metallicity environments. To improve upon this, we investigate the behavior of a suspected LBV in one of the most metal-poor dwarf galaxies, PHL 293B. Excitingly, we find the sudden disappearance of the LBV signature from our spectra obtained in 2019. Spectroscopic observations of PHL 293B between 2001 and 2009 consistently revealed both narrow and broad strong emission components in the hydrogen Balmer lines, with minimal variation between observations. These broad components combined with P Cygni profiles have been associated with a massive Luminous Blue Variable (LBV) star. However, such features are absent from our spectra obtained in 2019 with the ESPRESSO and X-shooter instruments of the ESO's VLT, as well as archival data from 2011 and 2016.


    43. Has evidence been discovered that a previous cosmos existed before ours?

    https://arxiv.org/abs/1808.01740
    Apparent evidence for Hawking points in the CMB Sky
    Daniel An, Krzysztof A. Meissner, Pawel Nurowski, Roger Penrose
    (Submitted on 6 Aug 2018 (v1), last revised 2 Mar 2020 (this version, v4))

    (Current abstract) This paper presents strong observational evidence of numerous previously unobserved anomalous circular spots, of significantly raised temperature, in the CMB sky. The spots have angular radii between 0.03 and 0.04 radians (i.e. angular diameters between about 3 and 4 degrees). There is a clear cut-off at that size, indicating that each anomalous spot would have originated from a highly energetic point-like source, located at the end of inflation -- or else point-like at the conformally expanded Big Bang, if it is considered that there was no inflationary phase. The significant presence of these anomalous spots, was initially noticed in the Planck 70 GHz satellite data by comparison with 1000 standard simulations, and then confirmed by extending the comparison to 10000 simulations. Such anomalous points were then found at precisely the same locations in the WMAP data, their significance confirmed by comparison with 1000 WMAP simulations. Planck and WMAP have very different noise properties and it seems exceedingly unlikely that the observed presence of anomalous points in the same directions on both maps may come entirely from the noise. Subsequently, further confirmation was found in the Planck data by comparison with 1000 FFP8.1 MC simulations (with l ≤ 1500). The existence of such anomalous regions, resulting from point-like sources at the conformally stretched-out big bang, is a predicted consequence of conformal cyclic cosmology (CCC), these sources being the Hawking points of the theory, resulting from the Hawking radiation from supermassive black holes in a cosmic aeon prior to our own.

    (Previous abstract) This paper presents strong observational evidence (99.98% confidence) of anomalous individual points in the very early universe that appear to be sources of vast amounts of energy, revealed as specific previously unobserved signals found in the CMB sky. Though seemingly problematic for cosmic inflation, the existence of such anomalous points is an implication of conformal cyclic cosmology (CCC), as what could be the Hawking points of the theory, these being the effects of the final Hawking evaporation of supermassive black holes in the aeon prior to ours. Although of extremely low temperature at emission, in CCC this radiation is enormously concentrated by the conformal compression of the entire future of the black hole, resulting in a single point at the crossover into our current aeon, with the emission of vast numbers of (mainly) photons, whose effects we appear to be seeing as the observed anomalous points. Remarkably, the B-mode location found by BICEP 2 is at one of these anomalous points (an additional expectation of CCC).
    Do good work. —Virgil Ivan "Gus" Grissom

  27. #87
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    44. Why does the binary star HD 139139 dim and brighten randomly? (Not Tabby's Star, this one is the "Random Transiter".)

    https://www.sciencealert.com/a-star-...-the-milky-way
    https://phys.org/news/2019-07-binary...g-pattern.html

    https://academic.oup.com/mnras/advan...dFrom=fulltext
    The Random Transiter – EPIC 249706694/HD 139139
    S Rappaport, A Vanderburg, M H Kristiansen, M R Omohundro, H M Schwengeler, I A Terentev, F Dai, K Masuda, T L Jacobs, D LaCourse, et al.
    Monthly Notices of the Royal Astronomical Society, Volume 488, Issue 2, September 2019, Pages 2455–2465, Published: 28 June 2019
    ABSTRACT: We have identified a star, EPIC 249706694 (HD 139139), that was observed during K2 Campaign 15 with the Kepler extended mission that appears to exhibit 28 transit-like events over the course of the 87-d observation. The unusual aspect of these dips, all but two of which have depths of 200 ± 80 ppm, is that they exhibit no periodicity, and their arrival times could just as well have been produced by a random number generator. We show that no more than four of the events can be part of a periodic sequence. We have done a number of data quality tests to ascertain that these dips are of astrophysical origin, and while we cannot be absolutely certain that this is so, they have all the hallmarks of astrophysical variability on one of two possible host stars (a likely bound pair) in the photometric aperture. We explore a number of ideas for the origin of these dips, including actual planet transits due to multiple or dust emitting planets, anomalously large TTVs, S- and P-type transits in binary systems, a collection of dust-emitting asteroids, ‘dipper-star’ activity, and short-lived starspots. All transit scenarios that we have been able to conjure up appear to fail, while the intrinsic stellar variability hypothesis would be novel and untested.

    https://arxiv.org/abs/1910.03711
    Breakthrough Listen Follow-up of the Random Transiter (EPIC 249706694/HD 139139) with the Green Bank Telescope
    Brzycki, Bryan, et al.
    Abstract: The star EPIC 249706694 (HD 139139) was found to exhibit 28 transit-like events over an 87 day period during the Kepler mission's K2 Campaign 15 (Rappaport et al. 2019). These events did not fall into an identifiable pattern and could not be explained by a multitude of transit scenarios explored by the authors. We conduct follow-up observations at C-band frequencies with the Green Bank Telescope as part of the ongoing Breakthrough Listen search for technosignatures. We search for narrow band signals above a signal-to-noise threshold of 10 and with Doppler drift rates within +-5 Hz/s. We detect no evidence of technosignatures from EPIC 249706694 and derive an upper limit for the EIRP (Equivalent Isotropic Radiated Power) of putative transmissions to be 10 TW.
    Last edited by Roger E. Moore; 2020-Apr-05 at 08:44 AM. Reason: correction
    Do good work. —Virgil Ivan "Gus" Grissom

  28. #88
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    Last edited by Roger E. Moore; 2020-Apr-05 at 08:25 AM. Reason: corrected links
    Do good work. —Virgil Ivan "Gus" Grissom

  29. #89
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    Quote Originally Posted by Roger E. Moore View Post
    Mystery #3: The Lick Object (or Bright Object) of 1921 -- Probably a comet, as carefully researched in a paper from 2015. Amazing detective work.

    I was introduced to this story through William Corliss's excellent, Mysterious Universe, a Fortrean-style collection of weird astronomical reports dating back centuries, with strong emphasis on the 19th and 20th centuries (newspaper accounts, etc.).

    The tale of the Mysterious Lick Object of 1921 is often repeated in UFO literature as "proof" that UFOs exist, aliens are among us, etc. Regardless of that, the story is a classic. At a dinner party on the evening of August 21st, 1921, given by the director of Lick Observatory in California, W.W. Campbell (https://en.wikipedia.org/wiki/William_Wallace_Campbell) and his wife, a bright object was seen near the sun. In attendance were the following guests who also saw the bright object:

    * Captain Eddie V. Rickenbacker, WWI flying ace and Medal of Honor recipient, later head of Eastern Airlines (https://en.wikipedia.org/wiki/Eddie_Rickenbacker);
    * Major Reed Chambers, WWI flying ace, and Mrs. Chambers (https://en.wikipedia.org/wiki/Reed_McKinley_Chambers); and
    * Professor Henry Norris, director of Princeton Observatory, New Jersey (https://en.wikipedia.org/wiki/Henry_Norris_Russell), co-creator of the Hertzsprung–Russell diagram.

    Wikipedia links are provided to show how well known all the viewers were in their time, and thus how huge an impact the 1921 Bright Object made on the science world, despite the very short viewing time they had. Their reputations were unquestionable. If they said they saw something, they saw it.

    ================

    W.W. Campbell wrote the first record of the object's existence, as seen from the U.S.A. The story, told from the third person, is electric in effect as it is an eyewitness account.

    http://articles.adsabs.harvard.edu/f...ceQiYBCFlI_89Y
    (click through the story, page by page, and read story that comes after)

    Observations of an Unidentified Object Seen near the Sun on Sunday, August 7, 1921

    Campbell, W. W.
    Publications of the Astronomical Society of the Pacific, Vol. 33, No. 195, p.258 (PASP Homepage)
    Publication Date: 10/1921

    =================

    More news.

    http://articles.adsabs.harvard.edu/f...RASC..15..364P
    (click through the story, page by page)

    The Unidentified Bright Object Seen Near the Sun, August 7, 1921

    Pearce, J. A.
    Journal of the Royal Astronomical Society of Canada, Vol. 15, p.364
    Publication Date: 12/1921

    ===========

    The object was also briefly seen in Germany, per this article in French, also from 1921.

    http://articles.adsabs.harvard.edu/c...&filetype=.pdf

    ===========

    The probable solution: it was a long-period comet, visible for only a tiny fraction of time.

    https://arxiv.org/abs/1510.06445

    Pairs and Groups of Genetically Related Long-Period Comets and Probable Identity of the Mysterious Lick Object of 1921

    Zdenek Sekanina, Rainer Kracht (Submitted on 21 Oct 2015 (v1), last revised 26 Oct 2015 (this version, v2))

    We present the history of investigation of the dynamical properties of pairs and groups of genetically related long-period comets (other than the Kreutz sungrazing system). Members of a comet pair or group move in nearly identical orbits and their origin as fragments of a common parent comet is unquestionable. The only variable is the time of perihelion passage, which differs from member to member considerably due primarily to an orbital-momentum increment acquired during breakup. Meter-per-second separation velocities account for gaps of years or tens of years, thanks to the orbital periods of many millennia. The physical properties of individual members may not at all be alike, as illustrated by the trio of C/1988 A1, C/1996 Q1, and C/2015 F3. We exploit orbital similarity to examine whether the celebrated and as yet unidentified object, discovered from the Lick Observatory near the Sun at sunset on 1921 August 7, happened to be a member of such a pair and to track down the long-period comet to which it could be genetically related. Our search shows that the Lick object, which could not be a Kreutz sungrazer, was most probably a companion to comet C/1847 C1 (Hind), whose perihelion distance was ~9 R-sun and true orbital period approximately 8300 years. The gap of 74.4 years between their perihelion times is consistent with a separation velocity of ~1 m/s that set the fragments apart following the parent's breakup in a general proximity of perihelion during the previous return to the Sun in the 7th millennium BCE.
    Additional information on the Bright Object of 1921: more references to the sighting, possible other sighting

    http://articles.adsabs.harvard.edu/p...HarO.759Q...1B
    http://articles.adsabs.harvard.edu/p...HarO.757Q...1B
    http://articles.adsabs.harvard.edu/p...PA.....29T.592.
    Last edited by Roger E. Moore; 2020-Apr-05 at 12:32 AM.
    Do good work. —Virgil Ivan "Gus" Grissom

  30. #90
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    Quote Originally Posted by Roger E. Moore View Post
    How do you get a one-armed barred spiral galaxy? No idea, man.

    https://www.space.com/34-image-day.html
    https://phys.org/news/2020-03-image-...rm-galaxy.html

    Actually, I think the Large Magellanic Cloud was thought at one time to be a one-armed barred spiral.
    Ah, I see that the LMG really is classified as a one-armed barred spiral galaxy.

    https://en.wikipedia.org/wiki/Magellanic_spiral
    Do good work. —Virgil Ivan "Gus" Grissom

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