Dipole repeller

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Gravitation induces movement in denser areas and at the same time pushes matter out of an empty area, according to the model of the "dipole repeller". The small circles and their lines represent the galaxies and directions of their respective movements.

The dipole repeller is a very sparsely populated area of ​​the cosmos from which neighboring galaxies are moving away. He plays a repulsive role in velocity streams as opposed to the role of the Shapley atractor.

discovery

The discovery was made on January 30, 2017 by a team of scientists from the French CEA and the University of Paris- Saclay (Daniel Pomarède), the University of Lyon I (Hélène M. Courtois), the University of Hawaii ( R. Brent Tully ) and the Hebrew University of Jerusalem (Yehuda Hoffman) announced. The data comes from the Cosmicflows-2 project. They identify the structure as the dominant influence that explains the direction and speed of 631 km / s compared to the CMB of the local group . For comparison: the orbital speed of the earth around the sun is 30 km / s. The solar system moves around the center of the galaxy at a speed of 230 km / s .

The Shapley supercluster , another area around the Milky Way , creates an attractive force on the movement of galaxies. This localized attraction, complemented by the position of the dipole repeller, is the main factor behind the dipole anisotropy of the background radiation .

The dipole repeller is positioned at a distance of 220 megaparsecs (220 Mpc) from the Milky Way and coincides with an area of ​​lower galaxy density.

This complex, from the Shapley supercluster to the dipole repeller, spans almost 1.7 billion light years and represents the largest mapped area in the observable universe in 2017 .

The authors of the article, published in January 2017 in the journal Nature Astronomy, argue that the measurements of the distance velocity from the dipole repeller are inconsistent with an explanation based solely on an attractive gravitational force. According to the authors, not a single observed concentration of matter (gravitationally attractive) could explain the observed speeds and directions of distance of stars and galaxies:

“We show here that the repulsion from a subdensity range is important and that the dominant influences that create the observed flow are a single attractor - connected to the Shapley supercluster - and a single previously unidentified repellant area (repeller) that contribute roughly equally to the CMB dipole. […] We conclude that the dipole repeller is not a fictional structure caused by a data edge effect, and that subsets of data selected by distance or galaxy type reveal a repulsion basin that the local group into the dated CMB dipole indicated direction "pushes". "

One of the authors, Hoffman, told the Guardian , “We are showing that the Shapley supercluster attractor really does attract us, but almost 180 degrees in the other direction there is a region with no galaxies, and that region pushes us back. So now we have an attraction on one side and a nudge on the other. It's a story of love and hate, attraction and repulsion. "

Hoffman also told Wired , “In addition to the attraction to the well-known Shapley supercluster, we are also pushed away by the newly discovered repulsive dipole. This made it clear that push and pull are of similar importance in the position of our galaxy. "

Hoffman told IFLScience, "After subtracting the average extent of the universe, the net gravitational force of above-average dense regions is that of gravitational pull and that of below-average dense regions that of repulsion." This position is in line with that of the CNRS , according to a press release :

“Over the years the debate about the relative importance of these two attractors has gotten lost, as they are insufficient to explain our movement, especially since it does not point exactly in Shapley's direction as it should. […] The team thus discovered that at the location of our galaxy the repulsive and attractive forces of distant objects are of comparable importance and concluded that the main influences on the movement of our galaxy are the Shapley attractor and a huge empty region (i.e. without visible and invisible matter) which had not been identified until then and which was called the dipole repeller. "

The same research team identified a second loophole with repulsive effects in September 2017: the cold spot repeller. These many and immense cavities, which repel matter like a reverse gravitational force, are among the main components of the cosmic web of speeds ("cosmic V-network").

While the overwhelming number of astronomers (including the original authors) assume a quasi-repulsive effect due to the below-average density of matter in the empty regions, the cosmologist Jean-Pierre Petit takes the view that the theory of gravity and cosmology to explain a repulsive component according to his Janus- Model had to be expanded and that the observation would support his model.

Individual evidence

  1. ^ A b Hélène M. Courtois, R. Brent Tully, Daniel Pomarède, Yehuda Hoffman: The dipole repeller . In: Nature Astronomy . tape 1 , no. 2 , February 2017, ISSN  2397-3366 , p. 1–5 , doi : 10.1038 / s41550-016-0036 ( nature.com [accessed February 8, 2019]). , Arxiv (the Arxiv preprint is not exactly the same as the final publication).
  2. ↑ a b Poussée par un vide, notre galaxie surfe à plus de 2 millions de km / h , press release CEA, Univ. Lyon, CNRS, 30th January 2017
  3. ↑ CEA: Poussée par un vide, notre galaxie surfe à plus de 2 millions de km / h. January 30, 2017, accessed February 8, 2019 (French).
  4. ↑ Cosmic Void “Pushes” Milky Way. In: Sky & Telescope. January 30, 2017, Retrieved February 8, 2019 (American English).
  5. ↑ L'attraction et la repulsion à l'origine du déplacement de notre galaxy. February 23, 2017, accessed on February 8, 2019 (fr-fr).
  6. ^ Mānoa: Newly discovered intergalactic void repels Milky Way | University of Hawaii News. Retrieved February 8, 2019 .
  7. ↑ MVS Import: Kosmos: "Center of Repulsion" discovered . In: scinexx | The knowledge magazine . January 31, 2017 ( scinexx.de [accessed February 10, 2019]).
  8. ↑ Résumé: notre position et nos mouvements: du système solaire à l'Univers. Retrieved February 8, 2019 .
  9. ↑ In the original: We show here that repulsion from an underdensity is important and that the dominant influences causing the observed flow are a single attractor - associated with the Shapley concentration - and a single previously unidentified repeller, which contribute roughly equally to the CMB dipole. (S. 1) We conclude that the dipole repeller is not a fictitious structure induced by an 'edge of the data' effect, and that subsets of the data, chosen either by distance or galaxy type, uncover a basin of repulsion that 'pushes 'the Local Group in the direction pointed by the CMB dipole. (P. 4)
  10. ↑ Ian Sample Science editor: Milky Way being pushed through space by cosmic dead zone, say scientists . In: The Guardian . January 30, 2017, ISSN  0261-3077 ( theguardian.com [accessed February 8, 2019]). " We show that the Shapley attractor is really pulling, but then almost 180 degrees in the other direction is a region devoid of galaxies, and this region is repelling us," said Hoffman. “So now we have a pull from one side and a push from the other. It's a story of love and hate, attraction and repulsion .
  11. ↑ Victoria Woollaston: The Milky Way is being pushed through space by a void called the Dipole Repeller . In: Wired UK . January 30, 2017, ISSN  1357-0978 ( wired.co.uk [accessed February 8, 2019]). In addition to being pulled towards the known Shapley Concentration, we are also being pushed away from the newly discovered Dipole Repeller. Thus it has become apparent that push and pull are of comparable importance at our location.
  12. ↑ The Milky Way Is Running Away From An Extragalactic Void. Retrieved February 8, 2019 . . After subtracting out the mean expansion of the universe, the net gravitational force of the overdense regions is that of an attraction and that of the under-dense regions is that of repulsion .
  13. ↑ What is meant is the large attractor and the Shapley supercluster.
  14. ↑ In the original: Mais, aufil des ans, le débat s'est enlisé sur l'importance relative de ces deux attracteurs, ceux-ci ne suffisant pas pour expliquer notre mouvement, d'autant qu'il ne pointe pas exactement dans la direction de Shapley comme cela devrait être le cas. ... L'équipe a ainsi découvert qu'à l'emplacement de notre galaxie les forces répulsives et attractives provenant d'entités lointaines sont d'importances comparables et en a déduit que les influences majeures qui sont à l'origine de notre mouvement sont l'attracteur Shapley et une vaste région de vide (c'est-à-dire dépourvue de matière visible et invisible), précédemment non identifiée, qu'il sont nomméle Dipole Repeller.
  15. ^ Hélène M. Courtois, R. Brent Tully, Yehuda Hoffman, Daniel Pomarède, Romain Graziani: Cosmicflows-3: Cold Spot Repeller? In: The Astrophysical Journal . tape 847 , no. 1 , September 1, 2017, ISSN  2041-8205 , p. L6 , doi : 10.3847 / 2041-8213 / aa88b2 .
  16. ^ Daniel Pomarède, Yehuda Hoffman, Hélène M. Courtois, R. Brent Tully: The Cosmic V-Web . In: The Astrophysical Journal . tape 845 , no. 1 , August 1, 2017, ISSN  0004-637X , p. 55 , doi : 10.3847 / 1538-4357 / aa7f78 .
  17. ↑ About the Dipole Repeller | Request PDF. Retrieved February 8, 2019 .
  18. ↑ G. D'Agostini, JP Petit: Constraints on Janus Cosmological model from recent observations of supernovae type Ia . In: Astrophysics and Space Science . tape 363 , no. 7 , June 6, 2018, ISSN  1572-946X , p. 139 , doi : 10.1007 / s10509-018-3365-3 .

See also

Web links

  • The Dipole Repeller This video was produced as an appendix to the original publication "The Dipole Repeller" by Yehuda Hoffman, Daniel Pomarède, R. Brent Tully and Hélène Courtois Nature Astronomy .
  • The Cosmic V-Web This video was produced as an appendix to the original publication by Yehuda Hoffman, Daniel Pomarède, R. Brent Tully and Hélène Courtois "The Cosmic V-Web" in the Astrophysical Journal .
  • A visualization of the cosmic V-Web in virtual reality is available on the Sketchfab platform.