It appears the article is showing an increase in speed from the low density region, a repulsion, as an addition to the attractors forces.
“that our galaxy is not only being pulled, but also pushed. In a new study in the forthcoming issue of Nature Astronomy, they describe a previously unknown, very large region in our extragalactic neighborhood. Largely devoid of galaxies, this void exerts a repelling force on our Local Group of galaxies.
“By 3-d mapping the flow of galaxies through space, we found that our Milky Way galaxy is speeding away from a large, previously unidentified region of low density. Because it repels rather than attracts, we call this region the Dipole Repeller,” said Prof. Yehuda Hoffman. “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.”
When you bring the paper up it indicates that they are talking about a lack of density in a region, not a repulsive force.
You can treat it as a repulsive force, in the same way you can treat the absence of an electron in a semiconductor as a particle with a positive charge (a ‘hole’). With matter density from the bulk of the rest of the universe all around it, the gravity of that matter pulls things near the edge of the low density region away from it and this is functionally similar to repulsion away from the void. The paper finds that the flow away from the low density region towards the generalized rest of the bulk universe is about as important for our galaxy’s motion as the attraction towards the local overdensity of the various nearby attractors.
If there is no anti-gravity force, then how can an galactic scale empty section be “pushing” us toward the Great Attractors....
“Discovery of the “Dipole Repeller” confirms that both attraction and repulsion are at play in our extragalactic neighborhood”
http://new.huji.ac.il/en/article/33403
Some decent visualizations linked, and an original one on Utube from a French team is one of the coolest large scale animations i’ve ever seen...
Edit: and there it is, linked at bottom of viz page! http://irfu.cea.fr/cosmography
Are you just wondering what ‘pushing’ means in this context? Or speculating about the existence of anti-gravity?
I’m pretty sure that this is just interpreting as region of low density as ‘pushing’ because it ‘pulls less’ than a region of average density would.
This is similar to how electron ‘holes’ in a metal’s atomic lattice can be treated as positive particles.
It appears the article is showing an increase in speed from the low density region, a repulsion, as an addition to the attractors forces.
“that our galaxy is not only being pulled, but also pushed. In a new study in the forthcoming issue of Nature Astronomy, they describe a previously unknown, very large region in our extragalactic neighborhood. Largely devoid of galaxies, this void exerts a repelling force on our Local Group of galaxies.
“By 3-d mapping the flow of galaxies through space, we found that our Milky Way galaxy is speeding away from a large, previously unidentified region of low density. Because it repels rather than attracts, we call this region the Dipole Repeller,” said Prof. Yehuda Hoffman. “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.”
When you bring the paper up it indicates that they are talking about a lack of density in a region, not a repulsive force.
You can treat it as a repulsive force, in the same way you can treat the absence of an electron in a semiconductor as a particle with a positive charge (a ‘hole’). With matter density from the bulk of the rest of the universe all around it, the gravity of that matter pulls things near the edge of the low density region away from it and this is functionally similar to repulsion away from the void. The paper finds that the flow away from the low density region towards the generalized rest of the bulk universe is about as important for our galaxy’s motion as the attraction towards the local overdensity of the various nearby attractors.