#dipole repeller

How Does Earth Move Through Space? Now We Know, On Every Scale

“Ask a scientist for our cosmic address, and you'll get quite a mouthful. Here we are, on planet Earth, which spins on its axis and revolves around the Sun, which orbits in an ellipse around the center of the Milky Way, which is being pulled towards Andromeda within our local group, which is being pushed around inside our cosmic supercluster, Laniakea, by galactic groups, clusters, and cosmic voids, which itself lies in the KBC void amidst the large-scale structure of the Universe. After decades of research, science has finally put together the complete picture, and can quantify exactly how fast we're moving through space, on every scale.”

It’s hard to believe, but despite being at rest here on the surface of Earth, we’re actually hurtling through the Universe in a variety of impressive ways. The Earth spins on its axis, giving someone at the equator a speed of some 1700 km/hr. Yet at even faster speeds, the Earth orbits the Sun, the Sun moves through the Milky Way, and there’s a great cosmic motion that applied to the Milky Way galaxy beyond even that. For a long time, we’ve been able to measure the total effect of all these motions, summed up, by measuring our motion relative to the cosmic microwave background: the leftover glow from the Big Bang. But it’s only very, very recently that we’ve identified the source of all the gravitational causes of this motion. While we’ve known of stars, galaxies, and the large-scale structure of where matter is, it’s new that we’ve quantified the effects of these great cosmic voids.

Ask Ethan: If Gravity Attracts, How Can The 'Dipole Repeller' Push The Milky Way?

“What are the mechanics behind a dipole repeller? How can an area of space void of matter repulse galaxies to any meaningful extent (or at all?)?”

There’s been a longstanding puzzle in astrophysics that’s finally coming to a head. For nearly a century, we’ve known that our Universe is expanding, and that the distance to a galaxy determines its average apparent recessional speed from us. But on top of that is an additional motion -- a peculiar velocity -- caused by the local gravitational field of the Universe. When we look at the motion of our own galaxy, we see it’s moving about twice as fast in one direction as the attractive masses would allow. But underdense regions, where there’s less mass and gravity than average, can serve as an effective repeller, failing to attract other matter just as much as overdense regions can attract it. Thanks to a newly mapped and accounted for cosmic void, we might finally understand how our galaxy is moving through the Universe.

The Strange Case Of The Pushy Void

The Strange Case Of The Pushy Void By Judith E Braffman-Miller Billions upon billions of galaxies, blazing with the furious, brilliant fires of a host of dazzling stars, trace out the heavy and gigantic filaments of the Great Cosmic Web–a structure that would otherwise be invisible to our eyes, were it not for these sparkling and revealing flecks of starlight. This mysterious Web, which is…