Ashley Strickland from CNN explains in her article, “Milky Way galaxy is being pushed across the universe” that the Milky Way is being pushed across the universe from the newly discovered Dipole Repeller. For the past 30 years researchers have known that the universe has been moving at a constant speed. Everything in the universe is moving. The planets orbit the sun, while the sun and our solar system orbit the Milky Way, and our Milky Way along with other galaxies in the Laniakea Supercluster travel in space at about 2 million kilometers per hour. It has been believed that our galaxy was attracted to an area called the Shapley Concentration about 750 million miles away. Galaxies are flying apart from each other due to the expansion of the universe, however each one experiences tugs from neighboring galaxies that cause deviant motion, meaning the move towards areas of high density. Researchers have created a 3-D map of galaxy flow which shows the distribution of matter, resulting in the discovery of the Dipole Repeller. Luminous galaxies are dense and have a high mass concentration which creates a pull of the Shapley Attractor. However the Milky Way is also being pushed from a cosmic void that is behind it. The Dipole repeller is contains only a few galaxies in its massive void, meaning the empty region acts as a repellent force, with the universe being full of repellers and attractors.
It is weird to think that our entire galaxy is moving across space. It seems normal that our planet moves around the sun, but it seems strange even that our whole solar system moves too. It is interesting that galaxies don’t just have a pull on them from other galaxies but they are also being pushed from a void of galaxies. I don’t understand how a lack of density repels an object away, I feel like it would just has no affect or just a tiny amount of gravitational pull. What questions me is that it seems like most objects in space are in orbit with something; planets around a star, a star around the center of the galaxy, then do whole galaxies orbit something or are they just being pushed and pulled by other galaxies. However, scientists do know that the universe and the galaxies are expanding outwards, relating to our 17th conceptual objective. A theory about our expanding universe I found interesting is the balloon theory as discussed in our lecture-tutorial notes “Making sense of the universe and expansion.” The universe is viewed as a balloon in which the entire universe exists on only the surface of the balloon. As the balloon is blown up, the surface area spreads causing all the galaxies to spread apart. Because everything is on the surface, there is no center or edge. This theory doesn’t make too much sense to me since the universe isn’t two dimensional. We see stars in every direction not just up and down and side to side. So if everything as just on the surface and nothing inside of the “Balloon” not even light, how could we see galaxies that are in front of or behind us but also up, down and side to side. Regardless of the theories, scientists do know that the universe is expanding. This is known because of the Doppler shift. Galaxies are moving away from us are red shifted. Hubble’s law explains that galaxies that are farther away have a faster velocity, as seen in the graph from “Hubble’s Law” from our Lecture-tutorial notes.
This graph shows that farther away galaxies directly correlate with the velocity of them expanding. These galaxies will have more of a red shift since they are moving away at a faster velocity.