Where are we in the universe?

Previously we discussed how to understand our (Earth’s) location relative to other galaxies and planets in the universe by considering the cosmic microwave background (CMB). But this 2D background picture doesn’t give us much information to the Milky Way’s relative position. An exhaustive study of neighboring galaxies led to a new visualization of our Solar System in the larger supercluster of galaxies Laniakea- Hawaiian for “the infinite heaven”. The Milky Way is at the edge of this supercluster- the picture below shows the connection between Laniakea (black) and the neighboring supercluster Perseus-Pisces, with the Milky Way in the middle:

laniakeaperciuspeices1
Wiener filter flow lines show the gravitational attraction lines within the two superclusters. Source: Laniakea Supercluster

The above picture looks similar to the electric field lines of two attractive charges, right? Similar to how our galaxy has a supermassive black hole in its center (Sag A*), Laniakea has a “Great Attractor” in its center towards which all galaxies tend to flow. The movement lines of galaxies is determined by the redshift of the stars within the individual galaxies. So we can know understand the motion of our galaxy relative to its neighbors over the next few million years. Of course, we must consider the imminent collision with the Andromeda Galaxy in roughly 4 billion years- but hey, our Sun would have already become a red giant and swallowed the Earth at that point. So why worry?

The original video describing the efforts by researchers at the University of Hawaii: Laniakea: University of Hawaii

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