I was wondering if the whole universe spun. The laws of physics apply to all of space and everything spins around something, more or less. We orbit a star that orbits the black hole which holds our galaxy together. Our galaxy is gravitationally connected to the Local Group of galaxies and so on/so forth. There are outlying statistical anomalies – asteroids rotating the opposite direction, captured moons orbiting in reverse when compared to other moons, rogue planets and stars that have been launched do to tidal interactions etc.
It got me thinking.. does the universe in which all of this exists, itself, spin? If so, how would one find out?
It turns out that I wasn’t the first to ask (duh), and research is currently under way. I will spoil it right away: the results hint that, yes, it seems we are in a spinning universe.
I shall attempt to explain. Let’s say the big bang is an expanding balloon. If the universe was spinning shortly before and after it’s infancy, that motion will be transferred to the galaxies born within. Being that wherever you are is the center of the universe (explaining that is an entirely different post), imagine standing in the center of that expanding ball.
First, you look above. You see the imprinted lines of the basketball and see the universe/ball is spinning clockwise. However, you look below and you see it spins counterclockwise. This is called mirror symmetry. Both above and below are spinning the same way, but your central perspective makes it so that one was is clockwise and the other is counter-clockwise.
So, one sign the universe is spinning is that a majority galaxies in our northern hemisphere will spin one way, and in the southern hemisphere, they’ll have the opposite spin.
Easy enough, right? Now, not all objects will play by these rules, Matter attracts matter, so knowing that will let you know that over time, galaxies will interact with galaxies, stars interact, clusters etc. This changes the spin due to whatever tidal forces said object is experiencing. Or perspective can change how something appears to spin. If a galaxy was approaching us, once it overtook and passed us, we’d be viewing from the opposite end, thus changing the direction it appears to spin.
Anyhow, to the point! A professor and group of students at the University of Michigan recently began recording proper motion of all (relatively) nearby northern hemisphere galaxies which was gathered by the Sloan Sky Survey. Kaboom, most of these objects shared the same relative spin. Sure, this could be a statistical ‘oopsie’ or sheer happenstance. However, the odds of that are one in a million, so I will stick with what the findings imply.
As I said earlier, this study is underway. Once the southern hemisphere “nearby” galaxies are tallied, if their spin is opposite, we can say this implies the motion all galaxies are born with come from the womb that is the universe.
Post-note: They are searching and basing this on relatively near galaxies because anything super far away happened billions of years ago. Gathering information from more current representations of galaxies is more accurate. A distant picture of galaxies a mere billion years after the Big Bang may seem smarter, but considering they existed in an exponentially smaller universe with conditions we can’t guess, taking more current information is a bit more fool-proof.