It's hard to wrap your head around the vastness of the universe. But a recent discovery has made it just a little easier to understand our place among the stars.
Scientists have mapped more than 8,000 galaxies to find the Earth's official address, and it turns out the universe is even bigger than we thought.
Have you ever wondered where in the universe the Milky Way actually is? Like, literally where? In the vast expanse of nothingness that we call outer space, where exactly are we? You might think that sounds rhetorical, but it's not. And a recent discovery, as seen in this new video from Nature, has made it even easier to understand.
Well. Kind of.
Just as a group of celestial bodies is a galaxy and a group of galaxies is a cluster, a group of galactic clusters is known as a "supercluster" (not very original, I know).
Scientists had previously thought that our own galaxy was positioned at the edge of the Local Supercluster that itself was centered on the Virgo Cluster, which they believed to be about 100 million light-years wide. That's the equivalent of 1.03461597 × 1022 American football fields (or so Google tells me), which is such a ridiculously huge number that it probably didn't do anything to help you understand the scope of it.
But that's OK, because that number was off. Like, waaaaaaay off. So throw away all your preconceived notions of incomprehensibly exponential intergalactic football fields and say hello to your new home supercluster!
Our local supercluster has been named Laniakea, which means "immeasurable heaven" in Hawaiian. Because it's that freaking huge.
By defining the boundaries of Laniakea, we have a greater view of the universe as a whole — and a clearer understanding of our exact position in relation to it.
Scientists rely on physics, and waves of light in particular, to measure things on a galactic scale. Because Home Depot is always sold out of their light-year measuring tapes (plus those things are pretty hard to fit into the bed of your pickup truck), they examine the behavioral patterns of light waves and color spectrums to figure out how they work in a room, then apply that understanding to see how it works across an open field, then across an entire planet, then from the sun to the Earth, and so on.
By identifying and understanding the behavior of waves in a supercluster, they're better able to identify similar patterns beyond Laniakea. But it's hard to know what patterns are occurring beyond Laniakea if you don't know where it ends.
Think of it this way: Sometimes it's easier to define a thing by the lack of the thing. If we can identify something's absence, then the opposite of that absence must be the thing itself, right? So we're able to understand Laniakea because of what is not Laniakea — and now that we've defined it, we can start to figure what all that not-Laniakea stuff is actually about.
Each celestial body has its own gravitational pull, but everything within the supercluster is being pulled toward the Great Attractor.
Right now you're probably all wide-eyed like: "Hey tell me more about your friend the Great Attractor. I'd like to get to know the Great Attractor, if ya know what I'm sayin'." Which I get. Because the Great Attractor is very attractive. And I would totally love to set you two up but, well, we're not entirely sure what the Great Attractor is beyond its pretty massive gravitational pull.
(....waiting for you to get your "that's what she said" giggles out....)
Basically, the universe is like a Russian nesting doll. Kind of.
You know, the ones where each recursive doll contains a smaller but otherwise identical doll within it, and so on and so on? Our moon revolves around the mass of the Earth — that's our smallest doll. By understanding the relationship between the moon and the Earth, we're able to extrapolate and understand how the Earth revolves around the Sun. That's our next-size-up doll. And it keeps going.
It's not a perfect analogy. But it's good enough for now as a macrocosmic shorthand. Anyway...
As we continue to increase in size, each successive celestial body helps us understand the next piece of the puzzle.
Back to superclusters. Right now, Laniakea is the largest of the galactic Russian nesting dolls (excepting for the universe as a whole, which, being that it's infinite, is kind of hard to distill into a single egg-shaped wooden babushka). And everything within the Laniakea supercluster — ourselves included — is being pulled toward this same mysterious Great Attractor.
But things still exist beyond Laniakea. If we understand that everything within Laniakea shares the same attractor, then we can use the same approach to figure out if things in Not-Laniakea also share a mutual force that's opposite from our own. And that's exactly what these scientists did, and how they were able to identify and define our friendly next-door supercluster, Perseus-Pisces.
TL;DR — Laniakea is bigger than we thought, and now that we know it exists, we also know that there's another equally ginormous supercluster that exists opposite it.
So what does this actually mean for us as individuals, or for humankind as a whole? Well, at the moment ... not much.
We think of outer space as an endless expanse of incomprehensible nothingness. Which it is. But figuring out a new way to map it brings us that much closer to figuring out how it works, and what else is out there, and what our relationship is to all of it. If scientists can figure out how to map our immediate (ha!) supercluster, then they can use the same formulas to map uncharted territories as well. And from there, who knows what they'll find?
That being said, you might want to update your address book to read "Street, City, State, County, USA, North America, Northern Hemisphere, Earth, The Solar System, The Milky Way, Local Group, Virgo Supercluster, Laniakea, The Universe." Just in case you're worried that the Intergalactic Postal Service won't be able to deliver your holiday cards across the infinite blackness of space.