How far away is the Great Attractor? What happens if our Galaxy gets pulled into it? And will we ever be able to see the source of its power?
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What If is a mini-documentary web series that takes you on an epic journey through hypothetical worlds and possibilities. Join us on an imaginary adventure through time, space and chance while we (hopefully) boil down complex subjects in a fun and entertaining way.
Is there anything in the universe that’s just so eccentric, so breathtaking, and so beyond our understanding, that it gets a badass name? That’s what we’ll find out together in today’s episode! What is the Great Attractor?
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Okay, let’s do a bit of thought experiment to kick off the show.
I bet everybody here has been to the mall, right? Have you ever experienced a time when you are walking, and suddenly, you saw a bunch of people moving towards something?
Now, you don’t know what it is. You don’t know if it’s some food stall that’s really hitting the sales, or a new product being sold. You just know that it’s pulling people towards it. And to top it all off, you, with your ever curious mind, gets drawn to it as well! So, before you know it, you start walking.
It’s crazy, right? You don’t know why people are gathering, and yet you are attracted to that place where you’re absolutely clueless about what’s there to see, or even if what’s there could harm you. You just know that you’re curious and you want to find out. Something that you don’t understand is too charismatic for you to resist.
That, my dear friends, is the characteristic of our topic for today. A weird thing in space that is so bizarre, so unimaginably weird, and so difficult to grasp, that all we can do is to give it an appropriate name, The Great Attractor.
I hope we can say that The Great Attractor is a gigantic floating Harry Styles or Captain Ri from CLOY lightyears away in space from us, but that’s the problem. We don’t exactly know what it is. But we don’t actually know, so why not? It may actually be Henry Cavill in space.
Is he still popular now? I’m not keeping up with Hollywood stuff. Moving on.
Okay, here’s what we know about it so far. We don’t know what it is, but we know that it’s there. We’re sure it’s there, and we can see signs that it’s there.
It’s like having a gigantic stuffed toy in a very, very dark room. We can touch the fur, and we can feel how soft it is, maybe even smell it a bit, but that’s all the information we have. We’re not sure if it’s really a stuffed toy. It could be something else entirely.
So what are our observations leading us to think that it’s there? What are our touches to the fur and our sniffs to it?
We know that Hubble’s observations in 1929 lead us to believe that the universe is actually expanding, after he realized that a lot of galaxies are moving away from us. And not just moving away, it’s moving at an extremely fast pace faster than the speed of light.
This phenomenon is now something that we know as the Hubble flow: the movement of the galaxies due to the expansion of the universe.
To make that more visually appealing, say that you have a balloon that hasn’t been blown up yet. To add a little more playfulness, let’s say you decided to draw some random dots on it.
Now, you can measure the distance between the dots you made in the balloon, right? Okay, say at this point, you find a pump and you start blowing air into the balloon. Naturally, the balloon expands. But what else is happening here? The dots you drew earlier are now moving apart from one another. If earlier, one dot is a centimeter from another, now it’s maybe 5 centimeters.
The dot didn’t move, but it’s now farther away from the other because where it’s drawn at expanded.
The universe does this as well. It expands in a way similar to what we described in the balloon analogy. The galaxies are moving apart from one another at some velocity, so we expect them to be farther and farther from one another at a constant rate, right?
Oddly, this is not what scientists observe to be actually happening. Instead, they see a lot of galaxies seemingly gravitate towards a region in space. Even our very own Milky Way galaxy! The Great Attractor!
What scientists are sure of is that whatever it is, it’s definitely one powerful gravitational anomaly.
So how exactly did scientists arrive at this conclusion? That we are heading something so mysterious and puzzling?
Well, firstly, there’s this thing called expectation. The universe is expanding at an astoundingly fast rate of 2.2 million kilometers per hour!
So keeping this in mind, then, if we try to measure the speed at which a nearby galaxy is moving away from us, say, Andromeda, then we ought to get that speed right? Apparently not. This is one of the first odd measurements scientists found.