Where are we heading?

Yes, I know that the Milky Way galaxy is headed for a collision with the Andromeda galaxy in 4 billion years, but what I want to know is where are we actually headed. That sounds like a useless question, but it could explain just how fast the Milky Way galaxy is moving relative to something.

This is where we get into a problem. It turns out that all of the galaxies in the universe are moving in what's called the 'Hubble flow'. This is the apparent movement of all galaxies because of the expansion of space. As you know, the universe is expanding, but it's really space itself that's expanding. Therefore, we can measure the velocity of the Milky Way relative to this Hubble flow. If we use this as a reference we could say that our galaxy is moving at 630 kilometers per second.
Okay, now that we know how relatively fast we're moving, where are we headed? As it turns out our Milky Way galaxy, as part of the local group of galaxies, including Andromeda, is moving along with the Local Supercluster because our Local Group is part of the Virgo Cluster, which is in turn part of that Local Virgo Supercluster. In other words, the whole dang thing is moving together. But, where are we going?

Our galaxy is moving toward the Great Attractor, which is a gravity anomaly in intergalactic space. What the heck does that mean? It means that it's some concentration of mass tens of thousands of times more massive than our galaxy. For some strange reason this anomaly is pulling all sorts of galaxy clusters toward it. It's like a big vacuum suction in space and its effect is being felt over hundreds of millions of light years.

Some astronomers believe that it's connected to the newly discovered Laniakea Supercluster, which is where our Milky Way galaxy is located. This massive supercluster contains 100,000 galaxies and includes the Virgo Supercluster, the Hydra-Centaurus Supercluster, the Hydra Supercluster, the Pevo-Indus Supercluster, and the Southern Supercluster. Basically, all of these superclusters are linked together gravitationally. It turns out that the Great Attractor is part of the Laniakea system, which means that it's gravitationally connected to it.
We also know that this Great Attractor anomaly is moving towards the Shapley Supercluster, which is the largest concentration of galaxies in the nearby universe. This big boy is 650 million light years away.

What's really hard to understand is the idea that these galaxy clusters and superclusters are moving toward somewhere while the universe is expanding forcing all of the galaxies apart. This can be reconciled by remembering that the galaxies are not really moving away, but rather it's the space itself that's being stretched. In other words, space is expanding, not the relative distances between galaxies. However, this expansion effect will eventually make the galaxies appear to be moving apart because space will become inflated.

Think of it this way. Take a balloon and use a marker pen to make dots on it equidistant from one another. Then, blow the balloon up more. What happens? The dots appear to move away from another. This is the effect of the universe's expansion. The balloon is like space. It's like a balloon that's inflated when you blow it up. That's what's happening, and it's something that wasn't really understood until just recently.

Thanks for reading.