Collision Course

We're all headed for a gigantic collision....in a few billion years.

The view from Earth as the collision begins to happen

It's true. It's pretty much an accepted prediction that about 4 billion years from now (Earth itself formed 4.5 billion years ago) our Milky Way Galaxy is about to collide with one of our nearest neighbors; the Andromeda Galaxy. 

As horrible as it sounds and despite the fact that each galaxy containing billions of stars, the scale is so large that the stars are way too far apart to actually collide with each other. 

Expected views from Earth as the collision takes place..really really slowly (3 billion years)

But that doesn't mean there won't be drastic changes for us on Earth...(if we're actually around).

1) Our Solar system will likely get re-located some where further away from the center and this will likely change what the sky looks like

2) The collision itself will take about 3 billion years to complete

3) As the Andromeda Galaxy approaches closer and closer, about 3.75 billion years from now it will fill the sky much like the first image in the posting

4) Once the collision begins the sky will be filled with bright new star formation

It's bound to be an incredible light show that will alter human behaviour. Except here's the part I didn't tell you, 

Humans are likely not going to be around to catch it. Find our more in the upcoming Part 2 of this post.

What is the Milky Way?

What is the Milk way?*

To some it's an excellent chocolate bar that tastes a lot like a Mars Bar and/or 3 Musketeers...

To others, it's usually a strip of sparkling stars in the night sky:

And then finally to some others it's the iconic spiraling image of the milky way galaxy:

But what I'm asking is not simply what is the Milky Way? *But rather what and where is the milky way in the context of us? The short answer is..well we're in it.

A few years back, more recently than I'd like to admit, I asked myself a simple question - how can we see the Milky Way when we're supposed to be in it, and if we're in it why does it look nothing like the iconic images of the galaxy we've all seen?

After a little bit of research I suddenly had this profound moment of clarity - I was able to imagine exactly where we were and how/why we saw what we did when we looked up at the night sky.

Turns out, since we're inside the Milky Way, and are looking in, and what we are able to see from earth is the very bright and dense center of the galaxy but not the whole thing. It's like driving to downtown Toronto and only seeing part of the skyline but not all of it... Needless to say, the meaning of the word "scale" took on a whole new level of meaning for me. 

The Milky Way galaxy as we see it from earth is our first major "landmark" in our local area of the Universe. If we were to give someone directions on how to find us it would be sort of like this:

How awe-inspiring is that? 

Enough to make you wonder whether it's worth trying to win every argument, always make your point and do anything to get your way.
Enough to make you realize that there really aren't a lot of us and we're lonely as hell stuck out in one of the Milky Way's outer spiral arms.

In fact, it's enough to warrant a Morgan Freeman narrated "zoom out". And that is the video I will leave you with tonight along with a fun inequality to ponder...

Us < Earth < Solar System < Local Interstellar Cloud < Orion–Cygnus Arm < Milky Way....