Good morning John,
I was just taking my dog for a walk, and I thought to myself; "Hank you know what you should do today? You should BLOW JOHN GREEN'S MIND. So that's what I decided to do. John, get ready to have your mind blown.

So let's start right here on Earth. Earth is big, it's massive, it's freaking huge. It's so big that we didn't even know how big it was until, like, a few hundred years ago.

(That's not actually true. People had figured out how big the Earth was a long, long time ago; using math and being really smart.)

But we certainly hadn't mapped the whole thing. I mean 500 years ago Columbus was sailing around thinking he was going to run into India, because he didn't know that North America was there.

But John, as massive as the Earth is, the Sun is much bigger (as They Might be Giants have, I'm sure, informed you). If the sun were hollow, a million Earths would fit inside.

So John, I know I didn't just blow your mind, there's more coming.

Our Sun is very big. In our galaxy there are at least 200 billion of them. It could be as many as 400 billion. Turns out, not easy to count all the stars in the galaxy.

I know, I know I have not blown your mind yet. That is not even the mind-blowing stuff.

The Hubble space telescope is the most powerful telescope ever created by humankind. (I say humankind because by the end of this video you will probably think that there are other large telescope wielding species in the universe.)

John, right now I am going to draw a dot on my hand. Dot.

Ok you see that dot? Now I'm going to move that dot out here.

This is the size of a piece of our universe that the Hubble space telescope was once pointed at.

A scientist at NASA pointed that space telescope at that tiny, tiny bit of our sky. This tiny dot of sky was rare. Because there was nothing there. There were no stars in our own galaxy, there were no galaxies that we could see, there were no nebula or any smudge of anything. It was just a pure, black spot of sky.

Now some people were like "WTF NASA? Why are you taking this extremely expensive piece of machinery and taking a picture of nothing with it?"

But they did it. They pointed it at that little piece of sky and they opened the shutter and they left it open for days. They'd done it once before but now they've done it again in December of 2009. It's called the Hubble ultra deep field.

When they downloaded the picture, that speck of nothing, that grain of inky black contained over 3000 galaxies! Galaxies just like the one that our massive planet takes up a tiny fraction of a corner of a crevice.

Every dot, every smudge, every speck in this image is a galaxy with billions of stars in it.

That is a big universe, and let me blow your mind further by telling you that I think that we have an important place in it.

we don't know what's going on. It took humanity 99.9 per cent of it's existence to even understand that we live on a ball of rock, circling a globe of plasma. But you watch that video, and you understand the scope of the universe. That understanding, the act of understanding, i think is more important, in it's self, than the existence of all of the star stuff in the universe.

People have a lot of different reactions to the knowledge that we are on a tiny, pale blue dot. But that's mine. I want to know what yours is, so leave 'em down in the comments; in my pants.

John, I will see you on Wednesday.