OK, dad, I want to talk about the mystery metal thing.

What do you remember about that?

Well, I remember pretty clearly.

I was coming back from the sawmill, and I just heard a loud bang in the back of my truck.

I looked in the back, and there was a round piece of metal that was kind of-- it wasn't hot.

It made a dent, and I have no idea where it came from.

Maybe it was from something nearby, like it had fallen from a building nearby?

No, there were no buildings.

This is what I remember, OK-- my 10-year-old memory.

You had brought this piece of metal in and you gave it to me.

And so I was imagining, like, oh my god, it's a meteor, or it's, like, space junk.

And so this was my prized possession when I was a kid.

The other thing, dad, is that you came out and took it away and you were like, this might be radioactive.

We need to test it.

And I'll test it in a lab and then I'll give it back to you.

Well, I'm sure it's still around.

It's definitely not around.

I don't know.

We've looked.

I so wish we had it so that I could show a picture of what this looked like.

Uh!

[CHUCKLES] We still don't know what it was, and it's still a mystery.

It is, and it may always be a mystery.

[CHUCKLES] So why am I telling you about 10-year-old Diana's deep unsolved mystery?

Because mysteries are awesome!

They're almost as good as free food.

41 00:01:34,770 --> 00:01:37,830 But I also wanted to prepare you for this other intriguing mystery in physics, and it also starts with things falling from the sky-- like sprinkles on a cupcake.

And here to help me tell that story is Daniel Whiteson and Jorge Cham.

NARRATOR: In the 1980s, physicists built a facility in a high altitude desert in Utah.

It was basically an observatory, except instead of looking for stars, they were looking for the flashes of light that occur when mysterious particles hit the atmosphere.

And on October 15th, 1991, boy, did they find one of these particles.

They found one with unimaginable amounts of energy.

This thing was traveling at 99.9999% of the speed of light.

The world record for speediest and most energetic particles on earth are at the enormous Large Hadron Collider in Switzerland.

This particle had more than two million times the energy of those fools.

This submicroscopic sprinkle, around the size of an atom's nucleus, hit with enough energy to lift a bag of 50 cupcakes a meter off the ground.

Nobody had ever seen anything like it.

Physicists started calling it the "Oh My God Particle."

The Oh My God Particle?

It's a good thing physicists don't name Pokemon.

So these mysterious particles scientists were searching for are called "cosmic rays."

The name's kind of misleading, because cosmic rays aren't actually rays of light.

They're particles, protons and atomic nuclei that might get ejected from stars like the sun, or even from supernovas outside the solar system.

Here on earth, cosmic rays are constantly raining down on us-- like sprinkles on a cupcake.

A cupcake-sized part of the atmosphere gets about 50 cosmic rays per second.

These particles have a lot of energy-- enough energy to strip electrons off of molecules in the atmosphere and make them glow like neon signs.

That's what causes the northern lights.

But there's a pretty big range of energies.

Some sprinkles just dust earth, some hit a little harder, and sometimes, just a handful of times a year, one super Goliath, incredible Hulk, blue whale of a cosmic ray hits earth.

And the mystery is that no one knows where these things come from.

Nobody knows.

After scientists found the oh my god particle, they found more.

And we don't know of anything in the universe that's capable of making such high energy, high speed particles.

Just ask an astrophysicist to come up with an estimate for the highest speed a particle could ever go anywhere in space-- which sounds kind of hard, and it is.

Which is why they come up with crazy situations like particles surfing on exploding supernovas, or a black hole swinging particles around like slingshots.

The highest energy a cosmic ray should ever have, knowing what we know now about the universe, is 10 to the 17 electron volts.

The Oh My God Particle blows past that estimate with 1,000 times more energy.

So that means there must be a new kind of object in the universe that we don't know about yet.

So that's where we're at.

We don't know what kind of object could make the Oh My God Particle, but we can spec-ulate.

One possibility is that they were made by a supermassive black hole.

As black holes inhale everything within reach, they cause a huge mass of gas and dust to swirl around, which has been observed to generate incredibly energetic radiation.

But scientists are a little doubtful on this one, because they don't seem to see that cosmic rays come from the areas in space where we know supermassive black holes are.

Another possibility is that there's some unknown force in the universe we don't know about yet.

And then there's my favorite possibility.

What if these cosmic rays are the result of alien experiments?

Sounds crazy, but it's possible.

I mean, creativity is the key to revolutionary ideas.

The Oh My God Particle could be pollution from alien experiments.

Listen, I know you're just as disappointed as me that there's no resolution to this mystery yet-- but get on my excitement level, because we have a clue!

Cosmic rays slow down as they travel through space because they interact with the cosmic microwave background, which means that they have to be made by something close by.

So we're going to have to detect a lot more of these to figure out where they came from.

Unfortunately, they only arrive about one every square kilometer, every 1,000 years.

That's why cosmic ray observatories, like the Pierre Auger Observatory in Argentina is huge-- so that they have a better chance of detecting one.

And imagine this-- a small particle detector that everyone could fit in their pocket, and everyone around the earth could carry with them at all times.

Sounds crazy, but it's smart-- phone.

157 00:06:31,210 --> 00:06:33,220 But seriously, the camera in your smartphone can be used as a particle detector.

So scientists have come up with the idea that if enough people ran a particle finding app, we'd have a much better chance of finding these crazy energetic particles.

So maybe one day I'll be able to help solve a space junk mystery.

Finally!

Thank you for watching.

And by the way, this video was inspired by a chapter in the book by Daniel Whiteson and Jorge Cham called, fittingly, "We Have No Idea."

You should check it out.

Happy physics-ing!