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This might not look like much. But every day, tiny little things like this are raining down on our planet. Each one is small, about a millimeter across. But over the course of a year, each individual piece that makes its way to Earth’s surface adds up to around 30,000 tons.

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Today is the last day that you can pre-order our brand new Diatom t-shirt at

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This doesn't look like much. If you saw it on the street, you’d think, "Yeah that's, that's a bit of gravel." But every day, tiny little things, just like this are raining down on our planet from space. Each one is small, about a millimeter across.

So when they land, we barely notice. But over the course of a year, each individual piece that makes its way to Earth adds up to around 30,000 tons. That’s a lot of tons of stuff that are so tiny that they escapes our notice.

But of course, here on journey to the microcosmos, these are exactly the kinds of things that we like to look at. These are micrometeorites, just a few of millions that pass through our atmosphere every single day. Most don’t survive the journey from space.

They simply vaporize in our atmosphere. But those that do survive go through quite a transformation as they soar through our planet’s atmosphere, melting with the friction of their entrance. Depending on their speed and rotation and chemical composition, their shapes warp and recrystallize in new shapes.

They may become more elongated, or perhaps develop pointed shapes around their body. But from a distance, they could be anything. A piece of sand or a speck of dust… so, if it seems difficult to find a micrometeorite, that’s because it is.

James, our master of microscopes, received these samples from a friend of his, Scott Peterson, who has been hunting micrometeorites for some time, examining rooftops and their relatively undisturbed environments to see what he can find. And if you want to see how well you would do as a micrometeorite hunter, here’s a little test for your skills. Let’s say you’re looking at this array of pearly looking bits and bobs.

Do you think you can find micrometeorites there? You can pause, take a moment. This is the micrometeorite.

Alright so now that you’ve seen one, can you find them in the next few slides we’ll show you? Again, just pause if you need a moment, take a look, and we will show you the micrometeorites at the end. Let’s start with this.

Then this. Then this. And last, this.

So now that you’ve had a moment to look at them all, let’s go through them to see how well you did. First, we have the micrometeorite here, which looks similar to the other pearly round things, except that it’s a little less shiny. And then here, the micrometeorite was right in the middle of everything.

While here, it was off in the corner. And our last one seems practically impossible to distinguish from everything else. Sorting out these micrometeorites feels a bit like trying to navigate the microcosmos.

There’s just so much stuff to sort through, it requires patience and it requires knowledge. But at the end, the result is understanding that allows us to identify and classify our universe so that we can build some kind of framework to understand it. So it is weird and cool that we just walk around our world surrounded by these little bits of the cosmos that got past our atmosphere.

Sort of like it’s weird and cool that we just walk around our world surrounded by microbes that we never see or think about. And for us, as people who talk about microbes a lot, it’s hard to not spend some of this time imagining what it would be like for our microbes to make the opposite journey. To go from our world, past the atmosphere, and back into whatever is beyond.

Unfortunately, as talented as our master of microscopes is, he has yet to go into space. So just know that the footage we’re showing now are not actually microbes in space. Think of them more as a vibe, a background for us to project onto as we consider the possibilities.

Microbes are crafty, hardy creatures. In the billions of years that they have existed, they’ve managed to adapt to countless environments and survived monumental shifts in climate. But we also live on a planet that has so far shown itself to be uniquely nurturing.

What about everywhere else? Now we’re not talking about aliens, though of course we could. There is a rover on Mars right now, seeking out the possibility that life may have existed there.

But we don’t need to consider aliens to imagine microbes in space. Because... there are microbes there. We brought them there.

Because well, humans have gone to space, and where we go, microbes go as well. In our cargo, our food, and of course, our bodies. In 2020, researchers studying the International Space Station found that after two decades of humans living there, the space station itself seems to have a microbiome of its own, made up of 55 microbial genera—an array of bacteria and fungi and protists and other creatures that are invisible roommates to the astronauts.

And if you’re painting an image of superpowered microbes that have been mutated into something unrecognizable and dangerous by cosmic rays…fortunately, NASA looked into it, and they found the microbes are not dangerous. Though there were some microbes, particularly fungi, that have caused some damage to windows because of their unusual ability to grow on metal. And even when humans aren't being sent to space, our microbial marks can be left on the things we do send to space, which does pose some challenges.

For example, the Perseverance rover is looking for microbes on Mars, but it needs to make sure that any signs of microbial life it sees aren’t actually accidental terrestrial hitchhikers. So NASA had to build the spacecraft while keeping it as clean as possible, ensuring that the Mars 2020 Mission was launched with 10 times less bacteria on it than the amount that live in a teaspoon of seawater. Because space might not kill those microbes for us.

The ones that can form spores or cysts can use those adaptations out in space as well. So even with the vacuum and the radiation and the massive shifts in temperatures, some microbes can survive. ln 2020, a team of researchers created dried aggregates of the UV radiation-resistant bacteria Deinococcus radiodurans and they put them on panels outside the International Space Station— a place where not much seems like it should survive. But after three years, they found bacteria in those pellets that survived, buried under a surface layer that hadn’t survived but was able to protect those underneath.

There’s something about that—about the way a mass of bacteria can be dried out and placed in an environment so far from its origins—that feels perfect as a meeting of the microcosmos and the cosmos. Just as micrometeorites burn through our atmosphere and blend with our planet, microbes can find their own way to become a part of the world outside our planet. Thank you for coming on this journey with us as we explore the unseen world that surrounds us And if you've forgotten what we said at the beginning, yes today is the last day to to pre-order our new Diatom T-shirt over at

Now that the video is over, you can just go do that. But since you stayed to the end of the video, we also wanted to let you know that you can get 10% off our set of 4 plan objectives if you wanna use the promo code PLAN10 at checkout. That deal only runs through March 6th, so you will want to pick those up soon, if you want to upgrade your Microcosmos Microscope.

The link for those and our diatom t-shirt are both in the description below. Thanks so much to all the people on the screen right now. They are our patrons on Patreon.

They are the reason that we're able to make Journey to the Microcosmos and explore topics as diverse as bacteria on the outside of space stations and micro meteorites that are all around us all the time that we never even notice. So if you like what we do here, these are some of the people to thank. And if you'd like to become one of them, you can go to

If you'd like to see more from our Master of Microscopes, James Weiss, you can check out Jam & Germs on Instagram. And if you'd like to see more from us, there's probably a subscribe button somewhere nearby.