Do you remember when Elon Musk launched a car  into space?

It is still out there, but it might   not be in the best shape.

It's not just peacefully  drifting through a vacuum.

It is hurtling around   the sun at 63,592 miles per hour, being bombarded  by solar radiation.

That car might be in pieces.

But not the same pieces it would be in if it  was down here on Earth.

The environment of   space breaks stuff down differently.

And  the space debris a little closer to us,   all the stuff that we humans have blasted  into space and just left there in orbit?

Yeah, the unusual environment of space means that  it too breaks down and degrades differently than   it would have if it was just down here on Earth.

But how long does it take to break down?

And does   it all break down?

And how is that car looking  right about now?

Today we're talking space trash.

In space pants.

Look at my space  pants, very excited about that.

There are a few different types of space debris.

First you have natural meteoroids.

These are   hunks of rock or iron in orbit around the sun, but  sometimes pieces of them can get stuck in Earth's   orbit too.

There's also orbital debris.

This is  defined by NASA as any human made object in orbit   around the Earth that no longer serves a useful  function.

These could include old satellites,   abandoned launch stages from rockets, paint  chips and stuff left behind by space missions,   or even pieces left behind when all of these  things start to crash into one another.

Orbital   debris can be made up of all different kinds  of materials, including things like polymers,   like paints and plastics, metals  and their alloys, oxides, sulfides,   halides, carbides.

Anything that we send up in  space could be out there.

And a lot of it is in   low Earth orbit or LEO, where many satellites and  the International Space Station also hang out.

The majority of it is only between 1mm and 1 cm in  diameter…but estimates suggest there could be over   130 million pieces of it.

Now it's a bit hard to  conceptualize how much of a problem space debris   is because space is really big and a lot of this  debris is pretty small.

And as of June 2022,   the Space Surveillance Network is currently  tracking nearly 40,000 objects larger than a   softball.

Softball.

But no matter the size, you  got to remember that this stuff is traveling at   17,500 miles per hour, zipping around us.

If  you launch a rocket into the path of a 70,500   mile per hour softball, you are going to have  problems.

That's one hell of a pitch.

And past   collisions have caused damage to satellites and  spacecraft.

In the past space shuttle windows   had to be replaced after collisions with debris  as small as paint chips.

Things like the ISS   even have to move sometimes to avoid crashing  into debris.

Just recently in June of 2022,   the mirror of the James Webb Space Telescope was  struck by a micro-meteoroid.

Thankfully it's built   to withstand that and many more because  we know that collisions happen in space.

Also sometimes whole satellites can just crash  into one another, which feels like a thing that   shouldn't happen.

In 2009, two communication  satellites called Iridium 33 and Cosmos 2251   collided at 11.7 kilometers per second.

That is  26,000 miles per hour.

The Space Surveillance   Network tracked over 2000 pieces of debris  from that one crash alone.

Since Cosmos 2251   wasn't active at the time, it's one of the events  that has caused the space community to call for   organizations to remove their old satellites from  orbit when they've hit the end of their life.

If it's not there, it can't crash into anything.

And every collision that happens between  debris can just lead to more debris.

In 1978, Donald Kessler proposed a theory  that describes, "a self-sustaining cascading   collision of space debris in LEO," or low  Earth orbit.

That just sounds really bad.

This theory is now referred to as the  Kessler Syndrome or collision cascading.

It describes a situation where  debris collisions create more debris,   which creates more collisions, and on and on  and on.

The fear was that if this happened,   the continued buildup of debris could make certain  orbital spaces useless, dangerous, debris fields.

Thankfully, we don't seem to  be headed in that direction   quite yet.

Now some of the debris just falls  out of orbit, burning up in our atmosphere,   but depending on how far out into orbit it  is, it can take a while for that to happen.

Orbital debris less than 370 miles up  usually falls back to Earth in a few years,   but things over 620 miles up could orbit us  for more than a century.

And we're putting   more stuff up there all the time, faster than  the rate that it is falling back down to Earth.

Now, if you leave trash just sitting  out on Earth it'll break down over time.

So let's take a car, for example.

If you  let a car sit in a field for a century   it would look pretty rough at the end of it.

Bugs might eat away at the leather interior.

Rain and fog would cause any iron parts to rust  and crumble.

The sun would slowly fade and then   break down plastics.

But there aren't bugs or rain  in space so the car wouldn't rust up in orbit,   right?

Surprisingly, wrong.

There isn't  water out there with the orbital debris,   but up to 700 kilometers up there is oxygen.

And at that altitude, it exists as atomic   oxygen rather than the O2 that we breathe down  here.

Atomic oxygen is just a single O, which is   very reactive.

So reactive, in fact, that things  can start to rust even with no water around.

The typical chemical reaction for  rust looks something like this.

You need iron, oxygen, and water, but the  atomic oxygen doesn't need water around   to start reacting with metals and creating  oxides or rust.

The oxygen atoms can react   directly with metals on the surface of the  debris.

Things like aluminum and steel will   form layers of oxides on their surface that  cling on top and prevent further corrosion.

An Earth orbiting car with a steel frame would  likely be okay for a while, but iron and silver   oxides can flake or break off and allow the metal  underneath to keep corroding, eventually wearing   away the surface.

Depending on the conditions  a silver surface could lose between 11.5 and   300 micrometers of metal a year.

That's around a  hair's width a year.

In the case of space debris,   this wearing away could be a good thing since it  could eventually remove the object from orbit.

But for active satellites, this corrosion can be  really damaging.

So one way to protect components   is to cover them in gold since atomic oxygen won't  break down that gold.

Plastic can also be broken   down by atomic oxygen, so they too are often  coated in more resistant silicone paints.

And   this is incredible, there is so much fast  moving atomic oxygen and other reactive species   crashing into objects in LEO, that the collisions  cause the emission of lots of short lived, excited   state species that emit visible radiation around  the surface of whatever they're crashing into.

Basically stuff up there glows.

This phenomena  was first observed by astronauts aboard early   space shuttle missions, giving it the nickname of  shuttle glow.

And it's honestly really beautiful.

One of the most likely chemical players here  is nitric oxide on the surface of the shuttle.

Is this laughing gas we're talking about?

When fast moving atomic oxygen hit nitric   oxide on the shuttle surface, it may have  created excited nitrogen dioxide molecules.

Those could then release their energy as light  and then become regular old NO2.

Okay, total aside   here.

When trying to figure out how new materials  will respond to the damaging environment of space,   scientists can just stick them out into space  and see how they do.

And they do so on delightful   little trays that look like this, each material in  its own little cutout ready to be compared before   and after flight.

And I find it so satisfying  because it is both incredibly orderly and also   wildly chaotic considering that they're  being bombarded by reactive oxygen and   solar radiation.

Just love this so much.

And that's another thing that a car orbiting   around the Earth would have to deal with,  radiation.

Down here on Earth our car sitting   in a field has all of the atmosphere and Earth's  magnetic field to protect it from solar radiation.

But out in orbit, above the atmosphere, orbiting  debris is left unprotected.

This can break apart   carbon-carbon bonds and organic materials  like fabrics and leather, some polymers and   carbon fiber.

And that last one is important for  our orbiting car because that Tesla Roadster up   in space, it has a carbon fiber frame.

So either  orbiting around the Earth or orbiting around the   Sun, it is likely that its frame is looking  a little worse for wear these days.

In fact,   at the time of launch one scientist estimated that  it would likely start to break down within a year.

Atomic oxygen and radiation aren't the  only things that space debris encounters.

They also have to deal with things like  temperature changes, vacuum conditions,   and charged particles.

There's a lot going on up  there.

And another weird thing that can happen to   debris up in orbit is called cold welding.

Here  I have two pieces of metal.

This is indium.

If I   press them together really tightly and turn them,  they stick together, but it is more than just   sticking.

With nothing between them some of the  indium molecules from one hunk of metal have bound   to some of the indium molecules from the other  hunk of metal.

They don't know that they're not   from the same hunk of metal anymore.

This is cold  welding.

When two surfaces made out of the same   material collide and there's nothing in between  them, not even air molecules, say, like in the   vacuum of space, they can cold weld together.

Sometimes this can cause problems when surfaces   on two pieces of a spacecraft stick together.

This can be referred to as adhesion, sticking, or,   hilariously, stiction.

Thankfully, this  actually doesn't happen a lot by chance in space   since most stuff has a layer of oxides all  over it, either from before launch or due   to all of that atomic oxygen just flying around.

So chemistry is breaking down some space debris,   but it's doing it really slowly, a lot slower  than we're putting more debris up there.

So there   are some physical solutions to space debris that  have been proposed, things like satellites with   grappling hooks to pull debris out of orbit  or big spinning magnets to move it around.

All right, so finally, back to the Roadster.

Currently, it is way out of LEO and orbiting way   past Mars at the moment.

So it's definitely out of  the range of all of that oxygen.

No corrosion fear   there.

When it launched a bunch of articles came  out saying that the radiation would rip lots of   it to pieces, just like we talked about, tearing  through those carbon-carbon bonds in things like   leather and fabric and plastics, as well as its  carbon fiber frame.

And some people predict that   the tires, paint, and plastic are potentially  already deteriorated by radiation as well.

But while there are a lot of processes breaking  down materials in space, they're all pretty   slow.

So some experts have stated that the  overall car will probably still be recognizable   as a car for about a million years, as it slowly  breaks down.

Unfortunately, the battery powering a   loop of Bowie songs has long since died.

There's  no charging station up in space quite yet.

Hey, no.

No, we are not getting a  copyright strike.

We turn that off.

We don't need that here.

We don't want that  on our channel.

None of those vibes.

I mean,   we want the Bowie, we just don't want the  copyright strikes.

Take Bowie any day.