Dr Karl

It gets very hot, hot enough to melt aluminium.

And what we've been finding is that with the satellites that we've been putting in orbit, there are so many returning that we are now contaminating the stratosphere of

with aluminium.

They use aluminium in spacecraft where it's not heat critical because it's so light and relatively strong.

And we've recently found that 10% of all of the droplets of fluid that we've found in the stratosphere are contaminated with aluminium from returning spacecraft.

And this is going to increase enormously as the number of working satellites in orbit increases.

It was a few thousand in 2018, 2019, currently about 14,000 by the year 2030.

which is only four years away, to 50,000.

And they'll be returning at the rate of 10,000 a year or several every day.

And so we'll be ending up with you seeing lots of these things coming back to Earth and unfortunately contaminating the upper atmosphere, which is something we should think about now because we don't want to damage our planet too much.

So the short answer to your question is the pressure creates heat.

The air molecules bang into each other and it can get hot enough to melt aluminium and even iron.

So what's your son's name?

Raymond?

Raymond.

Raymond, this is for you.

We hope you enjoy it from Lucy and me.

Yeah.

We love you, Raymond.

Bye.