Science & technology | Where the air is clear

Satellites are polluting the stratosphere

And forthcoming mega-constellations will exacerbate the problem

A string of SpaceX StarLink satellites passes over an old stone house
Photograph: AP

In January more than 100 communications satellites burned up in Earth’s atmosphere, vaporising as they crashed towards the planet at about eight kilometres a second. These spectacular exits are intentional, meant to prevent satellites from clogging up orbital real estate or plummeting to the surface in an out-of-control manner. Three years ago the Federal Communications Commission (FCC), an American agency that approves communications-satellite applications, ordered that all such satellites had to fall out of orbit after five years to reduce space debris. Similar regulations apply elsewhere.

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An illustration of hands and arms going through a nest of lines.

AI models are dreaming up the materials of the future

Better batteries, cleaner bioplastics and more powerful semiconductors await

Colossal woolly mouse

Mice have been genetically engineered to look like mammoths

They are small and tuskless, but extremely fluffy



How artificial intelligence can make board games better

It can iron out glitches in the rules before they go on the market

The skyrocketing demand for minerals will require new technologies

Flexible drills, distributed power systems and, of course, artificial intelligence