Emily Kwong

You're listening to Shortwave from NPR.

Amanda Meng was on vacation the day before New Year's Eve when the messages began.

Amanda is a part of a research project called IOTA, or Internet Outage Detection Analysis.

Her research partners were telling her that something weird might be happening with the internet in Iran.

This is not the first time the Iranian regime has shut down the internet.

And of course the government has said it's shutting down the internet for national security.

The current Internet shutdown came as a response to protests across Iran, with crowds calling for political change amid rising inflation and a devastating drop in the value of Iranian currency, the rial.

Since protests began, more than 5,000 people have been killed, according to the U.S.-based human rights activist news agency.

NPR hasn't independently verified that number, and observers and activists estimate the death toll may be much higher.

Now, when it comes to the internet, initially it was a total digital blackout.

But over time, some selective services have come back online.

These are known as whitelisted services.

So emails cannot be sent outside of Iran, for instance.

Yeah, we're not seeing Gmail up at all.

Despite the near-total internet shutdown, some voices are getting through.

Like this protester, who sent a voice memo to NPR's Arazu Razvani.

This man is among the 3% of Iranians who have managed to stay online through the satellite internet system Starlink.

But doing so is a crime.

Today on the show, you're on offline, how computer networking happens, how a government can shut it down, and how scientists are monitoring that connectivity from afar.

I'm Emily Kwong, and you're listening to Shortwave, the science podcast from NPR.