Ask Dr. Universe – The Internet

How does the Internet actually work? I know you can type in most anything and it just pops up and all that, but how? – Eden, age 8, Oregon

Dear Eden,

If you wrote me a physical letter, it would take a few days to reach me. You put the letter in your mailbox. A postal worker picks it up. Then it travels between different post offices on its journey from you to me.

But within seconds of you sending this question over the Internet, it was sitting in my inbox. How can this be?

The whole Internet works like the mail system—but much faster. That’s what I learned from Adam Hahn, an Assistant Professor of Computer Science at Washington State University.

You can think of the Internet as one big network connecting different devices. They’re all able to “talk” to each other because they follow the same rules, called protocols. Computers all have their own address, called an “IP address.” An IP address is a long combination of letters and numbers.

The Internet carries information through electronic signals, invisible to you. But it needs physical things to carry these signals. Special devices called “routers” pick them up and push them to their destination, using wires and cables.

Some computers play a special role as “servers.” Servers are like filing cabinets, keeping all the information of a particular website. They receive your request for information, find the right file, and send it back to you.

When you search for something, your request goes from your IP address to the nearest router. That router bounces it to another router, and so on, until it reaches the server. The server sends information back to your IP address the same way, through the router network.

But what are those electronic signals made of? All the information on the Internet travels in the form of “packets.” Packets are broken-up pieces of a file. They’re written in a language of 1s and 0s, which computers can read. Everything you send or receive is made of packets—whether it’s this question, a Google search, or even a video call with family far away.

“You can think of a packet like an envelope, and your IP address as like a zip code or mailing address,” Hahn explained. If you wrote me a letter, you’d send it in a single envelope. But on the Internet, your message travels as lots of packets.

Imagine writing a letter, cutting it into tiny pieces, and sending them in their own individual envelopes. When the letter arrives, it would have to be taped back together!

But on the Internet, information travels faster sliced into pieces. Packets take different routes to arrive at the same place. When all the packets arrive, your computer puts them all back together like a puzzle. This all happens in under a second.

I’m glad the Internet does this work for us. There’s nothing more exciting to me than reading your curious questions. Thanks to the Internet, I don’t have to wait long to see them.

Dr. Universe