Every airport has its own specific three-letter code. Phoenix Sky Harbor Airport is PHX, for example, and Denver International Airport is DEN. It turns out that the way these codes are assigned is much more complicated than just abbreviating the city or state. If you fly to Montreal, Canada the call sign is YUL. Why is this and how does the system work?

We keep track of the biggest threats to your online safety and security so you don't have to. Get Kim's alerts to see the news that impacts you — and what you can do about it.

Cracks of lightning followed by booms of thunder are sure to send your pets cowering under the blankets. But there's a form of electricity even more powerful than regular lightning. It’s called a superbolt, and scientists are just starting to figure out exactly what it is and why it occurs.

When space exploration eventually evolves to the point where we have colonies on the Moon or even Mars, we'll have to find new sources of food. So, how are scientists working to make this a reality and what will future space explorers eat?

There's no question that electricity is a daily necessity. We need it to cool or heat our homes, preserve our food and so much more. But what would happen if electricity suddenly went out worldwide? Well, it would be a disaster to say the least but how quickly things would devolve is truly surprising.

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