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When James Oberg [right] suggested to IEEE Spectrum an article about how a knotty telecommunications problem was solved, we were interested for two reasons. First, the circumstances were unusual: they centered on a spectacular plunge by a probe known as Huygens into the soupy atmosphere of a moon 1.5 billion kilometers away.

Spectrum has always been interested in space exploration. Apart from its intrinsic fascination for many readers, it pushes technology's limits. And even when new technologies are not developed, operating spacecraft requires engineers to test the boundaries of their expertise, insight, and creativity. Second, we knew that Spectrum could tell the story best. When it was originally revealed that a communications screw-up threatened Huygens's mission, most reports glossed over the nature of the problem. Only by explaining what the snafu really was, how it snuck in, and how it was discovered and corrected, can useful lessons be drawn. By working with Oberg, we knew we could tell that story in a compelling way: he is a regular contributor to Spectrum and has spent decades working in and reporting on the space industry.

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From WinZips to Cat GIFs, Jacob Ziv’s Algorithms Have Powered Decades of Compression

The lossless-compression pioneer received the 2021 IEEE Medal of Honor

11 min read
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Photo of Jacob Ziv
Photo: Rami Shlush
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Lossless data compression seems a bit like a magic trick. Its cousin, lossy compression, is easier to comprehend. Lossy algorithms are used to get music into the popular MP3 format and turn a digital image into a standard JPEG file. They do this by selectively removing bits, taking what scientists know about the way we see and hear to determine which bits we'd least miss. But no one can make the case that the resulting file is a perfect replica of the original.

Not so with lossless data compression. Bits do disappear, making the data file dramatically smaller and thus easier to store and transmit. The important difference is that the bits reappear on command. It's as if the bits are rabbits in a magician's act, disappearing and then reappearing from inside a hat at the wave of a wand.

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