Week of Aug. 16-22, 2026

It was 20 years ago that our solar system lost a planet. Well, it didn't really go anywhere, but Pluto is no longer a planet because it's been reclassified.

I'm sure you figured out in school that scientists love to classify things. Rocks, clouds, plants and, yes, even stars and planets. So why did they feel the need to reclassify Pluto? Because Pluto doesn't seem to fit the pattern of the rest of the major worlds of our solar system.

First, it's a world not even 1,500 miles across; in other words, if we could bring it to Earth, it would fit inside of Mexico. Its orbit is tipped about 17 degrees to the orbits of all the other planets and is so elongated that every 240 years it crosses the orbit of Neptune. In addition, Pluto is an icy world with only five known moons, yet it exists in the realm of the gassy, ringed giants, around which hundreds of moons orbit.

This is one strange world, so on Aug. 24, 2006, when the International Astronomical Union reclassified it as a "dwarf planet" — one of five currently known — some folks became quite upset. I hear people say all the time, "Pluto was a planet when I was in school, and by God, it's still a planet!"

But that's not how science works. As we learn more about nature, we find characteristics and patterns that don't match up with our previous notions. Sometimes when that happens, we must change the way we think. It's all good science, and it happens more frequently than you might imagine.

Ages ago, anyone on the high seas would have considered whales as fish. Though whales were known to have characteristics different from fish, it wasn't until 1758 that the 10th edition of Carl Linnaeus' "System Naturae" officially branded them as mammals.

I'd be willing to bet that if the internet had existed back then, folks would have been screaming for Linnaeus' hide, and proclaiming, "Whales were fish when I went to school, and by God, they're still fish!" But here we are, three centuries later, and no one's upset any longer.

No, Pluto just doesn't fit the patterns of all the other planets, so for that reason, it seems to me, Pluto cannot legitimately be categorized as a planet.

So if Pluto's not a planet, what is it? A moon of one of the outer planets that broke free? A monster comet? A weird missing link? Good questions, all. Unfortunately, we just don't know.

It was in 1930 that Clyde Tombaugh found Pluto, and some of his ashes were carried onboard the New Horizons spacecraft as it sped past and explored this distant world in 2015. Those who are more sentimental than scientific believe that this reclassification is an insult to the man who was so very proud of being the discoverer of the last planet of our solar system.

I knew Clyde, and I'm pretty sure this wouldn't bother him one bit. In fact, I suspect he would be even more honored to be the discoverer of the first of an entirely new class of worlds!

On Aug. 24, 2006, Pluto was reclassified as a "dwarf planet."

Visit Dennis Mammana at dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

On Aug. 24, 2006, Pluto was reclassified as a "dwarf planet."