Unlike the other planets whose tracks around our star are pretty much circles, Pluto's orbit swings in and out on a highly elliptical orbit. It comes as "close" to the sun as 30 or so AU (inside Neptune's orbit) and as far out as almost 50 AU. At an average distance of 3.7 billion miles from the sun, wee Pluto lives in a world of perpetual twilight.

But exactly how far is 3.7 billion miles?

The problem with astronomical distances is simple. Once you get past a couple hundred thousand of anything, who can really tell the difference? How much bigger is 10 billion miles compared to 75 million miles? It's not like we have day-to-day experience with this kind of thing. So, what do we have visceral experience with when it comes to distance?

Driving. We do a lot of driving.

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