In Under Alien Skies: A Sightseer’s Guide to the Universe (Norton, Apr.), astronomer Plait explores what readers would encounter elsewhere in the cosmos.

What’s the story behind your nickname, the Bad Astronomer?

I would see people saying things on TV that weren’t true about astronomy. For example, that you can only stand a raw egg on end at the moment of the vernal equinox. That’s not true. Back in the early days of the internet, I wrote an article about that and put it up on the web. A few months later, there was a space shuttle launch. On one of the morning shows, the hosts were laughing about how they didn’t understand the stuff that they were reading off the teleprompter, and it was really basic science. Why was it okay to make fun of your ignorance of science? So I wrote about that as well. That started me writing about myths, misconceptions, and bad interpretations of astronomy. I called my blog Bad Astronomy, and then people started calling me the “Bad Astronomer.”

What’s a fact from your book that will surprise readers?

Saturn’s rings are extremely flat compared to their width. You see a lot of TV shows where people are flying through the rings and they’re miles deep. They’re actually 30 or 40 feet deep in most places.

When you were writing, were there concepts that were challenging to explain for a general audience?

I don’t think the public really understands what it’s like to stand on the moon in a spacesuit. You hear things like the temperature goes up to 250 degrees Fahrenheit and drops to minus 200 degrees Fahrenheit, but temperature on the moon doesn’t work the way we’re used to. You’re in a vacuum and there’s no air around you, so the concept of temperature isn’t the same as you’re familiar with on Earth, and that’s hard to describe.

If you could witness any of the alien skies you write about, which would be your top choice?

It’s tough because they’re all really cool, but I’d have to say Saturn. There’s just something about being near that planet and seeing those moons up close, but also traveling over the rings and seeing them with your own eyes. You can look at pictures of the Grand Canyon all you want and say, “Wow, that’s really beautiful,” but until you’re standing there on the rim, you can’t really appreciate it. And seeing Saturn that way I think would be a lifetime achievement.