 Two intrepid travelers jump randomly from star to star in a ship that tunnels through folds in space. Their quest? A new world, one that could be a second home for us all. But on the leading edge of exploration, there are no navigation apps, no reviews from previous exoplanetary vacationers to guide them. Instead, they must rely on their observations, wits and scientific insights to determine whether New Planet truly has all the right stuff. Even when it lies in a place astronomers call, the habitable zone. Oh, why, oh why does that ship's computer always do that every time we jump? I think it's funny, especially when it annoys you. Maybe I wouldn't be so annoyed if the computer did anything more useful than just dropping us in some random system every time I hit that thing. And ruin the surprise? Besides, if you could choose, would you actually know where to find a habitable planet? Obviously, you know, it's going to have a lot of stuff. Yeah, me neither. So, let's see what's out here. From the measurements, this one looks like an early K-type star, just a little smaller and cooler than our sun. Are you detecting any planets? Dragon telescopes have found one, no, two Earth-sized planets. We're pretty close to the outer one. Want to go for a look-see? Let's do it. This is promising. Our instruments looking at the planet's atmosphere are detecting signs of water. Oh, we like water. That's good for making coffee. Yeah, and showers. I'm going to ignore that. Oh, halfway there. Hang on. It's time to decelerate into a nice cozy orbit. Nice parking job. From the flight data, it looks like this planet is about one astronomical unit away from its star. Just like Earth. That's good news, right? Sadly, since this star is smaller than our sun, it puts out less light and heat. So at this distance, the planet is really cold. Define really cold. You ever spent a winter in Antarctica? No, can't say that I have. Well, that'd be a tropical paradise by comparison. Yikes. An ocean of water is down there, but you can see it's all ice. That'd be a big fat no on the habitable scale. What about that other planet you found? It's in a closer orbit. Maybe it's got water in liquid form, shall we? Some infrared measurements of the planet during our approach and the temperature looks pretty comfortable. I'm all for more ocean and less ice. Hopefully. But I don't have a good reading on the composition yet. Well, my professional opinion, there ain't no water down there. There is an atmosphere, but it looks pretty unpleasant. Nitrogen, sulfur compounds, carbon dioxide, but no oxygen or water to speak of. The orbital stats show that the planet's almost the same mass as Earth, but it's a little bit smaller. That makes the planet denser. Why are you looking at me? It's rich in heavier elements, but it doesn't have a good balance of the lighter ones like carbon, hydrogen, oxygen. What you kind of need if you want H2 and breathable air, right? Yeah, we find an Earth-sized world right in the habitable zone. But because of what it's made of, it ain't habitable. Certainly not by us. Time to try again. Plenty more star systems out there. Well, pilot, then we go find us another one. You know, you only call me pilot when I'm about to hit that jump drive button. Maybe. It ain't got no control. I mean, I may as well be spinning a roulette wheel for as much piloting as I'm doing. Well, give it a spin, pilot. Let's see where we end up. Thank you, Miss Mepoint. Here we go. Our valiant voyagers have run afoul of what could be called a Goldilocks paradox. While one planetary bowl contained porridge that was simply too cold to eat, the other planetary bowl that was just right in temperature had no porridge at all. In the quest for world's rich in liquid water, proximity to the star is only part of the equation. A planet also needs to be made of the right stuff. If it lacks the ingredients that nurture life, then it will not be habitable, even if its orbit falls within the habitable zone.