In this episode we learn about Mars’ ancient past, meet an architect hoping to build cities there and we hear from Mars itself, thanks to the planet’s video blog, of course. Plus: Our Moment of Um answers a question about money with the help of Kai Ryssdal and Molly Wood, from the Marketplace podcast, Make Me Smart.

Do you ever dream of visiting Mars?

How about living there? It could happen.

Scientists are currently studying the planet for clues about its past and this information might help us make Mars a little more like Earth. One day, we may even be able to build cities there.

Of all the planets in the solar system, Mars is the most like our own. It’s about half the size of Earth and has about one third the gravity. That means you’d be able to jump higher and farther there, but you’d need a really warm space suit. Today Mars is a frozen desert where temperatures can drop to -100 degrees Fahrenheit at night. Brrrrr! There’s no breathable air or liquid water on the surface. However, it may have been a quite different place 3 to 4 billion years ago.

“It looks like Mars long ago once had lakes, it had rivers,” said Bethany Ehlmann, a planetary scientist with Caltech.

She studies information gathered by the NASA rovers about the rocks and dirt on the Red Planet. With this data, Ehlmann and other scientists are discovering that 3.5 billion years ago Mars might have been a warmer, wetter place with “plenty of water to potentially support life,” she explained.

But, things change. Mars once had a decent blanket of gas surrounding the planet, something called an atmosphere. Earth has one too and they help trap heat from the sun, keeping a planet warm. Over time, Mars lost most of its atmosphere, turning it into the cold place we know today. Earth on the other hand, kept a relatively thick atmosphere.

“We’re trying to figure out why do some planets continue to as great places for life while others maybe become a little bit worse over time,” Ehlmann added.

Still, if we wanted to make Mars more like Earth, Ehlmann says we’d have to try to bring back that gas blanket, perhaps by evaporating the planet’s ice caps or sending plants there that could help make more oxygen. For now these ideas are in the realm of science fiction.

Tristan Bassingthwaighte thinks we might be able to find another way to live on Mars.

He’s an architect and was part of an experiment called HI-SEAS, or the Hawai’i Space Exploration Analog and Simulation. It’s a project where people live in a fake Mars base on the side of a volcano. They must act like they are really on an alien planet at all times, Bassingthwaighte explains.

“So the idea of maybe just going outside for a walk or to enjoy the weather does not exist… You are in a suit, you don’t really feel the wind or the sun, it’s quite hot and uncomfortable.”

Still he enjoyed the experience enough to want to live on the real Mars. In fact he’s thought a lot about what a Mars city would look like.

“The first Mars colonies, sort of out of necessity are actually going to be underground,” he said.

That’s because Mars is constantly bombarded with harmful cosmic rays and solar radiation. Earth has a strong magnetic field which shields people from this stuff, but Mars doesn’t. The rays and radiation on Mars could make humans very sick and even kill them over time. Fortunately, dirt can block this stuff!

“So until we get better suits and better protection for the surface you probably want your main living area be underground,” said Bassingthwaighte.

He imagines one day whole cities could be built in Martian caves. They could be sealed off and filled with air to breathe. They could have ceilings with digital images of clouds and fake sunlight to make you feel like you were outside. They could have homes and neighborhoods and downtown areas.

Bassingthwaighte admits, this would take a lot of planning, money and time. The people of Earth would have to work together and really focus if they wanted to pull off a plan this extreme. Still, he thinks it could happen if we set our minds to it.

“This is definitely something that could happen sooner than people realize,” he added. “I have every intention of retiring to Mars.”