“I’m looking at Mars in a point of view of a microbe. And as a microbe, I really need very, very tiny amount of water. I could probably live my entire life happily in a tiny drop of water about the size of the point of a pen. Now we’ve shown over the years that organisms living in salt crust on the earth have enough sunlight coming in so that they can go through their day-to-day activities but still be protected from the radiation. And we know there’s salt crust on Mars.”

 

Mars has a long term wobble to its orbit and every five million years or so the poles end up titling 45 degrees toward the sun. 

 

“A way of thinking about the Phoenix landing site is thinking about the polar regions on earth. Imagine you are there in winter,/ very inhospitable, very cold, very alien. You think how can anything survive here. Come back six months later and it’s like a different world. The sun is shining, it’s wet, it’s warm. Things are alive and skirring around. So we may be being misled seeing it’s frozen, cold site. And in fact, we are just there at the wrong season.”

 

We know that on earth, some bacteria can survive being frozen for millions of years. They can also eat perchlorate, a highly reactive chemical Phoenix found in the Martian soil. 

 

“Presumably if there was life at the Phoenix site, it had learned the same trick. So there might be organisms that are literally eating the rocks and reacting with perchlorate, below the surface, shielded from the ultraviolet light, just having a great old time five million years ago. The party is over because every body froze, but another five million years, the party will start up again as the Martian summer comes to the north polar regions and the ice turns to water.”