If Mars had an active core then there would be somewhat recent evidence that somewhere on the planet there was an eruption. But since there has been no sign of volcanic activity, and there is no magnetic field, this is scientific proof the core is dead. NASA is speculating as usual and committing themselves to err at tax payers expense. I wonder how much longer people are gonna have this debate until they realize Mars is actually very dead? It goes back to my dead deer carcass analogy. You can leave food out for it but it won't eat. The reason why the dead deer won't eat the food is because the deer is dead. Likewise you can leave nutrients in the soil of Mars but without an active core nothing is gonna happen. For the core of earth is what makes plant growth possible. If our core became as Mars we would all die. And talk about colonizing Mars is silly on all levels. We have a nice beautiful blue planet full of life and oxygen. Maybe it would be wiser to take care of the planet we do have. Those people who want to take a one way trip to Mars are welcome to do so. They will die on Mars, though. They will only accomplish moving their place of death from earth to Mars, and die a premature death there. They will find no water there or a means to grow food.