If Mars used to have liquid water on the surface, and atmospheric oxygen, What happened? Any theories on that?
Their Democrats came into power.
One is that Mars suffered a cosmic collision. If you look at planet itself, the “texture” is different between the N-S hemispheres, leading to the theory that the South got hit really hard, geologically impacting the South, and cataclysmically destroying the atmosphere.
One theory is that Mars lost its magnetic field, so the atmosphere was eventually stripped away by solar radiation.
Most of the atmosphere was lost to space and water either evaporated or sublimated into the ground.
Today Mars is a dry, barren cold desert. At one time in its past it was a warm, wet world lush with water and life.
Well, yes there are. But they want trillions of more space dollars to find that out and conclusively determine something which will make no difference whatsoever on the state of things on this planet.
Planet X (orbiting where the asteroid belt is today) exploded, stripped away Mars atmosphere and water, and left the side”sprayed” on the planet.
Did it have a mag field?
Global warming by those pesky Martians.....