Roughly four billion years ago, Mars was a wet world. Liquid water pooled into a vast northern ocean, rivers carved channels through highlands, and the chemistry needed for life sloshed across a planet that today sits frozen and bone-dry. So where did all that water go? This mini-doc from a tiny channel (just 3 subscribers) walks through the leading scientific answers.

Expect a tour through the physics of planetary atmospheres: how Mars lost its magnetic field when its core cooled, how the solar wind then stripped away the upper atmosphere molecule by molecule, and how hydrogen — too light to be held by Mars's weaker gravity — escaped to space. The remaining water either sublimated, froze into the polar caps and subsurface ice, or chemically bonded into the planet's rusty crust.

It's a useful primer on atmospheric escape and magnetospheric protection — the same mechanisms that make Earth habitable and Venus a runaway greenhouse. Understanding why Mars dried out is also directly relevant to current missions like Perseverance and the search for ancient microbial life in dried riverbeds and lakebeds.

The channel is brand new, but the topic is substantive and rooted in real planetary science rather than speculation.