Chris Packham gets down to Earth

EARTH

In this episode, Chris Packham tells the almost implausible story of how our world went from a barren rock with a sky of endless black, to the planet we know today, cloaked in the thin blue line of our life-sustaining atmosphere.

When Earth first formed from clouds of dust and gas 4.6 billion years ago, it was – like so many other lifeless worlds in the universe – devoid of an atmosphere, an inhospitable rock floating in the black void of space. But as the young planet was pummelled by asteroids a period of extraordinary upheaval began.

Over a two billion year period, the planet faced violent eruptions and a toxic orange haze, vast oceans of water in the sky and seas turning rusty red. Eventually, with the emergence of life and photosynthesis recalibrating the gases in our atmosphere, the stage was set for Earth to become the vibrant azure-skied planet we call home today.

BBC Two, 9pm