The Cosmic Chronicles – The Inner Planets

From the Earth, to the Sun and out towards the great interstellar unknown every object has it’s story. All these things making up the universe, our solar system and life on Earth is as much a part of this great infinite clockwork. In fact the word Cosmos means the universe as a complex, ordered entity, delicately tied together with forces and matter. We are the great paradox, the universe looking upon itself and learning, maybe giving it meaning. Epic and almost unimaginable events have unfolded to make the Cosmos as we see it now, stories have unravelled before there was even a human around to tell the story. Long after the human race is gone the great cosmic story will keep unfolding until time is meaningless. Slowly we pick up the events piece by piece and these Stories of the Cosmos tell some of what currently know and understand.

Inner Planets

When we look at our solar system, working away from the Sun the first proper worlds or planets are Mercury, Venus, Earth and Mars. Each of these worlds different from the others.

Mercury – a hot airless world where the day is longer than the year and the surface is not unlike our Moon, cratered and barren.

Venus – an even hotter world, similar in size to our Earth and with a thick toxic atmosphere of Carbon Dioxide that exerts 90 times the pressure on it’s surface than Earth’s does.

Earth – A world of land and water, erosion has erased almost all the marks of it’s violent birth and is currently the only world we know if in the universe where liquid water exists on it’s surface and where life flourishes.

Mars – A cold dead world where the marks of oceans and melting glaciers give an insight to the hope of possible life millions of years ago. It’s thin atmosphere incapable of holding onto liquid water except perhaps in it’s deepest crater.

All these inner planets are different, in very dramatic ways. Yet all of them are rocky, all of them would have formed at roughly the same time, condensed from the dust and rock left over from the Sun, pulled together by the gravity that bound all these objects in the Early solar system.

At first glance Earth is the only inner planet that has the right conditions to sustain liquid water and therefore life. It was not always this way though, over time changes in the planets and Sun have left their mark.


Mercury is a strange word, seemingly mostly made up of a rocky core and being as close to the Sun as it is it seems strange to think that water could exist there. Yet it does, ice has been found at the bottom of deep craters where the bottom is perpetually in darkness where the Sun’s glare gives way to freezing temperatures. This water could be a clue to it’s ancient past, this water may be the long lost remains of oceans lost in some barbaric cosmic act that took not only it’s oceans but it’s outer layers.


Venus lost it’s oceans long ago to a runaway greenhouse effect, the young Sun warming over millions of years to turn what would have been a water world much like own own into a version of hell, with a surface hotter than Mercury. Volcanoes, lava floes and battered rocks make up the surface now – any water on the surface of the planet would now evaporate instantly. If the balance of atmosphere and heat was different, Venus could have been warm ocean world as some had predicted before our probes lifted the thick veil of it’s atmosphere.


Mars is a nearly airless world, any hope of that life now gone, stripped with it’s now thin atmosphere. The dynamo that generates it magnetic field stopped millions of years ago. This left the atmosphere at the mercy of the Sun’s cosmic rays, which stripped the planet of it. With it the vast oceans and glaciers that once dominated the planet are now gone leaving only dust.


Only our own Earth has managed to sustain the right conditions for the millions of years long enough to sustain life while the others lost their oceans long, long ago. Existing in what is called the Goldilocks zone, where temperatures are neither too hot or too cold. Our own atmosphere plays a part too – creating a greenhouse effect keeps the planet temperate while protecting us from the worst of the Sun.

Earth – Credit NASA

Without our atmosphere Earth would be a much cooler -18C so as we look outward towards Mars we see that some greenhouse effect is good for us, however when we look inwards Venus shows us the cost of too much. This is the balance the human race lives in, a balance that has remained in place long enough to become a cradle for life and for civilization.

By examining the surface of the inner planets we’re able to pick out the details that make them unique, these help us to work out their histories and the stories they have to tell. We don’t yet have all the pieces of the puzzle and so there are holes in the stories but each clue brings us closer to understanding them and ultimately where we came from.

Β© Simon Farnell 2013 – 2022

No credit claimed on images – Images remain property of original owners.

Did you Know… In 2017 How to make Slime was the most popular…

Fact, snippets of useless information and all of that kind of thing makes up most of what’s in my brain – so I thought I would infect the general interweb with al of this and see what fact I can trawl for you! Enjoy! Did you know… I have nothing to say on this one, … Continue reading Did you Know… In 2017 How to make Slime was the most popular…

11 thoughts on “The Cosmic Chronicles – The Inner Planets

  1. Beautiful article on inner planets! There are four outer planets also which we called geint planets! Only earth we can find life but may in future we can get life in Mars also. Well shared geography revision.☺️😊thank you.πŸ™πŸ»

    Liked by 1 person

  2. Beautiful article on inner planets there are four outer planets also whom we called geint planets! The Venus is called twins of Earth! Thanks for sharing 😊 Geography revision.

    Liked by 1 person

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