JOURNEY TO A STAR – ASTEROIDS – SHAPERS OF EARTH

 

                                                                                                      

 In this post I will concentrate on asteroids. After planets they represent the largest objects and most numerous in the solar system. They are a real danger to our star mission as we have to travel through them at the start of our journey. 

[see previous post – Asteroid Belt

But crucially, we human beings would probably not be here was it not for a piece of rock, 10 km wide, flung out of the asteroid belt 66 million years ago – but more of that later.

So what is an asteroid and where did they come from?

There is still some doubt amongst scientists as to the true origins of asteroids. The simplest explanation is that they were the result of failed planets during the formation of the solar system 6.5 billion years ago. Then through multiple collisions and the influence of the huge gas giant Jupiter, the larger fragments, called planetissimals, shattered into billions of pieces and formed the asteroid belt. Some larger asteroids survived – the largest object is Ceres, a dwarf planet at 950 km diameter, followed by Vesta, Pallas and Hygiea which are all in excess of 400 km.

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Typical asteroid

Asteroids are very rocky structures with irregular shapes. None of them is spherical as they did not have sufficient mass during formation – unlike the major planets. Their composition is not unlike Earth as they contain many similar compounds and elements. Asteroids are made of different minerals and substances and their composition depends on which planet they may have originated from. Many asteroids are the result of larger asteroids hitting planets or each other during the fiery beginnings of the Solar System. The chemical reactions that they have undergone over the millennia also effects their composition. The asteroids that are nearest the Sun are mostly made of carbon while the ones further away are made up of silicate rock. The metallic asteroids are composed of up to 80% iron and 20% a mixture of nickel, iridium, palladium, platinum, gold, and other precious metals. There are those few that are made up of half silicate and half metallic.

The metallic asteroids are of particular interest as they could be a source of precious metals in the future when we can find a way to harvest these objects. [But perhaps something has already been capturing asteroids for their own ends? Quest of the Dicepterons?]

Asteroids have been smashing into one another and other planets and moons since the start of the solar system. You can see the craters on the Moon, other planets and even on asteroids themselves – space can be a very dangerous and violent place. Our planet is covered with impact craters and one of these in the Yucatan Peninsula resulted in us – mankind!

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Crater on Earth

So finally let us talk about an event 66 million years ago which radically changed the direction of evolution on planet Earth. Back then the world was dominated by the dinosaurs who had reigned supreme for 165 million years. They ruled the land, seas and skies and ranged from small chicken sized raptors to monsters such as Tyrannosaurus Rex. They were so successful and aggressive that hardly any other creatures could co-exist with them. A small number of vole-like mammals lived underground, only venturing above ground at night to scavenge for food.

In terms of longevity, the dinosaurs are the most successful species that have inhabited Earth. They lived for 165 million years whereas we have existed in our humanoid form for a mere 200,000 years. BUT – the dinosaurs did not know that something was on a collision course with Earth and even if they did would not have had the technology to do something about it.

Earth was struck by an object 10 km in diameter which formed a crater 180 km wide. The impact threw so much debris into the atmosphere that the sun was blocked out and fires raged over most of the surface of the world. The effect on the dinosaurs was devastating – those that were not immediately wiped out by the impact lost their food source and warmth of their star. The extinction of the dinosaurs had begun and few survived – some of the sea dwelling creatures and birds lived through this calamitous time and their descendents, eg crocodiles and alligators, are with us now. 

But out of disaster came opportunity. The small vole-like mammals were safe in their burrows and ultimately were able to venture above ground as there were no predators left to attack them. They grew, evolved and spread across a new Earth and 64 million years later humanoid forms stood on two legs in the cradle of Africa.  These migrated to every corner of the world and became ….. us. Certainly the most technically advanced species to occupy planet Earth. But will we outlive the dinosaurs?  I doubt it – but what do you think?

The weight of scientific argument points to an asteroid strike 66 million years ago but there are still some who dispute this and have offered alternate theories. Whatever it was, it changed the history of planet Earth.

But what if it wasn’t an asteroid that wiped out the dinosaurs? Ah, well, you’ll have to wait for Volume 2 of my trilogy to find the answer to that question……..

…… but meanwhile why not catch up on Volume 1 and book your seats on a dangerous one way mission to the stars? 

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